Comparison of antioxidant effect and phenolic compounds in tropical fruits

Abstract

There is a growing interest in consumption of tropical fruits because of their higher degree of antioxidant effects. In present study, we assessed the antioxidant potential as a functional food using popular three tropical fruits, such as litchi (Litchi chinensis Sonn.), rambutan (Nephelium lappaceum L.) and mangosteen (Garcinia mangostana L.). Tropical fruits were extracted in water, 70% ethanol and 70% methanol for 48 h. Then, we analyzed the antioxidant effects of tropical fruit extracts using α, α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging, thiobarbituric acid reactive substance (TBARS) and reducing power assay. The DPPH radical scavenging and TBARS activities showed the highest degree in rambutan 70% ethanol extract compared with other tropical fruit extracts, as well as total phenolic and flavonoid contents were also highly identified in rambutan 70% ethanol extract. Furthermore, DPPH radical scavenging activity and reducing power was higher in the EtOAc fraction and the F-2 sub-fraction of rambutan 70% ethanol extract as compared with other fractions at the same concentrations. The EtOAc fraction and the F-2 sub-fraction had a large amount of phenols and flavonoids. The antioxidant effects of rambutan extract were closely associated with phenolic compound such as (−)-epicatechin. In conclusion, our results indicate that tropical fruits containing natural antioxidants might be used as supplements for human health, but this deserves further studies.