Antioxidant capacity and total phenol content of commonly consumed selected vegetables of Bangladesh.

BACKGROUND

The purpose of the study was to determine the antioxidant capacity (AC) and total phenolic content (TPC) of selected commonly consumed Bangladeshi vegetables and herbs.

METHODS

Hydrophilic extracts from edible portions of ten vegetables and two herbs were analysed. The total phenolic amount ranged from 27.65 +/- 1.45 mg to 1.08 +/- 0.15 Gallic Acid Equivalent (GAE)/ g on a fresh weight (FW) basis. Contents of total phenol were determined spectrophotometrically according to the Folin-Ciocalteau method and the antioxidant capacity was determined by 2,2-diphenyl-1-1-picrylhydrazyl radical scavenging activity (DPPH-RSA).

RESULTS

Antioxidant capacity varied from 8328.80 +/- 29.15 to 0.61 +/- 0.19 micromol Trolox Equivalent (TE)/g of FW. Ipomoea leaves showed the highest AC (8328.80 +/- 29.15 micromol TE/g), while the lowest AC (0.61 +/- 0.19 micromol TE/g) was seen in radish. A linear relationship was observed between Trolox Equivalent Antioxidant Capacity (TEAC) values and total phenol. Antioxidant capacity of the assayed samples correlated significantly and positively with total phenolic content (R2 = 0.814, p < 0.01). Vegetables with high polyphenol like Ipomoea leaves and mint showed high AC with the exception of raw banana which demonstrated moderate AC though it contained high TPC. Moderate TPC vegetables like amaranths and coriander leaves did not show substantial AC.

CONCLUSIONS

The data indicates that indigenous vegetables containing high polyphenols may be a potential source of dietary antioxidants.