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| Saint johns wart flowers |
Latin name: Hypericum perforatum L. [Clusiaceae]
Plant parts: Flower, leaf
St. John’s wort is an herb with bright yellow flowers, whose benefit
in treating psychiatric disorders may have been recognized by Paracelsus
during the Renaissance. St. John’s wort is native to Europe,
North America, South America, and Asia. Most contemporary preparations
of St. John’s wort are aqueous alcoholic extracts with plant/
extract ratios of 4 to 7:1. St. John’s wort products have been characterized
and standardized to the content of hypericin and hyperforin. The
dried buds, flowers, and distal leaves contain 0.2 to 0.3 percent and 1 to
4 percent of these constituents, respectively (Schulz, Hänsel, and Tyler,
2001).
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| st johns wort |
Hypericin content is often measured using ultraviolet (UV) spectroscopy
using a method described by the German Pharmaceutical
Codex (Deutscher Arzneimittel-Codex [DAC]) that determines the
total quantity of a class of compounds called dianthrones, which includes
hypericin, psuedohypericin, protohypericin, and protopseudohypericin.
The UV spectroscopy results are quoted as total hypericin.
These constituents are also analyzed using high performance liquid
chromatography (HPLC), a system that allows for measurement of
individual constituents. Measurements generated from UV and HPLC
analysis are not interchangeable and should not be confused. The
other ingredient commonly used to characterize St. John’s wort products,
hyperforin, is quantified using HPLC analysis.
The most common indication treated with St. John’swort is mild to
moderate major depression. The essential feature of a major depressive
episode, as defined in the DSM-IV (Diagnostic and Statistical
Manual of Mental Disorders, Fourth Edition), is a period of at least
two weeks during which depressed mood or the loss of interest in
nearly all activities is observed (American Psychiatric Association,
1994). Additional symptoms of depression include changes in appetite
or weight, sleep, and psychomotor activity, decreased energy,
feelings of worthlessness or guilt, difficulty concentrating, or recurrent
thoughts of death or suicidal ideation. Major depressive episodes
can be mild, moderate, or severe. Depressive disorders are also defined
in theWorld Health Organization’s (WHO) International Classification
of Diseases, Tenth Revision (ICD-10) (WHO, 1992). Some
of the reviewed trials had inclusion criteria according to earlier
versions of these manuals: DSM-III and ICD-9.
The Hamilton Depression Rating Scale (HAM-D) is an observer
rating scale used to evaluate the degree of depression, and is often
used to evaluate the success of treatment. The physician interviews
the patient and assigns a score based on the severity of 17 or 21 items.
The definition of therapeutic success is usually a 50 percent reduction
in the total HAM-D score or a total score less than ten.
The usual treatment for depression includes psychotherapy and
antidepressant medication, which includes selective serotonin reuptake
inhibitors (SSRI), tricyclic antidepressants, and, more rarely,
monoamine oxidase inhibitors.
The majority of the reviewed studies indicate that St. John’s wort
extracts may be a viable treatment option for patients with mild to
moderate depression. However, some recent trials have not shown
any efficacy compared to placebo, casting doubt upon the benefit for
depression. However, we must keep in mind that at least one-third of
published clinical trials of approved antidepressants are negative for
efficacy (Thase, 1999). Nevertheless additional studies are required
to explore treatment for longer than eight weeks.
Two mode-of-action studies explored the effect of LI 160 and WS
5570 on pituitary hormone secretion as a means of exploring the effects
on neurotransmitters. The theory is that antidepressants that act
via noradrenaline reuptake inhibition pathways stimulate growth hormone
secretion, whereas those that act via serotonin reuptake inhibitors
stimulate prolactin. Cortisol secretion is increased by both noradrenaline
and serotonin reuptake inhibitors. In addition, plasma
levels of growth hormone can be elevated by dopamine reuptake inhibitors.
A small, one-day study with eight healthy males exploring
the mode of action of LI 160 found that administration of one dose of
2,700 mg LI 160 extract caused an increase in plasma concentrations
of growth hormone, a decrease in prolactin levels, and no effect on
cortisol levels compared to placebo. The authors of this study interpreted
the results to be due to an increase in the dopamine function
(Franklin et al., 1999). In contrast, another study found that administration
of 300 or 600 mg WS 5570 had no effect on prolactin levels,
only a minimal, inconsistent effect on growth factor levels, and a significant
effect on cortisol levels. The authors of this study suggested
an effect on noradrenaline and serotonin reuptake inhibitors due
mainly to the constituent hyperforin. Further, they suggested that the
discrepancies between the two studies might be a function of dose
(Schüle et al., 2001).
