Natural Remedies A-Z
St. John's Wort |
This herb really needs little introduction. This herb is a shrubby perenial that can reach a height of up to 2 feet. The stems are oval and irregular, and release a beautiful warm red sap when pressed. The leaves are easily distinguishable due to their pin prick/perforated appearence (hence the latin name Hypericum perforatum). The bright yellow flowers of this herb bloom in the summer.
Out of all the natural remedies that have recieved considerable press over recent years, St Johns Wort has been towards the top of the pile. It is of course most famed for its antidepressant actions, but has also been traditionally used as an anti-inflammatory agent, and an analgesic.
Constituents
Antraquinone derivatives: hypericin, isohypericin, protohypericin, peudohypericin
Flavanoids: quercetin, hyperoside, quercitrin, isoquercitrin, rutin, campherol, luteolin,
13-II8-biapigenin.
Prenylated phloroglucinols: hyperforin and adhyperforin
Procyanidines
Phenols
Phloroglucinols
Tannins
Antidepressant action
This appliction has been the widest documented of all of St Johns Wort’s actions. The exact mechanism of this action is unclear, although many studies have indicated a few key actions. It is most likely that the antidepressant action arises from a combination of these.
There have been a miriad of placebo controlled studies that provide evidence that this herb is considerably more effective than a placebo. Studies have shown that a St Johns Wort extract inhibited the synaptosomal re-uptake of serotoinin, dopamine, noradrenalin, and GABA (Heinrich et al 2004:239). All of these substances are directly involved in moods, and neurological impulses. It is worth noting that many studies have shown extracts to induce a rise in noradrenalin within the brainstem, an area that is often associated with depression (Barnes et al 2002:445). There are other studies that indicate that this herb has dopaminergic activity and has some effects upon cortisol. There is also evidence to suggest that it acts as a monoamine oxidase inhibitor (Heinrich et al 2004:239).
One particular issue that has arisen in recent years is debate over which constituent is actualy responsible for all of this. Hypericin was the first constituent believed to be instigating these effects, and was the focus of a large body of trials. Recently, more attention has been placed upon hyperforin, and low and behold, similar results have been found.
Anti-inflammatory action
St Johns Wort has a long standing traditional use as an anti-inflammatory agent, particularly when used topically. This action mainly stems from an inhibition of prastaglandin E1, TNF, and leukotrienes. These are all mediators of the allegic response, so supression of these will lead to a reduction in inflammation. There is also a notable reduction in 12-lipoxygenase, which is another inflammatory mediator.
Analgesic action
There is another well renowned traditional application of this herb, and that is as an analgesic. The mechanics of this action is not known, however, the chemical group believed to be responsible for this action are the flavanoids (Barnes et al 2002:446). It is also worth considering that the anti-inflammatory action is likely to contribute to pain relief. Reduction in swelling = reduction in pain.
References
Heinrich M, Barnes J, Gibbons S, Williamson EM (2004). Fundamentals of Pharmacognosy and Phytotherapy. USA, Philadelphia: Churchill Livingstone.
Barnes J, Anderson LA, Phillipson JD (2002). Herbel Medicines (2nd ed). UK,London: Pharmaceutical Press).