Novaxenicins A-D and xeniolides I-K, seven new diterpenes from the soft coral Xenia novaebrittanniae

Seven new diterpenes, novaxenicins A-D (1-4) and xeniolides I-K (5-7), have been isolated from the Kenyan soft coral Xenia novaebrittanniae. The structures and relative stereochemistry of the compounds were elucidated by interpretation of MS, COSY, HSQC, HMBC, and NOESY experiments. The structure of novaxenicin A (1) was secured by X-ray diffraction analysis. Compound 5 possesses anti-bacterial activity at a concentration of 1.25 μg/ml and compound 2 induces apoptosis in transformed mammalian cells at a concentration of 1.25 μg/ml.