Influence of the solvents on the extraction of major phenolic compounds (punicalagin, ellagic acid and gallic acid) and their antioxidant activities in pomegranate aril

Phenolic compounds of fruits have been shown to maintain human health. However, the relative amounts of phenolic compounds and the variation in the types of phenolics are still poorly understood. The purpose of this study was to investigate the most effective solvent for extracting the potent antioxidant compounds, especially phenolics from pomegranate aril. Pomegranate aril was subjected to extraction using different solvents viz., water, ethanol, acetone and diethyl ether either alone or in combination, and the extraction yield, total phenolic contents, and antioxidant activity were investigated. The extracts derived from various solvents were also analysed using high performance liquid chromatography (HPLC) for quantification of major polyphenols (punicalagins, ellagic acid and gallic acid) of pomegranate. Amongst the tested solvents, combination of ethanol, diethyl ether and water (8:1:1) extract exhibited the highest 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging power (IC50 = 10.12 mu g mL-1). Further, HPLC analysis of different extracts revealed that ethanol, diethyl ether and water (8:1:1) mixture contained significantly higher (p < 0.05) amounts of punicalagin A (1.06 mu g mg-1 extract), punicalagin B (2.07 +/- 0.03 mu g mg-1 extract), ellagic acid (34.5 mu g mg-1 extract) and gallic acid (3.37 mu g mg-1 extract) in comparison to the other solvents used for extraction. The results demonstrate that pomegranate aril is a good source of phenolic compounds with high antioxidant activity and the antioxidant activity is dependent on the type of solvent system that extracts different phenolic compounds with varying polarity. The solvent extracts that showed effective antioxidants activities have the potential for application in suitable food products.