Background: The previous studies found that metabolic dysfunction in rats induced by high-fat feeding apparently subsides if they were co-fed with either the water extract from rice bran or herbs, Benjakul (BWE) or Wild betel leaf bush (WWE). The extracts contain a mixture of substances but carbohydrate was found as a majority. Therefore, the tentative active carbohydrates, dietary fiber and phenolic compounds, were evaluated.
Materials and Methods: Dietary fiber was analyzed by AOAC Method 2009.1 and 2011.25 using the reagent kits. Phenolic compounds were determined by the HPLC.
Results: The results showed that the possible active substances in RB, BWE and WWE were 2 kinds of soluble dietary fiber, the nonprecipitated and the precipitated fiber in 78% ethanol, since the combination of these 2 kinds of soluble dietary fiber were
approximately equal among the specimens (60.93+10.70 plus 55.56+5.33 mg/g rice; 72.72+1.36 plus 16.33+1.20 mg/g BWE; 104.38+0.54 plus 1.77+0.08 mg/g WWE). The content of phenolic compound, p-coumaric acid, tended to be equal among the specimens as well (38.02+2.36 μg/g rice bran enzymatic extract; 38.92+2.49 μg/g BWE; 59.019+5.42 μg/g WWE).
Conclusion: The molecular weight of the soluble dietary fibers found in RB, BWE and WWE are similar to oligosaccharides those known to be the prebiotics. The similar content of soluble dietary fiber concomitant with the similar ability to ameliorate the metabolic syndrome in the animal studies. The other possible activity to ameliorate the signs of metabolic syndrome found in the specimens is the antioxidant effect as due to p-coumaric acid in the extracts.

Keywords: Rice bran, Benjakul, Wild betel leaf bush, Dietary fiber, Antioxidant