Callicarpa dichotoma Leaf Extract Alleviates Atopic Dermatitis through the Suppression of T Cells and Keratinocytes Activation

Atopic dermatitis (AD) is a highly recurrent chronic inflammatory skin disease, characterized by severe itching, immune imbalance, and skin barrier dysfunction. Damage to the skin barrier function is known to be the main cause of Th1/Th2 immune imbalance, due to the Th2-mediated immune response, and pro-inflammatory cytokines, including IL-4, IL-5, IL-13 and IL-31 and it plays an important role in further eliciting the environment of AD through stimulation. Currently, the most widely used drugs for the treatment of AD are corticosteroids, antihistamines and immunosuppressants (used by more than 60% of patients), which are reported to exhibit various side effects when taken for a long time. Therefore, interest in the physiological activity of safer plant-derived natural extracts is increasing. Callicarpa dichotoma is traditionally used in oriental medicine for bruises, habitual pain, gastric and postpartum hemorrhage. Recent studies have reported that it exhibits antioxidant anti-inflammatory and anti-hepatotoxic activity, but the role and activity of C. dichotoma in AD have not yet been studied. Therefore, in this study, the new physiological activity of C. dichotoma in the AD environment was investigated, suggesting its potential as a natural therapeutic agent.