Radical scavenging activity in fruit extracts

Phytochemicals in plants, vegetables and fruits have been reported to prevent oxidative stress related diseases, such as cancer, cardiovascular disease, cataracts, brain and immune-system dysfunction and inflammation. Many plant phenolic flavonoids have been shown to have antioxidant activity. In our study, the polyphenolic content and the radical scavenging activity of a number of Thai fruit extracts were determined by Folin-Ciocalteu reagent and scavenging of DPPH (2,2-diphenyl-1-pierylhydrazyl) radical respectively. We found that grape skins, mulberries, mango, carambola, guava and lichee possess strong activity to scavenge the DPPH radical (IC50 from 1.10 to 9.60 mg/ml). Moderate antioxidant activity was found in mangosteen, orange, pamelo, grapes and papaya (IC50 from 11.18 to 32.80 mg/ml). Low antioxidant activity (IC50 from 50.62 to 110.46 mg/ml) was found in orange juice, grape, rose apple and jackfruit.