Anatomical characterization and physicochemical standardization of Gongronema latifolium Benth. (Apocynaceae)

Gongronema latifolium Benth belongs to the family Apocynaceae. Generally, the leaves and stems of G. latifolium are used as medicine and spices for sauces, soups and salads in Southern Nigeria. In view of its medicinal uses, the present study aimed at documenting anatomical characters and physicochemical properties for its standardization. The leaf epidermis, transverse section of the midrib, petiole and stem were prepared using standard procedures. Physicochemical properties of the powdered plant were conducted following standard methods. The leaf epidermal layer revealed anomocytic stomata, calcium oxalate crystals (rosette), uniseriate multicellular trichome (non-glandular). The midrib has an abundantly non glandular trichome with numerous rosette crystals. The percentage extractive values for ethanol, distilled water and petroleum ether in the leaf powder were 16.71±0.53, 13.24±0.71 and 2.08±0.13%, respectively, while that of stem were 12.51±0.15, 10.90±0.53 and 1.10±0.21, respectively. The moisture content and total ash values for the leaf powder were 11.45±0.53 and 9.70±0.17%, respectively while for the stem were 11.07±0.38 and 7.50±0.05, respectively. In the light of frequent consumption and use of G. latifolium as medicine, some of the pharmacognostic standards provided herein may be useful for its proper identification and subsequent compilation in a monograph.