Phenolic derivatives from soy flour ethanol extract are potent in vitro quinone reductase (QR) inducing agents

The fractionation of soy flour directed by a cellular bioassay for induction of phase 2 detoxification enzymes was used to identify quinone reductase (QR) inducing agents. A phospholipid-depleted, 80% methanol-partitioned isolate from a crude ethanol extract of soy flour was resolved using normal phase medium-pressure liquid chromatography (MPLC). Early eluting fractions were found to be the most potent QR inducing agents among the separated fractions. Fraction 2 was the most potent, doubling QR at <2 mug/mL. Further fractionation of this isolate led to the identification of several constituents. Fatty acids and sn-1 and sn-2 monoacylglycerols were identified, but were not highly potent QR inducers. Benzofuran-3-carbaldehyde, 4-hydroxybenzaldeyde, 4-ethoxybenzoic acid, 4-ethoxycinnamic acid, benzofuran-2-carboxylic ethyl ester, and ferulic acid ethyl ester (FAEE) were also identified as QR inducing constituents of this fraction. FAEE was the most potent of the identified constituents, doubling QR specific activity at 3.2 muM in the cellular bioassay.