Isoflavones and biotransformed dihydrodaidzein production with in vitro cultured callus of Korean wild arrowroot Pueraria lobata

Pueraria lobata, a medicinally important leguminous plant produces various isoflavones including puerarin, daidzin and daidzein which are metabolized to equol via dihydrodaidzein and tetrahydrodaidzein by the bacterial fermentation of natural isoflavone sources in human intestines. In this study, we described callus proliferation and isoflavone production in callus of Korean wild arrowroot and dihydrodaidzein biosynthesis in callus extract fermented with Pediococcus pentosaceus. Proliferation was the best at callus cultured in the medium containing 1.0 mg/L TDZ and 1.0 mg/L NAA at light condition for 12 days. Puerarin was significantly more produced at callus cultured in the medium containing 2.0 mg/L kinetin and 1.0 mg/L NAA at dark condition for 16 days, but daidzin and daidzein were not significant. Callus extract was successfully fermented with P. pentosaceus and dihydrodaidzein, which is one of equol precursors formed by biotransformation, was confirmed to be produced. These results will facilitate mass production of callus and isoflavones as equol precursors from Korean wild arrowroot and can be applied for the production of equol by biotransformation in vitro.