Determination of total phenolics, flavonoid contents and antioxidant activity of different mBHT fractions: A polyherbal medicine.

In this study, antioxidant activity, total phenolic and flavonoids content of four different fractions from the traditional Korean polyherbal medicine of Modified Bo-yang-Hwan-o-Tang (mBHT) was determined using spectrophotometric methods. Antioxidant activity of fractions was expressed as percentage of DPPH radicals inhibition and IC₅₀ values (μg/ml). Values in percentage ranged from 48.35 to 77.43%. The reducing powers of all the extracts were comparable with that of positive control sample of Butylated hydroxyl tolune (BHT) and ascorbic acid which was found to be dose dependent. Total phenolic content ranged from 106.83 ± 0.002 to 188.661 ± 0.002 mg/g, expressed as gallic acid equivalents. The total flavonoid contents varied from 28.44 ± 0.001 to 105.25 ± 0.001 mg/g, expressed as quarcetin equivalents. Ethyl acetate fractions of mBHT showed the highest phenolic (188.66 mg GAE/g) and flavonoids (105.25 mg QAE/g) contents and strong antioxidant activity. Total phenolics and flavonoid content of all the mBHT fractions were found reasonably correlated with IC₅₀ of DPPH (R²=0.980 and 0.932, respectively). The high contents of phenolic compounds indicated that these compounds responsible for antioxidant activity. Therefore, ethyl acetate fractions of mBHT can be regarded as promising candidates for natural plant sources of antioxidants.