Tyrosinase inhibitors: a patent review (2011-2015).

INTRODUCTION: Tyrosinase is responsible for melanin production. The overproduction of melanin causes many skin disorders. The inhibition of tyrosinase activity would appear to be the most rational and explicit way of overcoming these issues. AREAS COVERED: Thirty eight patents on synthetic tyrosinase inhibitors issued since 2011 were reviewed. Inhibitors were categorized by chemical structure and assigned to eight classes. Information on potent inhibitors in each class is provided. EXPERT OPINION: Many tyrosinase inhibitors of natural or synthetic origin have been identified, but very few are qualified for clinical use. Thus medicinal scientists have to work more on the identification of potent and safe tyrosinase inhibitors. Various chemical scaffolds have been explored. Among them, the scaffolds such as resorcinol, biaryl, imidazolethione, β-phenyl-α,β-unsaturated carbonyl, and some double strand oligonucleotides have shown high tyrosinase inhibition, low toxicities, and great potencies. Detail structure activity relationship studies of these potential scaffolds could provide directions for a new and potent tyrosinase inhibitors. Furthermore new trends, such as the use of synergistic phenomena, salt formation, drug repositioning and designing of multi-targeted tyrosinase inhibitors could expand search areas for much improved tyrosinase inhibitors.