Occurrence of Pectolinarigenin Glycosides in Clerodendron, phlomids a Possible Source of Antimicrobial Agents

The antimicrobial activity of the petroleum ether extract and the different fractions of the methanol extract of the leaves of Clerodendron phlomids (Family-Verbenaceaea hah been enaluated. At 0. 1% concentration the ethylacetate fraction of methanol extract produced the maximum growth inhibition of the fungus Penicillium ilalicum followed db the hexane fraction nf methanol extract against Trichoderma sp. Column chromatography of both the fractions resulted in the isolation of a compound 5,7-dihydroxy-6_/4’-dimethoxy flavone, pectolinarigenin (I). From the ethylacetate fraction, two glycosides viz., 5,7-dihydroxy-6,4’-dimethoxy flavone 7-0-β-D (—) glucuronic acid methyl ester (II) and 5,7-dihydroxy 6,4’-dimethoxy flavone-7-0-β-D (—) glucose (III) have also been isolated. The occurrence of II and III is being reported for the first time in the genus Clerodendron. The entifungal lctivity yf the hexane and the ethylacetate fractions of methanol extract might be in part attributable to the presence of the flavone either in aglycone form (I) or in glycosidic combination (II & III). None of the crude extracts and the pure compounds tested could produce any significant growth inhibition of the bacteria Xanthomonas samvestris and Pseudomonas aeruginosa and also against the fungus Alternalia sp