Cucurbitacin
Encyclopedia
Cucurbitacin is any of a class of biochemical
compounds that some plants — notably members of the family Cucurbitaceae
, that includes the common pumpkin
s and gourd
s — developed in order to defend themselves from herbivore
s. Cucurbitacins are chemically classified as steroid
s, formally derived from cucurbitane
, a triterpene
hydrocarbon
— specifically, from the unsaturated variant cucurbita-5-ene, or 19-(10→9β)-abeo-10α-lanost-5-ene. They often occur as glycoside
s.
Cucurbitacins are generally cytotoxic and poisonous to some animals, and some of them are among the bitterest tastes to humans. They and their derivatives have been found in many plant families (including Brassicaceae
, Cucurbitaceae
, Scrophulariaceae
, Begoniaceae
, Elaeocarpaceae
, Datiscaceae
, Desfontainiaceae, Polemoniaceae
, Primulaceae
, Rubiaceae
, Sterculiaceae
, Rosaceae
, and Thymelaeaceae
), in some mushroom
s (including Russula and Hebeloma) and even in some marine mollusks.
fruit (Citrullus colocynthis) is a cucurbitacin.
The 2-O-β-D-glucopyranosides of Cucurbitacins K and L can be extracted with ethanol
from fruits of Cucurbita pepo
cv
dayangua, at concentrations of 40 mg/15 kg and 32mg/15 kg, respectively.
Pentanorcucurbitacins A and B can be extracted with methanol
from the stems of Momordica charantia, at concentrations of 1 mg/18 kg and 4.5 mg/18 kg, respectively.
Cucurbitacins B and I, and derivatives of cucurbitacins B, D and E, can be extracted with methanol from dried tubers of Hemsleya endecaphylla at the concentrations shown above.
Some cucurbitacins and their derivatives are also cytotoxic. The toxicity of one cucurbitacin is enhanced by the introduction of a double bond
at carbon
C23, of an acetyl
group at C25, or a double bond at carbons C1-C2. It is decreased by reduction of the ketone
group at C3, or introduction of a hydroxyl
group at C24. The compound cucurbitacin E is particularly cytotoxic; a concentration of 4.5×10−7μg/ml will destroy half of the cancer cells present.
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
compounds that some plants — notably members of the family Cucurbitaceae
Cucurbitaceae
The plant family Cucurbitaceae consists of various squashes, melons, and gourds, including crops such as cucumber, pumpkins, luffas, and watermelons...
, that includes the common pumpkin
Pumpkin
A pumpkin is a gourd-like squash of the genus Cucurbita and the family Cucurbitaceae . It commonly refers to cultivars of any one of the species Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita moschata, and is native to North America...
s and gourd
Gourd
A gourd is a plant of the family Cucurbitaceae. Gourd is occasionally used to describe crops like cucumbers, squash, luffas, and melons. The term 'gourd' however, can more specifically, refer to the plants of the two Cucurbitaceae genera Lagenaria and Cucurbita or also to their hollow dried out shell...
s — developed in order to defend themselves from herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s. Cucurbitacins are chemically classified as steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
s, formally derived from cucurbitane
Cucurbitane
Cucurbitane is a chemical compound with formula . It is a polycyclic hydrocarbon, specifically a triterpene. It is an isomer of lanostane , from which it differs by the formal shift of a methyl group from the 10 to the 9β position in the standard steroid numbering scheme.The name is applied to...
, a triterpene
Triterpene
Triterpenes are terpenes consisting of six isoprene units and have the molecular formula C30H48.The pentacyclic triterpenes can be classified into lupane, oleanane or ursane groups.Animal- and plant-derived triterpenes exist, such as:*squalene...
hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
— specifically, from the unsaturated variant cucurbita-5-ene, or 19-(10→9β)-abeo-10α-lanost-5-ene. They often occur as glycoside
Glycoside
In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...
s.
Cucurbitacins are generally cytotoxic and poisonous to some animals, and some of them are among the bitterest tastes to humans. They and their derivatives have been found in many plant families (including Brassicaceae
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
, Cucurbitaceae
Cucurbitaceae
The plant family Cucurbitaceae consists of various squashes, melons, and gourds, including crops such as cucumber, pumpkins, luffas, and watermelons...
, Scrophulariaceae
Scrophulariaceae
Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...
, Begoniaceae
Begoniaceae
Begoniaceae is a family of flowering plants with about 1400 species occurring in the subtropics and tropics of both the New World and Old World. All but one of the species are in the genus Begonia. The only other genus in the family, Hillebrandia, is endemic to the Hawaiian Islands and has a single...
, Elaeocarpaceae
Elaeocarpaceae
Elaeaocarpaceae is a family of flowering plants. The family approximately contains 605 species of trees and shrubs in 12 genera. The largest genera are Elaeocarpus, with about 350 species, and Sloanea, with about 150....
, Datiscaceae
Datiscaceae
Datiscaceae are a family of Dicotyledonous plants, containing two species of the genus Datisca. Two other genera, Octomeles and Tetrameles are now classified in the Tetramelaceae family....
, Desfontainiaceae, Polemoniaceae
Polemoniaceae
Polemoniaceae are a family of about 25 genera with 270-400 species of annual and perennial plants, native to the Northern Hemisphere and South America, with the center of diversity in western North America, especially in California.Only one genus is found in Europe, and two in Asia, where they...
, Primulaceae
Primulaceae
Primulaceae is a family of flowering plants with about 24 genera, including some favorite garden plants and wildflowers. It is also known as the primrose family.- Genera :...
, Rubiaceae
Rubiaceae
The Rubiaceae is a family of flowering plants, variously called the coffee family, madder family, or bedstraw family. The group contains many commonly known plants, including the economically important coffee , quinine , and gambier , and the horticulturally valuable madder , west indian jasmine ,...
, Sterculiaceae
Sterculiaceae
Sterculiaceae is a botanical name for a group of flowering plants at the rank of family, which is now considered obsolete. As is true for any botanical name, the circumscription, status and placement of the taxon has varied with taxonomic point of view...
, Rosaceae
Rosaceae
Rosaceae are a medium-sized family of flowering plants, including about 2830 species in 95 genera. The name is derived from the type genus Rosa. Among the largest genera are Alchemilla , Sorbus , Crataegus , Cotoneaster , and Rubus...
, and Thymelaeaceae
Thymelaeaceae
Thymelaeaceae is a cosmopolitan family of flowering plants composed of 50 genera and 898 species. It was established in 1789 by Antoine Laurent de Jussieu.Thymelaeaceae is in the order Malvales...
), in some mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
s (including Russula and Hebeloma) and even in some marine mollusks.
Cucurbitacin A
- Cucurbitacin A found in some species of CucumisCucumisCucumis is a genus of twining, tendril-bearing plants in the Cucurbitaceae family which includes the cucumber, true melons, the horned melon, and Cucumis anguria, the West Indian gherkin...
- Pentanorcucurbitacin A, or 22-hydroxy-23,24,25,26,27-pentanorcucurbit-5-en-3-one , white powder
Cucurbitacin B
- Cucurbitacin B from Hemsleya endecaphylla (62 mg/72 g) and other plants; anti-inflammatory, any-hepatotoxic
- Cucurbitacin B 2-O-glucoside, from Begonia heracleifolia
- 23,24-Dihydrocucurbitacin B from Hemsleya endecaphylla, 49 mg/72 g
- 23,24-Dihydrocucurbitacin B 2-O-glucoside from roots of Picrorhiza kurrooa
- Deacetoxycucurbitacin B 2-O-glucoside from roots of Picrorhiza kurrooa
- Isocucurbitacin B, from Echinocystis fabacea
- 23,24-Dihydroisocucurbitacin B 3-glucoside from Wilbrandia ebracteata
- 23,24-Dihydro-3-epi-isocucurbitacin B, from Bryonia verrucosa
- Pentanorcucurbitacin B or 3,7-dioxo-23,24,25,26,27-pentanorcucurbit-5-en-22-oic acid, , white powder
Cucurbitacin D
- Cucurbitacin D, from Trichosanthes kirilowiiTrichosanthes kirilowiiTrichosanthes kirilowii is a flowering plant in the family Cucurbitaceae. It is one of the 50 fundamental herbs used in traditional Chinese medicine, where it shares the name guālóu with the related T...
and many other plants- 3-Epi-isocucurbitacin D, from species of PhysocarpusPhysocarpusPhysocarpus, commonly called Ninebark, is a genus of about ten species of flowering plants in the family Rosaceae, native to North America and northeastern Asia ....
- 22-Deoxocucurbitacin D from Hemsleya endecaphylla, 14 mg/72 g
- 23,24-Dihydrocucurbitacin D from Trichosanthes kirilowii also from H. endecaphylla, 80 mg/72 g
- 23,24-Dihydro-epi-isocucurbitacin D, from Acanthosicyos horridusAcanthosicyos horridusAcanthosicyos horridus is an unusual melon that occurs only in Namibia; it is locally called !nara.The edible seeds are known locally as butterpips....
- 22-Deoxocucurbitacin D from Wilbrandia ebracteata
- Anhydro-22-deoxo-3-epi-isocucurbitacin D from Ecballium elateriumEcballium elateriumEcballium elaterium, also called the squirting cucumber or exploding cucumber, is a plant in the cucumber family. It gets its unusual name from the fact that, when ripe, it squirts a stream of mucilaginous liquid containing its seeds, which can be seen with the naked eye...
- 25-O-Acetyl-2-deoxycucurbitacin D (amarinin) from Luffa amara
- 2-Deoxycucurbitacin D, from Sloanea zuliaensis
- 3-Epi-isocucurbitacin D, from species of Physocarpus
Cucurbitacin E
- Cucurbitacin E (aelaterin), from roots of Wilbrandia ebracteata. Strong antifeedant for the flea beetleFlea beetleFlea beetles is a general name applied to the small, jumping beetles of the leaf beetle family . They make up the tribe Alticini, which is a part of the subfamily Galerucinae, though they were historically classified as a subfamily in their own right...
, inhibits cell adhesionCell adhesionCellular adhesion is the binding of a cell to a surface, extracellular matrix or another cell using cell adhesion molecules such as selectins, integrins, and cadherins. Correct cellular adhesion is essential in maintaining multicellular structure...
- 22,23-Dihydrocucurbitacin E from Hemsleya endecaphylla, 9 mg/72 g, and from roots of Wilbrandia ebracteata
- 22,23-Dihydrocucurbitacin E 2-glucoside from roots of Wilbrandia ebracteata
- Isocucurbitacin E, from Cucumis phrophetarum
- 23,24-Dihydroisocucurbitacin E, from Cucumis phrophetarum
Cucurbitacin F
- Cucurbitacin F from Elaeocarpus dolichostylus
- Cucurbitacin F 25-acetate from Helmseya graciliflora
- 23,24-Dihydrocucurbitacin F from Helmseya amabilis
- 25-Acetoxy-23,24-dihydrocucurbitacin F from Helmseya amabilis (hemslecin AHemslecinHemslecin is any of several compounds obtained from plants of the Helmseya genus, which are used in Asian folk medicine. They are triterpene derivatives, specifically with the cucurbitane skeleton, related to cucurbitacin F.The hemslecins include:...
) - 23,24-Dihydrocucurbitacin F glucoside from Helmseya amabilis
- Cucurbitacin II glucoside from Helmseya amabilis
- Hexanorcucurbitacin F from Elaeocarpus dolichostylus
- Perseapicroside APerseapicrosidePerseapicroside is any one of several chemical compounds isolated from certain plants, notably Persea mexicana. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin F.They include...
from Persea mexicana - Scandenoside R9ScandenosideScandenoside is any one of several chemical compounds isolated from certain plants, notably Hemsleya panacis-scandens. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin F.They include...
from Hemsleya panacis-scandens - 15-Oxo-cucurbitacin F from Cowania mexicana
- 15-oxo-23,24-dihydrocucurbitacin F from Cowania mexicana
- Datiscosides B, D, and HDatiscosideDatiscoside is any one of several chemical compounds isolated from certain plants, notably Datisca glomerata. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin F.They include...
, from Datisca glomerataDatisca glomerataDatisca glomerata is a species of plant native to California, Nevada, and Baja California known by the common name Durango root. It is one of only two to four species in the plant family Datiscaceae. It is an erect perennial herb with distinctive long, pointed, often sharply serrated leaves. It is...
Cucurbitacin G
- Cucurbitacin G from roots of Wilbrandia ebracteata
- 3-Epi-isocucurbitacin G, from roots of Wilbrandia ebracteata
Cucurbitacin H
- Cucurbitacin H, stereoisomer of cucurbitacin G, from roots of Wilbrandia ebracteata
- Cucurbitacin I (elatericin B) from Hemsleya endecaphylla, 10 mg/72 g , also from Ecballium elaterium and Citrullus colocynthis, deters feeding by flea beetleFlea beetleFlea beetles is a general name applied to the small, jumping beetles of the leaf beetle family . They make up the tribe Alticini, which is a part of the subfamily Galerucinae, though they were historically classified as a subfamily in their own right...
- Hexanorcucurbitacin I from Ecballium elaterium
- 23,24-Dihydrocucurbitacin I see Cucurbitacin L
- Khekadaengosides D and KKhekadaengosideKhekadaengoside is any one of several chemical compounds isolated from certain plants, notably Trichosanthes tricuspidata. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacins H and L....
from the fruits of Trichosanthes tricuspidata - 11-Deoxocucurbitacin I, from Desfontainia spinosa
- Spinosides A and BSpinosideSpinoside is any one of several chemical compounds isolated from certain plants, notably Desfontainia spinosa. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin H.They include...
, from Desfontainia spinosa - 23,24-dihydro-11-Deoxocucurbitacin I from Desfontainia spinosa
Cucurbitacin J
- Cucurbitacin J from Iberis amara
- Cucurbitacin J 2-O-β-glucopyranoside from Trichosanthes tricuspidata
Cucurbitacin K
- Cucurbitacin K, stereoisomer of cucurbitacin J, , from Iberis amara
- Cucurbitacin K 2-O-β-glucopyranoside from Trichosanthes tricuspidata
Cucurbitacin L
- Cucurbitacin L, or 23,24-dihydrocucurbitacin I,
- Brydioside ABrydiosideBrydioside is any one of several chemical compounds isolated from certain plants, notably Bryonia dioica. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin Lor 23,24-dihydrocucurbitacin I....
from Bryonia dioicaBryonia dioicaBryonia dioica, known by the common names red bryony and white bryony, is a perennial climbing vine indigenous to Central and Southern Europe. It is a flowering plant of the genus Bryonia with five-pointed leaves and blue or white flowers. The vine produces a red berry fruit.-Medicinal use:A...
- BryoamarideBryoamarideBryoamaride is a chemical compound isolated from certain plants, notably Bryonia dioica. It can be seen as a derivative of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin L or 23,24-dihydrocucurbitacin I....
from Bryonia dioica - 25-O-Acetylbryoamaride from Trichosanthes tricuspidata
- Khekadaengosides A and BKhekadaengosideKhekadaengoside is any one of several chemical compounds isolated from certain plants, notably Trichosanthes tricuspidata. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacins H and L....
from Trichosanthes tricuspidata
- Brydioside A
Cucurbitacin O
- Cucurbitacin O from Brandegea bigelovii
- Cucurbitacin Q 2-O-glucoside, from Picrorhiza kurrooa
- 16-Deoxy-D-16-hexanorcucurbitacin O from Ecballium elaterium
- Deacetylpicracin from Picrorhiza scrophulariaeflora
- Deacetylpicracin 2-O-glucoside from Picrorhiza scrophulariaeflora
- 22-Deoxocucurbitacin O from Wilbrandia ebracteata
Cucurbitacin P
- Cucurbitacin P from Brandegea bigelovii
- Picracin from Picrorhiza scrophulariaeflora
- Picracin 2-O-glucoside from Picrorhiza scrophulariaeflora
Cucurbitacin Q
- Cucurbitacin Q from Brandegea bigelovii
- 23,24-Dihydrodeacetylpicracin 2-O-glucoside from Picrorhiza kurrooa
- Cucurbitacin Q1 from Cucumis species, actually Cucurbitacin F 25-acetate
Cucurbitacin T
- Cucurbitacin T, from the fruits of Citrullus colocynthis
28/29 Norcucurbitacins
There are several substances that can be seen as derving from cucurbita-5-ene skeleton by loss of one of the methyl groups (28 or 29) attached to carbon 4; often with the adjacent ring (ring A) becoming aromatic.Other
Several other cucurbitacins have been found in plants.Occurrence
One of the active constituents of the colocynthColocynth
Citrullus colocynthis, commonly known as the colocynth, bitter apple, bitter cucumber, egusi, or vine of Sodom , is a viny plant native to the Mediterranean Basin and Asia, especially Turkey , Nubia, and Trieste...
fruit (Citrullus colocynthis) is a cucurbitacin.
The 2-O-β-D-glucopyranosides of Cucurbitacins K and L can be extracted with ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
from fruits of Cucurbita pepo
Cucurbita pepo
The species Cucurbita pepo is a cultivated plant of the genus Cucurbita. It includes varieties of squash, gourd, and pumpkin.*Acorn squash*Delicata squash*Dodi marrow, grown in South Asia*Gem squash*Heart of gold squash*Pattypan squash...
cv
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
dayangua, at concentrations of 40 mg/15 kg and 32mg/15 kg, respectively.
Pentanorcucurbitacins A and B can be extracted with methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
from the stems of Momordica charantia, at concentrations of 1 mg/18 kg and 4.5 mg/18 kg, respectively.
Cucurbitacins B and I, and derivatives of cucurbitacins B, D and E, can be extracted with methanol from dried tubers of Hemsleya endecaphylla at the concentrations shown above.
Uses
Some cucurbitacins have the action of a potent cathartic purgative.Some cucurbitacins and their derivatives are also cytotoxic. The toxicity of one cucurbitacin is enhanced by the introduction of a double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
at carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
C23, of an acetyl
Acetyl
In organic chemistry, acetyl is a functional group, the acyl with chemical formula COCH3. It is sometimes represented by the symbol Ac . The acetyl group contains a methyl group single-bonded to a carbonyl...
group at C25, or a double bond at carbons C1-C2. It is decreased by reduction of the ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...
group at C3, or introduction of a hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
group at C24. The compound cucurbitacin E is particularly cytotoxic; a concentration of 4.5×10−7μg/ml will destroy half of the cancer cells present.
See also
- HemslecinHemslecinHemslecin is any of several compounds obtained from plants of the Helmseya genus, which are used in Asian folk medicine. They are triterpene derivatives, specifically with the cucurbitane skeleton, related to cucurbitacin F.The hemslecins include:...
- MomordicosideMomordicosideMomordicoside is any of several related glycosides that can be extracted from the bitter melon vine . They include:*Momordicoside A *Momordicoside B *momordicoside F1 *momordicoside F2 *Momordicoside K *Momordicoside L...
- MomordicineMomordicineA momordicine is any of several compounds found the bitter melon vine, Momordica charantia. They are glycosides of cucurbitane derivatives. They include* Momordicine II...
- MogrosideMogrosideA mogroside is any of several chemical compounds found in certain plants, such as the fruit of the gourd vine luo han guo . They are glycosides of cucurbitane derivatives...
- NeomogrosideNeomogrosideNeomogroside is a cucurbitane glycoside isolated from the fruit of Siraitia grosvenorii....
- GoyaglycosideGoyaglycosidegoyaglycoside is any of several related glycosides found in the fruits bitter melon vine , called goya in Okinawan language. They include:* goyaglycoside c.* goyaglycoside d....
- Picfeltarraegenins I-VI from Picria feltarrae
- Picfeltarraenone from Picria feltarrae
- Picfeltarraenins IA, IB, II–VI from Picria feltarrae
- carnosifloside from Helmseya carnosiflora
- Scandenosides R1–R8,R10-R11ScandenosideScandenoside is any one of several chemical compounds isolated from certain plants, notably Hemsleya panacis-scandens. They can be seen as derivatives of the triterpene hydrocarbon cucurbitane , more specifically from cucurbitacin F.They include...
- Siamenoside I