Antimicrobial activity against Streptococcus sobrinus and glucosyltransferase inhibitory activity of taxifolin and some flavanonol rhamnosides from kempas (Koompassia malaccensis) extracts

摘要: Twenty plant materials collected from the islands of Java and Kalimantan in Indonesia were extracted with 50% aqueous ethanol (crude extract). The crude extracts assayed for antimicrobial activities against Streptococcus sobrinus glucosyltransferase (GTase) inhibition. Fourteen inhibited growth S. by more than six GTase activity at a concentration 100 μg/ml. Koompassia malaccensis (kempas) showed 90% depression 80% inhibition Kempas subjected to column chromatography using Sephadex LH-20 then preparative high-performance liquid isolate four compounds A, B, C, D. These identified as taxifolin flavanonol rhamnoside isomers neoastilbin, astilbin, isoastilbin, respectively, 1H 13C nuclear magnetic resonance (NMR) spectra other two-dimensional NMR techniques (COSY, HMBC, HMQC). Each compound depressed over range 9.3242.7 μg/ml inhibitory IC50 values 27.4–57.3 Taxifolin isolated first time kempas could be potent preventing dental caries.