Studies on chemical constituents of Gracilaria verrucosa.

A new sterol glucoside, (24R)-5 alpha-stigmast-9-(11)-en-3beta-D-glucopyranoside (1) has been isolated from a methanol extract of the red alga Gracilaria verrucosa, while cholesterol and (Z)-9-hexadecenoic acid (palmitoleic acid) have been isolated from a dichloromethane-acetone extract of the same alga. Additionally, an oily fraction of a dichloromethane-acetone extract has been investigated by gas chromatography/mass spectrometry (GC/MS). The main components in the oily fraction were heneicosanoic acid (49.8%), (Z)-9-octadecenoic acid (15.8%), and 15-tetracosenoic acid (15.6%) in addition to a few hydrocarbons, simple aromatics and a new compound, namely 3,4-dimethyl-5-carboxyclic acid-1-oxacyclopent-3-en-2-one. The structures of the isolated compounds have been elucidated by spectroscopic methods.