2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L) in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated melanin formation in intact B16 melanoma cells.

Clinically useful antibiotics, β-lactams and vancomycin, are known to inhibit bacterial cell wall peptidoglycan synthesis. Methicillin-resistant Staphylococcus aureus (MRSA) has a unique cell wall structure consisting of peptidoglycan and wall teichoic acid. In recent years, new anti-infectious agents (spirohexaline, tripropeptin C, DMPI, CDFI, cyslabdan, 1835F03, and BPH-652) targeting MRSA cell wall biosynthesis have been discovered using unique screening methods. These agents were found to inhibit important enzymes involved in cell wall biosynthesis such as undecaprenyl pyrophosphate (UPP) synthase, FemA, flippase, or UPP phosphatase. In this review, the discovery, the mechanism of action, and the future of these anti-infectious agents are described.