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Author: search.filters.author.Mohanlall, VireshSubject: search.filters.subject.Antioxidant

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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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    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.