Chemical Composition and Antimicrobial Activity of the Essential Oil and Methanol Extract of Hypericum aegypticum subsp. webbii (Spach) N. Robson.

Hypericum aegypticum subsp. webbii is an evergreen shrub spread in Mediterranean part of central and southeastern Europe. The chemical composition and antimicrobial activity of the essential oil and MeOH extract of H. aegypticum subsp. webbii were investigated. The monoterpenes α-pinene (63.4 - 68.5%) and ß-pinene (16.9 - 17.0%) were main compounds in the volatile oil from aerial parts. In the cluster analysis, the essential oil of H. aegypticum subsp. webbii was separated and chemically different from the oil of other subspecies of H. aegypticum as well as other Hypericum species from Greece. SIMPER analysis revealed that α-pinene (24.79%) was the component that contributed the most to differences between all oils. Also, there was extremely high overall dissimilarity between three subspecies of H. aegypticum. MeOH extract of aerial parts of H. aegypticum subsp. webbii contained flavonoids rutin (56.4 ± 0.9 mg/g), hyperoside and quercetin, and phenolic acids chlorogenic and caffeic acid, while naphthodianthrones were not detected. The antimicrobial activity of essential oil was moderate (MIC from 100 to >200 µg/ml), while MeOH extract inhibited the growth of Gram-positive bacteria Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, and Micrococcus luteus (MIC 50 - 100 µg/ml), more pronounced than the extract of H. perforatum (MIC 200 - >200 µg/ml).

Variability of the root essential oils of Seseli rigidum Waldst. & Kit. (Apiaceae) from different populations in Serbia.

The chemical compositions of the essential oils of seven natural populations of Seseli rigidum were analyzed. The essential-oil yield ranged from 0.16 to 2.09%. Analysis of variance (ANOVA) revealed that there were no statistically significant differences in the mean essential-oil yields between the populations, and no significant influence of the climate or soil type on the oil yield was observed. In all 67 analyzed samples, the polyacetylene falcarinol was the main compound, followed by octanal, methyl linoleate, α-muurolene, 3-butylphthalide, falcarinone, muurola-4,10(14)-dien-1ß-ol, ß-sesquiphellandrene, salvial-4(14)-en-1-one, δ-amorphene, spathulenol, and isospathulenol. The principal component analysis (PCA), the canonical discriminant analysis (CDA), and the cluster analysis (CA) revealed differentiation between the populations based on the climate. Three groups of populations were formed; the first group was composed of samples growing in regions with a humid climate, with oils having high falcarinol and low sesquiterpene contents, and the second and third groups comprised samples exposed to semi-arid climate, with oils characterized by a lower falcarinol and higher α-muurolene, δ-amorphene, ß-sesquiphellandrene, and salvial-4(14)-en-1-one contents. The semi-arid populations were divided into two groups, which were distinguished based on the oil contents of sesquiterpenes, falcarinone, and 3-butylphthalide. On the other hand, no clear separation between populations based on the different soil types could be observed.

Environment-related variations of the composition of the essential oils of rosemary (Rosmarinus officinalis L.) in the Balkan Penninsula.

Composition of the essential oils of Rosmarinus officinalis of ten populations from the Balkan Peninsula were determined by GC/FID and GC/MS. The main constituents were 1,8-cineole, camphor, α-pinene, and borneol. Multivariate statistical analysis (UPGMA cluster analysis and principal-component analysis (PCA)) revealed two major types of rosemary oil, i.e., 1,8-cineole and camphor-type, and two intermediate types, i.e., camphor/1,8-cineole/borneol type and 1,8-cineole/camphor type. The regression analyses (simple linear regression and stepwise multiple regression) have shown that, with respect to basic geographic, orographic, and 19 bioclimatic characteristics of each population, bioclimatic factor temperature of habitat represented the dominant abiogenetic factor, which, in chemical sense, led to differentiation of populations in the studied region. Also, the regression analysis have shown that some constituents of essential oils are independent of any single bioclimatic factors. However, some constituents display statistically significant correlations with some abiotic factors.