Bioactividad de las esponjas marinas Cliona varians y Cinachyrella kuekenthali provenientes de Isla Larga, Bahía de Mochima, Estado Sucre, Venezuela

The marine sponges Cliona varians and Cinachyrella kuekenthali, were collected in Isla Larga, Mochima Bay, Sucre state, Venezuela, to study their bioactivity. Each sponge was extracted with ethyl acetate (EtOAc) and then a chemical screening and the following biological tests were performed: antibacterial, antifungal and lethality against nauplii I of Artemia salina crustacean. The presence of alkaloids, unsaturated sterols and coumarins was detected for both sponges, and also tannins and metilenketones for C. varians. Bioassays showed that extracts have very strong lethal or toxic activity against A. salina nauplii, with LC50 values less than 103 µg/ml at 24 h of larvae exposure. After chromatographic fractionation of the EtOAc soluble fraction from each sponge, the toxic effect of the C. varians subfractions was magnified, obtaining LC50 values below to 4 µg/ml. EtOAc extracts of these sponges showed no activity against fungi and bacteria used in this study; this behavior was maintained when fractioning C. varians; however, CV1 subfraction showed mild antibacterial activity against Listeria monocytogenes. The C. kuekenthali subfractions did not show antifungal activity, but showed antibacterial effect against Escherichia coli, Staphylococcus aureus, Salmonella enteristiti, Listeria monocytogenes, Bacillus cereus, Pseudomonas aeruginosa, Salmonella ephimurium and Enterococcus faecalis. These results suggest these sponges as a promising source for future investigations of drugs with antitumoral activity, especially C. varians.