Alyssin is an isothiocyanate that has been found in W. japonica and has diverse biological activities, including antibacterial, fungicidal, CYP inhibitory, and antiproliferative properties. It is active against the bacteria B. subtilis, methicillin-sensitive S. aureus, methicillin-resistant S. aureus (MRSA), and E. coli, and the plant pathogenic fungus A. niger. Alyssin (0.5-2.5 µM) directly inhibits activity of the cytochrome P450 (CYP) isoforms CYP1A1 and CYP1A2 induced by the polycyclic aromatic hydrocarbons (PAHs) anthracene and dibenzo[a,h]anthracene in MCF-7 breast cancer cells. It inhibits proliferation of HCT116 colon cancer cells (IC = <4 µM). Alyssin also inhibits platelet aggregation induced by ADP or arachidonic acid (ICs = 168 and 20 µM, respectively).