Antimicrobial and antioxidant activity of methanol extracts of Arnebia benthamii (Wall ex. G. Don) Johnston—a critically endangered medicinal plant of North western Himalaya

Abstract

Arnebia benthamii is one of the promising folklore medicinal plants which is being traditionally used over the years for the treatment of various prevailing diseases in the area. The aim of this research work was to evaluate the antimicrobial activity and antioxidant activity of methanolic plant extract. Antimicrobial activity of the plant extract (250–500 μg/ml concentration) was analyzed against Escherichia coli CD0006, Pseudomonas aeruginosa CD0023, Shigella flexneri CD0033, Klebsiella pneumonia CD0049, Salmonella typhimurium CD0003, Staphylococcus aureus CD0001, Aspergillus versicolor CDF0011, Candida albicans CDF0032, Candida kruesie CDF0016, Candida parapsilosis CDF0013, Aspergillus flavus CDF0024, and Acremonium spp. CDF0027. The free radical scavenging assay of the plant extracts was evaluated by various antioxidant methods. Comparative analysis reveals that the aerial part exhibited the highest antibacterial activities against almost all tested bacterial strains with the highest inhibition zone diameter (IZD) (30 ± 0.54) was recorded on P. aeruginosa CD0023 and E. coli CD0006. All the fungal strains except C. parapsilosis CDF0013 were more or less inhibited by both aerial and root part extracts of the plant. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values recorded revealed that the P. aeruginosa CD0023 was inhibited by the least concentration of 75 μg/ml of the aerial part methanol extract. The antioxidant activity of the aerial and root part extracts was almost of the same strength with the root part slightly showing a higher scavenging effect in a concentration-dependent manner in superoxide anion and hydroxyl radicals. The plant has got a broad spectrum antimicrobial and antioxidant activity and has a promising potential for treating diseases.