Phytochemical Screening, Proximate, Mineral, and Heavy Metal Composition of Stem Bark of Cylicodiscus gabunensis Harms (Leguminosae)

Abstract

The trade in herbal medicines such as supplements, cosmetics, and additives has witnessed an exponential increase in recent times. Therefore  authentication of herbal plant materials is important in establishing the quality of herbal medicines in a bourgeoning market. This study aims to  determine the phytochemical constituents, proximate parameters, mineral composition, and levels of toxic metals in the stem bark of Cylicodiscus  gabunensis to establish its safety. The phytochemical and proximate analysis of the plant sample was carried out using standard procedures. The  mineral elements and heavy metals were determined using a flame photometer and AAS. The phytochemical analysis revealed the presence of  alkaloids, tannins, phenols, flavonoids, saponins, steroids, deoxysugars, and carbohydrates. The proximate analysis showed the moisture content,  total ash value, acid insoluble ash, water-soluble ash, alcohol extractive value, and water extractive value to be 10.91%, 5.62%, 1.83%, 0.72%, value  11.74%, and 10.90%, respectively. The elemental analysis gives the content of calcium, zinc, iron, magnesium, copper, manganese, sodium, and  potassium at 4,100 ppm, 2.5 ppm, 144 ppm, 169 ppm, 2 ppm, 13.5 ppm, 75 ppm, and 4,200 ppm, respectively. The concentrations of the heavy  metals were found to be 3.5 ppm, 2.5 ppm, and 1.5 ppm for nickel, lead, and cadmium, respectively. It thus reveals that the wide range of secondary  metabolites in the plant sample may be responsible for its pharmacological activity and use in ethnomedicine. The proximate  parameters showed that the crude powdered plant is a rich source of vital minerals, could withstand longer shelf storage, and is free from inorganic  materials contaminants. However, the levels of cadmium and lead are above the permissible limit for plants samples.