Sesquiterpene lactones from Sonchus arvensis L. and their antibacterial activity against Streptococcus mutans ATCC 25175.

Two new sesquiterpene lactones, 1beta-sulfate-5alpha, 6betaH-eudesma-3-en-12, 6alpha-olide (1) and 1beta-(p-hydroxyphenyl acetyl)-15-O-beta-D-glucopyranosyl-5alpha, 6betaH-eudesma-3-en-12, 6alpha-olide (2) were isolated from Sonchus arvensis L. (Asteraceae), together with eight known compounds. Their structures were elucidated through spectroscopic and chemical methods. They were evaluated for antibacterial activity. Among them, compounds 1 and 7 exhibited antibacterial activity against oral pathogen Streptococcus mutans ATCC 25175 with MIC values of 15.6 and 62.5 microg/ml, respectively.