Medical Attributes of St. John's Wort
Browse articles:
Auto Beauty Business Culture Dieting DIY Events Fashion Finance Food Freelancing Gardening Health Hobbies Home Internet Jobs Law Local Media Men's Health Mobile Nutrition Parenting Pets Pregnancy Products Psychology Real Estate Relationships Science Seniors Sports Technology Travel Wellness Women's Health
Browse companies:
Automotive Crafts, Hobbies & Gifts Department Stores Electronics & Wearables Fashion Food & Drink Health & Beauty Home & Garden Online Services & Software Sports & Outdoors Subscription Boxes Toys, Kids & Baby Travel & Events

Medical Attributes of St. John's Wort

St. JohnÂ’s wort has been used as an herbal remedy to treat a variety of internal and external ailments since ancient Greek times. Since then, it has remained a popular treatment for anxiety, depression, cuts, and burns. Sales of products made from St. JohnÂ’s wort presently exceed several billion dollars each year.

St. John’s wort, known botanically as Hypericum perforatum, is a sprawling, leafy herb that grows in open, disturbed areas throughout much of temperate North America and Australia. St. John’s wort has been used as an herbal remedy to treat a variety of internal and external ailments since ancient Greek times. Since then, it has remained a popular treatment for anxiety, depression, cuts, and burns. Sales of products made from St. John’s wort presently exceed several billion dollars each year.

St. John’s wort produces dozens of biologically active substances, two being the most clinically effective. Hypericin and its naphthodianthrone analogs are produced by small, dark glands on the surfaces of the yellow petals, constituting 0.1–0.3% of the dry mass of the foliage. Hyperforin is a lipophilic phloroglucinol derivative derived from the buds and flowers, constituting 2–4.5% of the mass of the foliage.

H. perforatum has been intensively studied on isolated tissue samples, using animal models, and through human clinical trials. The effectiveness of St. John’s wort as an antidepressive agent has been particularly well studied. At the cellular level, hypericin and hyperforin both inhibit uptake of key neurotransmitters like serotonin (5-HT), dopamine, noradrenaline, GABA, and L-glutamate at the synaptic cleft in the brain. Hyperforinmay also increase the density of 5-HT receptors, thus providing potential long-term benefits.

Meta-analyses of clinical trials conducted in Europe since the 1980s indicated that St. John’s wort was more effective in alleviating depression than placebo. Moreover, St. John’s wort was shown to be as effective in treating depression as standard tricyclic synthetic drugs—with fewer adverse effects. However, two multicenter studies conducted in the United States between 1998 and 2001 did not find any difference between St. John’s wort and placebo, especially in patients with moderate to severe depression. Taken together the studies indicate that St. John’s wort appears to have some efficacy in treating mild to moderate depression, but no proven value in treating moderate to severe depression.

St. John’s wort has value as an antibacterial and antiviral agent. Hyperforin is particularly active against gram-positive bacteria, including meticillin-resistant and penicillin-resistant Staphylococcus aureus. Extracts have been shown to be active against enveloped viruses, especially when activated by light. In the 1990s, St. John’s wort was examined as a therapy for HIV, though a Phase I clinical trial published in 1999 indicated no discernible effect coupled with low tolerability.

Both hyperforin and hypericin show potential as anticancer therapies. Hyperforin inhibits tumor cell growth in vitro by induction of apoptosis through the activation of caspases. In the presence of light and oxygen, hypericin kills tumors by generating superoxide radicals that yield cytotoxic species. Hypericin has potential to be used in photodynamic therapy (PDT) against a variety of neoplastic tissues. However, St. John’s wort extracts may interfere with the success of treatments involving the anticancer agent irinotecan.

Though generally well tolerated, especially at typically recommended doses, St. John’s wort may produce adverse effects including gastrointestinal symptoms, dizziness, confusion, restlessness, and lethargy. More significantly, St. John’s wort can interact adversely with a wide range of prescription and over-the-counter medications, as well as with other herbal remedies. Especially noteworthy are adverse interactions with standard antidepressants, and with drugs that are metabolized by hepatic cytochrome enzymes. Individuals taking other medications or suffering from moderate to severe psychological or physical ailments should consult with their physician before taking extracts of St. John’s wort.

Need an answer?
Get insightful answers from community-recommended
experts
in Herbs & Herbal Supplements on Knoji.
Would you recommend this author as an expert in Herbs & Herbal Supplements?
You have 0 recommendations remaining to grant today.
Comments (1)

I never knew this before.

ARTICLE DETAILS
RELATED ARTICLES
RELATED CATEGORIES
ARTICLE KEYWORDS
RECENT SEARCHES ON KNOJI SHOPPING