Perforate St John's wort is a herbaceous perennial plant (Hypericaceae) with extensive, creeping rhizomes. Its stems are erect, branched in the upper section, and can grow to 1 m high. It has opposite, stalkless, narrow, oblong leaves that are 1–2 cm long. The leaves are yellow-green in color, with scattered translucent dots of glandular tissue. The dots are conspicuous when held up to the light, giving the leaves the 'perforated' appearance to which the plant's Latin name refers. The flowers measure up to 2.5 cm across, have five petals, and are colored bright yellow with conspicuous black dots. The flowers appear in broad cymes at the ends of the upper branches, between late spring and early to mid summer. The sepals are pointed, with black glandular dots. There are many stamens, which are united at the base into three bundles. The pollen grains are ellipsoidal. Hypericum perforatum is native to parts of Europe and Asia but, has spread to temperate regions worldwide as a cosmopolitan invasive weed.
It is a medicinal herb with antidepressant activity and potent anti-inflammatory properties as an arachidonate 5-lipoxygenase inhibitor and COX-1 inhibitor. St. Jon's wort roduces dozens of biologically active substances, although two—hypericin (a naphthodianthrone) and hyperforin (a lipophilic phloroglucinol)—have the greatest medical activity. Other compounds, including the flavonoids rutin, quercetin, and kaempferol, also appear to have medical activity.
The widespread popularity of SJW’s use as an herbal remedy results from studies that appear to verify its efficacy in treating a variety of diseases, especially depression. In turn, the herb’s use has generated widespread interest among scientists seeking to firmly evaluate its effectiveness. Such studies include analyses on the effects of SJW extracts on isolated tissue samples, studies using animal models, and clinical analyses and meta-analyses of humans given SJW extracts.
St. John's wort can help in seasonal affective disorder or the form of depression that occurs for some people during the winter months due to the absence of sunlight. It is also suggested as an alternative therapy for people with social phobia and obsessive compulsive disorder. Its effectiveness was also confirmed in the treatment of mental and vegetative disorders in menopause and has a beneficial effect on premenstrual syndrome.
H. perforatum preparations in some pre-clinical and clinical studies have shown strong anti-inflammatory, antiviral and antibacterial activity, and even anticancer activity but, St. John's wort should not be used by people with bipolar disorder as pregnant women.
