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Research Publications (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213

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    Green synthesis of silver nanoparticles from Hibiscus tiliaceus L. Leaves and their applications in dye degradation, antioxidant, antimicrobial, and anticancer activities
    (Elsevier BV, 2024-05) Konduri, Vinay Viswanath; Kalagatur, Naveen Kumar; Gunti, Lokanadhan; Mangamuri, Usha Kiranmayi; Kalagadda, Venkateswara Rao; Poda, Sudhakar; Krishna, Suresh Babu Naidu
    The present study reports the green synthesis of silver nanoparticles (AgNPs) from aqueous extract of Hibis cus tiliaceus L. leaves and their application in dye degradation, antioxidant, antimicrobial, and anticancer activities. Analysis using Fourier transform infrared (FT-IR) spectroscopy revealed that plant metabolite func tional groups had a role in the reduction and stability of AgNPs, and X-ray crystallography (XRD) demon strated that the AgNPs were in crystal form. The UV vis spectroscopy, dynamic light scattering (DLS), and zeta potential investigations revealed that the AgNPs were formed with an average size of 88.10 nm in colloi dal form and were stable (-49 mV). The field emission scanning electron microscopy (FE-SEM) and high-reso lution transmission electron microscopy (HR-TEM) confirmed the shape and size of the AgNPs as spherical with a particle size of 30 - 35 nm, respectively. The AgNPs exhibited potential antioxidant activity by total antioxidant, DPPH, and reducing power assays. The biosynthesized AgNPs displayed a wide range of antibac terial activity on Gram-ve and Gram+ve bacteria by the zone of inhibition assay. AgNPs showed good antican cer activity on MCF-7 cells with an IC50 value of 65.83 mg/mL. Furthermore, AgNPs acted as potential catalysts in combination with the reducing agent sodium borohydride (NaBH4) for the degradation of methylene blue (MB), methylene orange (MO), and methylene green (MG) dyes. The degradation efficiency of catalyst AgNPs in the attendance of NaBH4 for 15 min was noted to be 12.8 %, 26.92 %, and 47.56 % for MO, MB, and MG, respectively. The study concluded that green synthesized AgNPs could be highly applicable as an antioxidant, antimicrobial, and anticancer agents in the biomedical field. Furthermore, AgNPs could be helpful in the remediation of dye effluents.
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    Antioxidant potential of zephyranthes citrina seed extract in saccharomyces cerevisiae’s oxidative stress response system
    (Association of Biotechnology and Pharmacy, 2023-10-15) Patil, Sharangouda J.; Jyothi, Renuka; Sadashiv, S. O.; Vishwantaha, T.; Adam, Jamila Khatoon; Krishna, Suresh Babu Naidu
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    Biocatalytic and biological activities of cassia occidentalis mediated silver nanoparticles
    (College of Graduate Studies, Walailak University, 2022-01-01) Singh, Shashika; Mohanlall, Viresh
    Silver nanoparticles (AgNPs) were synthesized using the leaf extracts from Cassia occidentalis. The reactions were marked by a distinct colour change and the formation of AgNPs was monitored by measuring the UV-Vis spectra. The morphology and crystalline phase of the metal nanoparticles were determined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray analysis (EDX) and Fourier-Transform-Infrared Spectroscopy (FTIR). The biocatalytic activity of the AgNPs against nitrifying compounds was determined using 4-nitrophenol and 4-nitroalanine. The biological screening involved analyzing the AgNPs effectiveness against gram-negative and gram-positive bacteria (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus and Enterococcus faecalis). The AgNPs displayed minimal inhibition at low concentrations ranging from 25 to 50 μg/mL. The toxicity of the AgNPs was tested using the brine shrimp assay and was observed as non-toxic with a nearly zero mortality rate. The AgNPs exhibited an antioxidant potential of 70.90 % inhibition at 1000 µg/mL. C. occidentalis is noted as a potential bioresource for synthesizing AgNPs with applications as antibacterial, antioxidant and biocatalytic agents. HIGHLIGHTS The addition of Ag nanoparticles to C. occidentalis plant extracts resulted in the formation of AgNPs-C. occidentalis complexes The AgNPs-C. occidentalis complexes were characterized using Transmission Electron Microscopy, Scanning Electron Microscopy with EDX, UV-Vis spectrophotometry and IR spectroscopy These AgNPs-C. occidentalis complexes were very stable and showed antibacterial activity against a range of tested gram-positive and gram-negative bacteria at low doses, thus proving to be good antimicrobial agents The AgNPs-C. occidentalis complexes showed higher scavenging activity than leaf extracts of C. occidentalis. The AgNPs have increased catalytic ability for the reduction of 4-nitrophenol and 4-nitroalanine after a 30 min time interval GRAPHICAL ABSTRACT
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    Coumarin containing hybrids and their pharmacological activities
    (Phytochemistry & Organic Synthesis Laboratory, 2021-08-09) Kasumbwe, Kabange; Saheed, Sabiu; Makhanya, Talent R.; Venugopala, Katharigatta Narayanaswamy; Mohanlall, Viresh
    Coumarin moiety is of great interest to both chemists and biologists as it is present in a wide variety of naturally occurring bioactive compounds. Studies have lent scientific credence to the biological activities of several coumarin derivatives. The broad spectrum of biological activities linked with coumarin includes antibacterial, antimycobacterial, antioxidant, anticancer, antifungal, anti-inflammatory, anticoagulant and antiviral properties. The electron releasing and withdrawing substituent of coumarin affects the pharmacological properties of its resulting derivatives. Thus, identifying key structural features within the coumarin family is vital to the design and development of new analogues with enhanced pharmacological activity due to the variability in the structural complexity of coumarin. This article presents an up-to-date synopsis on the synthesis of coumarin derivatives and their pharmacological properties.
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    Emergent roles of garlic-based nanoparticles for bio-medical applications : a review
    (Association of Biotechnology and Pharmacy, 2021-08-18) Krishna, Suresh Babu Naidu; KRSS, Sambasiva Rao
    Garlic (Allium sativum L.) is well renowned for its antimicrobial potential and broadly consumed spice globally for its medicinal properties. Moreover, several studies advocate that garlic contains many bioactives that demonstrate strong therapeutic properties in treating cardiovascular diseases, digestive system, diabetes, cancer, obesity, hypertension, inflammation, antioxidant, and viral infection. Presently, therapeutics of natural origin are drawing major interest among consumers due to their antimicrobial efficacy and safety. Garlic extracts, chitosan by- products, several spices and antimicrobial peptides are illustrations for such products. The present review paper inspects briefly the major active ingredients and key biological functions of garlic based nanoparticles discussing the relevant mechanisms of actions.
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    Phytochemistry and anticancer activity of anthraquinones from Ceratotheca triloba (Bernh.) E. Mey. ex Hook.f: a review
    (Scientific and Academic Publications, 2020-06-29) Mohanlall, Viresh
    Ceratotheca triloba (Bernh.) E. Mey. ex Hook.f is native to tropical and subtropical African countries and is used in traditional medicine to treat painful menstruation, stomach cramps, nausea, fever and diarrhoea. Anecdotal reports of its effects in cancer treatment and prevention, with many successful cases, have warranted that these pharmacological properties be scientifically validated. A bibliographic search was conducted using the key words "Ceratotheca", "anticancer", and "antitumor" along with cross-referencing. No clinical or animal cancer studies were identified and only two in vitro cell-culture-based studies were reported; these indicate that extracts of C. triloba may alter the growth of several types of cancer cell lines. This review summarizes the results of anthraquinones and emphasizes the aspects that warrant future research to explore the anthraquinones in C. triloba for their anticancer activities.