Phytochemical analysis and investigation of antioxidant, antimicrobial and anticancerous properties of six medicinal plants of Nepal

Abstract

This study investigates the medicinal property of some popularly used medicinal plants of Nepal by evaluating their antioxidant, antibacterial and anticancer properties. Six plants namely, Calotropis procera, Clematis montana, Nardostychs grandiflora, Semecarpus anacardium, Terminalia chebula, and Withania somnifera were selected on the basis of their reported traditional use in the treatment of various ailments. Preliminary phytochemical screening of water and methanol extracts of the plants showed the presence of phytochemicals like alkaloid, steroids, tannins, saponins, polyphenols and terpinoids reducing sugars and proteins. More than 80% of extracts were found to contain high amount of polyphenol and flavonoid. The best antioxidant property was observed in the extract of Terminalia chebula comparable to that of standard compounds, Ascorbic acid and Gallic acid. During antibacterial screening all the methanolic extracts and some of the aqueous extracts were found to be effective against the strain of Staphylococcus aureus (gram positive) and Pseudomonas aeruginosa (gram negative). The methanolic extracts of T. chebula, S. anacardium and W. somnifera and aqueous extract of T. chebula showed exciting antiproliferative activity against HeLa cell with IC₅₀ value, 30.34±1.44, 43.79±2.88, 93.05±3.88, 34.77±0.63 µg/ml respectively. Cytotoxicity tests on mice peritoneal macrophage revealed the safety of the extracts towards normal cell with selectivity indices greater than 1. The overall comparison of aqueous and methanolic extracts in all assay revealed that the methanolic extracts showed significantly greater activity over aqueous extract as methanolic extracts were found to contain higher polyphenols and flavonoid and other bioactive compounds than that of the aqueous extracts. Key words: Medicinal plants, ethnomedical, antioxidant, Cytotoxicity, IC₅₀, extrcation, Nepal