The effect of methyl jasmonate on triterpene and sterol metabolisms of Centella asiatica, Ruscus aculeatus and Galphimia glauca cultured plants Susana Mangas a , Merce ` Bonfill a , Lidia Osuna b , Elisabeth Moyano c , Jaime Tortoriello b , Rosa M. Cusido a , M. Teresa Pin ˜ol a , Javier Palazo ´n a, * a Laboratorio de Fisiologı ´ a vegetal, Facultad de Farmacia, Universidad de Barcelona, Avda. Diagonal 643, E-08028 Barcelona, Spain b Centro de Investigacio ´ n Biome ´dica del Sur (Xochitepec, Morelos), IMSS, Mexico c Departament de Cie `ncies Experimentals i de la Salut, Universitat Pompeu Fabra, Avda. Dr. Aiguader 80, E-08003 Barcelona, Spain Received 30 March 2006; received in revised form 16 June 2006 Available online 28 July 2006 Abstract Considering that exogenously applied methyl jasmonate can enhance secondary metabolite production in a variety of plant species and that 2,3-oxidosqualene is a common precursor of triterpenes and sterols in plants, we have studied Centella asiatica and Galphimia glauca (both synthesizing triterpenoid secondary compounds) and Ruscus aculeatus (which synthesizes steroidal secondary compounds) for their growth rate and content of free sterols and respective secondary compounds, after culturing with or without 100 lM methyl jasmonate. Our results show that elicited plantlets of G. glauca and to a higher degree C. asiatica (up to 152-times more) increased their content of triterpenoids directly synthesized from 2,3-oxidosqualene (ursane saponins and nor-seco-friedelane galphimines, respectively) at the same time as growth decreased. In contrast, the free sterol content of C. asiatica decreased notably, and remained practically unal- tered in G. glauca. However, in the case of R. aculeatus, which synthesizes steroidal saponins (mainly spirostane type) indirectly from 2,3- oxidosqualene after the latter is converted to the plant phytosterol-precursor cycloartenol, while the growth rate and free sterol content clearly decreased, the spirostane saponine content was virtually unchanged (aerial part) or somewhat lower (roots) in presence of the same elicitor concentration. Our results suggest that while methyl jasmonate may be used as an inducer of enzymes involved in the tri- terpenoid synthesis downstream from 2,3-oxidosqualene in both C. asiatica and G. glauca plantlets, in those of C. asiatica and R. acule- atus it inhibited the enzymes involved in sterol synthesis downstream from cycloartenol. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Centella asiatica; Ruscus aculeatus; Galphimia glauca; Elicitation; Triterpenes; Ursane saponins; Spirostane saponins; Galphimine-B; Phyto- sterols 1. Introduction Perhaps one of the most diverse groups of plant second- ary metabolites are terpenoids, which are also found in microorganisms and animals. Included in this group are the triterpenes (C 30 ) and sterols (C 18 –C 29 ), whose structur- ally diverse molecules proceed from a common precursor, the squalene. Metabolic pathways originating from squa- lene form an extensive net of compounds with defined branching points that diversify the end products, including compounds with primary roles in membrane architecture (sterols such as sitosterol, stigmasterol and campesterol) as well as a variety of secondary metabolites specific to each plant species (Grunwald, 1980; Seigler, 1998). Centella asiatica (L.) Urban is a herbaceous plant with great medicinal value belonging to the Apiaceae family. Notable bioactive compounds of C. asiatica are the triter- pene saponins madecassoside and asiaticoside, with their respective ursane type sapogenins madecassic and asiatic acid. As shown in Fig. 1, these compounds, referred to as centellosides, proceed from the cyclisation of 2,3-oxido- squalene by a specific oxidosqualene cyclase (OSC), b-amy- rin synthase. 0031-9422/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2006.06.025 * Corresponding author. Tel.: +34 934024493; fax: +34 934029043. E-mail address: javierpalazon@ub.edu (J. Palazo ´n). www.elsevier.com/locate/phytochem Phytochemistry 67 (2006) 2041–2049 PHYTOCHEMISTRY