Evaluation of in Vitro Antidiabetic, Antioxidant Cytotoxic and Antibacterial activities of Some nepalese Medicinal Plants Extracts

Abstract

Medicinal plants have been recognized to treat simple to life-threatening diseases in different societies of Nepal since long time. Hexane, ethylacetate and aqueous extract of Phyllanthus emblica, Zanthoxylum armatum, Azadirachta indica, Ephedra gerardiana, Terminalia bellirica and Stereum ostrea were taken to evaluate the antibacterial, cytotoxicity, antioxidant and antidiabetic activities. Antibacterial test was done by agar well diffusion method and zone of inhibition (ZOI) was measured. The plants extract was found active against Gram-positive Staphylococcus aureus with the largest Zone of Inhibition (ZOI) as 1.77cm for ethylacetate extract of P. emblica. These extracts didn’t show effect on all of the tested Gram-negative Klebsiella penumoneae, Escherichia coli and Salmonella typhii bacteria. Brine shrimp lethality bioassay was performed for cytotoxicity assay. The highest LC50 (217.04 µg/ml) was showed by all 3 extracts of S. ostrea; hexane and ethylacetate extract of Z. armatum; water and hexane extract of E. gerardiana. DPPH free radical scavenging test was done for antioxidant activity. Ethylacetate extracts of S. ostrea (14.76 μg/ml), aqueous and hexane extract of A. indica (16.06 μg/ml, 18.03 μg/ml) showed potent antioxidant activity. Ethylacetate extract of S. ostrea contains 4.39 mg/g GAE TPC and 102.5 mg QE/ g TFC. Similarly, aqueous and hexane extract of A. indica contain TPC and TFC as 9.61 mg/g GAE, 44.1 mg QE/ g, 3.05 mg/g GAE, 60.9 mg QE/ g respectively. Alpha amylase inhibition assay was performed to test antidiabetic activity of plant extract taking Acarbose as standard. Ethyl acetate extract of S. ostrea had peak percentage inhibition i.e.99.89% with IC50 of 788.25µg/ml followed by same extract of P. emblica. whereas, hexane extract of E. gerardiana had the lowest inhibition i.e. 72.71% with IC50 of 138.67 µg/ml. The results recommended that plant extracts can be used against gram positive bacteria as they showed good inhibition on them. Furthermore, Stereum ostrea and Phyllanthus emblica can be consumed as diet as they reduce amylase in significant way thus might control diabetes. Although, the plant extracts were not cytotoxic to brine shrimp but further study in need to know the exact mechanism and bioactivities of plant extracts.

Key words: Biological activities, In-vitro, Medical plants, Terminalia bellirica