Hypericum neurotransmitters

Amino acid neurotransmitter Constituents of hypericum also appear to have effects on amino acid neurotransmission, particularly GABA. Hypericin and a crude extract bind to GABAA and GABAB receptors (Cott 1997). Hyperforin also inhibits synaptosomal GABA reuptake in the low micromolar range (IC50 values of 0.05-0.10 ug/ml). Activity at GABAA benzodiazepine receptors was noted in extracts of four hy-... 

Muller WE, Singer A, Wonnemann M, Hafner U, Rolli M, Schafer C. (1998). Hyperforin represents the neurotransmitter reuptake inhibiting constituent of hypericum extract. Pharmacopsychia y. 31(suppl 1) 16-21. 

Rollie M, et al. Effects of hypericum extract LI 160 on neurotransmitter receptor binding and S5mapsomal uptake system. Pharmacopsychiatry 1995 28 207-210. Muller WE, Rollie M, Schafer C, et al. Effects of hypericum extract LI 160 in biochemical models of antidepressant activity. Pharmacopsychiatry 1997 30(suppl 2) 102-107. 

St. John s wort is derived from the flowers of the Hypericum perforatum plant that grows throughout England, Europe, Asia, and parts of the United States. This herbal supplement has been used extensively to treat symptoms of depression and anxiety. Although the details are unclear, St. John s wort probably contains several chemicals that alter the balance of central nervous system (CNS) neurotransmitters affecting mood and behavior.46,84 As discussed in Chapter 7, depression seems to be associated with a fundamental defect in amine neurotransmitters such as serotonin, norepinephrine, and dopamine. St. John s wort may promote changes in these neurotransmitters in a manner similar to conventional prescription antidepressants.56,84 Many people have therefore used St. John s wort as an alternative medication to help improve mood and resolve the symptoms of depression.46,72... 

St. John s wort. The St. John s wort plant (Hypericum perforatum Figure 6.4) is an increasingly popular herbal supplement that proponents claim has the ability to cure a vast array of ailments. St. John s wort appears to boost the release of the neurotransmitter serotonin in the brain, which may be the reason it is able to treat anxiety and depression. The herb contains numerous substances, two of which, hypericin and hyperforin, maybe key active ingredients. St. John s wort appears to be effective in relieving the muscle pain associated with fibromyalgia and the tissue pain associated with hemorrhoids. The herb comes in tablet, capsule, cream, and ointment forms and must be taken for several weeks before it takes full effect. St. John s wort should not be taken with antidepressants such as... 

The exact mechanism of action responsible for St. John s wort s neurological effects is not known. Additionally, it is not known if any one chemical constituent is responsible for its activity or if it is a combination of multiple components. It is known that the extracts of H. perforatum appear to inhibit the synaptic uptake of several neurotransmitters including norepinephrine, serotonin (5-HT), and dopamine (3,11-13). Rats that were fed high doses of hypericum extracts standardized to flavonoids (50%), hypericin (0.3%), and... 

Other studies have shown that hypericum extracts inhibit in vitro the reuptake of monoamine neurotransmitters such as serotonin, dopamine and noradrenaline [10,87]. 

Assays with extracts devoid of hypericin but with a high content of hyperforin as well as assays with pure hyperforin demonstrated that this metabolite can modulate the function of various neurotransmitters involved in depression, being a potent inhibitor of serotonin, dopamine, noradrenaline and GABA uptake with almost equal potency. Moreover, results from clinical studies evidenced that the antidepressant efficacy of Hypericum preparations correlates with their content of hyperforin [6,87],... 

---