Concerns regarding increased risks of stroke and breast cancer have prompted many women to consider botanical dietary supplements instead of conventional hormone therapy for the management of menopausal symptoms such as hot flashes. Among botanical supplement alternatives to hormone therapy, licorice (Glycyrrhiza sp.) is an increasingly popular alternative and has a long history of use in Traditional Chinese Medicine as well as in Western pharmacopeias. To ensure the safe use of licorice dietary supplements, we investigated their potential for drug interactions. Standardized licorice extracts of Glycyrrhiza glabra, G. inflata, and G. uralensis, the three most common species used in dietary supplements, were studied for possible inhibition or induction of cytochrome P450 enzymes involved in drug metabolism. In studies using human liver microsomes and a cocktail probe substrate assay, all three licorice species showed inhibition of CYP2B6, CYP2C8, CYP2C9 and CYP2C19. G. inflata also inhibited CYP1A2, CYP2D6 and CYP3A4. Cryopreserved human hepatocytes were used to predict effects of the extracts and individual licorice compounds on cytochrome P450 enzyme induction. CYP3A4 was unaffected by all Glycyrrhiza sp, and CYP1A2 and CYP2B6 were induced in hepatocytes by G. uralensis and G. inflata. Due to these data, dietary supplements containing G. uralensis and G. inflata are more likely than G. glabra to cause clinically relevant drug interactions.

Pharmacokinetic interactions between drugs and licorice botanical dietary supplements used by menopausal women

254th National Meeting (2017)

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