Pages: 9-17

Abstract

Medicinal plants are by far the crucial source of life saving drugs for nearly 80% of world’s population. Proximate analysis is carried out with a view to determining macronutrients contents in a plant, compound or feed. Studies available on ethnomedicinal plants have indicated that potent phytochemicals capable of mitigating many health problems can be developed. Medicinal plants are thought to contain reasonable amounts of heavy metals that may constitute health hazards. This study aims at evaluating the proximate and phytochemical compositions as well as levels of Cadmium (Cd), Lead (Pb), Chromium (Cr), Nickel (Ni) and Copper (Cu) of medicinal plants including Senna singuena, Nymphaea lotus, Cochlospermum planchoni and Acacia nilotica. The plants extracts were prepared using cold aqueous maceration method. The proximate analysis for each plant was conducted using standard procedure; preliminary phytochemical screening was carried out on each extract using method of Trease and Evans; and assay of heavy metal was quantitatively measured using atomic absorption spectrophotometer. S. singuena was investigated to have the lowest moisture content (5%), highest fat and crude protein (3.9 and 39.5%), S. singuena and N. lotus have same carbohydrate content (41%), N. lotus has the highest ash content (20%) while C. planchoni was found to have the highest fiber content (42%). Preliminary screening of phytochemicals of the plant extracts revealed different classes of secondary metabolites including saponons, phenolics, phlobatanins, quinines, alkaloids, tannins, anthroquinones, steroids, flavonoids, terpenoids and glycosides. Cd level in S. singuena and N. lotus was found to be above the permissible limit recommended by WHO. Ni and Cu levels in the four plants were found to be below the WHO recommended permissible limit in the plants except the Ni level of A. nilotica that resulted to be above WHO permissible limit. Conversely, Pb and Cr were absent in all the plants assayed. All together, S. singuena has the lowest moisture content and highest crude protein and fat; C. planchoni has the highest fiber content and Cd was found to be totally absent; S. singuena and N. lotus contain toxic level of Cd; the four plants contain different secondary metabolites which may be responsible for their ethnomedicinal usage.