Alkamides are the most abundant lipophilic constituents of Echinacea purpurea (L.) Moench (Asteraceae), a well-known medicinal plant, widely used as immunomodulant in the treatment and prevention of upper respiratory tract infections, such as common cold and influenza [1]. Over 20 alkamides were identified in Echinacea species, differing one from the other by the insaturation degree of the aliphatic chains. E. purpurea roots were found richer in alkamide content than aerial parts [2]. Recent studies suggested that alkamides are involved in the immunomodulatory, anti-inflammatory, and antiviral activity of the plant, due to their high bioavailability [3]. The role of bacterial endophytes in immunomodulatory activity of E. purpurea was recently evidenced, suggesting that it could originate from its endophytic communities [4]. In order to investigate the interaction between E. purpurea and its endophytic bacterial community and the role of microbiota on the secondary metabolite production, axenic in vitro E. purpurea plants were infected with a pool of bacterial strains isolated from the aerial compartment [5]. Roots and leaves of axenic and endophyte-infected plants were extracted with n-hexane, then the methanol soluble part of these extracts was subjected to a phytochemical study. In particular, the alkamide content was analysed by HPLC coupled to a photo diode array (PDA)/UV detection and electrospray ionization mass spectrometry (ESI-MS). A total of 15 different alkamides were identified comparing their HPLC elution orders, ESI-MS/MS, and PDA/UV spectra with data reported in the literature [6]. Root and leaf extracts displayed different alkamide profiles, with leaf extract showing more alkamide constituents. On the other hand, the alkamide chemical profiles were similar in control and infected plants for both root and leaf extracts. A relative estimation of the alkamide level revealed instead a major alkamide content in endophyte-infected roots and leaves, when compared to not-infected organs, leading to suppose that alkamide biosynthesis should be modulated by endophyte infection.
Chemical profile of alkamides in Echinacea purpurea axenic in vitro plants infected with their endophytic bacteria
De Leo Marinella;Bandeira Reidel Rose Vanessa;Pistelli Luisa;
2017-01-01
Abstract
Alkamides are the most abundant lipophilic constituents of Echinacea purpurea (L.) Moench (Asteraceae), a well-known medicinal plant, widely used as immunomodulant in the treatment and prevention of upper respiratory tract infections, such as common cold and influenza [1]. Over 20 alkamides were identified in Echinacea species, differing one from the other by the insaturation degree of the aliphatic chains. E. purpurea roots were found richer in alkamide content than aerial parts [2]. Recent studies suggested that alkamides are involved in the immunomodulatory, anti-inflammatory, and antiviral activity of the plant, due to their high bioavailability [3]. The role of bacterial endophytes in immunomodulatory activity of E. purpurea was recently evidenced, suggesting that it could originate from its endophytic communities [4]. In order to investigate the interaction between E. purpurea and its endophytic bacterial community and the role of microbiota on the secondary metabolite production, axenic in vitro E. purpurea plants were infected with a pool of bacterial strains isolated from the aerial compartment [5]. Roots and leaves of axenic and endophyte-infected plants were extracted with n-hexane, then the methanol soluble part of these extracts was subjected to a phytochemical study. In particular, the alkamide content was analysed by HPLC coupled to a photo diode array (PDA)/UV detection and electrospray ionization mass spectrometry (ESI-MS). A total of 15 different alkamides were identified comparing their HPLC elution orders, ESI-MS/MS, and PDA/UV spectra with data reported in the literature [6]. Root and leaf extracts displayed different alkamide profiles, with leaf extract showing more alkamide constituents. On the other hand, the alkamide chemical profiles were similar in control and infected plants for both root and leaf extracts. A relative estimation of the alkamide level revealed instead a major alkamide content in endophyte-infected roots and leaves, when compared to not-infected organs, leading to suppose that alkamide biosynthesis should be modulated by endophyte infection.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
