The Ghirardi Botanical Garden : a “natural laboratory” for studying the morphological and phytochemical diversity of selected medicinal plants in an integrated ecological framework

The Botanical Garden “G.E. Ghirardi” (BGG, Toscolano Maderno - Brescia) of the Department of Pharmaceutical Sciences of the Milan University has a long tradition in the cultivation, study and preservation of the genetic resources of officinal species, in accordance with the priority tasks of the Convention on Biodiversity. Recently a dedicated research project started, integrating multidisciplinary analyses on target officinal species preserved at BGG, with the principal aim of characterizing these “plants” as interacting components of their own ecosystem. Indeed, the project was planned combining a dual perception: phytocentric, through the study of the biotic mutualistic interactions, mediated by the emission of secondary metabolites, and anthropocentric, referring to the potential importance to humans in the therapeutic, food and cosmetic sectors. The work program includes: (i) the census of the plant heritage preserved at BGG; (ii) the selection of target-species for the morphological characterization of the secretory tissues and for the analysis of phytochemical profiles; (iii) the analysis of the biological activities of the secondary metabolites; (iv) case-studies on their ecological and functional roles. In this perspective, BGG will represent a “natural laboratory” for studying the morphological and phytochemical diversity of officinal plants in an integrated ecological framework, aiming at assessing their importance for potential future exploitation by humans. As preliminary activities of the project, we addressed our interest towards a better understanding of the micro-morphology and anatomy of the secreting structures, and on the characterization of VOC and essential oil profile of target-species belonging to the Lamiaceae family: Ballota acetabulosa Benth., Ballota rupestris Vis., Lavandula angustifolia Mill., Lavandula dentata L., Salvia greggii Grey, Scutellaria sieberi Benth., Scutellaria altissima L. and Scutellaria brevibracteata Stapf. We report the results of the preliminary micromorphological observations on a) the structure and distribution of glandular tissues, b) the histochemical nature of the secreted substances, c) the mode of production and release of the secretory products. In addition, the VOC fingerprint and the characterization of essential oil produced in the glandular tissues are presented.