Comparing and authenticating on anatomical aspects of Abrus cantoniensis and Abrus mollis by microscopy

BACKGROUND: Abrus cantoniensis is popularly used as traditional Chinese medicine and a cool tea in South of China. However, due to diminishing source of A. cantoniensis, it is usually interchanged or adulterated with other species of Abrus genus because of the limited knowledge in identification and differentiation. Especially, Abrus mollis is widely mixed on herbal markets and pharmaceutical preparation. OBJECTIVE: To ensure safety and efficacy, a detailed comparison was undertaken to carry out an anatomical and micro-morphological study of two species of A. cantoniensis and A. mollis. MATERIALS AND METHODS: Microscopic characteristics of roots, leaves and stems, including transverse sections and the crude drug powder, were observed using a light microscope according to the usual microscopic techniques. RESULTS: The basic diagnostic features of A. cantoniensis include that stem is extremely thin; xylem vessels of root are radially arranged in 10 or more bundles; pith is hollow in stem, and the palisade tissue is made up of two layers of palisade cells. Furthermore, scanning electron microscopy was used to compare nonglandular hairs and the stomata of the leaflet surface. A table of the key authentication parameters based on the analyzed microscopic characteristics was drawn up. CONCLUSION: The study demonstrated that the microscopy and related techniques provided a systematic method that is convenient, feasible, and can be unambiguously applied to the authentication of the species of Abrus.