Improved In Vitro Fertilization Ability of Mouse Sperm Caused by the Addition of Licorice Extract to the Preincubation Medium

Abstract

Artificial fertilization is used for the stable production of domestic animals, conservation of rare animals, and infertility treatment. However, the success rate of artificial fertilization is limited; thus, a more effective approach is desired. Cattle workers in Japan often add licorice grass to the herbage given to their animals before performing artificial insemination in an effort to increase the pregnancy rate. To examine the effects of licorice on fertilization success in mice, an aqueous extract of licorice was added to the culture medium used for insemination. The results were compared to those using glycyrrhizin, a major active constituent of licorice. The fertilization rate was improved by the aqueous licorice extract, but not specifically by glycyrrhizin. Thus, flavonoids in licorice other than glycyrrhizin may improve the success rate of artificial fertilization.

In vitro Fertilization with Mouse Sperm Activated by Components of Licorice Root Extract

“…We examined the viability of embryos treated with isoliquiritigenin or formononetin and found that the embryos were morphologically normal (Figure 7), consistent with previous observations using licorice crude extract [14].…”

“…n-BuOH, EtOAc fractions and GC were added to the conditioned medium [14]. Numbers indicate mean ± SE.…”

“…Furthermore, Traditional Chinese herbal medicine have been searched widely for female infertility [12,13]. We previously investigated the effects of crude licorice extract on the IVF rate [14] and isolated two active components of licorice that may be responsible for these effects [15]. In this review, we describe the active components of licorice extract, their isolation, and potential applications for improving IVF rates.…”

In Vitro Fertilization Activators for Future

“…In the case of forononetin, the ratio was slightly higher (50.2 ± 9.5%) but not significantly, than that of isoliquiritigenin as indicated in Figure 6. We examined the viability of embryos treated with isoliquiritigenin ( Figure 7A) or formononetin ( Figure 7B) to confirm that both embryos were morphologically normal similar to the previous observations using licorice crude extract [28]. …”

“…On the other hand, IVF efficiency using the sperm of aged BALB/cA mice (>48 weeks of age) is low, albeit fluctuated between mice [27]. However, we found that the licorice crude extract improved the fertilizing ability of BALB/cA mouse sperm in vitro as indicated in Figure 2 and that the fertilized eggs developed normally [28]. We performed five separate experiments using five different BALB/cA mice.…”