To prove more information on the chemical composition of the essential oils of Thymus taxa collected in different Algeria areas, and to determine the effect of harvesting periods on the composition of these essential ...To prove more information on the chemical composition of the essential oils of Thymus taxa collected in different Algeria areas, and to determine the effect of harvesting periods on the composition of these essential oils： three Thymus species （T. numidicus, T.ciliatus and T. algeriensis） were collected during two periods of development, the EOs （essential oils） obtained by steam distillation of the aerial parts were analyzed by GC/MS （gas chromatography coupled with mass spectrometry）. During the pre-flowering stage, the RP% （relative percentage） of Eos varied between 1.00% and 1.34% for all the species. The content of EOs increased during the flowering stage and reached particularly 2.10% and 2.85% for T. numidicus （from Berrahal） and T. numidicus （from Tacha）, respectively. GC/MS analysis showed that these oils are very rich in oxygenated monoterpenes group （76.96%-82.11%） when the plants were harvested during the flowering stage of growth. Thymol was the major compound in the EOs contained in T. numidicus （Berrahal） and T. ciliatus with more than 39% and 54%, respectively. Thymus numidicus （Tacha） and T. algeriensis EOs were characterized by high content in p-cimene-7-ol （78.06% and 26.98%, respectively）. These two chemotypes （thymol and p-cimene-7-ol） are considered as antioxidant and antimicrobial agents providing the basis for many applications in processed food preservation and pharmaceutical products.展开更多
文摘To prove more information on the chemical composition of the essential oils of Thymus taxa collected in different Algeria areas, and to determine the effect of harvesting periods on the composition of these essential oils： three Thymus species （T. numidicus, T.ciliatus and T. algeriensis） were collected during two periods of development, the EOs （essential oils） obtained by steam distillation of the aerial parts were analyzed by GC/MS （gas chromatography coupled with mass spectrometry）. During the pre-flowering stage, the RP% （relative percentage） of Eos varied between 1.00% and 1.34% for all the species. The content of EOs increased during the flowering stage and reached particularly 2.10% and 2.85% for T. numidicus （from Berrahal） and T. numidicus （from Tacha）, respectively. GC/MS analysis showed that these oils are very rich in oxygenated monoterpenes group （76.96%-82.11%） when the plants were harvested during the flowering stage of growth. Thymol was the major compound in the EOs contained in T. numidicus （Berrahal） and T. ciliatus with more than 39% and 54%, respectively. Thymus numidicus （Tacha） and T. algeriensis EOs were characterized by high content in p-cimene-7-ol （78.06% and 26.98%, respectively）. These two chemotypes （thymol and p-cimene-7-ol） are considered as antioxidant and antimicrobial agents providing the basis for many applications in processed food preservation and pharmaceutical products.
