St. John's Wort

Figure 1. The St. John's Wort (or Hypericum perforatum) plant.

St. John's Wort or Hypericum perforatum is a herbaceous perennial plant with extensive, creeping rhizomes in the family Hypericaceae characterised by their yellow, star-shaped flowers. The species can be found across temperate areas of Eurasia, much of North and South America, South Africa, and Australia. St. John's Wort has been used in folk medicine for centuries as an antidote for poisons and universal panacea.

Due to its diverse phytochemicals, St. John's Wort is a popular dietary supplement. The plant contains flavonoids, phenolic acids, naphthodianthrones, phloroglucinols, tannins, volatile oils, fatty acids, alkanols, vitamins and their analogues (e.g. carotenoids, choline, nicotinamide), and other compounds.

Taken as a dietary supplement, St. John's Wort is promoted to help with easing the symptoms of depression and mood disorders. Studies have shown that the phytochemicals in St. John's Wort act on neuro messengers in the brain that regulate mood. In addition, St. John’s Wort also has strong antiviral activity that may promote healing and repair of wounds.