Abstract: To investigate the volatile components in the leaves and twigs of Machilus thunbergii and Machilus yunnanensis, seedlings from the nursery of Nanning Liangfengjiang National Forest Park in Nanning City, Guangxi Zhuang Autonomous Region, were used as materials. The leaves and one-year-old twigs were collected, and the volatile components were extracted using the n-hexane immersion method, followed by analysis via gas chromatography-mass spectrometry (GC-MS). The results showed that the components with the highest relative content in Machilus thunbergii leaves, Machilus thunbergii twigs, Machilus yunnanensis leaves, and Machilus yunnanensis twigs were β-elemene (10.49%), β-eudesmol (16.60%), tetracosane (11.22%), and δ-cadinene (9.88%), respectively. The relative content of terpenoids was dominant in both the leaves and twigs of Machilus thunbergii, accounting for 74.82% and 77.29%, respectively. The leaves had a higher relative content of aromatic hydrocarbons (11.05%), while the twigs had a higher relative content of alcohols (18.94%). The relative content of terpenoids in Machilus yunnanensis leaves was 38.78%, which was significantly lower than that in Machilus thunbergii leaves, Machilus thunbergii twigs, and Machilus yunnanensis twigs. However, the relative content of alkanes was higher (27.51%), and it also contained a considerable amount of alcohols, ketones, and esters. The relative contents of terpenoids, alkanes, and organic acids in Machilus yunnanensis twigs were relatively high, at 57.50%, 20.52%, and 15.88%, respectively. The leaves and twigs of both Machilus thunbergii and Machilus yunnanensis contained abundant volatile components, and the relative contents of these components varied among different tree species and different plant parts.

Key words: Machilus thunbergii, Machilus yunnanensis, leaves, twigs, volatile components, gas chromatography-mass spectrometry (GC-MS)