Authentication of Harpullia arborea (Blanco) Radlk. - a traditional medicinal plant from India using microscopic techniques

Abstract

Harpullia arborea (Blanco) Radlk., Sapindaceae, known as “black doll’s eyes” or “tulip tree” is a rainforest tree distributed in the tropical forests of peninsular India. Out of the 26 species of the genus, H. arborea is therapeutically more studied and widely used in folk and ayurvedic medicine. In this work, anatomical study of the leaves and stem of H. arborea was performed to provide a microscopical diagnosis for its characterization due to its increasing use in folk and ayurvedic medicine and its differentiation from other species with the same popular name. Standard light and scanning electron microscopy procedures were carried out using paradermal sections of leaf surfaces and transverse sections of lamina, midrib, and petiole. Stem preparations include longitudinal, radial and transverse sections of tertiary branches. The leaf epidermis with stellate non-glandular trichomes, cyclocytic stomata, mucilaginous cells and mesophyll without secretory sclereids, and the stem with confluent axial parenchyma, biseriate xylem rays, and the presence of rhomboidal prismatic crystals in the axial cells are the diagnostic microscopic features of the species. This structural characterization of the stem and leaf allows the identification of H.arborea, allowing certification of the authenticity of raw material.