Natural products of algae Gelidium spp. and its applicability in the pharmaceutical, cosmetic and nutraceutical sector

Abstract

Gelidium canariensis [G. canariense (Grunow) Seoane Camba ex Haroun, Gil-Rodríguez, Díaz de Castro & Prud'homme van Reine] (family Gelidiaceae, order Gelidiales)], is an endemic macroalga of the canarian shore. It is known that the algae from genus Gelidium produce allomonas, but these are not elucidated jet from a chemical point of view. The mollusk Aplysia kurodai gets nourished well by eating Ulva pertusa, which contains phago-stimulators but rejects Gelidium amansii which is supposed to contain phago-rejecting metabolites. These metabolites induce movements – response in their jaw and radula. On the other hand, the extract of Gelidium latifolium inhibits a variety of bacteria taken from its marine environment as they have anti-fouling factors. With this background, in present study it was proposed to increase the chemical knowledge of the species G. canariensis, the aim is to study later the possible interactions of its metabolites with its main grazers that live in its ecosystem, principally sea urchins Arbaxia lixula and Paracentrotus lividus. Through maceration of pieces of the marine alga G. canariensis with acetone followed by filtration and concentration a dark syrup of raw extract of alga was obtained. With chromatographic column consecutive fractions of ascending polarity were obtained, eluted with mixtures of hexane/ acetone/ methanol. Pure metabolites, as well as its acetylated derivatives, were purified by preparative TLC and identified by spectroscopic methods (NMR, mass spectrometry, etc.). Among the isolated metabolites, aldehydic compounds and free fatty acids were present, like hexadecanoic acid (= palmitic acid) and octadecaenoic acid (=oleic acid). Right a mixture of two of the compounds of the last mentioned group (hexadecanoic acid and octadecaenoic acid) has been proposed recently as the responsible allomona for anti-fouling activity of the red alga Laurencia brandenii. Also in Gelidium serrulatum fatty acids and sterols were found recently which are supposed to be responsible of its antifouling activity.