Phytochemical, proximate and mineral composition of African black nightshade (Solanum nigrum L.) leaf and fruit

Abstract

This research was conducted on the phytochemical, proximate and mineral elements in Solanum nigrum L. leaf and fruit. The experiment  was carried out at the laboratory of Federal College of Forestry, Jos, Plateau State. Qualitative and quantitative  phytochemicals, proximate and mineral elements including phosphorus (P), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg)  and iron (Fe) were analyzed. Qualitative phytochemical result showed that alkaloids, saponins, tannins, flavonoids, cardiac glycosides,  proteins, phenols, coumarins and terpenoids were present in the leaf and fruit extracts. Carbohydrate was present in the ethanol leaf and  fruit extracts while phlobatanins and steroids were found to be absent. Anthraquinones was absent in the aqueous leaf extract while cardiac glycosides were absent in the aqueous fruit extract. Quantitative phytochemical showed flavonoid to have the highest value of  37.72 and 40.91, while tannins recorded to lowest value of 13.83 and 14.10 in leaf and fruit respectively. The proximate composition  showed high protein in the leaf and fruit (36.63% and 38.71% respectively) while other parameters are 12.80% and 11.82% (total ash),  18.44% and 16.35% (carbohydrate), 2.38% and 2.50% (crude lipid), 28.14% and 23.89% (total moisture) for leaf and fruit extracts  respectively. The energy value (Kcal/mol) was 193.34 for the leaf and 192.02 for the fruit extract. Mineral elements in the leaf are 60.49  mg/100 g of P, 52.48 mg/100 g K, 273.51 mg/100 g Mg, 5.28 mg/100 g Na, 16.44 mg/100 g Ca and 13.48 mg/100 g of Fe, while the fruit  contained 51.39 mg/100 g P, 48.52 mg/100 g , 261 mg/100 g Mg, 5.51 mg/100 Na, 14.83 mg/100 g Ca and 11.42 mg/100 g Fe. The various  phytochemicals, proximate and mineral elements constituents could justify the significant of using Solanum nigrum as a medicinal and   nutritional plant.