Variation of Antioxidant Properties of African Basil (Ocimum gratissimum) Leaves with respect to Various Drying and Solvents Extraction Methods

The cleaned leaves of African Basil (Ocimum gratissimum) were dried initially using various drying processes such as sun dry, shade dry, hot air oven dry and microwave dry. Dried samples were then extracted in three different solvents; water (Cold and Hot), methanol and butanol using maceration process. Various antioxidant activities of all the extracts were then evaluated both qualitatively and quantitatively to find out the best drying method and extraction of solvent for preserving the activity of bioactive compounds in the dry leaves of African basil. The result revealed that the hot water extract of microwave dried African Basil was rich in total polyphenolic content and the butanol extract of sun-dried African Basil was rich in total flavonoid content. In case of DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, lowest IC50 value was observed in the cold water extract of shade dried African Basil. Finally, in FRAP (Ferric Reducing Antioxidant Power) assay, maximum ferric reducing activity was observed in the hot water extract of microwave dried African Basil. After analyzing the overall data, it was revealed that the organic extract of sun-dried African Basil content high polyphenolics and flavonoids, and hence had strong antioxidant potential.