Conversion of Isoflavone Glucosides to Aglycones by Partially Purified β-Glucosidases from Microbial and Vegetable Sources.

Fujita, A.; Alencar, S.; Park, Y.

Isoflavone aglycones have been shown to be more rapidly and efficiently absorbed into intestines than isoflavone glucosides. Helpfully, β-glucosidases can be used to convert isoflavone glucosides to aglycones. In this study, β-glucosidases from microbial ( Aspergillus niger) and vegetable lima bean ( Phaseolus lunatus) sources were characterized, purified, and then employed to convert isoflavone glycosides to aglycones. The microbial crude extract showed maximum activity at 60 °C and pH 5.0. It was highly stable between 40 and 60 °C and between pH 4.0 and 9.0. Optimum activity for the vegetable crude extract was achieved also at 60 °C and pH 5.5. Similarly, it presented great stability at high temperatures and a wide pH range. The microbial enzyme was purified by a factor of 14-fold to a yield of 2.2 % and a specific activity of 17 IU/mg. The vegetable enzyme was purified by a factor of fourfold to a yield of 77 % and a specific activity of 0.18 IU/mg protein. Both β-glucosidases produced satisfactory conversion rates of daidzin and genistin into daidzein and genistein; however, the microbial enzyme performed better than the vegetable enzyme. Our results suggest a potential use of these enzymes to enhance the bioavailability of isoflavones in food products.

ISOFLAVONE glycosides; AGLYCONES; GLUCOSIDASES; INTESTINAL physiology; ABSORPTION (Physiology)

Applied Biochemistry & Biotechnology, 2015, Vol 176, Issue 6, p1659

0273-2289

Academic Journal

10.1007/s12010-015-1668-1