Abstract

IN VITRO STUDY OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF THE 2-(3,4-DIHYDROXYPHENYL)-3,5,7-TRIHYDROXY-4H-CHROMEN-4-ONE ISOLATED FROM THE METHANOLIC EXTRACT OF ANDROGRAPHIS ECHIOIDES LEAVES

S. Gurupriya*, L. Cathrine, J. Ramesh and P. Pratheema

ABSTRACT

Objective: The present study was undertaken to determine antimicrobial and antioxidant activities of the 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one isolated from the methanolic extract of leaves of Andrographis echioides. Materials and methods: Antimicrobial activity was tested against Escherichia coli (MTCC 25922), Enterococcus aerogenes (MTCC 29212). Pseudomonas aeruginosa (MTCC 27853), Staphylococcus aureus (MTCC 25923) and Proteus vulgaris (MTCC 7299) by disc diffusion assay method. Antioxidant activity was determined by DPPH free radical scavenging assay. The isolation was done using column chromatography using gradient elution with different mobile phase. Structural elucidation was carried out on basis of spectral analysis. Results: The 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one exhibited significant antioxidant inhibitory activities with an IC50 value 43.81 and 47.4% respectively and well compared with standard ascorbic acid drug. As the concentration of 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one increased from 20-100 μg/ml, the inhibitory actions of the isolated compound increased towards all the strains used in this study. At concentration 100 μg/ml, the 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one exhibited the antimicrobial activity all the five bacteria and five fungal pahogens, but was more susceptible against Staphylococcus aureus (11 mm), Proteus vulgaris (10 mm), Candida albicans (10 mm zone of inhibition) at 100 μg/ml, followed by the highest activity against Aspergillus flavus and Candida tropicalis (9 mm zone of inhibition). Conclusion: The result confirms that the isolated compounds 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one from the methanolic extract of leaves of Andrographis echioides exhibited antibacterial and antifungal activity against the tested strains.

Keywords: Andrographis echioides, leaves, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one, antioxidant, antimicrobial.