Pyrrolizidine
Encyclopedia
Pyrrolizidine alkaloids (PAs) are a group of naturally occurring alkaloid
s based on the structure of pyrrolizidine
. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect herbivores. More than 660 PAs and PA N-oxides have been identified in over 6,000 plants, and about half of them exhibit hepatotoxicity
. They are found frequently in plants in the Boraginaceae
, Compositae, Orchidaceae
and Leguminosae families; less frequently in the Convolvulaceae
and Poaceae
, and in at least one species in the Lamiaceae
.
It has been estimated that 3% of the world’s flowering plants contain pyrrolizidine alkaloids. Honey can contain pyrrolizidine alkaloids,, as can grains, milk, offal and eggs. To date (2011), there is no international regulation of PAs in food, unlike those for herbs and medicines.
Unsaturated pyrrolizidine alkaloids are hepatotoxic, that is, damaging to the liver
. PAs also cause hepatic veno-occlusive disease
and liver cancer
. PAs are tumorigenic. Disease associated with consumption of PAs is known as pyrrolizidine alkaloidosis
.
Of concern is the health risk associated with the use of medicinal herbs that contain PAs, notably borage
leaf, comfrey
and coltsfoot
in the West, and some Chinese
medicinal herbs.
Some ruminate animals, for example cattle, showed no change in liver enzyme activities or any clinical signs of poisoning when fed plants containing pyrrolizidine alkaloids. Yet Australian studies have demonstrated toxicity Sheep, goats and cattle are much more resistant and tolerate much higher PA dosages, thought to be due to thorough detoxification via PA-destroying rumen microbes. Males react more sensitively than females and fetuses and children.
Please note - list not complete.
Monocroataline is the main PA found in Crotalaria species.
Alkaloid
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...
s based on the structure of pyrrolizidine
Pyrrolizidine
Pyrrolizidine alkaloids are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect herbivores. More than 660 PAs and PA N-oxides have been identified in over 6,000 plants, and about...
. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect herbivores. More than 660 PAs and PA N-oxides have been identified in over 6,000 plants, and about half of them exhibit hepatotoxicity
Hepatotoxicity
Hepatotoxicity implies chemical-driven liver damage.The liver plays a central role in transforming and clearing chemicals and is susceptible to the toxicity from these agents. Certain medicinal agents, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure...
. They are found frequently in plants in the Boraginaceae
Boraginaceae
Boraginaceae, the Borage or Forget-me-not family, include a variety of shrubs, trees, and herbs, totaling about 2,000 species in 146 genera found worldwide.A number of familiar plants belong to this family....
, Compositae, Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
and Leguminosae families; less frequently in the Convolvulaceae
Convolvulaceae
Convolvulaceae, known commonly as the bindweed or morning glory family, are a group of about 60 genera and more than 1,650 species of mostly herbaceous vines, but also trees, shrubs and herbs.- Description :...
and Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
, and in at least one species in the Lamiaceae
Lamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
.
It has been estimated that 3% of the world’s flowering plants contain pyrrolizidine alkaloids. Honey can contain pyrrolizidine alkaloids,, as can grains, milk, offal and eggs. To date (2011), there is no international regulation of PAs in food, unlike those for herbs and medicines.
Unsaturated pyrrolizidine alkaloids are hepatotoxic, that is, damaging to the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
. PAs also cause hepatic veno-occlusive disease
Hepatic veno-occlusive disease
Hepatic veno-occlusive disease or veno-occlusive disease is a condition in which some of the small veins in the liver are blocked. It is a complication of high-dose chemotherapy given before a bone marrow transplant and is marked by weight gain due to fluid retention, increased liver size, and...
and liver cancer
Liver cancer
Liver tumors or hepatic tumors are tumors or growths on or in the liver . Several distinct types of tumors can develop in the liver because the liver is made up of various cell types. These growths can be benign or malignant...
. PAs are tumorigenic. Disease associated with consumption of PAs is known as pyrrolizidine alkaloidosis
Pyrrolizidine alkaloidosis
Pyrrolizidine alkaloidosis is a disease caused by chronic poisoning found in both humans and animals caused by ingesting poisonous plants which contain the natural chemical compounds known as pyrrolizidine alkaloids...
.
Of concern is the health risk associated with the use of medicinal herbs that contain PAs, notably borage
Borage
Borage, , also known as a starflower, is an annual herb originating in Syria, but naturalized throughout the Mediterranean region, as well as Asia Minor, Europe, North Africa, and South America. It grows to a height of , and is bristly or hairy all over the stems and leaves; the leaves are...
leaf, comfrey
Comfrey
Comfrey is an important herb in organic gardening. It is used as a fertilizer and also has many purported medicinal uses...
and coltsfoot
Coltsfoot
Tussilago farfara, commonly known as Coltsfoot, is a plant in the family Asteraceae.It has been used medicinally as a cough suppressant. The name "tussilago" itself means "cough suppressant." The plant has been used historically to treat lung ailments such as asthma as well as various coughs by way...
in the West, and some Chinese
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
medicinal herbs.
Some ruminate animals, for example cattle, showed no change in liver enzyme activities or any clinical signs of poisoning when fed plants containing pyrrolizidine alkaloids. Yet Australian studies have demonstrated toxicity Sheep, goats and cattle are much more resistant and tolerate much higher PA dosages, thought to be due to thorough detoxification via PA-destroying rumen microbes. Males react more sensitively than females and fetuses and children.
Ecology
Many plants contain pyrrolizidine alkaloids, and in turn there are many insects which consume the plants and build up the alkaloids in their bodies.Plants species containing pyrrolizidine alkaloids
- Ageratum conyzoidesAgeratum conyzoidesAgeratum conyzoides is native to Tropical America, especially Brazil. Herb 0.5–1 m...
- Ageratum houstonianumAgeratum houstonianumAgeratum houstonianum syn. Ageratum mexicanum Hort.) is a cool-season annual plant often grown as a bedding plant in gardens...
- Arnebia euchroma
- Borago officinalis(<10ppm, non-toxic)
- Cacalia hastata
- Cacalia hupehensis
- Chromolaena odorataChromolaena odorataChromolaena odorata is a species of flowering shrub in the sunflower family, Asteraceae. It is native to North America, from Florida and Texas to Mexico and the Caribbean, and has been introduced to tropical Asia, west Africa, and parts of Australia. Common names include Siam Weed, Christmas Bush,...
- Cordia myxaCordia myxaCordia myxa is a species of flowering plant in the borage family, Boraginaceae. It is a medium-sized broad-leaved deciduous tree. Common names include لسوڑا, Lasura, Assyrian Plum, Pidar, Panugeri, Naruvilli, Geduri, Spistan, and Burgund dulu wanan...
- Crassocephalum crepidioidesCrassocephalum crepidioidesCrassocephalum crepidioides, also called ebolo, thickhead, redflower ragleaf, or fireweed, is an erect annual slightly succulent herb growing up to 180 cm tall. Its use is widespread in many tropical and subtropical regions, but is especially prominent in tropical Africa...
- Crotalaria albida
- Crotalaria assamica
- Crotalaria crispat
- Crotalaria dura
- Crotalaria globifera
- Crotalaria mucronata
- Crotalaria sesseliflora
- Crotalaria spectabilis
- Crotalaria tetragona
- Cynoglossum amabileCynoglossum amabileCynoglossum amabile is a flowering plant native to Asia , which is also called Chinese hound's tongue , or Chinese forget-me-not . This plant is often used as an ornamental plant in gardens...
- Cynoglossum lanceolatum
- Cynoglossum officinaleCynoglossum officinaleCynoglossum officinale is a herbaceous plant of the family Boraginaceae, found in most parts of Europe, and also North America where it was accidentally introduced.-Growth:It can be either annual or biennial, with reddish-purple flowers blooming between May and...
- Cynoglossum zeylanicum
- Echium plantagineum
- Emilia sonchifoliaEmilia sonchifoliaEmilia sonchifolia also known as lilac tasselflower genus of Emilia and from the family of Asteraceae....
- Eupatorium cannabinum
- Eupatorium chinenseEupatorium chinenseEupatorium chinense is a plant species in Asteraceae. The exact boundaries of this species have been defined differently by different authors. King and Robinson's 1987 paper defines it broadly, to include Eupatorium japonicum, Eupatorium makinoi, some varieties of Eupatorium fortunei, and other...
- Eupatorium fortuneiEupatorium fortuneiEupatorium fortunei, in Chinese called 佩兰 pei lan, is a plant species in Asteraceae native from Asia where it is rare in the wild but commonly cultivated. The white to reddish colored flowers and herbage smell like lavender when crushed...
- Eupatorium japonicumEupatorium japonicumEupatorium japonicum, called in Chinese 白头婆 bai tou po, is a herbaceous plant species in Asteraceae. It is native to China, Japan and Korea.-Description:...
- Eupatorium purpureumEupatorium purpureumEutrochium purpureum , Kidney-root, Sweetscented Joe-Pie weed, Sweet Joe-Pye weed, or Trumpet weed is a herbaceous perennial plant native to eastern and central North America....
- Farfugium japonicumFarfugium japonicumFarfugium japonicum is a plant of the family Asteraceae, also known as leopard plant, green leopard plant, and ligularia.Farfugium japonicum is native to rocky coastal cliffs of Japan , Korea, and Taiwan.-Description:...
- Gynura bicolor
- Gynura divaricata
- Gynura segetum
- Heliotropium amplexicauleHeliotropium amplexicauleHeliotropium amplexicaule is a species of heliotrope known by several common names, including clasping heliotrope, blue heliotrope, and summer heliotrope. It is native to South America, especially Argentina, but it is known on several other continents where it is an introduced species, and in some...
- Heliotropium europaeumHeliotropium europaeumHeliotropium europaeum is a species of heliotrope known by the common names European Heliotrope and European Turnsole. It is native to Europe, Asia, and North Africa, but it is widely naturalized elsewhere, such as in Australia and North America. It grows as a roadside weed in some places...
- Heliotropium indicumHeliotropium indicumHeliotropium indicum, commonly known as Indian heliotrope, is an annual, hirsute plant that is a common weed in waste places and settled areas. It is native to Asia.-Description:...
- Lappula intermedia
- Ligularia cymbulifera
- Ligularia dentataLigularia dentataLigularia dentata, or summer ragwort and leopard plant, is a species of the genus Ligularia and the family Asteraceae.It is a perennial native to China and Japan.-Description:The plant is a clump-forming perennial...
- Ligularia duiformis
- Ligularia heterophylla
- Ligularia hodgsonii
- Ligularia intermedia
- Ligularia lapathifolia
- Ligularia lidjiangensis
- Ligularia platyglossa
- Ligularia tongolensis
- Ligularia tsanchanensis
- Ligularia vellerea
- Liparis nervosaLiparis nervosaLiparis nervosa is a species of orchid found in the Tropics of Asia, Africa and America. It is a terrestrial species growing in woodlands and grasslands....
- Lithospermum erythrorizon
- Neurolaena lobata
- Petasites japonicus
- Senecio argunensis
- Senecio brasiliensisSenecio brasiliensisSenecio brasiliensis or by its common name flor-das-almas, a perennial species of Senecio genus and the family Asteraceae grows as a native in the fields and meadows of central South America.-Description:S...
- Senecio chrysanthemoides
- Senecio cineraria
- Senecio glabellus
- Senecio integrifolius var. fauriri
- Senecio interggerrimus
- Senecio jacobaea
- Senecio lautus
- Senecio linearifolius
- Senecio madagascariensisSenecio madagascariensisSenecio madagascariensis also known as Madagascar ragwort is a species of the genus Senecio and family Asteraceae. Other common names include Madagascar groundsel and fireweed....
- Senecio nemorensis
- Senecio quadridentatus
- Senecio riddelli
- Senecio scandens
- Senecio vulgaris
- Syneilesis aconitifolia
- Symphytum officinaleSymphytum officinaleSymphytum officinale is a perennial flowering plant of the genus Symphytum in the family Boraginaceae. Along with several other species of Symphytum, it is commonly known as comfrey. To differentiate it from other comfreys, this species may be known as common comfrey, Quaker comfrey, and cultivated...
- Tussilago farfara
Please note - list not complete.
Monocroataline is the main PA found in Crotalaria species.