Phytoecdysteroids are plant-derived ecdysteroids. Phytoecdysteroids are a class of chemicals that plants synthesize for defense against phytophagous (plant eating) insects. These compounds are mimics of hormones used by arthropods in the molting process known as

ecdysis Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remna ...

. When insects eat the plants with these chemicals they may prematurely molt, lose weight, or suffer other metabolic damage and die. Chemically, phytoecdysteroids are classed as

triterpenoid Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squale ...

s, the group of compounds that includes

triterpene saponin Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed ...

phytosterol Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanols. More than 250 sterols and related compounds have been identified. Free phyto ...

s, and phytoecdysteroids. Plants, but not animals, synthesize phytoecdysteroids from

mevalonic acid Mevalonic acid (MVA) is a key organic compound in biochemistry; the name is a contraction of dihydroxymethylvalerolactone. The carboxylate anion of mevalonic acid, which is the predominant form in biological environments, is known as ''mevalonate ...

in the mevalonate pathway of the plant cell using

acetyl-CoA Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for ...

as a precursor. Over 250 ecdysteroid analogs have been identified so far in plants, and it has been theorized that there are over 1,000 possible structures which might occur in nature. Many more plants have the ability to "turn on" the production of phytoecdysteroids when under stress, animal attack or other conditions. The term phytoecdysteroid can also apply to ecdysteroids found in

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

, even though fungi are not plants. Some plants or fungi that produce phytoecdysteroids include ''

Achyranthes bidentata Achyranthes bidentata Blume (English common name: ox knee, Chinese: 牛膝 niu xi) is a species of flowering plant in the amaranth family, Amaranthaceae. It occurs in India, Nepal, China, and Japan. It is the source of the Chinese herbal medic ...

,'' ''

Tinospora cordifolia ''Tinospora cordifolia'' (common names gurjo, heart-leaved moonseed, guduchi or giloy) is a herbaceous vine of the family Menispermaceae indigenous to tropical regions of the Indian subcontinent. It has been used in Ayurveda to treat various diso ...

'', '' Pfaffia paniculata'', '' Leuzea carthamoides'', ''

Rhaponticum uniflorum ''Rhaponticum'' is a genus of flowering plants in the tribe Cardueae within the family Asteraceae. Description ''Rhaponticum'' species are perennial herbaceous plants with simple, rarely branched stems. The leaves are simple to pinnatifid. T ...

'', ''

Serratula coronata ''Serratula'' is a genus of plants in the tribe Cardueae within the family Asteraceae native to Eurasia. Plumeless saw-wort is a common name for plants in this genus. ''Serratula'' as traditionally defined contains at least two groups: one of whi ...

'', ''

Cordyceps ''Cordyceps'' is a genus of ascomycete fungi (sac fungi) that includes about 600 species. Most ''Cordyceps'' species are endoparasitoids, parasitic mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasiti ...

'', and '' Asparagus''.

References

{{Reflist Phytochemicals Steroids Insect ecology Chemical ecology

See also

References