AN IN VITRO INVESTIGATION OF ANTIMICROBIAL EFFICACY OF EUPHORBIA HIRTA AND MURRAYA KOENIGII AGAINST SELECTED PATHOGENIC MICROORGANISMS

摘要

Objective: To investigate the solvent-dependent antimicrobial activity and phytochemical analysis of extracts of Euphorbia hirta (leaves and flowers) and Murraya koenigii (leaves), as well as to evaluate the synergistic activity of these medicinal extracts with suitable antibiotic discs and antibiotics susceptibility of selected pathogenic microorganisms. Methods: The antimicrobial activity of the medicinal extracts was screened through agar well diffusion method and antibiotics susceptibility of selected microorganisms was investigated using disc diffusion method. A combined agar well diffusion and disc diffusion methods were used for the determination of synergistic activities of the extracts with antibiotic discs. Results: Among the different solvents, ethanol had maximum zone of inhibition against the test pathogens. Ethanolic leaf extracts of E. hirta exhibited the highest inhibitory activity against Candida albicans and Staphylococcus aureus with minimum inhibitory concentration value of 12.5 mg/mL and 25.0 mg/mL, respectively. Antimicrobial assay revealed that E . hirta extracts were active against all tested Gram-negative bacteria. However, none of the plant extracts had inhibitory activity against Gram-positive bacterium Propionibacterium acnes . Phytochemical screening for both the extracts from E. hirta revealed the presence of steroid, tannin, terpenoids, carbohydrates, alkaloid, flavonoid, diterpene, and glycoside, whereas M. koenigii extract was rich in saponins, protein, steroid, tannin, carbohydrates, alkaloid, flavonoid, and glycoside. Conclusion: The present study proposes that E . hirta and M . koenigii extracts are excellent sources of natural bioactive compounds that could be used as potent antimicrobial drugs to counter the emerging problem of antibiotic resistance of pathogenic microorganisms.