ST. JOHN’S WORT

ST. JOHN’S WORT



Botanical name: Hypercium perforatum


Family name: Clusiacaea


Synonyms: St. Joan’s wort


Part used: Flowers, upper 6 to 8 inches of the aerial portion of the herb, including leaf and flower







MECHANISMS OF ACTION


The precise mechanisms of action for the antidepressant effects of SJW are not understood. In vitro studies using hyperforin have demonstrated significant binding of GABA A and GABA B, adenosine, MAO, and benzodiazepine receptors. Only GABA A and GABA B receptor activity is likely to be achieved in concentrations to elicit a biological effect after oral administration in humans. Early studies focused on the inhibitory activity of hypericin on MAO receptors; however, most studies have demonstrated only weak binding if at all. It appears that there might be some effects in inhibition of synaptosomal uptake of serotonin (5-HT), dopamine, and noradrenaline, with an upregulation of 5-HT in rat cortex, with some increase in dopamine and noradrenaline. Studies have shown possible decrease in tryptophan degradation; tryptophan is a 5-HT precursor. Another possible explanation for the antidepressant effect of SJW is via inhibition of interleukin-6 (IL-6) by hyperforin and via inhibition of substance P mediated effects on depression.


Antiviral effects of SJW are attributed in part to the flavonoid and catechin fractions of the herb. Both hypericin and psuedohypericin have demonstrated in vitro inhibition of HSV Types 1 and 2, Varicella zoster virus, and HIV type 1 via a photoactivation process that is not yet elucidated.


Tannins in SJW have a mild astringent effect and may help to explain some of the vulnerary effects, as well as use in the treatment of hemorrhoids. A quercetin-like compound in SJW has been attributed with possible analgesic effects of the herb. SJW extract has also been observed to suppress inflammation and leukocyte infiltration in murine models. Hypericin has demonstrated in vitro ability to inhibit tumor necrosis factor induced activation of NF-kappa B and the release of arachadonic acid, as well as inhibition of 5-lipoxygenase and COX-1. SJW may have free-radical scavenging activity; however, this has not been a consistent finding in studies.

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Jul 24, 2016 | Posted by in GYNECOLOGY | Comments Off on ST. JOHN’S WORT

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