Tyrosinase

Overview

Tyrosinase (TYR) is a copper-containing oxidase enzyme that catalyzes key steps in the biosynthesis of melanin, including the oxidation of phenolic substrates to quinones. Because of this central role in melanogenesis, tyrosinase is biologically important in pigmentation processes in skin, hair, and other tissues. It is also a widely studied pharmaceutical and cosmetic target, particularly in the context of hyperpigmentation disorders, where reducing TYR activity can decrease melanin formation.

In biomedical research, tyrosinase is also used as a functional trigger for selective drug delivery strategies. Since TYR can be overexpressed in melanoma cells, it has been explored as an endogenous activation mechanism for prodrugs designed to become cytotoxic preferentially in melanoma. Beyond oncology and dermatology, tyrosinase inhibition is frequently assessed in natural product screening because many plant- and algae-derived extracts contain compounds that can chelate copper, interfere with enzyme kinetics, or otherwise suppress melanin-related oxidation reactions. Related bioactivity studies often evaluate tyrosinase alongside acetylcholinesterase, alpha-glucosidase, and antioxidant endpoints such as DPPH and ABTS assays.

Focus of Latest Publications

Recent publications have used tyrosinase in two main ways: as a direct inhibitory target and as an endogenous trigger for selective drug activation. In melanoma research, a general TYR-responsive prodrug strategy was developed to design melanoma-selective anticancer agents. This work explicitly leveraged the fact that tyrosinase is overexpressed in melanoma cells, using the enzyme as a trigger to activate prodrugs preferentially in the tumor environment. The study included human melanoma cells (A375) and combined AI-driven pathways with expert-guided optimization and reinforcement learning to support design and lead selection. The reported goal was to create anticancer agents with selectivity for melanoma through TYR responsiveness rather than broad cytotoxicity.

Several studies focused on discovering or characterizing tyrosinase inhibitors for dermatologic or cosmetic applications. A Science Advances study described discovery of TYR inhibitors for hyperpigmentation disorders using de novo molecular generation and dual-track lead optimization, framed as a competition between AI and chemists. This indicates that tyrosinase remains a major target for computational and medicinal chemistry approaches aimed at controlling melanin production.

Natural products and plant extracts were also repeatedly evaluated for tyrosinase inhibition. Extracts and isolated compounds from Andrographis paniculata were tested for tyrosinase inhibitory activity alongside acetylcholinesterase inhibition, using spectrophotometric assays. Similarly, a study of Salvia heldreichiana reported measurable inhibition of tyrosinase and acetylcholinesterase, suggesting possible relevance to both dermatological and neuroprotective applications. In another investigation, Boswellia serrata hexane extract and hydrodistilled oil were compared, and the oil showed more potent inhibitory activity against tyrosinase than the hexane extract, as well as activity against cholinesterase and alpha-glucosidase.

Tyrosinase inhibition was also highlighted in work on Bellis annua extracts, where method-specific differences were observed and supercritical or solvent-based extraction conditions yielded superior TYR inhibition in one preparation. A food chemistry study on wheat bran improved biological activity through steam explosion, reporting increased tyrosinase inhibitory activity after processing. Likewise, biotechnological upcycling of Laminaria japonica processing waste via Lactiplantibacillus plantarum fermentation generated antioxidant and tyrosinase-inhibitory compounds; the resulting material showed an IC50 of 8.84 ± 0.04 mg/mL against tyrosinase and followed reversible mixed-type kinetics, with copper ion chelation and fluorescence quenching proposed as primary inhibitory mechanisms.

Cosmetic formulation research also incorporated tyrosinase as a readout. A Lycium barbarum extract-loaded pectin polysaccharide emulsion showed higher antioxidant activity and stronger inhibition of tyrosinase, elastase, and hyaluronidase, with no cytotoxicity reported, supporting its potential as an anti-aging cosmetic formulation. Across these studies, tyrosinase was consistently treated as a biologically meaningful target for pigmentation control, enzyme inhibition screening, and selective activation strategies in melanoma.