One of the principal active constituents of St. John’s Wort (Hypericum perforatum). Hypericin is a photosensitive pigment/chromophore with bright red fluorescence emission (lambdamax: 594nm). Has a high triplet quantum yield and ability to produce considerable amounts of singlet oxygen and other ROS species when photoactivated. Antiviral, anticancer and antidepressant agent. Inactivates enveloped viruses (including HIV). This photosensitizing agent has shown to induce apoptosis and necrosis in cancer cells during photodynamic therapy. Selective inhibitor of protein kinase C (PKC). Has been shown to inhibit other kinases and targets such as EGFR-PTK, PI3K, CKII, MAPK and insulin receptor (IR). Necrosis-avid contrast agent investigated for use in non-invasively targeting necrotic tissues, based on to be defined components in the phospholipid bilayer.