Abdolhossein Rustaiyan

Terpenes are present in the essential oils obtained from herbs and spices. They are produced by these plant species as a chemical defense mechanism against phytopathogenic microorganisms. Therefore, terpenes have attracted great attention in the food industry, e.g., they have been used in foods such as cheese as natural preservatives to prevent fungal growth. Herein, we describe the microbial transformation of onopordopicrin (1) by Aspergillus niger. Four product 11α H-dihydroonopordopicrin (2), 11β H-dihydroonopordopicrin (3), 3β-hydroxy-11β H-dihydroonopordopicrin (4), and 14-hydroxy-11β H-dihydroonopordopicrin (5) were obtained. Their structures were identified on the basis of chemical and spectroscopic data. All the four compounds were novel.

Water-distilled essential oils from the aerial parts of Micromeria persica Boiss., leaves and stems of Hymenocrater platystegius Rech. f., which are endemic to Iran, and the aerial parts of Scutellaria pinnatifida A. Hamilt. subsp. pinnatifida were analyzed by GC and GC/MS. Twenty-four components representing 96.1% of the oil of M. persica were identified of which linalool (15.2%), α-pinene (15.0%) and (E)-nerolidol (13.8%) were found to be the major constituents. Seventeen compounds representing 91.7% of the leaf oil and 10 compounds representing 90.7% of the stem oil of H. platystegius were identified. Both oils were rich in α-pinene (16.7% and 18.6%, respectively) and spathulenol (17.1% and 17.9%, respectively). The other main component of the leaf oil was 1,8-cineole (12.9%), and of the stem oil, cis-calamenene (11.2%). Methyl chavicol (81.9%) was the main component among the 11 constituents characterized in the oil of S. pinnatifida representing 100% of the total components detected.

The water distilled essential oils from aerial parts of three Artemisia species: A. kermanensis Podl., A. kopetdaghensis Krasch., M.Pop. et Lincz. ex Poljak., and A. haussknechtii Boiss. have been analyzed by a combination of GC and GC/MS. The oil of A. kermanensis and A. kopetdaghensis were rich in davanone (21.4% and 47.9%, respectively). The other main components of the oil of A. kermanensis were 1,8-cineole (16.0%) and chrysanthenone (14.8%), whereas geranial (6.5%) and ethyl nerolate (6.3%) were the other considerable compositions of A. kopetdaghensis. In the oil of A. haussknechtii, 1,8-cineole (16.5%), camphor (14.5%) and artemisia ketone (10.5%) were found to be the major constituents.

Water-distilled essential oils from the aerial parts of three Stachys species: S. asterocalyx Rech. f., S. obtusicrena Boiss., which are endemic to Iran, and S. multicaulis Benth. were analyzed by GC and GC/MS. The major components of the oil of S. asterocalyx were α-bisabolol (25.1%) and linalool (18.0%). In the oil of S. obtusicrena, α-pinene (34.6%), germacrene D (8.0%) and bicyclogermacrene (7.8%) were found to be the major constituents. Bicyclogermacrene (23.0%), spathulenol (20.7%), germacrene D (12.4%) and caryophyllene oxide (11.1%) were the predominant compounds in the oil of S. multicaulis.

The composition of the essential oils from the aerial parts of three Labiatae species of Iran: Teucrium persicum Boiss., Thymus caucasicus Willd. ex Ronniger subsp. grossheimii (Ronniger) Jalas. and Marrubium crassidens Boiss. obtained by hydrodistillation were analyzed by GC and GC/MS. epi-α-Cadinol (23.2%) and α-pinene (17.3%) were the main components among the thirty-one constituents characterized in the oil of Teucrium persicum representing 95.9% of the total components detected. Seventeen compounds were identified in the oil of Thymus caucasicus representing 99.6% of the total oil with thymol (34.2%), methyl chavicol (25.1%) and γ-terpinene (12.7%) as the major constituents. The oil of Marrubium crassidens was characterized by higher amount of β-caryophyllene (20.3%), germacrene D (12.9%), caryophyllene oxide (11.1%) and cubenol (11.0%) among the fourteen compounds comprising 91.7% of the total oil detected. The oils (Teucrium persicum and Marrubium crassidens) consisted mainly of sesquiterpenes, while in Thymus caucasicus oil monoterpenes predominated over sesquiterpenes.

Water distilled essential oils from aerial parts of Nepeta sessilifolia Bunge, and Nepeta haussknechtii Bornm. were analyzed by GC and GC/MS. Thirty-three compounds representing 97.4% of the oil of N. sessilifolia, and 27 compounds representing 94.2% of the oil of N. haussknechtii were characterized. The major components of the essential oil of N. sessilifolia were linalool acetate (14.7%) and linalool (14.2%), whereas the major components of the oil of N. haussknechtii were 1,8-cineole (36.7%) and elemol (11.4%). Both oils were richer in oxygenated monoterpenes than sesquiterpenes.

The essential oils obtained by hydrodistillation from the flowers, leaves, stems and roots of Hypericum perforatum L. growing wild in the Northeast of Iran were investigated by GC and GC-MS. The major constituents of the flower and leaf oils appeared to be α-pinene (36.0 % and 14.5 %), β-selinene (10.1 % and 25.4 %) and α-selinene (10.0 % and 13.5 %), respectively. The other main component in the flower oil of the plant was β-pinene (15.5 %). Germacrene D (37.8 % and 22.2 %) was the predominant compound in the stem and root oils, respectively.

Water-distilled essential oils from the aerial parts of Tanacetum elburensis Mozaff. and Tanacetum persicum (Boiss.) Mozaff. were analyzed by GC and GC/MS. Thirty-one compounds representing 90.7% of the oil of T.elburensis were identified, among which menthyl isovalerate (20.0%) and 1,8-cineole (16.6%) were the major. The oil of T.persicum was characterized by higher amounts of borneol (24.3%), menthyl acetate (17.3%), isobornyl2-methyl butyrate (16.0%) and artedouglasia oxide D (14.3%) among the twenty-two components comprising 91.8% of the total oil detected. Both oils were richer in oxygenated monoterpenes than sesquiterpenes.

The essential oils obtained by hydrodistillation of the flowers, stems and leaves of Astragalus schahrudensis Bge, endemic in Iran, were analazed by GC and GC/MS. Seventeen compounds representing 96.6% of the flower oil of A. schahrudensis were identified; among them, germacrene D (47.6%) and germacrene B (17.8%) were the major ones. The stem oil was characterized by higher amount of β-selinene(29.4%),δ-guaiene (21.7%), α-guaiene (13.4%) and α-selinene (10.9%) among the 14 components comprising 94.6% of the total oil detected. Eighteen compounds representing 97.3% of the leaf oil of the plant were identified; among them, α-pinene (33.8%) bornyl acetate (14.2%), limonene (12.2%) and α-fenchyl acetate (10.0%) were the major ones. The flower and stem oils of A.schahrudensis consisted mainly of sesquiterpenes, while in leaf oil monoterpenes predominated over sesquiterpenes.