Kogure Noriyuki, Ishii Naoko, Kobayashi Hiromi, Kitajima Mariko, Wongseripipatana Sumphan, Takayama Hiromitsu
Graduate School of Pharmaceutical Sciences, Chiba University, Japan.
Chem Pharm Bull (Tokyo). 2008 Jun;56(6):870-2. doi: 10.1248/cpb.56.870.
Four new iridoids structurally related to gelsemide (5) were isolated from two Loganiaceous plants, Gelsemium elegans and G. rankinii. Among them, GEIR-1 (1) has a novel tetracyclic caged structure.