Phytoecdysteroid
Encyclopedia
Phytoecdysteroids are plant derived ecdysteroid
Ecdysteroid
Ecdysteroids are insect moulting and sex hormones which include ecdysone and its homologues such as 20-hydroxyecdysone. Ecdysteroids also occur in other invertebrates where they can play a different role. They also appear in many plants mostly as a protection agents against herbivore insects...

s. Phytoecdysteroids are a class of chemicals that plants synthesize for defense against phytophagous (plant eating)insects. These compounds are exact replicas of hormones used by the arthropod (insect) and crustacean (crab/lobster) families in the molting process known as ecdysis
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...

. 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 triterpenoids, the group of compounds that includes triterpene saponins, phytosterols, and phytoecdysteroids. Plants, but not animals, synthesize phytoecdysteroids from mevalonic acid in the mevalonate pathway of the plant cell using acetyl-CoA
Acetyl-CoA
Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its main function is to convey the carbon atoms within the acetyl group to the citric acid cycle to be oxidized for energy production. In chemical structure, acetyl-CoA is the thioester...

 as a precursor.

Over 250 ecdysteroid analogs have been identified so far in plants, and Dinan has been theorized that there are over 1,000 possible structures which might occur in nature. Dinan also theorizes that many more plants have the ability to "turn on" the production of phytoecdysteroids when under stress, animal attack or other conditions.

These phytoecdysteroids have medicinal value and are part of herbal adaptogen
Adaptogen
An adaptogen is a herbal product claimed to increase resistance to stress, trauma, anxiety and fatigue. The term is used mainly by herbalists who also refer to adaptogens as rejuvenating herbs, qi tonics, rasayanas, or restoratives...

ic remedies like cordyceps
Cordyceps
Cordyceps is a genus of ascomycete fungi that includes about 400 described species. All Cordyceps species are endoparasitoids, mainly on insects and other arthropods ; a few are parasitic on other fungi. The best known species of the genus is Cordyceps sinensis, first recorded as yartsa gunbu in...

, a fungus that grows out of the larvae of several insect species. (Although fungi are not plants, "fungalecdysteroid" does not exist as a category and phytoecdysteroid is the term used.) Medicinal plants tested to include phytoecdysteroids include Achyranthes
Achyranthes
Achyranthes is a genus of medicinal and ornamental plants in the Amaranthaceae family.Species include:* Achyranthes arborescens* Achyranthes aspera Achyranthes is a genus of medicinal and ornamental plants in the Amaranthaceae family.Species include:* Achyranthes arborescens* Achyranthes aspera...

 bidentata , Tinospora cordifolia
Tinospora cordifolia
Tinospora cordifolia, which is known by the common name Guduchi, is an herbaceous vine of the family Menispermaceae indigenous to the tropical areas of India, Myanmar and Sri Lanka....

, Pfaffia paniculata Leuzea
Leuzea
Leuzea is a genus of flowering plants in the daisy family....

 carthamoides, Rhaponticum
Rhaponticum
Rhaponticum is a Genus of plants in the Asteraceae family.- Description :The Rhaponticum species are perennial herbaceous plants, with simple, rarely branched stem. The leaves are simple to pinnatifid. The inflorescence is on the apex of the stem...

 uniflorum (Zhang et al. 2002), and Serratula
Serratula
Serratula is a genus of at least 17 species in the daisy family native to the old world. Serratula as traditionally defined contains at least two groups: one of which is basal within the subtribe Centaureinae and one of which is derived; the former group can be moved to the genus Klasea.Various...

 coronata. The ginseng
Ginseng
Ginseng is any one of eleven species of slow-growing perennial plants with fleshy roots, belonging to the genus Panax of the family Araliaceae....

s and Eleutherococcus
Eleutherococcus
Eleutherococcus is a genus of 38 species of thorny shrubs and trees in the family Araliaceae. They are native to eastern Asia, from southeast Siberia and Japan south to the Philippines, with the greatest diversity in central and western China. Some species, notably E. senticosus , are used for...

 have not been studied for these compounds but exhibit similar characteristics.

See also

  • Plant defense against herbivory
    Plant defense against herbivory
    Plant defense against herbivory or host-plant resistance describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Plants use several strategies to defend against damage caused by herbivores...



Also refer to a study in March 2001 in the journal phytochemestry entitled 'phtoecdysteroids in the genus Asparagus (asparagaceae)'

External links

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