Investigating the micromorphology and histochemistry of the ethnomedicinal plant Kedrostis nana (Lam.) Cogn.: A microscopic approach

• Micromorphological, ultrastructural and histochemical attributes of the leaves, stems and tuber of Kedrostis nana were examined. • Micromorphology showed a dense indumentum on the emergent leaves and stems. • Electron microscopy showed multicellular non-glandular trichomes that appear tapered and hooked; while ultrastructural investigation showed various organelles within the leaf and stem cells. • Histochemical assessments showed the distribution of various phytochemicals such as phenols, lipids, alkaloids, within the leaf and stem segments and corresponding trichomes. • These characteristics enhance the growing knowledge of this medicinal plant and contributes to the taxonomic and pharmacological profile. The quality control of medicinal plants starts with the correct identification of raw plant material. These medicinal plants are traded and used as potential drugs for various diseases. However, the incorrect identification of the traded medicinal plants could result in drastic consequences for the customer. More research needs to be conducted on medicinal plants, specifically on their morphology, to close the gap in not only plant misidentification but also taxonomy. Kedrostis nana (Lam.) Cogn. is a medicinal plant found along the coastal region of the Western Cape to KwaZulu-Natal. This plant has been used traditionally to treat illnesses and ailments such as diabetes, cancer, syphilis, malaria and hepatitis. There is very little research on the morphological attributes of this plant species. This research had been carried out to elucidate the micromorphology of the leaves and stems and the histochemical and fluorescence properties of the plant. The morphological characterization was carried out using stereomicroscopy and scanning electron microscopy. Transmission electron microscopy was used to investigate internal structures of the leaves and stems. The histochemical and fluorescence powder assessments were carried out using light and ultraviolet microscopy. The results showed that the emergent leaf contained a dense indumentum, particularly on the abaxial surface. As leaf maturity occurs, the density of trichomes decrease. The stem had a dense covering of trichomes. Scanning electron microscopy revealed that the trichome on the leaf and stem sections were non-glandular tapered and hooked multicellular. Transmission electron microscopy uncovered the various organelles within the leaf and stem cells, such as the plasmodesmata between cells, chloroplasts, small vacuoles, starch grains and nucleus. The histochemical assessment showed that the non-glandular trichomes stained positive for lipids, phenols and alkaloids. The entire leaf and stem sections stained positive for cellulose, carboxylate polysaccharides, polyaromatic substances and lipids, as well as alkaloids and phenols. Fluorescence microscopy on the powdered material showed drastic colour changes of the material when exposed to with UV light as compared to bright light. All characteristics that were examined in this study enhance the growing knowledge of this under evaluated medicinal plant.