| In the present study, four marine organisms were investigated for their organic constituents. The organisms were extracted and purified by chromatographic separation using a combination of isolation methods. Each compound isolated was fully characterized by spectroscopic data and physicochemical properties, in particular, NMR results (1D and 2D) were carefully analyzed and compared with the literature data.; The present investigation has led to the isolation of twenty-four organic compounds from an ethanol extract prepared from the soft coral Nephthea chabroli. These compounds can be catalogued into six types based on their skeletons: polyhydroxylated steroid, ceramide, fatty acid, glycoside, diterpene and norditerpenes, quinolone. Nine of the compounds are new. They include 24-methylcholesta-9(11), 24 (28)-diene-3β,12α,19-triol, 4α-methyl-3β,14β-dihydroxy-5α-ergost-24(28)-en-23-one, chabrolones A and B, and chabrolols A to E. Norditerpenes (chabrolone A, chabrolol E, chabrolol A, chabrolol B, and chabrolol C) possessing the chabrolol skeleton have not been found in the nature previously.; A further thirteen organic constituents were isolated and identified from an ethanol extract prepared form the sponge Geodia japonica. Of these, three are newly reported structures. They are geoditin A, geoditin B, and 26-methylergosta-5,24(28)-dien-7-one-3β-ol. The ten known constituents are stellettin A, stellettin B, cyclo (S-leu-S-pro), uracil, thymine, allopuriol, 26-methylergosta-5,24(28)-dien-3β-ol, 24-methylcholesta-5,24(28)dien-3β-ol, malonic acid and hexadecanoic acid.; An ethanol extract of the red alga Galaxaura sp. was purified by chromatography and recrystallization to afford eleven organic constituents. Of these, methyl cycloart-24-en-23-one-3β-ol-29-oate, methyl 23(E)-25-methoxycycloart-23-en-3β-ol-29-oate, methyl 23(E)-cycloart-23,25-dien-3β-ol-29-oate, 23( E)-25-methoxy-cycloart-23-ene-3β,29-diol, cycloart-24-ene-3β, 23, 29-triol, galaxaurol, and galaxauratin are new natural products. The other four known compounds are 23(E)-25-methoxycycloart-23-en-3β-ol, hexadecanoic acid, (24R)-stigmast-5-en-3β-ol and 3-O-α-L-arabinopyranosyl-28-O-[α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranosyl] hederagenin.; Finally, seven organic constituents were isolated from an ethanol extract prepared from the mangrove plant Acanthus ilicifolius. They were identified as 2-benzoxazolinone, acanthicifoamide, luteolin, stigmasta-5,22-dien-3β-ol and stigmasta-5,22-dien-3-O-β-D-glucopyranoside, glucose and ethyl glucoside. Of these only acanthicifoamide is a newly reported structure. |
