Phytochemical and microscopical evaluation of Desmodium velutinum (P. Beauv.) DC (Papilionaceae) used for pain management in Lokoja, Kogi State, Nigeria
Microscopical examination was conducted using powdered samples, transverse and longitudinal sections of the leaves of Desmodiumvelutinum. Both quantitative and qualitative studies were carried out on the leaves using standard methods.The leaf powder of D.velutinum was cleared using chloral hydrate and little quantity of it was mounted on a clean slide using dilute glycerol and observed under the compound microscope for the presence of cell inclusions such as cellulose, starch, oil, tannins, and calcium oxalate crystals. Thin layer chromatography was conducted using prepared silica gel plates.The methanol extract was spotted at about 1cm from the bottom end of the plate using a capillary tube. The plates were developed in the glass tank while closed. Thereafter, the plates were removed, the solvent front marked and dried in an oven at 1050C for about 3mins. Each chamber contained plates, some for ultraviolet examination and others sprayed with different reagents, observed, and sometimes heated before observation.The microscopic examination of the leaf powder of Desmodium velutinum(Papilionaceae) and thin section revealed various anatomical features of the plant. The epidermal cells were cuboidal in form. Anomocytic type of stomata which range from 10-12ìm long and 6-8ìm wide were observed only on the lower epidermis. Calcium oxalate crystals were observed in between veins in fresh leaf and numerous unicellular covering trichomes were observed all over the epidermis. The thin layer chromatography(TLC) of the leaf powder of the plant revealed the presence of tannins, steroids, flavonoids and terpenes but absence of alkaloid.