Estudo ficoquímico da alga marinha Sargassum vulgare var. nanum E. de Paula (Sargassaceae) do litoral paraibano

Abstract

Sargassum is a genus of brown seaweeds from the family Sargassaceae and is represented by 150 species. The literature reports the presence of alginates, phlorotanins, coumarins, chromones, quinones, phaeophitins and terpenoids. The metabolites produced by algae of the genus Sargassum show biological activities such as anticoagulant, antioxidant, antipyretic and analgesic. The objective of this study was to present phycochemical study of the species Sargassum vulgare var. nanum E. de Paula. The material was collected on the beach in Coqueirinho, Conde- PB, then was washed and lyophilized. The dried powder (841.19 g) was extracted by maceration with ethanol 96 oG.L, obtaining the crude extract (56.96 g) was dissolved in a solution H2O-MeOH (7:3) and partitioned with ethyl ether, dichloromethane and ethyl acetate. The ether extract (17.04 g) was subjected to silica gel chromatography column eluting with hexane, dichloromethane and ethyl and MeOH pure or in binary mixtures. The combined fractions (75-93) were subjected to chromatography with Sephadex LH-20 eluted with CH2Cl2-MeOH (1:1). The purified fraction Sv-1 was identified as fucosterol, the first reported in this specie. Other fractions (119-121 and 135.1) were subjected preparative thin layer chromatography (PTLC) with AcOEt-Hexane (25:75) and (40:60) to afford mixture -(132)-(R) and (132)-(S)-132-hydroxy-phaeophytin-a encoded as Sv-2 and 151-hydroxy-(151-S)-porphyrin lactone encoded as Sv-3. The R isomer of 132-hydroxy-phaeophytin-a is first reported in the genus and S isomer for the first time in this specie, while the porphyrin lactone is first reported in the family Sargassaceae. Structural elucidations were carried out based on the analysis of their 1H NMR and 13C NMR spectra and and on the basis of literature data.