Definition of hypericin in English:
 hypericin
noun hʌɪˈpɛrɪsɪnˌhīˈperəs(ə)n
mass nounA substance found in St John's wort, credited with chemical and pharmacological properties similar to those of antidepressants.
A polycyclic quinone; chemical formula: C₃₀H₁₄O₈
 Example sentencesExamples
-  In addition to its photodynamic properties, hypericin is also hydrophobic and binds to a variety of cell and enveloped virus membranes.
 -  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.
 -  Today, St. John's wort standardized to 0.3% hypericin easily outsells its pharmaceutical rival, Prozac, and its derivatives.
 -  The antitumor properties of St. John's wort are attributed to hypericin, which is a powerful photosensitizer.
 
Origin
  
Early 20th century: from hypericum + -in1.