new brevifolin carboxylic acid derivative from lagerstroemia indica L.: isolation, characterization and antibacterial activity

A new polyphenolic, 1-O-brevifolin carboxylyl-beta-[4]C1 glucopyranose 5, together with four known phenolics, 2,6-di-O-galloyl- beta -[4]C1-glucopyranose 1, vescalagin 2, castalagin 3 and 3, 4, 8, 9, 10-pentahydroxydibenzo [b, d] pyran-6-one 4 have been isolated from the aqueous alcohol extract of the leaves of Lagerstroemia indica L. All structures were established on the basis of analysis of [1]H, [13]C NMR, HMQC, HMBC and ESI-MS spectral data. The extract as well as the isolates 1-5 showed considerable antibacterial activity against drug-resistant bacterial strains