ANTIMICROBIAL ACTIVITY OF THE EXTRACTS AND ISOLATED COMPOUNDS OF CLERODENDRUM PHLOMIDIS

Objective: In the present work we made an attempt to assess the in vitro antimicrobial activity of the extracts and isolated compounds from roots of Clerodendrum phlomidis of family Verbenaceae against Staphylococcus aureus, Streptococus pyogenes, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. Method: Root extracts (Pet ether, Chloroform, Ethyl acetate and Ethanol) of Clerodendrum phlomidis was prepared by using Soxhlet apparatus. 30gms of ethanol extract was subjected to column chromatography. Three compounds such as Phenyl acetic acid, Ethyl- 2- hydroxy -4- methyl benzoate, 3,6,7-trihydroxy-2-(3-methoxyphenyl)-4H-chromen-4-one, was isolated and characterised by IR, NMR and Mass Spectroscopy. Different dilutions of extracts (106.66µg/ml, 200 µg/ml, 320 µg/ml and 400µg/ml) and isolated compounds (20, 40, 60 µg/ml) were prepared and their antimicrobial screening was carried out by disc diffusion method. The MIC of the extracts and isolated compounds was determined by broth dilution method of NCCLS. The selected microorganisms were also tested against standard drugs like (Amikacin 30µg/disc and Ketoconazole 20µg/disc). Results: The present experiment showed that ethanol extract at 106.66µg/ml showed a significant result against Escherichia coli was observed as the most sensitive (15.33mm). Chloroform extract also shows good antimicrobial activity against Staphylococcus aureus with a zone of inhibition of (14.67mm). Among the isolated compounds, Ethyl- 2- hydroxy -4- methyl benzoate shows good antimicrobial activity than other two compounds against Staphylococcus pyogenes, and Candida albicans with a zone of inhibition of 9mm respectively at 60µg/ml the zone of inhibition observed was also supported by the results obtained from MIC. Conclusion: In the present work, three compounds were isolated by column chromatography such as Phenyl acetic acid, Ethyl- 2- hydroxy -4methyl benzoate, 3,6,7-trihydroxy-2-(3-methoxyphenyl)-4H-chromen-4-one. The above compounds and their antimicrobial activity were not reported earlier. Ethyl- 2- hydroxy -4- methyl benzoate shows good antimicrobial activity than other two compounds.