Comparative morpho-anatomy and HPTLC studies of leaves of Agathosma betulina and Agathosma crenulata

Buchu is one of the South Africa's best-known medicinal plants valued for its medicinal uses as diuretic, antiseptic and stimulant tonic. It is also widely used against urinary tract infections and stomach troubles. In the USA, buchu is popularly consumed as tea and also used as a dietary supplement. The strongly aromatic buchu leaf is mainly derived from Agathosma betulina (syn. Barosma betulina), known as round-leaf buchu or short buchu. However, commercial buchus are often derived also from A. crenulata (oval-leaf buchu). The two species have different chemical profiles, and the oil of A. crenulata has a high level of pulegone, a potentially toxic component that renders the oil unsuitable for human consumption. Therefore, correct identification and differentiation of buchu is crucial. The present work illustrates detailed morphology and anatomy of leaves of the two species by bright-field and scanning electron microscopy. In this work high performance thin layer chromatography (HPTLC) is also used as an analytical tool to efficiently and accurately determine botanical identity and to authenticate the samples of A. betulina and A. crenulata.