The biomedical significance of the phytochemical, proximate and mineral compositions of the leaf, stem bark and root of Jatropha curcas

Objective: To analyse the phytochemical contents of leaf, stem bark and root of Jatropha curcas (J. curcas) in four solvent extracts and their proximate and mineral compositions. Methods: Standard analytical procedures were used for the determination of phytochemicals, proximate and mineral compositions of the leaf, stem bark and root extracts of J. curcas. Results: Results of the analysis showed the presence of polyphenols, flavonoids, alkaloids, cardiac glycosides, coumarins, saponins, terpenoids, steroids, triterpenoid saponins, carotenoids, phlobatannins and tannins in the leaf, stem bark and root of all the solvent extracts. Flavonoids were present in the highest amount in the ethyl acetate extracts of the leaf (7.35% ± 0.02%), stem bark (4.12% ± 0.01%) and root (3.35% ± 0.02%) followed by polyphenols in the methanol extracts of leaf (4.62% ± 0.02%), stem bark (2.77% ± 0.05%) and root (2.49% ± 0.02%). Poly-acetylated compounds were absent in all the solvent extracts of the leaf, stem bark and root. However, some anti-nutritional agents such as oxalates, phytates and cyanates were present in all the solvent extracts of the leaf, stem bark and root except the ethyl acetate. Phytates were high in the aqueous solvent of the leaf (6.12% ± 0.00%) but low in the stem bark (1.00% ± 0.05%) and root (0.89% ± 0.03%). Proximate composition showed appreciable amounts of total carbohydrate (36.33% ± 0.72%), crude protein (26.00% ± 0.47%) and reducing sugars (5.87% ± 0.14%) in the leaf, while crude fat was more in the stem bark (16.70% ± 0.30%). There was corresponding substantial energy in the leaf [(1514.77 ± 20.87) kJ/100 g] and stem bark [(907.00 ± 8.52) kJ/100 g]. Moisture and ash contents of the leaf, stem bark and root were within acceptable limits for the use in drugs formulation. The mineral composition showed substantial amounts of important elements such as Fe, Ca, Na, Mg and Zn. Others were P, K and Se. Conclusions: The outcome of this study suggests that the leaf, stem bark and root of J. curcas have very good medicinal potentials, meet the standard requirements for drug formulation and serve as good sources of energy and nutrients except for the presence of some anti-nutritional elements predominant in the leaf.