Assessment of Phytochemical, Antioxidant and Antimicrobial Activities of Some Medicinal Plants from Kaski District of Nepal

Abstract

Medicinal plants have been known to treat simple to life-threatening diseases in different communities of Nepal for many years. This study aims to analyze the phytochemicals as plant secondary metabolites, evaluate the antioxidant and antibacterial activities of Rubus ellipticus, Ziziphus mauritiana, Pyrus pashia, and Drynaria coronans extracts that are commonly being used as traditional medicine. Phytochemical analysis was performed to investigate the plant’s secondary metabolites such as polyphenols, alkaloids, flavonoids, terpenoids, reducing sugar, glycosides, tannins, carotene, phytosterols, coumarins, saponins, and anthracenes. The methanol extracts of the plants were used to evaluate the in vitro antioxidant activity by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and the antibacterial activity against Staphylococcus aureus (ATCC 25923), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 25922) and Salmonella typhi (ATCC 14028) by the agar well diffusion method. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by the Resazurin Microtiter Assay (REMA) method. Root extract of R. ellipticus was observed to have the highest antioxidant activity with IC50 of 42.40 ± 1.5 μg/ml followed by the root extract of Z. mauritiana (IC50 55.67 ± 7.41 μg/ml), leaf and bark extract of P. pashia (IC50 58.33 ± 2.9 μg/ml) and tuber extract of D. coronans (IC50 93.30 ± 5.19 μg/ml) as compared to the standard ascorbic acid with IC50 of 28.44 ± 0.97 μg/ml. The plants were found active against Gram-positive Staphylococcus aureus with Zone of Inhibition (ZOI) for R. ellipicus 17 mm, P. pashia 12 mm, Z. mauritiana 9 mm and D. coronans 8 mm. The extracts exhibited no effect on all of the tested Gram-negative bacteria. The MIC and MBC of R. ellipticus and P. pashia were 3.125 mg/ml, 12.5 mg/ml, and 12.5 mg/ml, 25 mg/ml respectively.