Definition of hypericin in US English:



  • A substance found in St. John's wort, credited with chemical and pharmacological properties similar to those of antidepressants.

    A polycyclic quinone; chemical formula: C₃₀H₁₄O₈

    • ‘Today, St. John's wort standardized to 0.3% hypericin easily outsells its pharmaceutical rival, Prozac, and its derivatives.’
    • ‘In addition to its photodynamic properties, hypericin is also hydrophobic and binds to a variety of cell and enveloped virus membranes.’
    • ‘The antitumor properties of St. John's wort are attributed to hypericin, which is a powerful photosensitizer.’
    • ‘The two compounds considered important in the plant's anti-depressant activity are hypericin and hyperforin.’
    • ‘St.John's Wort contains hypericin, which inhibits monoamine oxidase, a chemical associated with depression.’


Early 20th century: from hypericum + -in.