Effect of fermentation on the antioxidant activity of red beans (Phaseolus radiatus L. var. Aurea) ethanolic extract

The antioxidant activities of 50% ethanol extracts from red bean non-fermented and fermented by Bacillus subtilis or Aspergillus oryzae were determined using Sprague-Dawley rats as a testing model. Oral administration of all the extracts decreased the malondialdehyde (MDA) level in the liver but not in the brain tissue. Bacillus subtilis fermented extract increased the levels of ascorbic acid, alpha-tocopherol and glutathione (GSH) and the superoxide dismutase (SOD) activity in the liver tissue, while it increased only the ascorbic acid level in the brain tissue. Aspergillus oryzae fermented extract increased the levels of GSH and the SOD activity in the liver tissue, and it also increased GSH and ascorbic acid in the brain tissue. In general, the extracts from fermented red bean were more effective than the non-fermented extract in raising the antioxidant levels in the liver tissue.