Composition of the cloacal gland secretion of tuatara, Sphenodon punctatus

The lipophilic content of the cloacal gland secretion of the tuatara (Sphenodon punctatus) was investigated. GC/EI-MS Analysis of CH2Cl2 extracts of the secretions revealed triacylglycerols as major glandular constituents. Twelve major medium-chain fatty acids were found to be conjugated to glycerol in different combinations, resulting in complex mixtures. These acids were identified by transesterification and subsequent derivatization of natural samples, and their structures were verified by synthesis. The natural glycerides contain predominantly three of the following acids: octanoic (A), (E)- and (Z)-oct-4-enoic (B and C, resp.), (4E,6Z)-octa-4,6-dienoic (tuataric acid; D), (R)-2,6-dimethylheptanoic (E), (R)-2,6-dimethylhept-5-enoic (F), (Z)-dec-4-enoic (G), (4Z,7Z)-deca-4,7-dienoic (H), (R)-3,7-dimethyloct-6-enoic (I), (R)-4,8-dimethylnon-7-enoic (J), (2R,6S)-2,6,10-trimethylundec-9-enoic (K), and (2R,5E)-2,6,10-trimethylundeca-5,9-dienoic acids (L). Several additional acids, occurring in trace amounts only, were tentatively identified by MS. The elucidation of the absolute configuration of the acids was performed by GC on chiral phases. Individual tuatara show specific mixtures of glycerides with up to 100 components. The individual mixtures may permit individual recognition because the bouquets seem to be stable over years.