Philippine E-Journals

In Vitro Antioxidant and Reducing Properties of Flavonoid Extract from Leaves of Kulitis (Amaranthus spinosus L.)

Crislee M. Torio | Lilian De la Merced

 

Abstract:

Though a natural process, uncontrolled oxidation may lead to aberrances in biological systems or early spoilage of foodstuff and pharmaceuticals, necessitating the use of antioxidants and reducing agents. This study used experimental approach to produce flavonoid extract from Amaranthus spinosus leaves and test its antioxidant and reducing properties using ascorbic acid, sodium metabisulfite, and quercetin as positive controls. Determination of total phenolic and flavonoid content revealed 23.44 mg gallic acid and 58.26 mg quercetin equivalents per gram of extract, respectively. The extract’s antioxidant activity in terms of free radical DPPH and non-radical H2O2 scavenging activities, and Fe+3 to Fe+2 reducing property all exhibit concentrationdependent manner, similar to those of the positive controls. F-statistics analysis of the data revealed no significant difference among the antioxidant activities of the four groups, indicating that the extract’s antioxidant activity is comparable to those of ascorbic acid, sodium metabisulfite, and quercetin. However, in terms of ferric reducing power, the extract was revealed significantly different from ascorbic acid and quercetin in favor of the two controls, signifying that though the extract exhibits ferric reducing capacity, it is not comparable with that of ascorbic acid and quercetin. On the other hand, no significant difference was detected between the extract and sodium metabisulfite, showing that their ferric reducing powers are comparable. Thus, the leaves of A. spinosus make excellent source of dietary and medicinal antioxidants, and the extract can be a natural alternate for sodium metabisulfite in preserving foodstuff and pharmaceuticals that are prone to oxidation.