The genus Ajuga, belonging to Lamiaceae family (Ajugoideae subfamily) comprises about 90 species mostly distributed in the Northern temperate areas of Europe, Asia, America, Africa and Australia. In Italy, seven species belonging to this genus are present: A. orientalis L., A. tenorei C. Presl., A. pyramidalis L., A. genevensis L., A. reptans L., A. chamaepitys (L.) Schreb. and A. iva (L.) Schreb. In this study, we report the comparison of the secondary metabolites pattern observed in A. chamaepitys, A. genevensis and A. tenorei with a particular attention to iridoids as chemosystematic markers at family and genus level. These three species have different morphological characters and colonize areas with different pedoclimatic conditions [1]. In particular, A. chamaepitys has linear leaves, yellow flowers and lives on dry calcareous soils with neutral/alkaline reaction. A. genevensis has, instead, oblanceolate-crenate leaves with blue flowers and prefers a calcareous-siliceous soil with neutral/alkaline reaction. Lastly, A. tenorei is an endemic species of central-southern Italy growing in calcareous stony pastures of mountain belts up to 2200 m a.s.l. with leaves in a basal rosette. The chemosystematic markers ajugoside (1), harpagide (2) and 8-O-acetylharpagide (3) were recognized in A. tenorei [2] and A. chamaepitys [4] which showed also the presence of reptoside (4), two new diglycosidic derivatives of harpagide (5,6) and asperulosidic and deacetyl-asperulosidic acids (7, 8). These compounds are, indeed, more typical of Rubiaceae and have been rarely observed in Lamiaceae before [3]. Conversely, iridoids were not recognized in A. genevensis where rosmarinic acid (9) resulted to be the main component and was found with oleanolic (10) and maslinic (11) acids [4]. The phytochemical comparison revealed a marked variability among these species which may be related to their evolution and adaption to different habitats and might be the starting point for new studies with a multidisciplinary approach involving morphology, phytochemistry and molecular biology, in the taxonomy of Lamiaceae and, in particular, of Ajugoideae subfamily.
Secondary metabolites variability among selected species of Ajuga genus
F. Maggi;K. CIanfaglione;NICOLETTI, ELETTRA MARIA;
2017-01-01
Abstract
The genus Ajuga, belonging to Lamiaceae family (Ajugoideae subfamily) comprises about 90 species mostly distributed in the Northern temperate areas of Europe, Asia, America, Africa and Australia. In Italy, seven species belonging to this genus are present: A. orientalis L., A. tenorei C. Presl., A. pyramidalis L., A. genevensis L., A. reptans L., A. chamaepitys (L.) Schreb. and A. iva (L.) Schreb. In this study, we report the comparison of the secondary metabolites pattern observed in A. chamaepitys, A. genevensis and A. tenorei with a particular attention to iridoids as chemosystematic markers at family and genus level. These three species have different morphological characters and colonize areas with different pedoclimatic conditions [1]. In particular, A. chamaepitys has linear leaves, yellow flowers and lives on dry calcareous soils with neutral/alkaline reaction. A. genevensis has, instead, oblanceolate-crenate leaves with blue flowers and prefers a calcareous-siliceous soil with neutral/alkaline reaction. Lastly, A. tenorei is an endemic species of central-southern Italy growing in calcareous stony pastures of mountain belts up to 2200 m a.s.l. with leaves in a basal rosette. The chemosystematic markers ajugoside (1), harpagide (2) and 8-O-acetylharpagide (3) were recognized in A. tenorei [2] and A. chamaepitys [4] which showed also the presence of reptoside (4), two new diglycosidic derivatives of harpagide (5,6) and asperulosidic and deacetyl-asperulosidic acids (7, 8). These compounds are, indeed, more typical of Rubiaceae and have been rarely observed in Lamiaceae before [3]. Conversely, iridoids were not recognized in A. genevensis where rosmarinic acid (9) resulted to be the main component and was found with oleanolic (10) and maslinic (11) acids [4]. The phytochemical comparison revealed a marked variability among these species which may be related to their evolution and adaption to different habitats and might be the starting point for new studies with a multidisciplinary approach involving morphology, phytochemistry and molecular biology, in the taxonomy of Lamiaceae and, in particular, of Ajugoideae subfamily.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
