Pharmacognostic and Taxonomic Studies of Cola parchycarpa K. Schum. (Malvaceae)

Abstract

C. pachycarpa is a lesser-known member of the genus Cola in the family Malvaceae. In Nigeria its fruits are edible but with non-edible seeds as the general Cola ‘Kolanut” This study is carried out to evaluate the taxonomic and pharmacognostic characters of Cola pachycarpa K. Schum. for its identification, authentication and standardization. The pharmacognostic and taxonomic characters were determined from macroscopy, microscopy, petiole anatomy, powder microscopy, chemomicroscopy, micromeritic properties, ash values, extractive values, fluorescence analysis and phytochemical screening using standard methods. The leaves of C. pachycarpa were alternate, petiolate, compound and trifoliate. Petioles were within 45-50 cm long, leaflets 20-38 cm long, 10-19 cm wide, the middle leaflet were often longer than others. Leaflets were short petiolulate to subsessile, leaflet shape was elliptic, apex acuminate, margin entire and texture hairy on the abaxial surface of the leaflet with brown caducuous hairs on the abaxial surface only. Stem was erect, woody and scabrid about 4-10 cm in diameter. The fruit was 15 cm long and 7 cm wide with about 3-5 seeds occurring in a pod. Preliminary phytochemical screening revealed the presence of alkaloids, flavonoid, saponins, tannins and cardiac glycosides but anthraquinone was absent for the leaf while all were present except alkaloid, cardiac glycoside and anthraquinone in the stem. Epidermal cells were polygonal with straight anticlinal walls. Drusiferous crystals were observed on the petioles. Leaflets were hypostomatic with anisocytic stomata and stellate trichomes on the abaxial surface. The chemomicroscopic study revealed the presence of lignin, starch, cellulose, oils, calcium oxalate crystals, mucilage and protein for both leaf and stem. The fluorescence characteristics showed the presence of different colours supporting the presence of various phytoconstituents for both leaf and stem. The flow properties for both leaf and stem were fair and passable with the angle of repose of 35° and 45°respectively. The quantitative epidermal studies, chemomicroscopic and fluorescence characteristics revealed characteristic features for the drug. The physico-chemical results for leaf and stem gave total ash of 8.24% and 11.5%, water soluble ash of 3.71% and 3.20%, acid-insoluble ash of 0.99% and 4.33% and moisture content of 10.58% and 4.33%, water-soluble extractive of 12.50 % and 9.40%, ethanol-soluble extractive of 9.10% and 2.90%, methanol-soluble extractive of 8.00 % and 2.30% and ethyl-acetate acetate-soluble extractive of 2.00% and 0.50% respectively. The findings of the research will help in the identification and authentication of the plant as well as establishing standards for quality, purity, safety, efficacy and reproducibility in phytomedicine.