The leaf essential oils of five Vietnamese Desmos species (Annonaceae).

The leaf essential oils of five Desmos species from Vietnam have been extracted by steam distillation and subjected to GC and GC-MS analyses. The plant samples were Desmos cochinchinensis Lour., D. penduculosus (A. DC.) Ban, D. penducolosus var. tonkinensis Ban, D. chinensis Lour., and D. dumosus (Roxb.) Saff. The oils were rich in sesquiterpene hydrocarbons (65.9%-88.9%) and monoterpene hydrocarbons (6.3%-30.9%). The oxygenated counterparts were less common. The quantitatively significant constituents of the oils were alpha-pinene (2.4%-12.1%), beta-elemene (2.2-39.5%), beta-caryophyllene (13.9-26.3%), germacrene D (9.9-15.5%), bicyclogermacrene (2.0-11.4%) and alpha-humulene (3.8-7.5%). The studied oils could be classified into two chemical forms: oils with abundance of beta-caryophyllene, germacrene D and alpha-pinene (D. cochinchinensis, D. penducolosus var. tonkinensis, D. chinensis and D. Dumosus) and oil with high amounts of beta-elemene, beta-caryophyllene and germacrene D (D. penduculosus).