Localization of Herbal Medicine Substances in Sperm that Increase Fertilization Rate During Mouse IVF

Isoliquiritigenin and formononetin are flavonoids in licorice that significantly improve in vitro fertilization rates in mice. However, how these substances act on sperm is unknown. Since both are fluorescent substrates, the sperm in medium containing these substances was observed using a fluorescence microscope. We observed strong signals in the postacrosomal and midpiece regions. Various physiological activities of these molecules have been reported. It is thought that isoliquiritigenin and formononetin contribute to sperm motility after ejaculation and acquisition of fertility. The localization of these molecules in sperm would help to elucidate their function. The results will contribute to human infertility treatments.