St John's wort is a common or English name given to species of plants in the genus Hypericum in the angiosperm's family, Hyperiaceae. There are over 490 identified species within this genus. Many of the species grow as pretty little shrubs up to 1.5 m in height with yellow flowers, some grow as annual or perennial herbs, while others grow as trees.
When it comes to distribution, species of St John's species are perhaps one of the most widely distributed plant species in nature. They are found virtually everywhere in the temperate and tropical regions of the world. Some species of the plant are have been researched to have invasive attributes and thus, their spread is usually controlled by various means to prevent the dis-equilibrium of the ecosystem.
One of the Hyperium species, H. perforatum, grows around here in Nigeria where it is given different names by the locals depending on their tribes (there are over 250 tribes in Nigeria, but he way). The plant is popularly known for its ethnomedicinal application in the treatment of depression. Not just that, different preparations from the organs of the plant are used in the treatment of ailments such as insomnia, nervousness, skin disorders, and lesions, stomach disorders, and many other diseases.
The ethnomedicinal application of the plant in the treatment of the listed ailments has been researched to be due to the presence of relevant active metabolites in the various parts of the plant. The antidepressant potential has been linked to the activities of the hypericin and the hyperforin contents in the inhibition of the reuptake of neurotransmitters such as serotonin, dopamine, and other related compound's uptake. The metabolism of these compounds has been fingered as part of the cause of depression.
Other phytochemicals that have been screened from the extracts of H. perforatum include proanthocyanidins, different flavonol groups, bisanthraquinone glycosides, naphthodianthrones, Phenylpropanes, and many other metabolites of significant medicinal potentials.
The efficacy of H perforatum extracts in relieving the symptoms of depression goes beyond anecdotal evidence as there are some scientific pointers as well. One of such pointers is the research conducted by Laakmann and his colleagues in 2002 where they investigated the effects of the extract of the plant in the treatment of moderate to severe depression. In actual fact, a particular report revealed that the effects of the extract of the plant and that of synthetic antidepressants are clinically comparable.
Final Thoughts
Nature really has its own peculiar way of dealing with us humans. That a plant, like H. perforatum, with huge medicinal benefits, has invasive attributes is like an irony. Who else knows what the benefits of other plants that have been termed 'invasive' could be?
References
https://www.fs.fed.us/database/feis/plants/forb/hypper/all.html
https://en.wikipedia.org/wiki/Hypericum
https://pubmed.ncbi.nlm.nih.gov/29442047/
https://pubmed.ncbi.nlm.nih.gov/12212522/