ANTIOXIDANT POTENTIALITY OF PARTIALLY PURIFIED PROTEASE INHIBITOR FROM THE FRUITS OF AFRICAN NIGHTSHADE (SOLANUM ACULEATISSIMUM JACQ.)

Among the diverse medicinal outputs of plants, antioxidant potentialities have received global attention due to their pertaining role in preventing or down regulating myriads of oxidative damages caused by free radicals in the body. Oxidative stress is initiated by free radicals, which seek stability through electron pairing with biomolecules such as proteins, lipids and DNA in healthy human cells and cause protein and DNA damage along with lipid peroxidation. Most of the antioxidant studies are centralized around polyphenols or other secondary metabolites. Protease inhibitors are common among plants with multiple roles. Trypsin protease inhibitor was isolated from fresh fruits of African nightshade (Solanum aculeatissimum Jacq. (SAPI), and was partially purified by ammonium sulphate (20-90%) salt precipitation method. A single band of 26 kDa was obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This partially purified 26 kDa SAPI was evaluated for antioxidant potentials. To achieve this goal, several antioxidant assay parameters such as free-radical scavenging (DPPH*, ABTS .+ , FRAP, reducing power, H2O2, and . OH), iron chelating activity, reducing power and scavenging of superoxide radicals were examined. SAPI extracts presented a remarkable potentiality to scavenge all the tested reactive species with IC50 values being found at the µg / ml level and was comparable with reference compounds such as butylated hydroxytoluene and trolox. These results suggest the potential of Solanum aculeatissimum PI as a lead compound against free-radical-associated oxidative damage. WO