Hypericum perforatum

Hypericum perforatum is an herbaceous perennial plant with hairless (glabrous) stems and leaves. The root of each plant is slender and woody with many small, fibrous small side roots and also extensive, creeping rhizomes. The stems of H. perforatum are rusty-yellow to rosy in color with two distinct edges and usually have bark that sheds near the base. The stems persist through the winter and sprout new growth with flower buds in the following year; first year growth does not produce flowers. It has leaves that attach on opposite sides of the stems without a stalk (sessile). The leaves vary in shape from being very narrow and almost grass-like (linear), to a rounded oval slightly wider at the base with a rounded tip or not much of a tip (elliptic), or even narrow with the widest portion towards the end of the leaf like a reversed lance point, but still long and narrow (oblanceolate). The dots are clearly visible when held up to the light, giving the leaves a perforated appearance. The edges (margins) of the leaves usually have scattered black dots, often called dark glands, though sometimes they will appear away from the edges. The odor of the plant is faint, but aromatic, resembling that of resins like balsam. The taste of the plant is bitter and acrid. Each of the flowers normally has five large petals and five smaller leaf-like sepals below them. The sepals are about in length, green in color, are shaped like the head of a spear (lanceolate shape) with a pointed tip, and the same clear and black glands as the leaves. The petals are significantly longer, in length, and have an oblong shape. They completely hide the sepals from the front side of the flower. The many bright yellow stamens are united at the base into three bundles. Each flowering stem bears many flowers, between 25 and 100, and also is quite leafy. Each seed is about in size. The species contains a host of essential oils, the bulk of which are sesquiterpenes. In the wild, the concentrations of any active chemicals can vary widely among individual plants and populations. Notes: == Taxonomy ==

of H. perforatum by Jost Fitschen in Hypericum perforatum was selected to be the type species around which the genus Hypericum is based because of its wide cosmopolitan distribution; it is the most common species of the genus in many of the areas it is found, and is one of the most widely known plants among the St John's worts in folklore and medicine. Etymology and common names The genus name Hypericum is possibly derived from the Greek words (above) and (picture), in reference to the tradition of hanging the plant over religious icons in the home. The specific epithet perforatum is Latin and refers to the perforated appearance of the plant's leaves. Many other similarly fanciful names have been used for it including ''devil's scourge, Lord God's wonder plant, and witch's herb. In medieval Kent it was called herbe Ion (Ion in this case referring to "John") as recorded in the poem The Feate of Gardening. Other local names for Hypericum perforatum include balm of the warrior's wound in Somerset, penny John in Norfolk, rosin rose in Yorkshire, and touch-and-heal in Northern Ireland. Locally in the United States, it may also be referred to as Tipton-weed, goatweed, or Klamath weed''. In the 21st century, any species of the genus Hypericum can be referred to as St John's wort. Therefore, it is more accurate to call Hypericum perforatum the ''common St John's wort or perforate St John's wort''. Linnaeus also noted the species' habitat in the "meadows of Europe" and gave a short account of previous mentions of the plant. While Linnaeus' taxonomic priority for this species is not in question, there are a number of botanical synonyms that were published in the early years of formal botanical nomenclature. Gaterau published in 1789 which described and called the species Hypericum officinale, a name now considered to be illegitimate under the principle of priority. Likewise, the name Hypericum officinarum by the botanist Heinrich Johann Nepomuk von Crantz in 1763 also postdated Linnaeus' 1753 naming and description and is considered invalid. Subdivision Hypericum perforatum exhibits a great deal of variability in its appearance across its distribution. Thus, determining the exact nature of its infraspecific taxa is difficult because of the many intermediate forms that exist. • H. perforatum subspecies perforatum Stjep.-Vesel. is the type form of the species. It is distributed from the origin of the species in Siberia, west to central Europe, and east to northern Mongolia. The base changes as the plant grows from round to a broad wedge shape, and the seed capsule vittae are present throughout the plant's life cycle and are almost always narrow. • H. perforatum variety angustifolium DC. is a variety of the species that is found in drier climates within the range of ssp. perforatum. It has leaves that look more like those of ssp. veronense, but they have leaf stalks; the glands on the seed capsule are also distinct. • H. perforatum var. humile Stranski can be found in parts of the southern Balkans. These plants possess smaller, more ring-shaped leaves and the seed capsules have flattish vesicles on their surface. These appear to be adaptations of ssp. perforatum in response to the mountainous habitats of the region. • H. perforatum ssp. songaricum is likely the most primitive after ssp. perforatum. Previously described as a variety by Karl Koch, Norman Robson elevated the taxon to subspecies in his monograph of the genus. The leaves are sessile and have a heart-shaped base that partially surrounds the stem. • H. perforatum var. gracile has smaller leaves and is found in western Kazakhstan, southern Russia, and southern Ukraine. In the drier areas of this range the variety exhibits a dull grey-green color on the underside of its leaves. • H. perforatum ssp. veronense can be found in the Caucasus, across the Middle East to Tajikistan, and along North Africa to Macaronesia. These plants have narrower leaves and display diagonal vittae on the seed capsules. Where it meets the distribution of ssp. perforatum the two subspecies hybridize regularly. • H. perforatum var. ellipticum retains the diagonal vittae of the subspecies but the leaves are not as narrow. The variety is distributed in areas with greater moisture such as in the mountainous areas of Turkmenistan. • H. perforatum ssp. chinense is found across most of China and was introduced into Japan (under the synonym H foliosissimum Koidz.). Both its leaves and flowers are smaller, and the flower clusters are smaller and more crowded on the ends of longer branches. ==Distribution and habitat==

Distribution Hypericum perforatum is thought to be native to every nation in Europe, and is only absent from the far north such as north European Russia and Svalbard. It grows in parts of North Africa and is native to Morocco, Algeria, Tunisia, and Sudan. In the Arabian Peninsula it only grows in parts of Saudi Arabia. It is present and native to all of the Western Asia phytogeographic region from the Aegean Islands and Turkey to Israel and Palestine in the west to Afghanistan in the east, only being absent from the Sinai Peninsula. Just to the east of this area it is also native to Pakistan and the western Himalaya region of India. In North America, it is found in all of the continental US states except for Utah, Arizona, Florida, and Alabama. It has been introduced throughout much of Canada, as well as in Hawaii, Cuba, and Haiti. Altitudes greater than , rainfall less than , and daily mean temperatures greater than are also considered limiting thresholds. == Ecology ==

Reproduction pollinating the flowers of Hypericum perforatum'' St John's wort reproduces both vegetatively and sexually. Depending on environmental and climatic conditions, and the age of the plant, St John's wort will alter the way it grows to promote survival. Summer rains are particularly effective in allowing the plant to grow vegetatively, following defoliation by insects or grazing. St John's wort may also produce viable seeds without fertilization. Dieback among populations of St John's wort is also caused by fungal anthracnose, such as Colletotrichum gloeosporioides. This fungus causes the stems to lose their bark (girdling) and turn brown, and dries the aboveground parts of the plant. The infection often kills the plant within the first year of its growth, or reduces productivity over a three-year deterioration. Role as a herbivore food source Though Hypericum perforatum is generally avoided by mammalian herbivores, a number of insects are dependent on it and its close relatives as a food source. Chrysolina quadrigemina and C. hyperici are two beetle species that feed on plants from the genus Hypericum, including H. perforatum. Chrysolina quadrigemina can be colored metallic blue, purple, green, or bronze and is better adapted to warm and dry climates; Chrysolina hyperici is consistently smaller, metallic green, and tends to live in areas with wetter and cooler conditions. Another Hyericum specialist beetle is Agrilus hyperici, the St John's wort root borer, whose larvae feed on the roots of H. perforatum while the adults feed on the foliage. A moth, Aplocera plagiata, feeds heavily upon the leaves of H. perforatum as a caterpillar and is commonly known as the common St John's wort inchworm. As adults, they are a small moth with gray wings and dark gray bands. Another moth that feeds upon H. perforatum is Euspilapteryx auroguttella. Their caterpillars start by mining the inside of the leaves and later roll the leaves into cigar shapes to feed in greater safety. Agonopterix hypericella is another small () gray moth that exclusively feeds upon Hypericum. Young animals are more susceptible to H. perforatum poisoning, and the plant is most toxic in spring (when it is the most palatable to herbivores) and retains its toxic effects when dried in hay. Additionally, affected animals will become highly photosensitive, and exposure to sunlight can exacerbate their symptoms. As such, they should be moved to a dark area; administering of antihistamines or anti-inflammatory medicines may also help alleviate the symptoms. In pastures, St John's wort acts as both a toxic and invasive weed. It replaces native plant communities and forage vegetation to the extent of making productive land nonviable or becoming an invasive species in natural habitats and ecosystems. Effective herbicides for control of Hypericum perforatum include 2,4-D, picloram, metsulfuron, and glyphosate. ==Uses==

herba hyperici Antidepressant effects H. perforatum has approval in the European Union as a herbal product for the treatment of mild to moderate depressive episodes (according to ICD-10) and for the short-term treatment of symptoms in mild depression. It is more effective than placebo and as effective as standard antidepressants, including SSRIs, for mild to moderate depression, with some evidence suggesting fewer adverse effects and lower discontinuation rates. In America, H. perforatum is not approved as a treatment for depression, and its use in treating depression is discouraged by NIH and Cleveland Clinic. H. perforatum can cause serious side effects such as serotonin syndrome if taken with other antidepressants. In vitro, it acts mainly as a reuptake inhibitor of serotonin, dopamine, and norepinephrine; additional antidepressant effects may come from its interactions with GABA receptors. In traditional medicine Common St. John's wort has been used in herbalism for centuries. It was used in classical antiquity and was a standard component of ancient concoctions called theriacs, from the Mithridate of Aulus Cornelius Celsus' ( CE) to the Venice treacle of in 1686. One folk use included the oily extract known as St John's oil, a red, oily liquid extracted from H. perforatum that may have been a treatment for wounds by the Knights Hospitaller, the Order of St John. The dried flower is crushed to make the compound known as herba hyperici. using H. perforatum As a dyeing pigment H. perforatum generally produces a variety of yellows suitable for dyeing. When the pigments are extracted using ethanol, a violet-red colour is made which can be used to dye silk and wool when rinsed in vinegar. The colours produced are season-dependent. The flowers produce a series of four different shades on wool, if used in the correct sequence. Wool mordanted with alum and unmordanted wool is used. The flowers are simmered to produce a deep red liquid dye. The alum-mordanted wool skein is added and simmered until green is made. If unmordanted wool is added to the same dye, it will turn reddish-maroon. The final colour produced is by continuing the method, to produce yellow or gold. == Inability to treat cancer ==

There is no clinical evidence that St John's wort is effective to treat cancer. The National Cancer Institute has commented that "the FDA has not approved the use of St. John's wort as a treatment for cancer or any other medical condition". St John's wort may reduce the efficacy of chemotherapy. == Interactions with drugs ==

Use of H. perforatum may cause significant drug interactions, primarily through PXR activation and CYP3A4 induction linked to its hyperforin content, affecting the efficacy and safety of various medications. However, the concentration of St John's wort's constituent chemicals (including hyperforin) can vary widely between different products, and their dosage may not be properly marked on packaging. == Adverse effects ==

Use of H. perforatum may produce adverse effects when combined with other antidepressants through an increase in brain serotonin levels called serotonin syndrome, which may be life-threatening and is associated with rapid heart rate, acute hypertension, mydriasis, and fever. Photosensitivity and acute neuropathy upon sun exposure, and reduced response to chemotherapy are other possible effects. Common side effects of St John's wort products are headache, nausea, fatigue, dry mouth, sleepiness, and gastrointestinal upset. It should not be consumed during pregnancy and breastfeeding. == Regulation ==

In the United States, St John's wort is considered a dietary supplement by the FDA, is not regulated by the same standards as a prescription drug, and does not have clearly defined mechanisms in people. == References ==