Synergistic Antioxidant Activity of Sweet Potato Extracts in Combination with Tea Polyphenols and Pueraria Flavonoid in Vitro

Xiaojuan Liu,Lichao Zhao,Xin Liu,Fenglin He,Aimei Zhou

doi:10.19026/ajfst.6.13

Abstract

The antioxidant activity of Sweet Potato Extracts (SPE) can be enhanced by the presence of these other active antioxidants such as Tea Polyphones (TP) and Pueraria Flavonoid (PF). Since many of these natural antioxidants are consumed together in foods, the potential for synergistic interactions is high in the human diet. The aim of this study was to determine what concentrations and combinations of antioxidants among SPE, TP and PF are capable of producing synergistic antioxidant effects, based on potato-based food products. Solutions of the antioxidant activity of SPE, TP and PF, alone and in different combinations were measured using the stable free radical 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) and Ferric Reducing Anti-oxidant Power (FRAP) method. A comparison of the antioxidant activity of the combinations of antioxidants to the arithmetic sum of the antioxidant activity of the individual antioxidants was used to calculate the Synergistic Effects (SEs) between the antioxidants. The results showed that all concentrations of TP and PF combination with SPE (1 and 1.5%) could produce significant SEs (p<0.05) of DPPH and FRAP for the two or three component mixtures. With the concentration of 1% SPE,1×10<sup>-5</sup> g/mL TP and 5×10<sup>-5</sup> g/mL PF in the three-component mixture, the highest SE of DPPH and FRAP was both detected. The results suggested that the antioxidant property of this combination was substantially superior to the sum of the individual antioxidant effects and these interactions can enhance the antioxidant effectiveness of SPE. The results could guide in the formulation and development of functional food products that have high antioxidant potential.

Highlights

Sweet potato is important dietary source in developing countries
The antioxidant effect of Sweet Potato Extracts (SPE), Tea Polyphenols (TP) and Pueraria Flavonoid (PF): The SPE, TP and PF used in this study showed antioxidant activity in a dose-dependent manner in DPPH radical scavenging capacity and Ferric Reducing Anti-oxidant Power (FRAP) (Fig. 1)
This study highlighted the importance of the combined mixture of SPE, TP and PF to exhibit synergism that subsequently increased the antioxidant activity of the mixture

Summary

Introduction

Sweet potato is important dietary source in developing countries It is considered as a resource of functional foods because of its high contents of physiologically active compounds such as vitamin C, βcarotene, chlorogenic acid, caffeic acid, quercet in and rutin (Guang and Wu, 2006). The manufacturing procedures of sweet potato are mostly cooking and frying Under these conditions, the acceleration of both thermal and oxidative decomposition reactions occurs (Grangdgirard et al, 1984), which accelerated loss of vitamin C and βcarotene (Sheehy et al, 1994; Liu and Lee, 1998), leading to the decline of antioxidant capacity of the final product (Smith and Ray, 2007). It was found that green tea polyphenols showed strong synergistic ant oxidation activity with other antioxidants, such as vitamin E and vitamin C (Zhou et al, 2005; Niki et al, 1984)

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Conclusion