[GC-MS analysis of essential oils from four Vitex species].

The chemical constituents of the essential oils obtained from the leaves of Vitex negundo var. cannabifolia, V. negundo var. heterophylla, V. negundo and V. trifolia were analysed by GC-MS. Forty compounds including alpha-pinene, linalool, terpinyl acetate, beta-caryophyllene and caryophyllene oxide, etc. were identified. Their percentages in oils were given.