Comparative Anatomy of Ilex paraguariensis "Erva-Mate" and its Adulterant Citronella gongonha "Falso-Mate

Abstract Ilex paraguariensis (Aquifoliaceae), commonly known as “yerba mate” or “erva-mate”, is a shrub or tree native to South America. The leaves of the plant are traditionally used to prepare a caffeine-rich infusion with several medicinal properties, including antirheumatic, antithrombotic, anti-inflammatory, anti-obesity, diuretic, and hypocholesterolemic. Ilex paraguariensis is adulterated with several other species of Ilex, such as I. brevicuspis, I. dumosa, and I. theezans. It is also commonly adulterated with unrelated species, such as Citronella gongonha of Cardiopteridaceae. The latter species, commonly called “false-mate”, is one of the most frequent adulterants due to its similar habit and leaf morphology. Comprehensive studies on authentication and quality control of erva-mate are still scarce. This study provides a detailed comparative anatomy of the leaves and stems of I. paraguariensis and C. gongonha by light and scanning electron microscopy. The main distinguishing characteristics are the epidermal cell wall shape, type of stomata, crystal morphotypes, stem shape, presence or absence of glandular trichomes, and sclerenchymatous sheath. This data can help in the authentication and quality control of erva-mate raw materials.