Isodon kameba

Hirotsu, K., T. Kamikawa, T. Kubota, and A. Shimada Mebadonin, a New ent-Kaurane Diterpenoid from Isodon kameba Okuyama. Chemistry Letters 1973, 255. 

Fujita, T., T. Ichihara, Y. Takeda, Y. Takaishi, Y. Minato, and T. Shingu The Chemical Structure of a New Diterpene, Kamebakaurin from Isodon kameba. Abstract papers of the 21st Symposium on the Chemistry of Terpenes, Essential Oils, and Aromatics (Japan), p. 24 (1977). 

Isodon kameba. Abstract papers of the 23 rd Symposium on the Chemistry of Terpenes, Essential Oils, and Aromatics (Japan), p. 279 (1979). 

The diterpenoids of Isodon (Labiatae) species have been reviewed. The presence of an a-methylenecyclopentanone moiety in these diterpenoids is important for their anti-tumour and anti-bacterial activity. " Inflexin (79) is a cytotoxin and insect antifeedant which has been isolated from Isodon inflexus. Isodomedin (80) is another member of this series, isolated from /. shikokianus, which shows this type of biological activity. Its structure was assigned on the basis of its H and C n.m.r. spectra and on an interrelationship with kamebanin (81), isolated from /. kameba. 

Two new anti-tumour diterpenoids have been isolated from Isodon (Labiatae) species. Kamebanin, which was obtained from I. kameba, was assigned the structure (76) on the basis of a thorough n.m.r. study and a correlation with mebadonin, whose structure had been determined by X-ray analysis. Shikodonin (77) is a unique spiro-secokaurene which was obtained from I. shikokianus. Its structure was assigned by a combination of X-ray and spectroscopic methods. 

---