Antioxidant activity, total phenolic, and total flavaonoid of extracts and fractions of red fruit (Pandanus conoideus Lam)

Red fruit (Pandanus conoideus Lam) is one of the fruits commonly consumed as diet by societies, especially in Papua, Indonesia. Preliminary research revealed that among three extracts of red fruit evaluated, ethyl acetate extract had the highest antiradical activities; therefore, this research was directed to fractionate ethyl acetate extract, evaluate antioxidant activities using in vitro methods of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, reducing power, and metal chelating activity, and to determine the phenolics and flavonoid contents of ethyl acetate extract and its fractions. Ethyl acetate extract and its fractions can strongly scavenge DPPH radical with IC50 value ranged from 5.25 to 53.47μg/ml. Its antiradical scavenging activity revealed a moderate relationship with the total phenolics content (r2 = 0.645) and with flavonoid content (r2 = 0.709). Ethyl acetate extract and its fractions also had a capability to reduce Fe3+ to Fe2+ with reduction activity ranged 91.26 – 682.18 μg ascorbic acid equivalent/g extract or fraction. These extract and its fractions had metal chelating activity lower than that of EDTA (IC50 18.19 μg/ml). Red fruit can be used as natural antioxidant source to prevent diseases associated with free radical.