Cytotoxic and antimicrobial activities of two new sesquiterpenoids from red sea brittle star Ophiocoma dentata

Abstract

Bioactive compounds were extracted from a locally available brittle star; Ophiocoma dentata, collected from the Red Sea, Egypt. Two new sesquiterpenoids; 8, 11-epoxy-9(15)-himachaladiene-4-ol (O8-ophiocomane) and, 11-epoxy-9(15)-himachaladiene-4-ol (O7-ophiocomane) were isolated and characterized using appropriate techniques. Structure elucidation was estimated via 1D NMR, 2D NMR, FT-IR and mass spectroscopy analyses. The isolated compounds were tested for cytotoxic, antibacterial and antifungal activities. Pure compounds showed a dose dependent reduction in MCF-7 cells viability with LC50 of 103.5 and 59.5 μg/ml for compounds 1 and 2 respectively compared to the chemotherapeutic drug cisplatin (47.4 µg/ml). In vivo experiments showed that O. dentate extract significantly reduced tumor progression and improved hematological parameters and liver functions of tumor-bearing mice when administered either before or after tumor cells’ injection. The most remarkable antimicrobial effects of O. dentate crude extract were against Staphylococcus aureus, Vibrio damsela and Pseudomonasaeruginosa while the pure compounds showed activity against P. aeruginosa alone. Neither the crude extract nor the pure compounds have shown activity against Aeromonas hydrophila. These results indicates that O. dentata extract and newly isolated compounds have shown a promising cytotoxic, antiproliferative and antimicrobial activities that might be useful for pharmaceutical applications.

Marine natural products

“…A Red Sea, Egypt collection of the brittle star Ophiocoma dentata afforded two sesquiterpene ethers 1470 and 1471 . 599 The metabolites isolated from starfish are usually either ceramides/cerebrosides or steroid derivatives. A total of six new lipids, ceramides 1472 – 1474 and cerebrosides 1475 – 1477 , were isolated from extracts of a Far Eastern collection of the orange cookie starfish Ceramaster patagonicus .…”

Recent advances in therapeutic targets identification and development of treatment strategies towards Pseudomonas aeruginosa infections

“…Moreover, naturally derived hydroquinone has been found to rapidly disrupt the cell membrane, increase permeability and provoke leakage of intracellular potassium ions in P. aeruginosa MTCC 741 [ 95 ]. Furthermore, the marine organism brittle star Ophiocoma dentata crude extract and derived sesquiterpenoids molecules 8,11-epoxy-9(15)-himachaladiene-4-ol(O8-ophiocomane) and 11-epoxy-9(15)-himachaladiene-4-ol (O7-ophiocomane), exert noticeable antimicrobial effects against P. aeruginosa [ 96 ]. It is worth noting that human body naturally produces antimicrobial peptides that can combat infections driven by bacterial pathogens.…”

Fatty Acids of Echinoderms: Diversity, Current Applications and Future Opportunities

“…Two new sesquiterpenoids isolated from the brittle star Ophiocoma dentata have exhibited cytotoxic and anti-proliferative activities against the MCF-7 cell line and in Ehrlich tumor-bearing mice. The extract from this brittle star have also shown antimicrobial activities against several human bacterial pathogens [ 21 ]. The presence of sulfated steroids in brittle stars and starfish is an indicator of the phylogenetically close relationship between these two classes of echinoderms [ 22 ].…”