Phytochemicals, Antioxidant and Antimicrobial Potential of Ethnomedicinal Plants of Sikkim Himalaya

Abstract

In the present study, four important ethnomedicinal plants of Sikkim Himalaya viz., Astilbe rivularis Buch-Ham ex. D. Don, Eupatorium adenophorum Spreng., Bergenia ciliata (Haw.) Sternb and Artemisia vulgaris L. were investigated to ensure its ethno pharmacological potency. The methanolic root extracts of the selected plants were investigated for total phenolic content, total flavonoid content, antioxidant and antimicrobial activities. Among the tested extracts, the root methanolic extract of Bergenia ciliata contained the highest total phenolic content (911.4±0.124 mg gallic acid equivalents/g extract) and showed exceptional activity in 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid assays with halfmaximal inhibitory concentration value of 10 µg/ml and 1.0 µg/ml, respectively. The minimum inhibitory concentration of Bergenia ciliata root methanolic extract was also found to be the lowest for gram-negative bacteria Escherichia coli (600 µg/ml) and actinomycetes Streptomyces sp. (800 µg/ml), suggesting high and effective potency against microbes. Bergenia ciliata and Astilbe rivularis root extracts were further investigated for phenolic compounds using high performance liquid chromatography. The extracts of Bergenia ciliata and Astilbe rivularis were found to contain substantial amount of bergenin, gallic acid, chlorogenic acid, catechin, p-coumeric and m-coumeric acid. In conclusion, this study gives scientific evidence on the biological activities of the selected plant species and recommends Bergenia ciliata and Astilbe rivularis as candidate plants for pharmaceutical drug development.