Enhancement of the antioxidant and hypolipidemic activities of Puerariae radix by fermentation with Aspergillus niger

Abstract

Puerariae radix (PR) is a traditional Chinese food and medicine. In this study, the chemical profile and bioactivities of PR fermented with Aspergillus niger (PFA) were investigated. Based on HPLC analysis, PFA chemical profile changed and total phenols increased by 12.5% relative to PR. Consequently, the in vitro antioxidant activity significantly improved. According to the blood lipid analysis in mice, PFA showed a better ability to inhibit the increased blood lipid levels induced by Triton WR-1339 than PR. In a quantitative real-time PCR (qRT-PCR) study, PFA up-regulated cholesterol 7-alpha hydroxylase (CYP7A1) and low-density lipoprotein receptor mRNA expression, which were 50% and 44.8% higher than the levels induced by high-dose PR. Conversely, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoAR) mRNA expression was down-regulated to 46.8% lower than the levels induced by high-dose PR. The qRT-PCR results suggested that PFA displayed better hypolipidemic activity than PR, due to its superior ability to regulate mRNA expression.

Keywords: Antioxidant; Aspergillus niger; Hypolipidemic; Puerariae radix; Solid fermentation.

Fig. 1

Effects of Puerariae radix fermented by Aspergillus niger (PFA) and Puerariae radix (PR) on mRNA expression in the mouse liver. (A) Cholesterol 7 alpha-hydroxylase (CYP7A1), (B) 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCoAR), and (C) low density lipoprotein receptor (LDLR). Each value is expressed as the mean ± SD (n = 3). ^ap < 0.05 versus model control, ^bp < 0.05 versus normal control. C: normal control; M: model control; PR-L: PR treatment at 0.5 g/kg; PR-H: PR treatment at 1 g/kg; PFA-L: PFA treatment at 0.5 g/kg; PFA-H: PFA treatment at 1 g/kg; Lova: lovastatin treatment at 10 mg/kg