Essential oils from leaves, stems and ripened seed capsules of Hypericum undulatum

Hypericum undulatum Willd. (Guttiferae) is a common herb in Portugal, growing in wet places and in the riverside edges. The phenolic extracts of leaves and aerial parts of this species have already been studied, showing the presence of hypericin, quercetin, quercetin sulphate, rutin, mangiferin, chlorogenic acid [1; 2]. However studies of its volatile component are scarce. The essential oils were obtained by hydrodistillation of a small amount of fresh leaves, stems and ripened seed capsules harvested in September. More than 40 compounds were detected in the leaves and ripened seed capsules, while in the stems 20 compounds were detected. The compounds were identified by GC-MS and quantified by GC. Excepting for the stems, in which there wasn't any oxygenated compound, the identified compounds in the essential oils from all samples distributed by monoterpene hydrocarbons (MH), oxygenated monoterpenes (MO), sesquiterpene hydrocarbons (SH), oxygenated sesquiterpenes (SO) and alkanes. The most complex essential oils were those obtained from leaves. In both leaves and ripened seed capsules the major compound group was the sesquiterpene hydrocarbons. However, in both essential oils, the major compound was an n-alkane (n-nonane). Caryophyllene oxide and globulol were the two major oxygenated-sesquiterpenes in those two samples. n-Nonane was also the most represented in the stem essential oils, the major group of compounds being n-alkanes. β-Pinene, a monoterpene hydrocarbon, was also well represented in the three samples.

References : 1. Seabra, R.M. et al. (1991), Rev. Port. Farm. 12: 16–18. 2. Seabra, R.M. et al. (1992), Fitoterapia 68: 473–474.