Crude extracts from specimens of the brown seaweed Dictyota menstrualis, known to produce diterpenes as their major secondary metabolites, were analyzed according to storage procedures before extraction, and the solvent types used to obtain the crude extracts. The specimens of D. menstrualis were submitted to three types of storage procedures, such as wet, dry, and frozen and were extracted with a mixture of dichloromethane:methanol (2:1) and acetone. Qualitative differences were not observed by GC/MS analyses of all crude extracts containing mainly the diterpenes pachydictyol A (I), 6-hydroxy-dichotoma-3,14-diene-1,17-dial (II), 6-hydroxy-2,7-cycloxenia-3,14-diene-1,17-dial (III), and 6-acetoxy-dichotoma-3,14-diene-1,17-dial (IV). The most efficient and selective extraction of the compounds with intermediate polarity produced by D. menstrualis was obtained using acetone, but with less mass production. In general, the storage procedures produced very similar results, but the frozen samples furnished low amount of total diterpenes. According to these results on chemical analysis of crude extracts of seaweeds, the choice of solvent to extraction should be considered as important aspect to better screening bioactive compounds.
Dictyota menstrualis; Gas chromatography; Crude extract; Chemical profile