Chemical composition of Hypericum richeri subsp. grisebachii essential oil from Croatia.

The aerial parts of Hypericum richeri Vill. subsp. grisebachii (Boiss.) Nyman were collected from two different locations in Croatia and subjected to hydrodistillation. GC/FID and GC/MS analysis of the isolated essential oils revealed 64 compounds representing 94.7% and 98.2% of the total oils. Predominant constituents in both samples were: germacrene D (10.90%; 6.0%), bicyclogermacrene (4.7%; 3.5%), alpha-pinene (6.8%; 6.9%), beta-pinene (8.1%; 5.1%), decanoic acid (4.5%; 6.8%), beta-caryophyllene (3.3%; 7.5%), delta-cadinene (7.0%; 4.4%), spathulenol (6.0%; 9.5%) and tetracosane (3.1%; 5.8%). Comparison of both samples revealed similarity in the chemical composition with minor fluctuations of constituent percentages. The chemical profile of Croatian oils was in general similar to those reported for other geographic areas regarding major mono- and sesquiterpene constituents. However, spathulenol, delta-cadinene and bicyclogermacrene were more abundant in Croatian oils. The presence of decanoic acid (4.5%; 6.8%) in Croatian oils was the major difference between acids and fatty acids derivatives. Higher abundance of alkanes (particularly tetracosane and docosane) was also noticed.