Tephrosin and obovatachalcone with antibacterial activity from Hook.f.

In the search for new antibacterial agents from plants, two known compounds (rotenoid and chalcone) were isolated from Hook.f. (seeds), namely tephrosin (), and obovatachalcone (). The compounds were isolated using vacuum liquid chromatography and radial chromatography. The structures of isolates were determined by 1D and 2D NMR. Both compounds were evaluated for their antibacterial properties against the four pathogenic bacterial strains S33 R4, subsp. str. 168, TISTR 780, and Ty 21a, using the microdilution method to determine MIC and MBC. The results showed that tephrosin () had moderate antibacterial activity against with MIC values of 25 μg/mL and MBC values of 100 μg/mL. However, obovatachalcone () showed a weak antibacterial activity.