Phytochemical study and screening for antimicrobial activity of flavonoids of Euphorbia hirta.
Objective: This study aims to phytochemical and antimicrobial study of Euphorbia hirta (Euphorbiaceae).
Materials and Methods: Antimicrobial activity of flavonoids (free and bound) of Euphorbia hirta L. was
determined by disc diffusion assay against four bacteria (Escherichia coli, Pseudomonas aeruginosa, Proteus
mirabilis, and Staphylococcus aureus) and four fungi (Aspergillus flavus, Aspergillus niger, Trichophyton
mentagrophytes, and Candida albicans). Minimum inhibitory concentration (MIC) of the extract was
evaluated through micro broth dilution method, while minimum bactericidal/ fungicidal concentration was
determined by subculturing the relevant samples. Total activity (TA) of extracts against each sensitive
pathogen was also evaluated.
Results: Out of fungi; A. flavus, A. niger, and T. mentagrophytes were found to be resistant, against which
none of the tested extracts showed activity. Bound flavonoids extract of root showed best activity against C.
albicans (inhibition zone (IZ) 27.66, MIC 0.039, minimum fungicidal concentration (MFC) 0.039). TA of free
flavonoid extract of root was found to be the same for P. mirabilis and S. aureus (192.30 ml/g). Two
flavonoids quercetin and kaempferol were identified in the bound flavonoids of stem extract which showed
activity against all the microorganisms.
Results of the present investigation indicate that E. hirta has good antimicrobial activity with low range of
MIC, hence can be exploited for future plant‑based antimicrobial drugs.