Long-chain wax esterns and diphenylamine in fire coral Millepora dichotoma and Millepora platyphylla from Saudi Red Sea Coast

Abstract

The characterization of the non-protein constituents of two species of fire corals Millepora dichotoma and Millepora platyphylla, exhibits very interesting results. The compounds were identified by gas chromatography-mass spectrometry (GCMS) and nuclear magnetic resonance (NMR) spectroscopy. The solvent extracts of the two species revealed four wax esters. The compounds were identified as C30H60O2, C32H64O2, C34H68O2 and C36H72O2 respectively. The presence of these compounds has been reported previously in different marine organisms as well as in marine samples. It is interesting that there were some variations in the number and nature of isomers of similar wax esters reported earlier. Long-chain wax esters are normally waxy in nature and their presence in fire coral plays a vital role in the nutrient transfer to the coral mass. They may also act as a protective coating of the nematocyst of dactylozooid. The coral species were also subjected to mild acidic hydrolysis, followed by neutralization and partitioning between water and ether. The organic phase was dried and purified by column chromatography and thin layer chromatography (TLC). Diphenylamine was revealed as the main product in one of the fractions. It is worth noting that diphenylamine is reported for the first time as a marine natural product. Diphenylamine is known to be toxic and causes allergic reactions to the skin, so it can be considered as responsible for the stinging property of fire coral.

Keywords

• long-chain wax esters
• diphenylamine
• solvent extraction materials
• acid hydrolysate products
• fire coral
• millepora dichotoma
• millepora platyphylla
• red sea