Comparative study of the bioactive and chemical properties of three different Solanum spp. from Ghana

The family Solanaceae represent one of the most economically, nutritionally and medicinally important families of angiosperms. The genus Solanum is a hyper-diverse taxon of this family. There are about 2300 species of Solanum in the world that are mainly distributed in the tropical and sub-tropical areas, with a small number in the temperate areas. Solanum torvum has been extensively explored for its chemical constituents. To determine and compare the phytoconstituents of the fruits/berries of three different species of Solanum (torvum, erianthum, and macrocarpon) at different maturity stages. Fruits of Solanum (torvum, erianthum, and macrocarpon) were harvested at different maturity stages from local farms and around households in the Volta region and kept in sterile sample bags. Phytochemical and mineral analysis of the fruits was carried out according to the method of the Association of Official Analytical Chemists (AOAC), to determine the mineral composition of the fruits. Total phenolic content was determined by the Folin Ciocalteau method, Flavonoids content was determined by the Aluminum Chloride method. Antioxidant activity was determined by three assays; DPPH, FRAP, and ABTS. The elemental mineral analysis was done using the flame photometer according to methods by AOAC. The present study revealed that the levels of antioxidants, total phenolics, and flavonoids contents were significantly affected by both the physiological maturity stage and extraction solvents. Total phenolic content ranged between 16.97±0.03 - 40.62±0.00 µL GAE/10 µL. Flavonoids contents ranged from 52.33±0.36 - 434.00±0.31 µL CE/10 µL. Antioxidants activity values ranged between 37.79±036 - 878.34±4.36, 16.66±7.40 - 47.49±15.27 and 0.075±0.00-0.257±0.00 for DPPH, ABTS and FRAP assays respectively. Elemental mineral values recorded ranged between 4.87±0.03 - 11.55±0.05 mg/kg for Fe, 23.23±0.04 - 32.46±0.04 mg/kg for Mg and 34.317±0.03 - 15.3309±0.001 mg/kg for Na. This study revealed that the levels of antioxidants, total phenolics and flavonoids are significantly affected by both the physiological maturity stage and extraction solvents. It was clear that all methanolic extract showed significant variations with high values in antioxidants which included the DPPH scavenging activity, the ABTS• + scavenging activity, the Ferric reduction power assay, the total phenolics, and the flavonoid content.