TITLE:
Assessment of Phytochemical, Antioxidant and Antimicrobial Activities of Some Medicinal Plants from Kaski District of Nepal
AUTHORS:
Lekha Nath Khanal, Khaga Raj Sharma, Yuba Raj Pokharel, Surya Kant Kalauni
KEYWORDS:
Medicinal Plant, Phytochemical, Antioxidant, Antibacterial Activity, Resazurin
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.9,
September
18,
2020
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.