Hydrophilic antioxidant capacities and total phenol content of seasonal fruits of Bangladesh

Consumption of fruits and vegetables helps to scavenge free radicals owing to the presence of antioxidant nutrients and secondary metabolites, especially polyphenolic compounds. This may lead to a reduction in the risk of diet-related chronic diseases. The purpose of the study was to determine the antioxidant capacity (AC) and total phenolic content (TPC) of selected seasonal fruits of Bangladesh. Hydrophilic extracts from edible portions of fifteen fruits available in the summer season were analysed. Total phenol content was determined spectrophotometrically according to the Folin-Ciocalteau method while antioxidant capacity was determined by 2, 2-diphenyl-1-1-picrylhydrazyl radical scavenging activity (DPPH-RSA). TPC ranged from 0.6 +/- 0.01 to 0.01 +/- 0 mg Gallic acid equivalent (GAE)/g of fresh weight (FW). Antioxidant capacity varied from 4.882 +/- 0 to 0.113 +/- 0.03 micromol Torolox equivalents (TE)/g of FW. Carissa carandas showed the highest AC (4.882 +/- 0 micromol TE/g), while the lowest (0.113 +/- 0.3 micromol TE/g) was seen in Baccaura ramiflora. A positive and significant correlation (R2 = 0.957) between antioxidant capacity and total phenolic content of the analysed samples was identified. A significant and positive correlation (p < 0.05) between AC and TPC was found in Manikara zapota, Artocarpus heterophyllus, Litchi chinensis and Articarpus lakoocha. The data indicates that some indigenous seasonal fruits of Bangladesh contain high polyphenols that may serve as a potential source of dietary antioxidants.