Glabridin from Glycyrrhiza glabra Possesses a Therapeutic Role against Keloid via Attenuating PI3K/Akt and Transforming Growth Factor-beta 1/SMAD Signaling Pathways

Glabridin (Gla) is a typical flavonoid isolated from the Glycyrrhiza glabra with various bioactivities and is a common additive in many cosmetics. In our study, we evaluated the antiscarring effect of Gla from G. glabra in a rabbit ear hyperplastic scar model. Hematoxylin and eosin staining and Masson staining were applied to determine the pathological changes and collagen fibers of scar tissue in rabbits. The results suggested that Gla could reduce rabbit ear scar hyperplasia, inhibit inflammation, and decrease collagen production. Furthermore, the in vitro cell experiments were applied to determine the effects of Gla on human keloid fibroblasts (HKFs), and we observed that Gla suppressed the HKF cells' proliferation via inducing apoptosis. Subsequently, we found that Gla reduced collagen production in HKF cells. The further molecular mechanisms investigations suggested that Gla played a therapeutic role against keloid by attenuating PI3K/Akt and TGF beta 1/SMAD pathways. Our study would be beneficial for extending the applications of the known sweet plant of G. glabra.