Bio-active sesquiterpenoids and norsesquiternoids from the Red Sea octocoral .

Three previously undescribed nardosinane-type sesquiterpenes (-), together with six known compounds (-) were isolated from the alcyonacean soft coral and are 13-nornardosinane, and 6,7-seco-13-nornardosinane derivatives, respectively. could be an artifact due to C-6 epimerization of the known one . Chemical structures were elucidated based on 1 D, 2 D NMR and MS spectral data. Compounds - showed cytotoxic activity against NCI-H1299, HepG2 and MCF-7 with IC values between 0.0352-0.0974, 0.0717-0.3745 and 0.0341-0.1325 mM, respectively. The antibacterial activity of all isolated compounds have examined against a number of Gram-positive (, ) and Gram-negative (, and sp.) bacteria. Compounds and showed a high degree of inhibition against and sp. Interestingly, neolemnane ( showed strong inhibition against two fungi, and ; while showed positive inhibition against at 150 µg/mL.