A furanochromone derivative, visnagin stimulates melanogenesis via the activation of cAMP/PKA/CREB pathway

Melanin synthesis represents a crucial biological process with significant therapeutic implications for hypopigmentation-related disorders. Visnagin, a furanochromone derivative, constitutes one of the primary bioactive constituents of Ammi visnaga L. It has demonstrated pharmacological efficacy in various conditions, such as angina pectoris, urolithiasis, pertussis and colic. Nevertheless, its potential modulatory effects on melanogenesis have not yet been systematically investigated.

A series of in vitro and in vivo experiments were carried out to elucidate how visnagin enhances melanogenesis. Its biological activity, together with the implicated signaling pathways, was assessed using B16F10 melanoma cells, primary human epidermal melanocytes, and a murine model of chemically induced vitiligo.

To substantiate the melanogenesis-enhancing effects of visnagin both in vitro and in vivo, a broad set of analytical approaches was employed, including computational docking, melanin measurement, tyrosinase activity colorimetric assessment, intracellular cAMP levels determination, qPCR and Western blot analyses, dual-luciferase reporter assays, and an acute dermal irritation evaluation, as well as Fontana-Masson and H&E histological analysis.

Visnagin is found to stimulate melanin synthesis, dendrite structure formation and melanosomes transportation, via enhancing the intracellular levels of cAMP and inducing the phosphorylation of CREB in vitro through the PKA-dependent pathway. Furthermore, the topical application of visnagin markedly elevated melanin levels in hair follicles and ameliorated pigmentation defects in hydroquinone-induced vitiligo mice model.

The experimental findings indicate that visnagin demonstrates potential as a natural pharmaceutical candidate for the treatment of pigmentary disorders, thereby offering a promising therapeutic approach.