The active substances contained in St. John’s wort have a variety of effects on the human nervous system. In particular, hyperforin affects the nervous system in such a way that there is a restoration of the balance of messenger substances in the brain.
St. John’s wort: effect on mood
The mood-lifting, anxiety-relieving, and antidepressant effects of St. John’s wort are due to an increase in the concentration of certain neurotransmitters, such as dopamine, serotonin, and norepinephrine, which are released in the brain in reduced amounts during depressive moods.
Hyperforin inhibits the reuptake of these substances into the nerve terminal, making them available again more quickly or allowing them to have a lasting effect. Hypericin, flavonoids and xanthones additionally inhibit the breakdown of serotonin, which further enhances the effect.
With permanent use, St. John’s wort is thus able to regulate nerve metabolism.
Other effects of St. John’s wort
Other ingredients of the herb have growth-inhibiting effects on bacteria. The faster healing of wounds by St. John’s wort is probably due to the tannins it contains. These lead to a compaction of the surfaces of the tissue, making it harder for pathogens to penetrate and causing wounds to heal faster.
Side effects of St. John’s wort
In fair-skinned individuals, sunburn-like reactions are possible when taking high doses of St. John’s wort, especially when sunbathing. In rare cases, allergic reactions such as itching, skin swelling, restlessness or fatigue, or gastrointestinal problems occur.
Interactions with other medications
St. John’s wort increases the activity of a certain liver enzyme that is responsible for the breakdown of various drugs. Taking St. John’s wort may therefore increase the breakdown and thus decrease the effect of various immunosuppressants (e.g., cyclosporines), HIV medications, medications used to treat cancer (cytostatics), heart medications (digoxin), and many others.
St. John’s wort, on the other hand, can also enhance the effects of various other drugs, such as antidepressants or anesthetics.
St. John’s wort and the pill
Also of particular importance is the increased breakdown of some drugs used for hormonal contraception (the pill). When St. John’s wort and the pill are taken at the same time, and the resulting loss of effect of the pill, the risk of unwanted pregnancy is accordingly increased.
