Mohamed Sham

Bio: Mohamed Sham is an academic researcher from VIT University. The author has contributed to research in topics: Rhizome & Minimum inhibitory concentration. The author has an hindex of 2, co-authored 2 publications receiving 224 citations.

Antimicrobial activity and phytochemical analysis of selected Indian folk medicinal plants

Abstract: The success of chemotherapy lies in the continuous search for new drugs to counter the challenge posed by resistant strains. Methanol extracts of six plant species traditionally used in Indian folklore medicine for the treatment of various bacterial and fungal infections were investigated for in vitro antimicrobial activity against pathogens namely Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger by disc diffusion method. Methanol extracts of Eugenia jambolana and Cassia auriculata showed the highest toxicity against all the bacteria. The plant extracts showed antibacterial activity but not antifungal activity against any of the fungi used. Minimum inhibitory concentration (MIC) assay were determined for these two extracts against bacteria. E. jambolana revealed the highest antimicrobial activity at a minimum concentration (0.75 mg/ml) against S. aureus. The phytochemical analysis carried out revealed the presence of coumarins, flavanoids, glycosides, phenols, tannins, saponins and steroids. Alkaloids were not detected from any of the plant extracts under study. The results provide justification for the use of the plants in folk medicine to treat various infectious diseases.

Screening of fifteen indian ayurvedic plants for alpha-glucosidase inhibitory activity and enzyme kinetics

Abstract: Alpha-glucosidase inhibitory activity of fifteen Indian medicinal plants has been evaluated by in vitro enzyme assay. Methanol extracts of Cyperus rotundus (tubers), Plumbago zeylanica (root), Symplocos racemosa (bark), and Terminalia arjuna (bark) had displayed 100% inhibition with the IC 50 value of 3.98 µg/ml, 3.46 µg/ml, 8.16 µg/ml and 0.69 µg/ml, respectively. Bark extract of Terminalia arjuna is highly effective against alpha- glucosidase activity even at nanogram concentration. Plant parts of Piper retrofractum (stem), Zingiber officinale (rhizome), Acorus calamus (rhizome), Picrorhiza kurroa (rhizome), Marsdenia tenacissima (stem), Clerodendron serratum (root), and Rubia cordifolia (root) are not effective and they require high concentration to exhibit inhibition. Potential plants that show maximum inhibition at low concentration (<10 µg/ml) were subjected to kinetic analysis to determine the mode of inhibition of the enzyme. Cyperus rotundus, Symplocos racemosa and Terminalia arjuna exhibited uncompetitive inhibition and Plumbago zeylanica had displayed mixed inhibition to alpha-glucosidase enzyme activity. From the enzyme assay, we infer that Cyperus rotundus, Plumbago zeylanica, Symplocos racemosa and Terminalia arjuna contain potential alpha-glucosidase inhibitors that can be exploited for its use in the treatment of diabetes.

In-vitro α amylase and glycosidase inhibitory effect of ethanolic extract of antiasthmatic drug - Shirishadi

Abstract: Asthma and diabetes have strong relationship; both are cause and effect of each other. Oxidative stress due to bronchial asthma may cause insulin resistance whereas lack of proper insulin can cause defective smooth muscle relaxant. There is no single medicine available that can manage both diseases, rather the mainstay treatment of bronchial asthma causes hyperglycemia. Keeping this problem in focus, in this study the hypoglycemic effect of an indigenous antiasthmatic Ayurvedic drug Shirishadi was evaluated. Pancreatic alpha amylase and glucosidase inhibitors offer an effective strategy to lower the level of post prandial hyperglycemia via control of starch breakdown. For evaluation of hypoglycemic activity of drug, in-vitro alpha amylase and alpha glucosidase enzyme inhibition was calculated. Ethanolic extract of compound showed 76.40% + 0.88% reduction in alpha amylase activity and 63.85% + 0.36% in alpha glucosidase activity with IC50 0.68 mg/ml and 2.89 mg/ml, respectively. This study suggests that the ethanolic extract of Shirishadi polyherbal compound effectively acts as alpha amylase and glucosidase inhibitor leading to a reduction in starch hydrolysis and hence acts as antiasthmatic as well as hypoglycemic drug.

Antidiabetic potential of a peptide isolated from an endophytic Aspergillus awamori.

Abstract: Aim To exploit the potential of endophytic fungi for pharmaceutically important antidiabetic alpha glycosidase inhibitors. Methods and Results Thirty six endophytic fungi were isolated from Acacia nilotica and screened for the production of alpha amylase and glucosidase inhibitors. Inhibitory activity against both alpha amylase (81%) and alpha glucosidase (80%) was exhibited in an isolate, identified to be Aspergillus awamori. Purification of the inhibitor was carried out on Sephadex LH-20 column and semi prep HPLC. The inhibitor was characterized to be proteinaceous in nature with an approximate molecular mass of 22 kDa. UHPLC amino acid analysis indicated the presence of amino acids serine, threonine, tyrosine and valine in the peptide. The purified inhibitor exhibited mixed type of inhibition against alpha amylase and alpha glucosidase with IC50 values of 3·75 and 5·625 μg ml−1 respectively. The inhibitor was stable over a wide range of pH and temperature. Optimization of process parameters to increase the yield of the inhibitor was undertaken using one factor at a time approach as well as RSM statistical analysis. The interaction of dextrose and proteose peptone for the test organism was significant with first order effect of pH. Increase of 13% was obtained in the inhibitory activity after optimization of process parameters. Mutagenicity testing by Ames test revealed nonmutagenic nature of the peptide. Conclusion Endophytic A. awamori is capable of producing a peptide with alpha glycosidase inhibitory activity. Significance and Impact of the Study The inhibitor obtained in this study possesses dual (alpha glucosidase and alpha amylase) inhibitory activity, low IC50 values, is highly stable under extreme conditions of pH and temperature, and is nonmutagenic in nature. By virtue of its properties it can be commercially produced and exploited for better management of diabetes.