The Women's Health Initiative demonstrated increased risk of breast cancer associated with hormone therapy used for the alleviation of menopausal symptoms.  Therefore, many women turn to botanical dietary supplements as natural alternatives, without having sufficient evidence on their safety and efficacy.  The licorice species, Glycyrrhiza glabra L. and G. uralensis Fisch ex. DC, are common components of menopausal dietary formulations.  Our previous studies have demonstrated chemopreventive potential for hops botanical through activation of detoxification pathways in vitro and in vivo.  Considering that prenylated chalcones and flavanones are present in hops and licorice, the major goal of the current study was to evaluate the chemopreventive potential of licorice species that are used for women's health.  Our in vitro observations have shown that, similar to hops and its active constituent, the prenylated chalcone xanthohumol, licorice extracts containing the electrophilic 2'-hydroxychalcone, isoliquiritigenin, induced NQO1 in normal breast epithelial (MCF-10A) and hepatoma (hepa1c1c7) cells.  Induction of the antioxidant response element (ARE) in HepG2 cells implied the Keap1/Nrf2 pathway as the underlying mechanism.  Significant induction of chemopreventive responses by isoliquiritigenin over a narrow concentration range was comparable to other chemopreventive compounds such as curcumin and xanthohumol.  The extracts showed dose-dependent NQO1 induction with no toxicity suggesting the possibility of generating designer formulations with optimal NQO1 activity.  These observations were confirmed by in vivo analysis with fully characterized licorice extracts allowing the determination of the bioavailability of their active constituents and leading to a meaningful interpretation of NQO1 activity.  Our data demonstrate the relevance of simultaneous biological and chemical standardization of botanical dietary supplements.  Supported by P50 AT00155 provided by ODS and NCCAM.

Induction of the detoxification enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) by licorice species used in botanical dietary supplements for women's health

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.