Antioxidant compounds and antioxidant activity in acerola (Malpighia emarginata DC.) fruits and derivatives

Acerola (Malpighia ernarginata DC.) is a wild plant from Central America. This fruit is well known as an excellent food source of vitamin C, and it also contains phytochemicals such as carotenoids and polyphenols. The present work evaluates the antioxidant capacity of hydrophilic extracts of acerola pulps and juices by 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ORAC and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Antioxiclant activity values obtained for acerola juice were higher than those reported for other fruit juices particularly rich in polyphenols such as strawberry, grape and apple juices, among others. Vitamin C, total phenol index (TPI), total anthocyanins and polyphenolic compounds by high performance liquid chromatography (HPLC), as main factors responsible for antioxiclant activity, were determined. Contents in total ascorbic acid ranged from 6.32 to 9.20 g kg(-1) of pulp and 9.44 to 17.97 g L-1 of juice. Five different polyphenolic compounds were identified in the samples by means of HPLC and diode-array detection: chlorogenic acid, (-)-epigallocatechin gallate, (-)-epicatechin, procyanidin B1 and rutin, being the two last predominant. By means of solid phase extraction (SPE) three soluble polyphenolic fractions (phenolic acids, anthocyanins and flavonoids) were separated from the different sample extracts, and their respective antioxiclant activities calculated. Among them, phenolic acids are the main contributors to the antioxiclant activity. (C) 2008 Elsevier Inc. All rights reserved.