Antibacterial efficacy of some Indian medicinal plants against human commensal pathogens

Abstract

Background and Aim: The present study aimed to evaluate the antibacterial efficacy of the total flower extracts of
five medicinal plants widely used in folk medicine in India, against some Gram positive and Gram negative bacteria.
Methodology: The present work designed to assess the in vitro antibacterial activities of five medicinal plants
(flowers of Bauhinia purpurea, Clitoria ternatea, Millingtonia hortensis, Nyctanthes arbortristis and Combretum
indicum) against panel of Gram positive bacteria and Gram negative bacteria using disk diffusion assays. Results:
Among the plants screened, Combretum indicum showed effective and broad spectrum antibacterial activity with
zones of inhibition ranging from 10.33±0.57 to 23.33±1.52mm. Among the other four plants, only Clitoria ternatea
showed moderate antibacterial activity at high concentration. The other three did not show any antibacterial activity.
The phytochemical analysis of the active crude extract from C. indicum revealed the presence of steroids, terpenoids,
phenols, flavonoids, quinonoids, alkaloids, glycosides and saponins. Moreover, C. indicum showed the highest
activity against the tested pathogens with minimum inhibitory concentration (MICs) values ranging from 125-
1000μg/mL. The qualitative chemical characterization by using high performance liquid chromatography (HPLC)
revealed the presence of compounds such as beta-sitosterol, gallic acid, lupeol, rutin and quercetin which could be
responsible for its significant broad spectrum activity. Conclusion: The results of this study suggest that the C.
indicum flower extract could be probed further for possible use to control bacterial infections