Camellia sinensis tea melanin suppresses transformation of the aryl hydrocarbon receptor and prevents against dioxin-induced toxicity in mice

Assessing the frequency of adverse reactions induced by melanin containing formulations used for the management of solar dermatitis

BACKGROUND

Melanin from different sources is widely used by many manufacturers to produce cosmetics and sunscreens. Research data shows a wide spectrum of biological activities of melanin including the protection against UV radiation and oxidants. According to the research evidence, the topical use of melanin is more effective against inflammation than the hydrocortisone. The most common side effects of topical melanin ointment are local itching, burning and moderate hyperemia.

AIM OF THE STUDY

The purpose of this work is to describe the adverse outcomes of melanin containing formulas in patients with solar dermatitis, and to compare the frequency of adverse reactions with data from different research reports.

METHODS

A Pharmacovigilance questionnaire was developed to assess potential adverse events attributable to the use of melanin ointment. We used a modified survey tool created by Jaber and coauthors. This survey of melanin application documents validated reports of adverse events manifested by objective skin changes. MEDLINE (Ovid); MEDLINE In-Process Citations & Daily Update (Ovid); PubMed (NLM) (Internet); Embase (Ovid); Cochrane Database of Systematic Reviews were searched for the evidence on adverse reactions of topical melanin application.

RESULTS

The responses documented in this survey show reliability and safety of melanin formula used for the photoprotection and treatment of solar dermatitis. Most symptoms encountered in those using melanin were consistent with exposure to excessive amount (more than 4 times per day) of the compound applied topically. Of the total 534 survey responses received, 74% reported no adverse events. A total of 140 completed adverse event reports. Melanin ointment was being administered for the indications of photo injury (burns) in 75%, photo-dermatitis in 18%, and solar eczematous dermatitis in 7% of patients. Data were compared with rates from other reports.

CONCLUSION

We have no evidence that the chemical structure of melanin varies with currently available products, used locally or in other countries, nor that any such variability played any role in the events reported here. Further studies are required to compare the adverse events of topical melanin formulas containing melanins of different origin.

Pharmacological Properties of Melanin and its Function in Health

The biological pigment melanin is present in most of the biological systems. It manifests a host of biological and pharmacological properties. Its role as a molecule with special properties and functions affecting general health, including photoprotective and immunological action, are well recognized. Its antioxidant, anti-inflammatory, immunomodulatory, radioprotective, hepatic, gastrointestinal and hypoglycaemic benefits have only recently been recognized and studied. It is also associated with certain disorders of the nervous system. In this MiniReview, we consider the steadily increasing literature on the bioavailability and functional activity of melanin. Published literature shows that melanin may play a number of possible pharmacological effects such as protective, stimulatory, diagnostic and curative roles in human health. In this MiniReview, possible health roles and pharmacological effects are considered.