Anthocyanins from bilberry (Vaccinium myrtillus L.) alleviate pruritus in a mouse model of chronic allergic contact dermatitis

Background: Bilberry (Vaccinium myrtillus L.) is one of the richest sources of anthocyanins which are known to have anticancer, wound healing and anti-allergic effects. Here, we examined whether bilberry extract (Bilberon-25) alleviates pruritus in a mouse model of chronic allergic contact dermatitis. Materials and Methods: BALB/c mice with chronic allergic contact dermatitis induced by 3 weeks of repeated application of 2,4,6-trinitro-1-chlorobenzene (TNCB) were administered Bilberon-25 orally for 3 weeks after sensitization with TNCB. The effects of Bilberon-25 on pruritus and inflammation were evaluated by measurement of scratching behaviour and ear swelling, respectively. Results: Treatment with Bilberon-25 significantly attenuated the TNCB-induced increase in scratching behaviour, but dexamethasone did not. In contrast, ear swelling was ameliorated by dexamethasone treatment, and significantly decreased by Bilberon-25. Repeated application of TNCB induced a shift in the cutaneous cytokine milieu from a T helper cell type (Th)1 to a Th2 profile; Bilberon-25 and dexamethasone alleviated this Th2 predominance of the lesional skin. Conclusion: Anthocyanins from bilberry might be beneficial for the treatment of chronic pruritus which can occur in patients with inflammatory skin diseases such as atopic dermatitis.