Faculty of Applied Sciences

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12th International Conference on Sustainable Waste Management
(2022-12-02) Nibedita, Nath; Subhendu, Chakraborthy; Narsimha, Golla; Adam, Jamila Khatoon; Krishna, Suresh Babu Naidu
Today, nanotechnology generates a significant amount of interest among researchers as a result of the vast array of applications it provides for addressing various aspects of the eco-system. Additionally, it enables researchers to traverse the boundaries of a more specialised area of study than an already well-established one. It is an interdisciplinary field of study that focuses on the production and manipulation of nanoscale materials via scaling down the particle size scale from micrometres to nanometers (1–100 nm). They provide excellent options in the fields of health, industry, and medicine as they present a new vision for the treatment of medical conditions thanks to the fact that the particle size may be reduced, which gives them a distinct prospective characteristic. Researchers continue to be interested in finding new uses for metal nanoparticles (NPs) as the field of nanotechnology advances since these particles display distinctive properties. The public is interested in several different types of metal nanoparticles, including silver NPs. Synthesized silver nanoparticles (AgNPs) can be used in a wide variety of contexts, such as spectrally selective coatings for the absorption of solar energy, as intercalation material for electrical batteries, as optical receptors, as catalysts in chemical processes, and so on. Antibacterial and antifungal properties are only two of the biological uses of silver nanoparticles that have been the subject of much research. AgNPs are known to be cytotoxic to both normal and cancer cells in mammals, and the modalities of interactions of AgNPs have been examined in a variety of prokaryotic and eukaryotic systems. AgNPs are known to be cytotoxic to both normal and cancer cells in humans. The cytotoxic effects of silver ions have been seen and documented in a variety of cell lines. Silver nanoparticles have become important research topics due to the numerous applications they have in the fields of industry, agriculture, and biomedicine, as well as their excellent anti-bacterial, anti-fungal, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant, and photo-catalytic properties due to their chemical stability and good biocompatibility. The most important focus of this review is on recent advancements and trends in the field of AgNPs for use in biomedical applications. Keywords: Antimicrobial, silver nanoparticles, synthesis, biomedical applications, nanotechnology
Acceptance of a ready-to-use supplementary food by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients
(NISC (Pty) Ltd and Taylor & Francis, 2014) Pillay, K.; Siwela, M.; Feldman, F.J.; Amonsou, Eric Oscar; Mabaso, B.P.
Objectives: The objective of the study was to determine consumer acceptance and perceptions of a ready-to-use supplementary food (RUSF) by subjects treated for human immunodeficiency virus (HIV) and HIV and tuberculosis (co-infected subjects). Design: A cross-sectional study was conducted. Subjects: One hundred and thirty-nine stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients participated in the study. Sixty-eight healthy subjects served as the control group. Setting: The setting was Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Outcome measures: Acceptance of the RUSF was assessed using a five-point facial hedonic scale by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 139) from Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Perceptions of the RUSF were determined through focus group discussions in which HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 43) participated. Results: The overall acceptance of the RUSF was significantly associated with the health status of the subjects (p-value < 0.05). Overall, the product was liked by more than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals compared to 85% of the control group. More than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals liked the taste, compared to 87% of the control group. The colour and mouth feel were rated to be “good” by more than 80% of the HIV-treated and HIV and tuberculosis (co-infected)-treated group, compared to approximately 70% of the healthy group. Focus group discussions revealed that the subjects perceived the mouth feel of the RUSF to be “rough”, and that as a health supplement, the RUSF should be provided free of charge, or at a reasonable cost, at public health centres. Conclusion: The RUSF was found to be highly acceptable to stable HIV-treated and HIV and tuberculosis (co-infected)-treated subjects, although concern was raised about the mouth feel.
Active targeting of cancer cells using gemcitabine conjugated platinum nanoparticles
(2017) Odayar, Kriya; Odhav, Bharti; Mohanlall, Viresh
Nanotechnology is explained as the science of engineered materials and systems on a molecular scale. This innovation is currently used in a wide variety of applications which include using these nanoparticles as drug delivery vehicles. Such nanocarriers are relatively smaller than 100 nm in size with the ability to convey therapeutic drugs to a number of disease sites. Platinum-based nanoparticles have been extensively used in a number of applications namely catalysts, gas sensors, glucose sensors and cancer therapy. The properties of platinum nanoparticles (PtNP’s) typically depend on characteristics such as shape, particle size, elemental composition and structure, all of which can be manipulated and controlled in the fabrication process. Their unique size in the nanometer scale makes platinum nanoparticles an ideal candidate as targeted drug delivery vehicles. To target an anticancer drug to a diseased site is a distinctive feature of most studies, which aim to transfer an adequate dosage of the drug to cancer cells. Transport systems used as carriers of anticancer drugs offer numerous advantages, which include improved efficacy and a decrease in toxicity towards healthy cells when compared to standard drugs. The aim of this study was to determine the effect of platinum nanoparticles, gemcitabine and gemcitabine conjugated platinum nanoparticles (Hybrids) against cancer cells and healthy cells and to determine the mode of cell death and cell death pathways using flow cytometry. Platinum nanoparticles were synthesized via the reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. Synthesized platinum nanoparticles and the hybrids were characterized by observing peaks at 301 nm and 379 nm respectively using UV-visible spectroscopy. TEM images revealed that the PtNP’s and the conjugate compounds were spherical in shape with core sizes of 1.14 nm - 1.65 nm and 1.53 - 2.66 nm respectively. The bioactivity platinum nanoparticles, gemcitabine and the hybrids were investigated using MCF7 and Melanoma cancer cells at different concentrations from 0.10 to 100 µg/ml. Results indicated that conjugated nanoparticles induced the highest cell inhibition against both cell lines compared to gemcitabine and platinum nanoparticles. Bioactivity against PBMC (peripheral blood mononuclear) cells indicated that all three compounds show little or no effect towards the healthy cell line compared to the control. Melanoma cell line was used to determine the mode of cell death. Apoptosis was detected using Annexin V-FITC to detect membrane changes, JC-1 to detect a loss in mitochondrial membrane potential and caspase-3 assay kits. Results indicated that a significant amount of cell death was caused by cleavage of caspase-3. Nanoparticle drug delivery is an area that has shown significant promise in cancer treatment. Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Imagine, something that is atleast or more than 80,000 times smaller than the edge of the ridge on a fingertip and unlocks a new wilderness into cancer research. Nanotechnology, known as the science of minute, is changing the approach to cancer and especially future diagnosis and treatment. Nanotechnology permits scientists to fabricate new apparatuses that are definitely smaller than cells, giving them the chance to attack tumor diseased cells. This innovation not just empowers practitioners to recognize malignancies prior but additionally holds the guarantee of halting cancer growth before it further develops. This progressive approach is so exact, specialists will in future be able to outline a unique treatment for an individual’s own restorative and hereditary profile. Researchers are designing nanoparticles that detect and destroy diseased cells and this optimistic innovation could be personalized for targeted drug delivery, enhanced imaging and ongoing affirmation of cancer cell death. The National Cancer Institute remains hopeful that facilitated development, nanotechnology will drastically change cancer treatment.
Activity coefficients at infinite dilution for ILs : methyltrioctylammonium cation and bis(trifluoromethylsulfonyl)imide or thiosalicylate anions using glc
(2009) Gwala, Nobuhle V.; Deenadayalu, Nirmala
The activity coefficients at infinite dilution ( γ13 ) were calculated for alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols and aromatic compounds from gas liquid chromatography (glc) measurements at three temperatures (303.15 and 313.15 and 323.15) K. The γ13 values were calculated from the retention data for two ionic liquids (ILs) with the same cation but different anions. The ionic liquids: [methyltrioctylammonium bis(trifluoromethylsulfonyl)imide and methyltrioctylammonium thiosalicylate] were used as the stationary phase. The γ13 data for methyltrioctylammonium thiosalicylate were higher than for methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. For each temperature and each ionic liquid, γ13 values were determined for two columns and the average γ13 values were used for the calculation of the partial molar excess enthalpies at infinite dilution, H E 1 Δ , using the Gibbs-Helmholtz equation. Graphs of In γ13 vs 1/T were plotted to determine H E 1 Δ at T = 303.15 K. The selectivity, S12 , value for the hexane/benzene separation was calculated from the ratio of the avarage γ13 values to determine the suitability of the ILs as an entrainer for extractive distillation in the separation of aromatic and aliphatic compounds.The S12 values were also compared to the literature values for other ionic liquids. It was found that the longer chain alkyl group attached to the cation or anion gave lower S12 values. Both ILs have S12 values greater than one and in theory can be used as an entrainer for the hexane/ benzene separation. The capacities at infinite dilutions, k1 , were also calculated from the inverse of the avarage γ13 values for each IL at each temperature.
Advances in synthesis of biodiesel via enzyme catalysis : Novel and sustainable approaches
(Elsevier, 2015-01) Singh, Bhaskar; Mutanda, Taurai; Permaul, Kugen; Bux, Faizal; Guldhe, Abhishek
Biodiesel, a renewable fuel has a great potential in fulﬁlling an ever-increasing transport fuel demand. The enzymatic conversion process of feedstock oil to biodiesel is greener when compared to the conventional approach of chemical conversion due to mild reaction conditions and less wastewater generation. Lipases obtained from various microbial sources have been widely applied as catalysts for the conversion of oil to biodiesel. Biodiesel and glycerol obtained by enzymatic conversion have shown a higher purity as compared to that obtained by other conversion techniques. Enzymatic conversion of oil to biodiesel is less energy intensive because of milder reaction conditions and fewer puriﬁcation steps involved in processing. Lipases, due to their catalytic efﬁciency and speciﬁcity, have emerged as a great tool for converting a wide range of feedstock oils to biodiesel. This manuscript presents an overview of the use of enzymatic conversion for making biodiesel production sustainable and environmentally-friendly. The constraints of enzymatic conversion are the high cost of the enzyme and its inhibition by alcohol and glycerol. The possible solutions to overcome these constraints are discussed. Recent advances to develop an effective process for enzymatic conversion of feedstock oils into biodiesel are critically evaluated. Prospective and challenges in scaling up of this technology are also discussed.
Analysis of selected organic pollutants in water using various concentration techniques
(2014-08-08) Ramphal, Sayjil Rohith; Moodley, Kandasamy Govindsamy; Chetty, Deenadayalan Kisten
Among persistent organic pollutants, chlorobenzenes are some of the most frequently encountered compounds in aqueous systems. These compounds can enter the environment via natural and anthropogenic sources, and are ubiquitous due to their extensive use over the past several decades. Several chlorobenzene compounds, once in the environment, can biologically accumulate, and are reputed to be carcinogens and extremely hazardous to health. Several chlorobenzenes are listed as priority pollutants by the United States Environmental Protection Agency. Excessive exposure to these compounds affects the central nervous system, irritates skin and upper respiratory tract, hardens skin and leads to haematological disorders including anaemia. In spite of these harmful effects, chlorobenzenes are still used widely as process solvents and raw materials in the manufacture of pesticides, chlorinated phenols, lubricants, disinfectants, pigments and dyes. In the light of the above, it is imperative to monitor the levels of chlorinated benzenes in all types of surface waters, using low-cost but sensitive methods of preconcentration and detection. In this study, a simple and relatively cheap preconcentration method using direct immersion solid phase microextraction (DI-SPME) followed by gas chromatography equipped with a flame ionisation detector (GC-FID) was developed for the analysis of 7 chlorinated benzenes in dam water. Experimental parameters affecting the extraction efficiency of the selected chlorobenzenes, such as fibre type, sample size, rate of agitation, salting-out effect and extraction time, were optimised and applied to the Grootdraai Dam water samples. The optimised method comprises the use of a 100 µm polydimethylsiloxane (PDMS) fibre coating; 5 ml sample size; 700 revolutions per minute rate of agitation and an extraction time of 30 minutes. The calibration curves were linear with correlation coefficients ranging from 0.9957–0.9995 for a concentration range of 1–100 ng/ml. The respective limits of detection and quantification for each analyte was as follows: 1,3-dichlorobenzene, 0.02 and 0.2 ng/ml; 1,4-dichlorobenzene, 0.04 and 0.4 ng/ml; 1,2-dichlorobenzene, 0.02 and 0.2 ng/ml; 1,2,4-trichlorobenzene, 0.3 and 2.7 ng/ml; 1,2,4,5-tetrachlorobenzene, 0.09 and 0.9 ng/ml; 1,2,3,4-tetrachlorobenzene, 0.07 and 0.7 ng/ml; pentachlorobenzene, 0.07 and 0.7 ng/ml. Recoveries ranged from 83.6–107.2% with relative standard deviation of less than 9%, indicating that the method has good precision, is reliable and free of matrix interferences. Water samples collected from the Grootdraai Dam were analysed using the optimised conditions to assess the potential of the method for trace level screening and quantification of chlorobenzenes. The method proved to be efficient, as 1,3 dichlorobenzene, 1,4-dichlorobenzene and pentachlorobenzene were detected at concentrations of 0.4 ng/ml, 1.7 ng/ml and 1.4 ng/ml, respectively.
Anti-carcinogenic activity of Centella asiatica and Elytropappus rhinocerotis on a human colon cancer cell line
(2012) Dwarka, Depika; Odhav, Bharti; Sewram, Vikash
Recently our understanding of cancer has advanced in the realization that apoptosis and the genes that control it have a profound effect on the malignant phenotype. It is now clear that some oncogenic mutations disrupt apoptosis, leading to tumor initiation, progression or metastasis. Conversely, compelling evidence indicates that other oncogenic changes promote apoptosis, thereby producing selective pressure to override apoptosis during multistage carcinogenesis. Finally, it is now well documented that most cytotoxic anti-cancer agents induce apoptosis, raising the intriguing possibility that defects in apoptotic programs contribute to treatment failure. Because the same mutations that suppress apoptosis during tumor development also reduce treatment sensitivity, apoptosis provides a conceptual framework to link cancer genetics with cancer therapy. An intense research effort is uncovering the underlying mechanisms of apoptosis, such that, in the next decade, one envisions that this information will produce new strategies to exploit apoptosis for therapeutic benefit. Plants have a long history in cancer treatment. More than 3000 species have been known for their anti-cancer potential. Over 60% of currently used anti-cancer agents are derived in one way or another from higher plants. Indeed, compounds derived from natural sources, including plants, have played, and continue to play, a dominant role in the discovery of leads for the development of conventional drugs for the treatment of most human diseases especially cancer. Thus the aim of this study was to investigate if Centella asiatica and Elytropappus rhinocerotis possess anti-cancer potential and determine the effect on the modulation of apoptosis. In South Africa C. asiatica is known anecdotally to treat various forms of cancers and E. rhinocerotis is known to treat colic and diarrhoea. The anti-cancer activity of C. asiatica has been studied in some parts India but E. rhinocerotis has not been investigated. This study was conducted using polarity guided fractionation (aqueous, ethanolic, methanolic and hexane), thereafter these extracts were tested for their toxicity on a colon cancer cell line (CaCO-2) and on normal cells vi (PBMC). Subsequently, the most active extract was used to isolate the active fraction. The fraction that displayed toxicity on the CaCO-2 cells were further investigated for their ability to induce apoptosis by observing the morphological effects and DNA changes using acridine orange-ethidium bromide staining. Apoptosis was confirmed using Annexin V- PI staining. Nuclear effects were studied by DNA fragmentation and by agarose gel electrophoresis. Nuclear fragmentation was studied by flow cytometry using bromodeoxyuridine (BrDU). Pro-apoptotic changes were determined with Caspase III enzyme levels using flow cytometry. The results were compared to the effect of a known anti-carinogen - Taxol. The anti-oxidant activity was also evaluated for the different extracts. The ethanolic extracts of both C. asiatica and E. rhinocerotis showed more than 100% radical scavenging activity. The methanolic extract (125 μg/ml -500 μg/ml) showed cytotoxicity on the CaCO-2 cells and a proliferative effect on the PBMC. Apoptosis was confirmed in the methanolic extract for both plants and was therefore used to carry forth this study. This included early apoptotic changes observed by the morphological study i.e., membrane blebbing, nuclear condensation and the presence of apoptotic bodies, in both C. asiatica and E. rhinocerotis fractions demonstrated more non-viable apoptotic cells than the methanolic extracts. Late changes of apoptosis were also found as indicated by DNA laddering and a positive outcome with BrDU. Both the active fractions from C. asiatica and E. rhinocerotis showed more DNA laddering and active caspase III than the methanolic extract. These features indicate that C. asiatica and E. rhinocerotis cause apoptotic death of colon cancer cells CaC0-2. In conclusion, there was a significant increase in apoptosis of CaCO-2 cells with little alteration of PBMC in the presence of the methanolic extract of C. asiatica and E. rhinocerotis. The semipure fractions resulted in changes related to late apoptosis. The results suggest that C. asiatica and E. rhinocerotis induces apoptosis in CaCO-2 cells which is an important step in elucidating the underlying molecular mechanism for anti-tumour activity.
Anti-HIV activity of selected South African medicinal plants
(2013-09-17) Hurinanthan, Vashka; Odhav, Bharti; Parboosing, Raveen
South Africa has the largest number of people infected with HIV/AIDS. It also has more than 30 000 species of plants and many of these have a long tradition of medicinal use. It is highly likely that the treatment for HIV will come from this traditional knowledge. The need for effective preventative and therapeutic agents for HIV remains an urgent global priority. The aim of this study was to screen selected South African medicinal plants for anti-HIV activity and to identify and characterise an active compound from a plant that can be used for HIV treatment. The aqueous and methanolic extracts of the roots, leaves, flowers and stems of thirty eight plant species (108 extracts) were screened for anti-HIV activity. The plants which had anti-HIV activity were further screened for anti-reverse transcriptase activity. Thirty-two extracts exhibited varying degrees of anti-HIV activity. Cleome monophylla, Dichrostachys cinerea and Leonotis leonurus aqueous leaf extracts had anti-HIV-1 reverse transcriptase activity. The aqueous extracts of D. cinerea showed the best anti-HIV activity with a Selectivity Index of 43.5 and significant anti-HIV-1 reverse transcriptase activity. Crude phytochemical screening of D. cinerea showed that it had tannins, saponins, flavonoids and alkaloids but did not contain any phlobatannins, terpenoids, steroids or phenols. D. cinerea displayed a high degree of free radical scavenging activity with an IC50 of 25 μg/ml, therefore the anti-HIV activity could be attributed to the flavonoids present in the plant. Bio-guided fractionation was used to isolate and purify the active compound from the D. cinerea extract. Compounds were isolated by thin layer chromatography and were tested for anti-HIV-1 and anti-reverse transcriptase activity. From these results the active compound was identified, and purified using preparative TLC. The active compound was characterised by High Performance Liquid Chromatography, Ultraviolet-visible spectrophotometry, and Ultra Performance liquid chromatography coupled to MS/MS. Structural elucidation was performed using Nuclear Magnetic Resonance. From these results, it was deduced that the compound isolated from D. cinerea was a catechin. In this study we show that the catechins present in D. cinerea are responsible for the anti- HIV-I activity and inhibits the reverse transcriptase activity which is a key factor in the progression of HIV. Potentially, these results can be used to develop a new drug for the treatment of HIV or as a cost effective therapeutic agent in treating HIV-infected individuals with oxidative stress.
Anti-inflammatory, anti-oxidant and wound-healing properties of selected South Africa medicinal plants
(2017) Mzindle, Nonkululeko Betty; Odhav, Bharti
South Africa has a wide range of medicinal plants that are used traditionally by black Zulu South Africans for the treatment of a range of illnesses, including inflammatory ailments; disease conditions caused by oxidative stress and wound healing. It has been indicated that bioactive compounds isolated from plants contribute to their anti-inflammatory, antioxidant and wound healing properties; hence, herbal remedies have been widely used traditionally in many countries in the management and treatment of wounds. Inflammation is the main condition that relates to a variety of diseases affecting most of the world’s population. It is the body’s immune response to infection and injury and is induced by the release of pro-inflammatory mediator’s —prostaglandins and leukotrienes—following wound occurrence. Wounds result in disruption of living tissue caused by oxidative stress. Anti-inflammatory agents, antioxidants, and antimicrobials play an important role in the wound healing process and they prevent aggravated wound conditions.Controlling inflammation during wound repair is important to minimize any additional complications that may result; hence, chemical agents such as non-steroidal anti-inflammatory drugs (NSAIDS), synthetic antioxidantsand steroids are frequently used. These drugs block the enzymes that are responsible for prostaglandin synthesis in inflammation, react with free radicals thereby interfering with oxidation process as a result affect one or more phases of wound healing. The use of these drugs, however, has been limited as they can cause detrimental side effects when used over long periods of time.There is, consequently, a need to find alternative natural therapeutic drugs. Studies on medicinal plants confirmed that herbal drugs exhibit fewer side effects in comparison with chemical agents and are more cost-effective.Thus the aim of this study was to investigate South African medicinal plants, for anti-inflammatory, antioxidant and wound healing properties. Dissolved extracts of thirty-eight medicinal plants were evaluated for theiranti-inflammatory activity using the 5-lipoxygenase assay as well as free radical scavenging activity using the 1; 1-diphenyl-2-picrylhydrazyl (DPPH) assay.Their safety was evaluated using brine shrimp lethality assay. Proliferation and viability of fibroblast cells was determined by the3-(4, 5-dimethylthiazolyl)-2, 5-diphenyltetrazolium bromide(MTT) assay furthermore a scratch wound assay was used to study the properties of wound healing in vitro and to confirm the anti-inflammatory activities of the dissolved extracts. Migration rate was evaluated quantitatively by an image analyzer. Methanol was chosen for extraction because it completely dissolves extracts. Anova was used for statistical analysis. Almost all aqueous extracts were found to be effective in inhibiting lipoxygenase enzyme when compared to nordihydroguaiaretic acid (NDGA). Aqueous extracts exhibited remarkably high percentage inhibition of lipoxygenase with most above 100% when compared to methanolic extracts. Amaranthus dubius and Portulaca oleracea were found to have good biological activities in the inhibition of 5-lipoxygenase enzymes when compared to the other plants. However, Galinsoga parviflora and Syzygium cordatumwere least effective in inhibiting enzyme activity with percentages as low as -2% and 34% respectively. Percentage inhibitions for methanolic extracts were lower than that of aqueous extracts. Amaranthus spinosus had the highest percentage inhibition among all the methanolic extracts andGalinsoga parviflorahad the lowest. The methanolic plant extracts were found to be more effective in scavenging DPPH free radicals than the corresponding aqueous extracts. All the methanolic extracts exhibited free radical scavenging ability in the range of 60%–104%. Asystasia gangetica, Ficus sur, Heteropyxis natalensis, Hibiscus sabdariffa, Pelargonium sp. showed notably higher scavenging abilities, ranging from 101%–104% compared to Rutin. Methanolic extracts of Heteropyxis natalensis and Hibiscus sabdariffa exhibited scavenging ability even at the lowest concentration of 10μg/ml. Furthermore, aqueous extracts displayed remarkably lower activities than methanolic extracts with thirty-one extracts having a scavenging capacity ranging from 22%—59%. None of the extracts were found to be detrimental to brine shrimp. Almost all the extracts were shown to stimulate the growth of fibroblast cells except the methanolic extract of Solanum nodiflorum, which was shown to be killing the cells at high concentrations with a percentage viability of 46%.As the concentration decreased, however, the viability of cells with this extract increased to 143%. An increase in the number of fibroblast cells was observed in the scratched area of the treated cells and a significant migration rate was also noted with some of the extracts. Aqueous extracts of Sonchus oleraceus (86%), Justicia flava (85%) and Dichrostachys cinerea (85%) and methanolic extracts of Senna occidentalis and Hibiscus sabdariffa were found to have the highest migration rate compared to untreated cells that served as a control. No cell migration was observed with methanolic extract of Solanum nodiflorum.Instead, the extract was found to be toxic to the cells. Some of the plants evaluated in this study have been studied for either anti-inflammatory, antioxidantand wound healing properties in vivo, however, no work has been conducted to demonstrate a correlation between anti-inflammatory, antioxidant and wound healing properties of plant species in vitro. The current study was, therefore, conducted to review medicinal herbs considered as anti-inflammatory, antioxidants and wound healing agents as well as collecting evidence for their effectiveness and pharmacological mechanisms in modern science. In the plant species investigated Amaranthus dubius, Asystasia gangetica, Bidens pilosa, Buddleja saligna, Carpobrotus dimidiatus, Chenopodium album, Dichrostachys cinerea, Emex australis, Ficus sur, Guilleminea densa, Hibiscus sabdariffa, Physalis viscose, Syzygium cordatum, Taraxacum officinale and Tulbaghia violacea demonstrated good anti-inflammatory and wound healing properties.In conclusion the results from this study demonstrated promising anti-inflammatory and antioxidantactivities as well as wound healing properties,furthermoreit was aslo shown that the plant extracts were not toxic to the cells hencethis suggested that the plants investigated, can be used as substitutes or to formulate wound healing agents that are safe to use in primary healthcare.
Anticancer activity of ceratotheca triloba
(2016) Naicker, Leeann; Odhav, Bharti; Matsabisa, M.G.; Mohanlall, Viresh
Plants have provided a source of medicine from the beginning of human history and are the core of modern medicine. Moreover, plant based drug discovery has led to the development of various anticancer drugs (such as vincristine, vinblastine, etoposide, paclitaxel, camptothecin, topotecan and irinotecan). The use of botanical, phytochemical, biological and molecular techniques have facilitated the discovery of anthraquinones from Ceratotheca triloba that can inhibit the human topoisomerase II enzyme (target for anticancer drugs) and kill cancer cells. However, the C. triloba plant has not been extensively studied for its anticancer activity. Therefore, the aim of this study was to further investigate the anticancer activity of C. triloba and determine the classes of compounds that contributed towards its activity. In this study the leaf and root extracts were prepared by using hexane, DCM, hexane: DCM (1:1), methanol and/or water. These extracts were examined for their growth inhibitory potential on three cancer cell lines (A375 [melanoma], MDA-MB-231[breast] and WHCO1 [esophageal]) by using the MTT assay. Then, different mobile phases were prepared for optimizing the separation of the compounds of the active extract by TLC. Column chromatography was performed with the active extract by using five mobile phases (hexane : DCM [60 : 40, 40 : 60], DCM, DCM : ethyl acetate [90 : 10, 70 : 30, 60 : 40, 50 : 50, 50 : 60, 30: 60, 20 : 80], ethyl acetate and ethyl acetate: methanol [80 : 20, 70 : 30, 50 : 50]). The fractions collected from the column were examined for their growth inhibitory potential on two melanoma cell lines (A375 and UACC-62). The IC50 and TGI (total growth inhibition) values of the active fractions were determined. Also, the apoptosis inducing effects of the active fractions and standards (camptothecin and doxorubicin) were determined by using flow cytometer based assays (FITC annexin assay, PE active caspase 3 assay and BD MitoScreen assay). Subsequently, the chemical structures of the compounds that contributed towards the activity of these fractions were obtained by EI-LC-MS analysis. The results demonstrated that the hexane root extract exhibited the best percentage of growth inhibition (%GI) on all three cancer cell lines. The separation of the compounds of the hexane root extract was optimized on TLC plates by using different ratios of hexane and DCM. Column chromatography allowed for fractionation of this extract. Purified compounds were not obtained due to co-elution. Further research would have to be conducted to obtain purified compounds. This may involve the use of mini-column chromatography and PTLC. Overall a total of ten combined fractions were collected from the column. Four of these fractions (F2, F4, F5 and F8) displayed a high %GI on the A375 and UACC-62 cell lines. Moreover, fraction F4 was the most active fraction as it had the lowest IC50 (0.70 µg.ml-1 [A375] and 0.39 µg.ml-1 [UACC-62]) and TGI (12.50 µg.ml-1[A375] and 25 µg.ml-1 [UACC-62]) values in comparison to the other fractions. All four fractions induced depolarization of the mitochondria membrane potential (ΔΨ), caspase 3 activation, early apoptosis (phospholipid phosphatidylserine exposure) and/or late apoptosis in the melanoma cells. The results also revealed that fraction F4 (25 µg.ml-1) induced depolarization of the ΔΨ in a higher percentage of A375 (78.11%) and UACC-62 (87.4%) cells than the other fractions and standards. This fraction also induced caspase 3 activation in a high percentage of A375 (90.56%) and UACC-62 (96.78%) cells. Therefore fraction F4 was also the most active fraction in terms of apoptosis activity. Based on our results and literature findings we can deduce that the active fractions induced the intrinsic or extrinsic (type II) apoptosis pathway in the melanoma cells. Six classes of compounds were identified from the four active fractions. These were: benzothiophenones, benzopyranones, naphthoquinones, anthraquinones, androstanes and quinazolines. In conclusion, this is the first study that evaluated the growth inhibition potential of the leaf and root extracts of C. triloba on a panel of cancer cells. This research indicated that the hexane root extract displayed the best levels of cell growth inhibition. The active constituents of this extract were isolated into four fractions which elicited apoptosis inducing effects that promoted the extrinsic (type II) or intrinsic apoptosis pathway in the melanoma cells. Furthermore, fraction F4 contained the most active compounds from C. triloba as it had the lowest IC50 and TGI values (in comparison to the other fractions) and induced depolarization of the ΔΨ in the highest percentage of melanoma cells. It was confirmed that six classes of compounds were accountable for the anticancer activity of these fractions. Thus, the C. triloba plant is a rich source of anticancer compounds.
Anticancer and anti-reactive oxygen species activity of bioactive peptides isolated from vigna unguiculata
(2024-05) Ramsookmohan, Sonaal; Mellem, John Jason; Dwarka, Depika
Cancer is a major cause of death globally and continues to escalate with current anticancer drugs associated with severe side effects and resistance driving the need for safer alternative therapeutics. Food proteins, from legumes, are a source of bioactive peptides and studies revealed that they are associated with various therapeutic properties. Cowpea (Vigna unguiculata) is an underutilized nutritious legume crop with promising potential due to its documented protein profile. Therefore, this study evaluated the in vitro anticancer effect of V. unguiculata peptides derived from alcalase and flavourzyme. Physicochemical properties such as water and oil absorption capacities, emulsifying properties, sub-unit composition, amino acid composition among others, were also assessed. Peptides were also evaluated for their antioxidant activity using superoxide radical scavenging, 1,1-diphenyl-2-picrylhydrazil (DPPH) and 2,2’-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays as well as for their apoptotic potential using 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), reactive oxygen species (ROS) and caspase 3/7 assays on cancerous (Caco-2 and MCF 7) and healthy (C2C12) cell lines. From results obtained it was observed that the foam capacity for the peptides derived from alcalase and flavourzyme were 78.34 and 82.39%, respectively, which was noted to be significantly different. The physicochemical properties determined their potential application in food industries. Glutamic acid was the most abundant amino acid in all samples while methionine was noted to be the least concentrated amino acid in the flour and alcalase derived sample while proline was the least concentrated in the flavourzyme sample. Results from this study suggest that cowpea samples have antioxidant capabilities with enzymatic hydrolysis contributing to a higher capacity compared to that of raw flour flour samples. From the cowpea flour, the peptide sample derived from alcalase demonstrated the highest DPPH free radical scavenging activity (70.88-80.47%), followed by flavourzyme (67.27-75.84%), while the raw flour sample showed the lowest activity (24.28-66.17%). The ABTS scavenging capacity of the alcalase peptide was in the range of 35.26-85.92%. The MTT cytotoxicity assay revealed that the cowpea peptides and camptothecin showed different sensitivities on the MCF-7 cell lines. The IC50 values of flavourzyme peptide, alcalase peptide and camptothecin were 0.07, 0.09 and 0.07 µg/mL respectively. Cell viability of the cowpea peptides and camptothecin (control) on the Caco-2 cells varied with the different concentrations. Alcalase and flavourzyme samples had IC50 values of 0.15 and 0.11 µg/mL respectively. The apoptotic potential of the peptides was further shown by the caspase 3/7 activity. From the results in this study, it can be ascertained that the cowpea peptides have potential as an anticancer therapeutic agent. Further research is necessary to determine mechanism of action and to conduct in vivo evaluations of these peptides using animal models
Anticancer and antioxidant potential of Amaranthus cruentus protein and its hydrolysates
(2020) Ramkisson, Shanece; Mellem, John J.; Venter, Sonja
Traditionally, amaranth has been acknowledged to possess vital pharmacological properties with anticancer peptides having been found in Amaranthus cultivars. However, limited knowledge is available over the use of pepsin and alcalase enzymes to form hydrolysates. Thus, this study was aimed at comparing the in vitro anticancer effect of Amaranthus cruentus (grain) protein isolate and hydrolysates using alcalase, trypsin and pepsin. The safety of hydrolysates was investigated using the Ames mutagenicity and Brine Shrimp Lethality assay. Protein hydrolysates were thereafter investigated for their antioxidant potential using the FRAP, ABTS and DPPH assays. Subsequently, the protein hydrolysates were tested for their anticancer and apoptotic potential. The MTT assay was conducted to evaluate the cytotoxic potential of the protein hydrolysates using the HEK 293 (non-cancerous), A549 (cancerous) and MCF-7 (cancerous) cell lines. After that, morphological alterations were examined using the acridine orange and ethidium bromide double stain. Following this, the Annexin V apoptotic detection kit was used to quantify apoptosis together with the Glomax Caspase 3/7 kit to detect changes in the cell cycle Results show A. cruentus isolate and hydrolysates had no mutagenic response against Salmonella typhimurium TA 98 and TA 100 strains. The tested samples did not induce any significant increase in the death percentage of Artemia spp. in comparison to potassium dichromate (control). DPPH assay revealed that the hydrolysed samples had an enhanced scavenging activity compared to the unhydrolyzed sample, with pepsin having the greatest IC50 of 23.06 µg/ml. Amaranthus cruentus isolate (IC50 17.57 µg/ml) was a greater scavenger of the Fe+ ions compared to the control glutathione (IC50 79.81 µg/ml). For ABTS, all hydrolysates had a greater antioxidant scavenging potential compared to the isolate. The MTT cytotoxicity assay revealed that the isolate produced a greater cytotoxic effect on the MCF-7 and A549 cell line when compared to the control (camptothecin). For the non-cancerous cell line (HEK 293), trypsin hydrolysate had the highest toxicity. Apoptotic results revealed that trypsin hydrolysate was the most effective compared to the isolate, which was confirmed from morphological and Caspase 3/7 results. It may be concluded from the findings of this research that hydrolysates from food protein isolates have the potential for use as possible anticancer therapeutics. However, more research needs to be conducted to determine the peptides responsible for anticancer activity as well as the possible mechanism of action.
Antimicrobial activity of ciprofloxacin-coated gold nanoparticles on selected pathogens
(2014-08-08) Moodley, Nivrithi; Odhav, Bharti
Antibiotic resistance amongst bacterial pathogens is a crisis that has been worsening over recent decades, resulting in serious and often fatal infections that cannot be treated by conventional means. Diseases caused by these drug resistant agents result in protracted illnesses, greater mortality rates and increases in treatment costs. Improvements to existing therapies and the development of novel treatments are urgently required to deal with this escalating threat to human health. One of the more promising strategies to combat antibiotic resistance is the use of metallic nanoparticles. Research into this area has shown that the binding of antibiotics to nanoparticles enhances their antimicrobial effects, reduces side-effects due to requirement of lower dosages of the drug, concentrates the drug at the interaction site with bacterial cells and in certain cases, has re-introduced susceptibility into bacterial strains that have developed drug resistance. Furthermore, these nanoparticles can be used in cancer treatment in similar drug delivery roles. Based on the promising data that demonstrated the synergistic effects of antimicrobial agents with nanoparticles, the aim of our research is to determine the effect of ciprofloxacin-conjugated gold nanoparticles as antimicrobial agents. To achieve this aim our objectives were: (i) to synthesize citrate-capped and ciprofloxacin-conjugated gold nanoparticles; (ii) to determine the physical and chemical characteristics of the ciprofloxacin-nanoparticle hybrid molecule; (iii) to investigate the antimicrobial activity of the conjugated nanoparticles against various species of common pathogens and (iv) to investigate the anti-cancer potential of the citrate-capped nanoparticles against a Caco-2 cell line. In this study, citrate-capped gold nanoparticles were conjugated to the antibiotic, ciprofloxacin, and their antibacterial and anti-cancer activity was evaluated. Initial experiments involved the synthesis and characterization of gold nanoparticles and ciprofloxacin conjugated nanoparticles. The gold nanoparticles were synthesized using the Turkevich citrate reduction technique which has been extensively used in studies thus far. The synthesized nanoparticles were characterized for specific absorbance using a UV-Spectrophotometer. The bond between the nanoparticles and ciprofloxacin was characterized by FTIR. Ultra structural details of the gold nanoparticles were established by TEM. The colloidal stability of the nanoparticles was determined by spectroscopic analysis. The antibacterial activity of the ciprofloxacin-conjugated gold nanoparticles was studied by exposure to pathogenic bacteria (Staphyloccocus aureus, E. coli, Klebsiella pneumoniae, Enterocococcus spp., Enterobacter spp., and Psuedomonas spp.). MIC values were measured to give indication of antimicrobial effect. These bactericidal properties of the conjugate nanoparticles were further investigated by electron microscopy. To evaluate the action of the citrate capped gold nanoparticles on cancer cells, we exposed Caco-2 cells to various concentrations of the nanoparticles and its effect was evaluated by measuring the viability of the cells. The results showed that 0.5 mM trisodium citrate reduced gold chloride to yield gold nanoparticles, which were spherical and 15 to 30 nm (by TEM characterization) and had an absorption maxima of 530 nm. The ciprofloxacin conjugated nanoparticles had an absorption maxima of 667nm. The colloidal stability, which is used to assess whether the synthesized particles will retain their integrity in solution showed that citrate-capped GNPs were most stable at 37°C over a 14 day storage period while ciprofloxacin-conjugated GNPs were found to be most stable at 4°C over a 14 day period. The FTIR results showed that chemical bonding in the conjugated nanoparticles occurs between the pyridone moiety of ciprofloxacin and the nanoparticle surface. The antimicrobial results of ciprofloxacin-conjugated GNPs had a significantly improved killing response compared to ciprofloxacin on both Gram positive and Gram negative bacteria. The citrate-capped GNPs are shown to exert a similar cytotoxic effect to gemcitabine on the Caco-2 cell line at a concentration of 0.5 mM. These results indicate that combining gold nanoparticles and ciprofloxacin enhances the antimicrobial effect of the antibiotic. The conjugate nanoparticles increase the concentration of antibiotics at the site of bacterium-antibiotic interaction, and thus enhance the binding and entry of antibiotics into bacteria. This has great implications for treatment of infection, as these antibiotic-conjugated nanoparticles can be incorporated into wound dressings, be administered intravenously as drug delivery agents, be engineered to possess multiple functionalities in addition to antibacterial activity and act as dual infection tracking and antimicrobial agents. Likewise, in this study, gemcitabine, an anticancer drug and gold nanoparticles were shown to kill cancer cells. In addition to their use in photothermal therapy and as drug delivery agents, the nanoparticles themselves possess anti-cancer activity against the Caco-2 cells. Thus, they have potential to act alone as a form of cancer treatment if functionalized with certain targeting agents that are specific to cancer cells, reducing the side-effects that come with regular chemotherapeutic drugs. It can be concluded that ciprofloxacin-conjugated gold nanoparticles enhance antibacterial effects of the antibiotic ciprofloxacin against bacterial cells and citrate-capped gold nanoparticles have anti-cancer activity against the Caco-2 cell line.
Antimicrobial activity of plant phenols from Chlorophora excelsa and Virgilia oroboides
(Academic Journals, 2013-04-24) Padayachee, Thiriloshani; Odhav, Bharti
The anti-bacterial and anti-fungal activity of four aqueous plant extracts (1 x 104 µg/ml) of 2,3'4,5'-tetra hydroxy-4'-geranylstilbene (chlorophorin) and 3',4, 5' - trihydroxy - 4' - geranylstilbene (Iroko) from the tree Chlorophora excelsa and (6aR,11aR)-3-hydroxy-8,9-methylenedioxypterocarpan (Maackiain) and 7-hydroxy-4'-methoxyisoflavone (formononetin) from Virgilia oroboides were evaluated by the seeded agar overlay well diffusion method. The test organisms and bioautography used included: Bacillus coagulans, Streptococcus pneumoniae, Klebsiella pneumoniae, Escherichia coli, Mycobacteria tuberculosis, Aspergillus flavus and Fusarium verticilloides. Vancomycin, the drug of choice for these organisms was used as the control at 30 µg/ml. The extracts showed that chlorophorin at 1.95 µg/ml and Iroko at 3.125 and 6.25 µg/ml respectively were active in inhibiting the growth of S. pneumoniae and B. coagulans and not active against K. pneumoniae and E. coli. Maackiain; formononetin and formononetin acetate showed little activity against S. pneumonia, B. coagulans, K. pneumoniae and E. coli. None of the extracts showed activity against M. tuberculosis. Maackiain, formononetin, chlorophorin and Iroko inhibited F. vertiicilloides, maackiain being the most active compound. Formononetin, chlorophorin and Iroko inhibited A. flavus. A. flavus was most sensitive to chlorophorin and Iroko. The bioautography method confirmed these results and was attributed to the phenolic nature of the compounds.
Antimicrobial efficacy of nisin, oregano and ultrasound treatments against foodborne pathogens in ready-to-eat vegetables
(2020) Takundwa, Brianmax Aubrey; Ijabadeniyi, Oluwatosin Ademola; Pillai, Santhosh Kumar Kuttan
A marked increase in the prevalence of foodborne illnesses resulting in foodborne outbreaks globally have been noticed, primarily due to the contamination of foods with bacterial pathogens. Recently, there has been a growing interest in employing alternative decontamination methods against bacterial pathogens, as a result of problems associated with the commonly used chemical and thermal methods. Therefore, the current impetus is on employing decontamination techniques involving green technology (physical, biological) and hurdle technology. In this study, oregano, nisin and ultrasound treatments were employed on lettuce and cabbage at varying levels to elucidate their antimicrobial efficacy and subsequent effect on the physical and sensory properties of the vegetables. Specifically, fresh cut lettuce and cabbage samples were inoculated with Escherichia coli O157:H7 and Listeria monocytogenes and were subjected to a series of combined treatment applications, of nisin, oregano essential oil and ultrasound. The Box Behnken, response surface methodology (RSM) technique was used in formulating the various combination treatments that would, in turn, demonstrate the synergistic capabilities of the three factors, nisin, oregano and ultrasound when combined. Results from the RSM were then used in the optimization of the combined treatment parameters by maximizing the microbial log reduction in both ready-to-eat vegetables. The physical properties studied on lettuce and cabbage subjected to combined treatments were colour and texture, and their structural damage was investigated using electrolyte leakage. Sensory properties were also analyzed on non-inoculated cabbage samples previously subjected to combined antimicrobial treatments. The efficacy of nisin, oregano and ultrasound on the reduction of E. coli O157:H7 and L. monocytogenes on lettuce studied using RSM/Box-Behnken model design, was found to be reliable (p<0.05). The most effective treatment on both pathogens was a combination of 771.2 IU/g nisin, 0.185% v/v oregano and 14.65 min ultrasound which showed log reductions of 3.43 and 9.20 CFU/mL for E. coli O157:H7 and L. monocytogenes, respectively. Lettuce treatment with the combined antimicrobial treatments resulted in no significant differences in textural properties, specifically hardness. However, mild colour changes and a slight increase in the electrolyte leakage rate was observed, though they were within the permissible limits. The reduction of E. coli O157:H7 on cabbage was increased with the use of combined treatments of nisin, oregano and ultrasound. Hence, the combination (comprising 607.85 IU/g nisin, 0.20% v/v oregano and 14.98 min ultrasound) exhibited the highest log reduction of 3.66 CFU/mL. In the samples inoculated with L. monocytogenes, 731.25 IU/g nisin, 0.12% v/v oregano and 13.21 min ultrasound treatments were found to be the best combination exhibiting the highest log reduction of 8.27 CFU/mL. No significant colour and textural changes were observed between untreated and treated cabbage. However, a slight increase in the electrolyte leakage rate was observed after the application of the combined treatment. Sensory evaluation scores also had some factors that were slightly below par. Overall, results from the study demonstrated that a combination of nisin, oregano and ultrasound, is a promising alternative to chemical treatments for the reduction of E. coliO157:H7 and L. monocytogenes as well as retaining the quality characteristics of fresh produce. Prospectively, other studies could explore the frontier field of artificial intelligence and machine learning, in the form of predictive microbiology and mathematical modelling, in the fresh produce industry. This would present a better understanding of risk assessment that is powered by the technological advantage of data analytics.
Antimycobacterial, docking and molecular dynamic studies of pentacyclic triterpenes from Buddleja saligna leaves
(Taylor and Fancis Online, 2017) Singh, Alveera; Venugopala, Katharigatta Narayanaswamy; Khedr, Mohammed A.; Pillay, Mellendran; Nwaeze, Kenneth U.; Coovadia, Yacoob; Shode, Francis; Odhav, Bharti
Buddleja saligna (family Buddlejaceae) is a medicinal plant endemic to South Africa. Two isomeric pentacyclic triterpenes, oleanolic acid and ursolic acid, were isolated from the leaves of B. saligna using silica gel column chromatography. Compounds oleanolic acid and ursolic acid were subjected to derivatization with acetic anhydride in the presence of pyridine to obtain oleanolic acid-3-acetate and ursolic acid-3-acetate, respectively. The structures of these compounds were fully characterized by detailed nuclear magnetic resonance (NMR) investigations, which included 1H and 13C NMR. Molecular docking studies predicted the free binding energy of the four triterpenes inside the steroid binding pocket of Mycobacterium tuberculosis fadA5 thiolase compared to a reported inhibitor. Thus, their ability to inhibit the growth of M. tuberculosis was predicted and was confirmed to possess significant antimycobacterial activity when tested against Mycobacterium smegmatis, M. tuberculosis H37Rv (ATCC 25177), clinical isolates of multi-drug-resistant M. tuberculosis (MDR-TB) and extensively drug-resistant M. tuberculosis (XDR-TB) using the Micro Alamar Blue Assay. Ursolic acid was isolated from this plant for the first time.
Antioxidant and anticancer properties of bioactive peptides from Lablab purpureus
(2023-05) Sipahli, Shivon; Mellem, John Jason
Cancer can be described as a non-communicable disease that develops from defective cells in the human body and grows uncontrollably. Globally in 2020, statistics revealed that the disease had affected approximately 19.3 million people. With about 51% of these cases resulting in death. Cancer treatments usually comprise surgery, chemotherapy, radiotherapy, or a combination of the three. Traditional therapies such as chemotherapy and radiotherapy drugs are effective at shrinking tumours. However, a key disadvantage is that these drugs are unable to distinguish between cancerous and healthy cells. Subsequently, the human body experiences many adverse side effects such as hair loss, vomiting, lowered immunity, and a general deterioration of health. Drug resistance and rejection are also major disadvantages of these traditional therapies. Alternative therapies are required to mitigate these drawbacks. The vital factor to consider for alternative treatments should be to selectively target cancer cells thereby alleviating the unwanted side effects. Compounds derived from non-toxic edible plants have shown to have bioactive potential. These plants are regarded as non-toxic to the human body therefore they would be able to target the tumour cells alone. Plant compounds also provide additional protection such as their antioxidant abilities and apoptotic potential. Evidence suggests that bioactive peptides derived from legumes can act as both anticancer agents and strong antioxidants. This study investigated the bioactive potential of peptides derived from Lablab purpureus. This investigation began by assessing the antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic (ABTS), superoxide radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays) and antiproliferative abilities (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)) of L. purpureus protein isolate and hydrolysates (alcalase, trypsin and pepsin). The hydrolysate and fractions of interest were selected based on the MTT assay with the pepsin hydrolysate selected for further apoptotic studies (caspase-3 and -7, and annexin V-PI). Thereafter, the pepsin hydrolysate was fractionated by ultrafiltration (molecular weight cut-off: <1, 3, 5, 10, >10 kDa). The 3 kDa fraction was further fractionated by RP-HPLC. Five peaks appeared on the chromatogram, however, fraction 2 was selected, for apoptotic investigations (caspase -3 and -9, p53 and annexin V-PI). Antioxidant studies are a good measure of the isolate or hydrolysate's ability to perform as a bioactive compound. The 50% inhibitory concentration (IC50) observed for the respective antioxidant studies showed the radical scavenging ability of the isolate and hydrolysates to be 1.81-4.47 mg/mL (DPPH), 1.73-2.42 mg/mL (ABTS), 1.36-4.4 mg/mL (superoxide radical scavenging) and 19.20-21.94 mg/mL (FRAP). Anticancer activity was substantiated by the peptides' ability to induce apoptosis. The pepsin hydrolysate was selected using the MTT assay (IC50 values of A549, 119.6; MCF7, 9.80 and HEK293, 13.86 µg/mL). Pepsin hydrolysate inhibited cancerous cells (A549 and MCF-7) while causing minimal damage to healthy cells (HEK293). Thereafter apoptotic markers, caspase 3/7 and annexin V-PI were quantified. Visualisation of cells in different stages of apoptosis was investigated by Annexin V-PI staining quantified by flow cytometry. During early apoptosis; A549, 42%; MCF-7, 17%; HEK293, 34%. Caspase 3/7 assay verified that the pepsin hydrolysate caused an increase in apoptotic activity. Caspase-3 and -9 activity of cells, determined by ELISA showed that Fraction 2 treated cancer cells (A549 - 0.067 ng/mL, 21.966 ng/mL, and MCF-7 - 0.137 ng/mL, 0.205 ng/mL respectively) had a greater caspase concentration over camptothecin (A549 - 0.029 ng/mL, 20.486 ng/mL and MCF-7 - 0.051 ng/mL, 0.112 ng/mL respectively). Tumour suppressor protein, p53, acts as a protective mechanism by initiating apoptosis in ‘suspicious’ cells. The A549 cell line showed the greatest p53 expression compared to MCF-7 and HEK293. Increased p53 can regulate signalling pathways leading to targeted apoptosis. Finally, annexin V-PI confirmed that Fraction 2 did induce apoptosis in the cells (cells in early apoptosis, A549, 85%; MCF-7, 90%; HEK293, 94%). Results from this study have shown that peptides derived from L. purpureus (specifically fraction 2) have potential anticancer abilities which may be attributed to their antioxidant and apoptotic abilities.
Apoptosis in the human laryngeal carcinoma (HEp-2) cell line by Bulbine natalensis and B. Frutescens fractions
(IJBPR, 2012) Singh, Rishan; Reddy, Lalini
Many plants that belong to the genus Bulbine have compounds in their roots and leaves which are considered important for traditional treatments. The stems and roots of Bulbine species are believed to contain anticancer compounds such as anthraquinones, including chrysophanol and knipholone. However, in general, people utilise plants of the Bulbine genus for the treatment of rashes, itches, wounds, burns, cracked lips and cracked skin. This study assessed the effect of aqueous and organic fractions of Bulbine natalensis and Bulbine frutescens on the human laryngeal carcinoma cell line (HEp-2) for apoptosis. The MTT assay was used to determine the cytotoxicity of the fractions administered and to select fractions for analysis of bax and caspase-3 gene expression, which are induced during programmed cell death type 1, known as apoptosis. All of the B. natalensis fractions induced expression of caspase-3, while the tested B. frutescens aqueous root fractions failed to induce expression of caspase-3. The variation in bax gene expression indicated that HEp-2 cell death was due to apoptosis and other unknown forms of cell death that may or may not activate caspase-3 gene expression.
Application of selected ionic liquids for different separation problems : liquid-liquid equilibria and activity coefficients at infinite dilution
(2021) Kabane, Bakusele; Redhi, G. G.
This work focusses on the application and pre-screening of selected ILs for different industrial separation problems based on limiting activity coefficients at infinite dilution, and liquid-liquid equilibrium data at different temperatures. The selected ionic liquids for pre-screening based on activity coefficients at infinite dilution data include (1,3- dimethyimidazolium dimethylphosphate, trioctylmethylammonium chloride, trihexyltetradecylphosphonium dicyanamide, 2,3-dihydroxypropyl-N-methyl-2- oxopyrrolidinium chloride, 2,3-epoxypropyl methyl-2-oxopyrrolidinium chloride) and deep eutectic solvent (1-butyl-3-methylimidazolium chloride + glycerol) at 1:2 molar ratio. These ionic liquids were tested in 33 solutes (alkanes, alkenes, alkynes, alcohols, tetrahydrofuran, ketones, aromatic hydrocarbons, thiophene, acetonitrile) and water at T = (313 – 343) K and at p = 101 kPa. The use of ionic liquid as a stationary phase on the column loading ranged between (30 – 36) % by mass. Thermodynamic functions at infinite dilution such as (Gibbs free energy, , entropy term, Tref and partial molar enthalpy, ) were also computed to further elucidate the types of intermolecular interactions existing between solutes and the investigated ionic liquids. The separation potential of the ionic liquids was determined from the selectivity ( ), and capacity ( ), values. Different ionic liquids (1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolim dicyanamide, 1,3-dimethylimidazolium dimethylphosphate) were also tested in the separation of azeotropic mixture (ethyl acetate/hexane) and in the desulfurization (thiophene/hexadecane or octane) process. The extraction process was conducted at varying temperatures, T = (308 and 298) K and at p = 101 kPa. The results were compared to previously published ionic liquids involving thermodynamic data found in the literature. The separation capacity was based on the calculated values of selectivities (S) and distribution ratio (β). The data was successfully correlated using the thermodynamic non-random two liquids (NRTL). From this study, it was found that the investigated ionic liquids showed some possible application for selected industrial separation problems.
Assessment of biomarkers for normalization of SARS-CoV-2 concentrations in wastewater
(2023-09) Osman, Aaliyah; Sheena, Kumari; Amoah, Isaac Dennis; Bux, Faizal
During the COVID-19 pandemic, the measurement of SARS-CoV-2 RNA levels in wastewater quickly emerged as an additional tool for monitoring and to provide an early warning system. This led to development of several regional, national and international projects aimed at applying this approach. The main principle is based on the detection of the viral signature in untreated wastewater to provide an indication of infection levels within connected populations. However, the concentration of the viral signature in wastewater can be impacted by dilution factors or population changes in the sewer shed, leading to misinterpretation of measurement results. Therefore, there is the need for normalization of wastewater to ensure accurate representation of infection numbers. The aim of this study was to evaluate different viral and bacterial markers in wastewater for their efficiency in normalizing SARS-CoV-2 WBE data, which will enhance the accuracy when interpreting the SARS-CoV-2 RNA concentrations in wastewater. Weekly sampling was conducted from two wastewater treatment plants (WWTP A and WWTP B) within the eThekwini district over a period of three months (July-October 2022). Three biomarkers (crAssphage, Bacteroides (HF 183), and Pepper Mild Motile Virus) where chosen for this study to ascertain the most suitable for WBE data normalization. Biomarker and SARS CoV-2 concentrations in the wastewater samples were determined using the droplet digital PCR (ddPCR). Physicochemical characteristics of the wastewater samples were also determined to identify the potential impact of these characteristics on the concentration of SARS-CoV-2 and the biomarkers. To determine the most suitable biomarker, correlation analysis and the Adaptive neuro fuzzy inference system (ANFIS) model was used. Average concentrations of SARS-CoV-2 in the sampled WWTPs ranged from 0.28 copies/µL to 9.57 copies/µL. Among the three biomarkers studied, crAssphage recorded the highest concentration compared to PMMoV and Bacteroides HF183 in both the WWTPs. CrAssphage recorded the highest concentration of 7943 (±7.07) copies/µL for WWTP A and 8006 (±4.24) copies/µL for WWTP B. The Bacteroides HF183 highest concentrations were 10116 (±120.91) copies/µL for WWTP A and 2474 (±117.37) copies/µL for WWTP B. PMMoV had concentrations of 46 (±4.24) copies/µL for WWTP A and 84,1 (±5.48) copies/µL for WWTP B. PMMoV concentrations were observed to be the highest at Week 1. CrAssphage showed a greater association during the trend analysis with SARS-CoV-2 (0.499) than the other two biomarkers for WWTP A, (HF 183 and SARS-CoV-2 (-0.191) and PMMoV and SARS-CoV 2 (-0.562)). Among the physicochemical factors studied, electrical conductivity and temperature had a significant correlation with SARS-CoV-2 and the crAssphage biomarker for both WWTPs. Using the ANFIS model, it was shown that the levels of the measured biomarker concentrations in wastewater had a significant association with chemical oxygen demand (COD), dissolved oxygen (DO), and volatile solids (VS). These results indicate a possible impact of these parameters on the concentration of these biomarkers in the wastewater. Furthermore, the viral RNA quantities of SARS-CoV-2 in wastewater were demonstrated to be influenced by other parameters such as electrical conductivity, pH and temperature. This indicates a difference in the physicochemical parameters that influence both biomarkers and SARS-CoV-2. However, when all physicochemical parameters, biomarkers and SARS-CoV-2 were combined, it was determined that the best biomarker was crAssphage, with potential impact from COD and the VS. The results of this study highlight the significance of including wastewater characteristic in WBE studies for reliable and accurate results. As shown in this study, crAssphage can serve ix as a biomarker for efficient WBE for COVID-19 surveillance. In addition, it has been demonstrated that the detection and quantification of targets of concern, including SARS-CoV 2, may be enhanced when combined with wastewater characteristics, which may enhance the monitoring of COVID-19 infections.