Sterols from sponges of Anavilhanas

Sponges present a wide variety of metabolites, and are considered one of the hotspots in research on the chemistry of natural products. Sterols from sponges have received attention because they present patterns of branches that distinguish them from all other living organisms. Freshwater sponges, native to rivers and lakes, have been studied chemically throughout the world, but there have been no studies on sponges from the Amazon region. The present work describes the sterols present in freshwater sponges collected in Anavilhanas, the world's second largest river archipelago, in the Negro river (Amazonas-Brazil), focussing on species whose family has not been studied previously in regard to their chemistry of natural products. Using a set of derivatization reactions for identification by chromatographic and spectrometric techniques, it was observed that the steroid extracts of sponges of the species Metania reticulata, Drulia browni and Drulia uruguayensis (Metaniidae) present 24-ethyl-cholest-5,22-dien-3β-ol as the principal sterol. Cholesterol, the main sterol in Spongillidae and Lubomirskiidae, was already detected but as a minor component along with three other sterols.