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St. John’s Wort extract

St. John’s Wort extract was extracted from flowers and top parts of the whole dry St. John’s Wort with different solvents. Based on the experimental result about the yield, its concentration and extraction temperature for each kind of solvents, optimal yields were obtained with 80% methanol at temperatures of 80 °C. The supercritical CO2 method as its a ‘gentle’ way of extracting is the best extraction method to get high hyperforin content in the final St. John’s Wort extract.

Chemical composition in St. John’s Wort extract

HyperforinSt. John’s Wort Herb and flowers contain various polyphenols: flavonoids (epigallocatechin, rutin, hyperoside, isoquercetin, quercitrin, quercetin, I3,II8-biapigenin, amentoflavone, astilbin, miquelianin, phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid), and various naphtodianthrones: (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin). The naphthodianthrones hypericin and pseudohypericin along with the phloroglucinol derivative hyperforin are thought to be the active components. It also contains essential oils composed mainly of sesquiterpenes.

St. John’s Wort extract Specification:

Standardized St. John’s Wort extracts (Hypericum perforatum) are available in the market and fortunately the labels do often show that the product is standardized. However, when these St. John’s Wort extracts are subjected to analytical tests for determination of active constituents, one of the constituents is often missing. Today, Hypericin 0.3% and Hyperforin 2.8% are considered to be the standards for a typical standardized Hypericum perforatum (St. John’s Wort) extracts. The majority of the St. John’s Wort extracts fail these testing parameters with hyperforin content varying from 2 % to 5 %, or it may be completely absent.

Most St. John’s Wort products are standardized to constituent known as hypericin, and others are standardized to hyperforin. Dr. Sahelian comments: Practically speaking, I don’t think it makes too much difference which substance — hyperforin or hypericin — St. John’s wort is standardized to.

Despite intensive research efforts, it has not yet been possible to identify all the active components of St. John,s Wort extract. On the basis of current knowledge, it is certain that hyperforin is one of the active components and that hypericins (total hypericins: psudohypericin, precursors: protohypericin and protopseudohypericin) and possibly flavanoids contribute to the antidepressant properties of St John’s Wort

1 Standardized to contain 0.3% hypericin (900 mcg per capsule)



Most studies of St. John’s wort for treating depression used doses of 300 mg of an St. John’s Wort extract (standardized to 0.3 percent hypericin content) three times daily to achieve a therapeutic effect. Studies suggest taking from 300mg to 1,800 mg daily. There have not been any reports of overdose.

St. John’s Wort extracts contain at least ten constituents or groups of components that may contribute to the pharmacological effects. It is not yet possible to correlate the antidepressive mode of action with specific constituents; therefore, the pharmaceutical quality of the St. John’s Wort extracts was characterized on the basis of typical leading substances and especially the hypericins.

The red-colored hypericins have been found in very few other plants, while most other ingredients are found in many other plants.

The hypericins also have a photodynamic effect, and sometimes they do not occur until the crude drug has been processed and exposed to light. The concentration of hypericins (mainly hypericine and pseudohypericin) in buds and flowers can vary between 0.06% and 0.75%. A minimum content of 0.04% total hypericin is required for commercial qualities.

The hypericin content of Hypericum perforatum (St. John’s Wort) is determined by using spectroscopic method utilizing the visible absorption characteristics of hypericin in methyl alcohol. In atypical chromatogram of standardized Hypericum perforatum (St. John’s Wort) extract, absorbance occurs at 588nm and the peak at 10.67 min is characteristic of Hypericin

The fact that its standardised for Hypericin content does not mean that it contain no Hyperforin – just that they have not made sure that each batch contains a certain amount of it. In general all brands are extracted from some part of the whole plant – so all potentially have a range of the different compounds found in the plant. The trouble is that various factors can lead to some of these compounds degrading and so it is possible for a brand stabilised on Hypercin content alone to have very little Hyperforin.

2 A high-quality St John’s Wort extract supplement standardized to contain 5% hyperforin


Hyperforin has only been found in significant amounts in Hypericum perforatum (St John’s wort), where it accumulates in oil glands, pistils, and fruits, probably as a plant defense against herbivory. Other Hypericum species contain low amounts of hyperforin.

Hyperforin is one of the key phytochemical actives found in St. John’s Wort. Many products for Hyperforin claim a 3% to 5% level of hyperforin. The reason for this is that it is almost impossible to standardize the St. John’s Wort extract to an exact amount due to the fact that phytochemical content of St. Johns Wort can be affected by factors such as:

The amount of rain water the plant received in one season as opposed to another

The nutrients in the soil that was used to grow the St. John’s Wort

The specific time of plant harvest

The specific aerial part of the plant used (i.e. flowers, stem, leaves)


In a study, healthy volunteers were given hypercin orally in a dose of 900, 1800 and 3600 mg and blood samples were analyzed.The maximum plasma concentration was found after 6 hours.18

Some pharmacokinetic data on hyperforin is available for an St. John’s Wort extract containing 5% hyperforin. Maximal plasma levels (Cmax) in human volunteers were reached 3.5h after administration of an St. John’s Wort extract containing 14.8 mg hyperforin. Biological half-life (t½) and mean residence time were 9h and 12h respectively with an estimated steady state plasma concentration of 100 ng/ml (approx. 180 nM/L) for 3 doses/d. Linear plasma concentrations were observed within a normal dosage range and no accumulation occurred.

Even though both of the constituents are considered equally important, the active ingredient of Hypericum perforatum (St. John’s Wort) is not yet known. Hypericin has shown weak antidepressant activity. It is being used as a marker compound and has a significant role to play in quality control. Initially Hypericin was shown as an antidepressant constituent of Hypericum perforatum (St. John’s Wort) . It weakly inhibits the enzyme Monoamine oxidase (MAO). In addition, Hypericin has been shown to have antiviral activity and will inhibit succinoxidase, NADPH-oxidase, tyrosinkinase and protein kinase C. Hypericin belongs to a group of compounds known as napthodianthrones, which constituent 0.1-0.15% of the dried herb. Hypericin content varies from 0.02-2.5%. Standardization to the marker compound is important for quality control and consistency. The companies usually take 0.3% Hypericin as standard.

Hyperforin’s mechanism of action

Though the mechanism of action in hyperforin is unlike synthetic prescription medications, it has a similar effect. Clinical trials show that hyperforin taken over a period of 2 – 6 weeks can help to improve the function of neurotransmitters like serotonin, which are closely linked to feelings of anxiety. Some studies show that St. Johns Wort with hyperforin extract is just as effective in treating symptoms of anxiety as are some popular prescription SSRI’s.

In studies conducted using St. John’s Wort with two different concentrations of hyperforin showed very conclusive results in favor of the higher levels of hyperforin. All factors other than the hyperforin concentration were identical, leading scientists and doctors to believe that hyperforin is indeed the ingredient responsible for St. John’s Wort’s renowned ability to treat mild to moderately severe depression.

Not all St. John’s Wort sold in stores will be effective against depression because a lot of cheaper brands will have little or no hyperforin content so you really have to be careful to buy. Most St. John’s Wort supplements sold in the US have only .5% hyperforin content, the amount that proved to be ineffective against depression in clinical trials, so it’s very important to take the time to find something that definitely has 5% hyperforin if you wish to use the supplement to fight depression.

Hyperforin is a natural compound extracted from the St. Hyperforin exhibits significant antidepressant activity. Biochemical research demonstrates that hyperforin inhibits the reuptake of the neurotransmitters: Norepinephrine, serotonin and dopamine.

The ability of any St. John’s Wort extract to relieve depression depends mainly on its hyperforin content. In other words, only St. John’s Wort extracts with significant amounts of hyperforin are effective.

Hyperforin in animal studies has shown the ability to inhibit the uptake of neurotransmitters, and accumulated data strongly favors hyperforin as the possible antidepressant constituent of Hypericum perforatum. Hyperforin belong to acylphloroglucinol group of compounds and it is highly unstable compound. Hyperforin not only inhibits the neuronal uptake of serotonin, norepinephrine and dopamine like many other antidepressants, but it also inhibits GABA and L-glutamate uptake. The present scenario is such that companies have shifted to standardized St. John’s Wort extracts containing 2.8% of hyperforin. Some companies are marketing Hypericum perforatum (St. John’s Wort) extract standardized to contain 2.8 % of hyperforin and 0.3 % of hypericin.

Bedsides hypericin and hyperforin, contains flavonoids, xanthones and volatile oil. These additional compounds have not yet been thoroughly investigated as to their biological activities in humans. Therefore, they cannot be ruled out in contributing antidepressant activity of Hypericum perforatum (St. John’s Wort) extract. In animal models, it has been observed that xanthones potentiate the antidepressant activity of hyperforin.

As researchers strove to understand the compound’s antidepressant mechanism, it was concluded that possibly Xanthones present in Hypericum perforatum (St. John’s Wort) contributed to the antidepressant activity. The Xanthone content varies from was 2.6%-4%. Out of two different Xanthones, 1,3,6,7-tetrahydroxy-xanthone has been shown to be more active. Xanthones also possess serotonin receptor binding inhibiting activity in animal models. Based upon these results, it was concluded that the antidepressant activity of Hypericum is not limited to one of the constituents, but is probably the result of a mixtures of the constituents.

This plant is akin to a biosynthetic laboratory, not only for chemical compounds, but also a multitude of compounds like glycosides, alkaloids etc. These compounds exert physiological and therapeutic effects. The compounds that are responsible for medicinal property of the drug are usually the secondary metabolites. Additional investigations in determination of the actual constituent must be undertaken.

St John’s Wort extract Stability

Unfortunately, few St. John’s wort products contain a standardized amount of hyperforin due to the instability of hyperforin and its high sensitivity to oxidation.

St. John’s Wort components were found to be unstable in acidic aqueous solutions. More changes occurred under light exposure, with hyperforin and adhyperforin decreasing the most. Less severe changes were observed in the drink sample as compared to the pH 2.65 solution. Major degradation products of hyperforin in acidic aqueous solutions were identified as furohyperforin, furohyperforin hydroperoxide, and furohyperforin isomer a.

Flvonols, hypericins and hyperforins, Photostability testing showed all the constituents to be photosensitive in the tested conditions. However, different opaficients and pigments present in the capsules influenced the stability of the different classes of constituents. Amber containers suggested as secondary packages influenced only in part the photostability of the investigated constituents. Log-term thermal stability testing showed a very low (less than 4 months) hyperforins and hyperivcins t90. even if ascorbic and citric acids were added to the formulation.

You never know what you’re getting when you buy a St John’s Wort product off the shelf. While some brands contain enough hyperforin to improve mood, most contain little or none.

Hyperforin, hypericin and pseudohypericin are the main ingredients of St. John’s Wort extract, which is available over the counter for treatment of mild to moderate depression. To facilitate clinical studies, two sensitive HPLC methods were developed for determination of hypericin/pseudohypericin and hyperforin, respectively, in human plasma samples. The achieved limits of quantitation of 0.25 ng/ml for hypericin and pseudohypericin and 10 ng/ml for hyperforin were low enough to allow determination of pharmacokinetic parameters of the substances. Following liquid-liquid extraction of human plasma the samples were separated by isocratic reversed-phase HLPC and analyzed using fluorimetric detection for hypericin/pseudohypericin and UV detection for hyperforin.

Clinical uses

Studies across the world have demonstrated that Hypericum perforatum (St. John’s Wort) is equivalent to synthetic antidepressants like Tricyclic antidepressants (Imipramine and Amitrptyline) and Selective Serotonin Reuptake Inhibitors (Fluoxetine and Sertraline) and has a good safety profile.

Studies show that people taking St. John’s Wort have fewer feelings of sadness and hopelessness and they sleep better, without the side effects common to antidepressant drugs.

St. John’s Wort is antibacterial and antiviral and ointments made with St. John’s Wort have been used for centuries to treat burns, bites and other wounds. The antiviral activity is being studied as a treatment for HIV infection, and experimental studies show that hypericin and pseudohypericin exhibit strong antiviral activity against herpes simplex virus types 1 and 2 and influenza virus types A and B.

Other applications for St. John’s Wort include treatment of sleep disorders, eating disorders, anxiety disorders, bed-wetting, PMS, chronic tension headaches.

Unstable when exposed to air and light of hyperforin


Take orally 1 capsule 3 times daily preferably with meals or as directed by a physician. Use for up to 6 weeks for mild to moderate depression:

When using St. John’s Wort extract standardized to 0.3% hypericin content: 300 mg three times daily.

When using a St. John’s Wort extract standardized to 0.2% hypericin: 250 mg twice daily.

When using a St. John’s Wort extract standardized to 5% hyperforin: 300 mg three times daily.

For children under 12 years of age with depression: St. John’s Wort extract standardized to 0.3% hypericin 300 mg daily.

More information about St. John’s Wort



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