Cytotoxic neviotane triterpene-type from the red sea sponge Siphonochalina siphonella

Background: Siphonochalina siphonella is a marine sponge collected from saudi Red Sea water and scare study from this region. Objective: To isolate the anticancer triterpenes with potent cytotoxicity from marine sponge, Siphonochalina siphonella and state the mode of action in cancer cell lines. Materials and Methods: The sponge material was collected, extracted with organic solvent, and fractionated on different adsorbents. The structure of the pure metabolites were elucidated employing different spectroscopic techniques including 1D ( 1 H and 13 C) and 2D (COSY, HMQC and HMBC) NMR, and MS spectroscopy. Results: A new Neviotine-C (1) was obtained, along with four known metabolites (2-5). All compounds, except 5, were tested towards MCF-7, PC-3 and A549 and showed effects with IC 50 in range 7.9-87 μM, whilst, 3 showed potent anti-proliferative activity against PC-3 and A549 with IC 50 = 7.9 ± 0.120 and 8.9 ± 0.010 μM, respectively. Conclusion: Compounds (1-4) showed significant cytotoxic activities, while 3 showed potent effect. The antiproliferative of 3 was attributed to significant S-phase cell cycle arrest.