New biologically active allelochemical from the leaves of Dalbergia Paniculata Roxb

A new biologically active Allelochemical 3,5,7,3’,4’-pentahydroxyflavone-3-O-β-D xylopyranosyl -(1→4)- β-D-glucopyranosyl-4^’-O-α-L-arabinoside (A₁) whose m.p. is 340–345 ⁰C, m.f. [M⁺] 728 (EIMS) was isolated from methanolic leaf extracts of Dalbergia paniculata Roxb. It was characterized by several color reactions, spectral analysis FTIR, ¹H-NMR, GC-MS, and chemical degradations. The results of the antimicrobial activity of (A₁) at high concentration (100µg/mL) was 20, 17, and 15 mm zone of inhibition against E. coli, B. cereus, and S. aureus aeruginosa, respectively. The data demonstrated that the antimicrobial activity of CH₃ OH soluble fraction (A₁ ) at all concentrations was highest against E. coli and lowest S. aureus. E. coli, B. cereus, and S. aureus aeruginosa, respectively 7.3, 2.1, and 0.02mm, MIC was defined as the minimum concentration of assayed samples that inhibited the visible growth of the tested microorganism. MIC in E. coli, B. cereus, and S. aureus aeruginosa was 7.3, 2.1, and 0.02mm, respectively.