Rare pyrane-based cembranoids from the Red Sea soft coral Sarcophyton trocheliophorum as potential antimicrobial-antitumor agents

Two new rare pyrane-based cembranoids, sarcotrocheliol acetate (1) and sarcotrocheliol (2), along with two known cembranoids, cembrene-C (3) and sarcophine (4), and the aromadendrene sesquiterpenoid, palustrol (5), were isolated from the soft coral Sarcophyton trocheliophorum. Chemical structures were determined on the basis of extensive analysis of their spectroscopic data. 1 and 2 displayed significant antibacterial activity, especially against Staphylococcus aureus, Acinetobacter spp., and MRSA with minimal inhibitory concentrations (MICs) ranging from 1.53 to 4.34 A mu M, while 3 recorded antifungal activity against Aspergillus flavus and Candida albicans with an MIC of 0.68 A mu M. 4 and 5 showed lower antibacterial and antifungal activities compared to 1, 2, and 3. All the five metabolites displayed no appreciable cytotoxic activity against Artemia salina as test organism, while 4 and 5 recorded antitumor activities against Lymphoma and Erlish cell line with LD50 in the range of 2.5-3.79 A mu M.