Composition of volatile fraction from inflorescences and leaves of Dendrobium moschatum (Orchidaceae).

The volatile fractions from fresh inflorescences and leaves of Dendrobium moschatum (Buchanan-Hamilton) Swartz (Orchidaceae) were isolated by steam distillation with a yield of 0.498% and 0.041% (weight/fresh weight basis), respectively. From GC/FID and GC/MS analyses, coumarin was identified to be the most abundant constituent and quantified as 48.8% and 47.8% of the total volatiles from inflorescences and leaves, respectively. Hydrocarbons, ketones, esters, acids and aldehydes were also detected. Long chain mono unsaturated hydrocarbons were quantified in higher amount in leaves and their structures were elucidated by GC/MS of their dimethyl disulfide derivatives. These compounds together with long chain ethyl esters and methyl ketones may represent a particular feature of this plant species and can play a critical role in the interaction with pollinator insect.