St. John's wort
(Hypericum perforatum)

Perhaps without knowing it, many people have seen real St. John’s wort (Latin: Hypericum perforatum L.) while out walking. The shrub is found all the way from West Asia to Europe and down to North Africa. It also grows in Switzerland, Germany and Austria. It is hardy, can withstand the winter and does not have any special soil requirements. The plant is often found growing along pathways, on the sunny edges of forests and brush, in meadows that have not been excessively fertilised, and on railway embankments. It prefers sunny locations.

Hypericum perforatum L. is cultivated on an agricultural scale for the production of medicinal products. The crops are mainly found in Germany, Eastern Europe and Chile. The herb and its partially or fully blooming inflorescences are used for the production of St. John’s wort extracts.

There are nearly 500 different species in the Hypericum genus. The most well-known is true St. John’s wort (Hypericum perforatum L.), which is used for medicinal purposes. It is a herbaceous shrub and can grow to a height of up to a metre. The ovular or oblong leaves, which can reach a size of three centimetres, grow on angular, densely branched stalks. Upon closer examination, numerous translucent dots become visible on the edges and surfaces of the leaves. These are special oil glands where essential oils are found and the reason why the species is called perforatum in Latin. The leaves look like they are perforated (full of holes).

True St. John’s wort has bright yellow flowers between June and August. The flowers are radial with petals that are up to 13 millimetres in length. The centre of the golden yellow flowers is dominated by striking stamens that occur in bushy clusters. The petals also have oil glands that take the form of dark coloured pits. If you rub the flower buds between your fingers, it turns your fingertips red. This is due to the large quantity of hypericin, a dark red, fat-soluble substance that is concentrated in the pits.

The name of the plant refers to the holiday of St. John’s Eve, which is a church feast on 24 June celebrating the birth of John the Baptist. St. John’s wort is in full bloom during this time. Another common name for the medicinal plant is perforate St. John’s wort, which, as the Latin name perforatum suggests, refers to the clearly visible oil glands on the petals and leaves.

Hildegard von Bingen (1098 – 1179), in fact, described the plant as “a herb to fight off dark melancholia”. Only later was this effect rediscovered and studied by scientists. Today, numerous studies have shown that it is nature’s herbal version of an effective antidepressant, which is why St. John’s wort was named “Medicinal Plant of the Year” by the Würzburger Institut für die Geschichte der Medizin in 2015.

The main active ingredients in St. John’s wort include hypericin, hyperforin, flavonoids, catechin tannins, essential oils and phenol carboxylic acids. St. John’s wort extract has a positive effect on a person’s mood during emotional lows. It can also be used, for example, to treat minor to moderate depression. The mechanism of action has been attributed to the inhibition of neural serotonin reuptake and other neurotransmitters, among other things. The latest findings have shown positive effects on the membranes of stressed nerve cells. Researchers had long believed that the substance hyperforin is primarily responsible for this effect, However, this thesis is no longer tenable because St. John’s wort extracts containing very low levels of hyperforin also have an antidepressant effect. Presumably, there is a combination of several plant substances, which also include hypericin, that are probably responsible for the effect. This is why the complete extract of St. John’s wort is considered an active agent.

Researchers studying medicinal plants are in agreement that taking St. John’s wort extracts containing a high quantity of hyperforin can result in interactions with other drugs. Hyperforin increases the production of certain enzymes and transporter proteins in the human liver which are responsible for breaking down many medicinal products. Therefore, certain active ingredients become less effective in the presence of high doses of hyperforin as it breaks them down more quickly. This is particularly the case for certain antibiotics and steroid hormones, for example. The hyperforin content in the extract depends on numerous factors, such as the type of hypericum that is cultivated, growing conditions, harvesting time, cutting height of the plant as well as the extraction method. Therefore, it is a good idea to use an extract of St. John’s wort that is low in hyperforin in order to avoid interactions with certain medicinal products. Please talk to your doctor or pharmacist beforehand about which active ingredients should not be taken with St. John’s wort.

Medicinal products containing extracts of Hypericum perforatum L. are primarily used to treat episodes of depression and other depressive disorders. However, there are other internal and topical uses for St. John’s wort oil as well.

If you have been diagnosed with mild to moderate depression, preparations containing St. John’s wort may have a calming, balancing effect and help to raise your spirits and motivation levels. Typical symptoms of depression, such as despondency or a feeling of emptiness or joylessness, can be improved in many cases. This is also true during phases of depression caused by hormonal changes: for example, during menopause or at certain times during a woman’s menstrual cycle.

Preparations containing hypericum may also alleviate depressive symptoms such as anxiety, inner restlessness and nervousness. They may also be effective against sleeping disorders caused by these issues. Moreover, the medicinal herb can also help with intermittent episodes of mental exhaustion. The effect of St. John’s wort preparations usually sets in after taking them regularly for a period of four weeks.

St. John’s wort oil (also known as red oil) is produced by infusing vegetable oil with the flowers of the St. John’s wort plant. Because it contains hypericin, the oil turns red, especially when exposed to sunlight. St. John’s wort oil is traditionally applied to the skin for symptomatic treatment of smaller skin irritations (such as sunburn) and to support wound healing.

This is general information. For individual advice, please contact a specialist.