Biologically active sponge metabolites from Canary Islands

Abstract

The marine sponge Myxilla sp from Canary Islands is a rich source of steroids. The compounds where identified as stigmast-5-en-3β-ol (β-sitosterol) (75%), stigmast-5,25-dien-3β-ol (7%), stigmast-5,24(25)- dien-3β-ol (2%) and stigmast-5,23-dien-3β-ol (16%). The mixture of stigmasterols has the aspect of a white solid, is homogeneous by TLC and shows the physical properties as the main β-sitosterol: m.p. 277-278ºC, [α]D25ºC = -15,2º (c 0,2; CHCl3). Myxilla sp is also a rich source of pyrimidines and ceramides. The compounds where identified as uracil, thymine, a ceramide mixture and a ceramide-1-phosphate mixture. The 1:1 mixture of pyrimidines has the aspect of a white solid and is homogeneous by TLC. Although it had been isolated from sponges from Indonesia, this is the first time described for the genus Myxilla. The ceramide-1-phosphate mixture has the aspect of a white solid and also is homogeneous by TLC (Rf in agreement with the bibliography). The structures were confirmed by HRMS, HPLC-MS and two-dimensional nuclear magnetic resonance spectroscopy (COSY, NOESY, HSQC and HMBC). The marine sponge Ircinia sp from Canary Islands is a rich source of sesterterpenes. The compounds where identified as (8Z,13E,18R,20Z)-strobilinin and (8E,13Z,18R,20Z)-strobilinin. The mixture of strobilinins has the appearance of oil and is homogeneous by TLC. In 13C-NMR spectroscopy we can see a doubling of signals of the carbons 8 (δ 134.5/ 135.1), 10 (δ 123.5/ 124.5), 13 (δ 134.9/ 135.7) and 15 (δ 123.9/ 125.1), which informs us that the marine natural product is a mixture of the stereoisomers (8Z, 13E) and (8E, 13Z), in agreement with the described in bibliography. The structures were confirmed by HRMS, and two-dimensional nuclear magnetic resonance spectroscopy (COSY, HSQC and HMBC). The marine sponge Verongia aerophoba from Canary Islands is a rich source of bromotyrosine derived cytotoxics. To obtain enough of the bioactive compounds for application in human therapy, sponges have to be cultured. Before sponge mariculture is accepted as a commercially viable method of supplying bioactive metabolites, it must be demonstrated that adequate production of sponge biomass and metabo- lite is possible. In this study we provide recent data related with both aspects. Sponge growth rates have been measured in terms of projected area, and the production of three main metabolites (11R,17R-epi- Fistularin-3, Verongiolide and Verongic Acid) in diferent culture conditions in fish farm effluents have been measured by HPLC (reverse phase, methanol/ water as eluent). The results show that the bioprocess is feasible. The progresses towards quantification of cytotoxic and antileukemic factors (Aeroplysininnone) also will be presented.