A new antibacterial sesquiterpene glycoside and other bioactive compounds from Biebersteinia heterostemon

In addition to the plant sterols beta-sitosterol and daucosterol, a new bis abolane-typed sesquiterpene glycoside and three bioactive compounds (arteme tin, geniposide and 6 beta-hydroxygeniposide) were characterized from the w hole plant of Biebersteinia heterostemon endemic to the Tibetan area. The s tructure determination of the novel glycoside and identification of the kno wn phytochemicals were accomplished by a combination of modem spectroscopic methods. Tests of all isolates for the antimicrobial activity indicated th at the new sesquiterpene glycoside exhibited pronounced antibacterial activ ities against Bacillus subtilis, Staphylococcus aureus and Pseudomonas sp. with MICs at 50, 50 and 70 mu g/ml, respectively.