Structural and phytochemical investigation of the leaves of Ricinus communis

Ricinus communis L., also known as the castor oil plant, is a highly toxic species indigenous to the south-eastern Mediterranean. Leaf anatomy was investigated by light and electron microscopy (SEM and TEM). Histochemistry and composition of secondary metabolites, were also investigated. The amphistomatic leaves of R. communis are of simple structure with a single layered palisade parenchyma. They contain numerous idioblasts with crystals and present a strong positive reaction to histochemical reagents for terpenes, flavonoids, phenolics and alkaloids. Only a few protective trichomes appear on the adaxial epidermis. The phytochemical analysis of leaf extracts using UHPLC-HRMS and GC-MS confirmed the results of the histochemical tests and, among other metabolites, the flavonoids rutin, isoquercetin, and nicotiflorin, as well as the toxic alkaloid ricinine were detected.