摘要：The composition of the leaf oils, obtained by hydrodistillation, of five endemic Psiadia species of the Asteraceae family were studied by GC/MS on both polar and non-polar columns. The analysis showed that the volatile components of the oils were made up essentially of monoterpenes, sesquiterpenes, aliphatics and other shikimic acid derivatives. With respect to the non-volatile components, great variations were observed: P. lithospermifolia contained ( E )-isoasarone (51.5%); P. penninervia : eugenol (5.1%); P. terebinthina : eugenyl-acetate (4.0%); P. viscosa : pentyl-4-(1-methylethyl benzoate) (25.8%); P. arguta : isoeugenol (56.5%). In vitro antimicrobial assays using the agar-well diffusion method, revealed that most of the oils were not very active against the tested microorganisms except for that of P. lithospermifolia , which significantly inhibited the growth of Bacillus cereus , Staphylococcus aureus and Pseudomonas aureofaciens , Aspergillus ochraceus , Candida pseudotropicalis , Kluyveromyces lactis and Fusarium moniliforme . This activity has been attributed to the presence of δ-elemene, ( E )-farnesene, α-curcumene, selina-4,7(11)-diene, ( E , Z )-α-farnesene, β-bisabolene some of which have established antimicrobial profiles. Likewise, the fungi toxic action of the oil of P. arguta against Aspergillus ochraceus , Candida pseudotropicalis , and Fusarium moniliforme , may be attributed to the presence of isoeugenol, eugenol being known to be mycotoxic especially against Aspergillus species.
