Five new manoyloxide-type sesterterpenes were isolated from aerial parts of Salvia mirzayanii, a species endemic to Iran. The planar structures were established by means of 1D and 2D NMR and HRESIMS. Compounds 1-3 differed only in their configurations at C-13 and C-14. Assignment of relative and absolute configurations was achieved by NOESY experiments and by comparison of experimental and simulated ECD spectra of possible stereoisomers. The absolute configurations of 4 and 5 were established in a similar manner.
Dracocephalum kotschyi essential oils obtained by hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and solvent-free microwave extraction (SFME) were investigated by GC-FID (Gas Chromatography-Flame Ionization Detector) and GC-MS (Gas Chromatography-Mass Spectrometry). The percentage of oxygenated compounds was significantly increased from 62.52% in HD to 76.47% in MAHD, and 84.52% in SFME. Conversely, the monoterpene hydrocarbons were decreased from 30.84% in HD to 13.71% in MAHD, and 5.85% in SFME. The main compound in the essential oil obtained by HD is limonene, which accounted for more than 30% of the oil, while the percentage of this compound was reduced to 9.52% in MAHD, and 5.60% in SFME. The percents of other oxygenated compounds such as neral, geranial, geraniol, geranyl acetate, α-terpineol, trans-verbenol, carvon, and transcarveol were noticeably higher in microwave methods than those present in HD method. In aqueous medium, linear oxygenated monoterpenes may be converted to a monocyclic terpinyl cation, which it could lose a proton to give limonene. The main biosynthetic pathway of these compounds, as well as a possible route of their conversion into limonene, due to prolonged heating in the HD method, was proposed. The antimicrobial activity of D. kotschyi essential oils against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was evaluated by broth microdilution susceptibility manner. The most sensitive bacteria to these oils was found to be S. aureus with the lowest minimum inhibitory concentration value of 2 mg mL −1 for MAHD and SFME specimens. The results indicated that oils obtained by microwave methods were more active against S. aureus. ARTICLE HISTORY
Dracocephalum kotschyi is one of the medicinal and fragrant herbs that can be found in natural locations of mountainous areas. In this investigation the hydrodistilled essential oils obtained from aerial parts of two populations of D. kotschyi collected from Siahbisheh and Baladeh were analysed by capillary GC-FID and GC-MS. Essential oil analysis led to the identification of 48 compounds that represented 85.9 and 90.0% of the total oil compositions, respectively. As the major group of compounds, oxygenated monoterpens comprised 45.5 and 57.4% in the essential oils of compounds as the main group in the essential oils of Siahbisheh and Baladeh samples, respectively. Disagreement in the major contents of the essential oils of these two samples may be ascribed to differences in the ecological, climatic and genetically factors.
The hydrodistilled essential oils obtained from aerial flowering parts of Teucrium stocksianum ssp. stocksianum (TSS) and T. stocksianum ssp. gabrielae (TSG) from Iran were analyzed by capillary GC and GC/MS. The oil analysis of two subspecies led to the identification of 65 compounds that accounted for 93.3 and 95.1% of the total oil compositions, respectively. Sesquiterpenoids (52.9%) constituted the main compounds in the essential oil of TSS represented mainly by cis-sesquisabinene hydrate (12.0%), followed by epi-β-bisabolol (6.6%), guaiol (5.4%), and β-eudesmol (4.4%), whilst monoterpenoids (61.2%) were found to be the major components of the oil of TSG, represented by α-pinene (23.0%), β-pinene (13.0%), myrcene (6.3%), and sabinene (6.3%). The principal component in both subspecies, TSS and TSG, was α-pinene (22.0 and 23.0%, resp.) and β-pinene (6.5 and 13.0%, resp.). epi-α-Cadinol, myrcene, and sabinene, which were detected as principal compounds of TSG, were characterized in lower amounts (<1.5%) in the oil of TSS. Seven components were identified in the oil of TSS corresponding to 25.9% of total oil, which were totally absent in the oil of TSG, of which cis-sesquisabinene hydrate (12.0%), guaiol (5.4%), and β-eudesmol (4.4%) were in considerable amounts. Taxonomic position of the subspecies is discussed on the basis of phytochemical data.
Salvia macilenta Boiss. is a fragrant subshrub which grows wild in some regions of Iran. In this work, we contrasted essential oil contents and components of two wild populations under two different ecological situations (Kerman and Baluchistan Provinces, Center and South East of Iran, respectively). For the first time the antibacterial and the antimycotic properties of these essential oils were also evaluated against seven bacterial and fungal strains. The essential oils were isolated by hydrodistillation method and the chemical compositions of the samples were examined by GC and GC-MS. Kerman (K) specimen was found to be rich in α-pinene (29.0%), p-cymene (10.7%), veridiflorol (9.1%), α-eudesmol (8.7%), bornyl acetate (7.3%) with lesser concentrations of borneol (4.9%). Principal components were identified as α-eudesmol (35.6%), α-pinene (7.7%), bornyl acetate (7.6%), (E)-nerolidol (6.5%) and veridiflorol (5.9%) from Baluchistan (B) sample. Oxygenated sesquiterpenes were found to be the principal class of components in the oil of Baluchistan sample (53.0%) whereas monoterpene hydrocarbons were the main class in Kerman specimen (46.6%). The results demonstrated that the variety in the volatile compounds could be considered as chemotaxonomic importance and it may be ascribed to their different ecological and geographical source.
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