Phytochemical study of the leaves of the medicinal plant Isodon rubescens led to the isolation of three novel abietane diterpenoids, rubesanolides C-E (1-3). These diterpenes contain a unique.-lactone subgroup formed between C-8 and C-20. Their structures were determined from analysis of spectroscopic data, and were further confirmed by X-ray crystallographic data. The compounds were evaluated for their antibacterial activity, and rubesanolide D (2) demonstrated inhibition activity against biofilm formation of the dental bacterium Streptococcus mutans.
1.Guiyang Coll Tradit Chinese Med, Guiyang 550002, Guizhou, Peoples R China 2.Chinese Acad Sci, Kunming Inst Bot, State Key Lab Phytochem & Plant Resources W China, Kunming 650201, Yunnan, Peoples R China 3.Univ Illinois, Coll Pharm, Dept Med Chem & Pharmacognosy, Chicago, IL 60612 USA 4.Univ Iowa, Coll Dent, Dows Inst Dent Res, Iowa City, IA 52242 USA 5.Hong Kong Baptist Univ, Sch Chinese Med, Kowloon, Hong Kong, Peoples R China