Pharmacological Activities, Toxicity, and Drug Interactions of Hypericum Perforatum L.

Abstract

Hypericum perforatum L. (St. John's Wort) has been utilized throughout history as an herbal remedy. Today, it continues to attract attention from researchers due to the wide variety of bioactive constituents present in the plant. These include naphthodianthrones, phloroglucinols, flavonoids, biflavonoids, xanthones, phenolics, and volatile oils. While St. John's Wort has gained popularity primarily for its use in treating depression, research has demonstrated that the plant exhibits a broad spectrum of biologic actions, including anti-inflammatory action, antibacterial activity, antioxidant properties, protection against neurodegenerative disorders, enhanced healing of wounds and possibly some anticancer properties. As a monotherapy, St. John's Wort appears to be relatively safe; however, the potential for photosensitivity as well as mania induction has been documented. One of the primary concerns regarding the clinical use of St. John's Wort is its capacity to activate cytochrome P-450 enzymes and P-glycoprotein, resulting in decreased levels of many co-administered medications. Drug interactions have been documented with several classes of medication, including warfarin, cyclosporine, theophylline, digoxin, HIV protease inhibitor drugs, certain antiepileptic drugs (i.e., carbamazepine), selective serotonin reuptake inhibitors (SSRIs), triptans, oral contraceptive pills, antiretrovirals and various chemotherapy agents. Given this complex pharmacology and significant potential for drug interactions, the use of H. perforatum should be accompanied by caution and professional supervision.