Adaptogen
The term adaptogen is used by herbalists to refer to a natural herb product that is proposed to increase the body's resistance to stress, trauma, anxiety and fatigue. In the past, they have been called rejuvenating herbs, qi tonics, rasayanas, or restoratives.  All adaptogens contain antioxidants, but antioxidants are not necessarily adaptogens and that is not proposed to be their primary mode of action.
The concept of adaptogens dates back thousands of years to ancient India and China, but modern study did not begin until the late 1940s. In 1947, Nikolai Lazarev defined an adaptogen as an agent that allows the body to counter adverse physical, chemical, or biological stressors by raising nonspecific resistance toward such stress, thus allowing the organism to "adapt" to the stressful circumstances.
In 1968, Israel I. Brekhman , PhD, and I. V. Dardymov formally gave adaptogens a functional definition, as follows:
- An adaptogen is nontoxic to the recipient.
- An adaptogen produces a nonspecific response in the bodyan increase in the power of resistance against multiple stressors including physical, chemical, or biological agents.
- An adaptogen has a normalizing influence on physiology, irrespective of the direction of change from physiological norms caused by the stressor.
Under this definition, adaptogens would be nontoxic in normal doses, produce a general defensive response against stress, and have a normalizing influence on the body.
It is claimed that adaptogenic herbs are unique from other substances in their ability to balance endocrine hormones and the immune system, and they help the body to maintain optimal homeostasis.  Adaptogens are proposed to have a normalizing effect on the body and to be capable of either toning down the activity of hyperfunctioning systems or strengthening the activity of hypofunctioning systems. However, they are also proposed to be functional at the level of allostasis, which is a more dynamic reaction to long term stress, lacking the fixed reference points of homeostasis.

# Adaptogenic herbs and other organisms
Most herbal adaptogens that have been identified have long been used in either Ayurveda or Traditional Chinese Medicine (TCM).
Some of the more commonly used herbs described as adaptogens include:
Possible adaptogens with less scientific research include:
Panax ginseng is an example of an adaptogen that has demonstrated an "overall normalizing effect." Among the active ingredients found in Panax Ginseng are substances called ginsenosides. The herb contains ginsenosides Rg1, which can stimulate the nervous system, and ginsenosides Rb1, which calms it. However ginsenosides alone do not determine the active strength of ginseng and some preparations with higher ginsenosides have lower activity, indicating that cofactors are necessary to potentiate the adaptogenic properties of ginseng.

# Constituents common to adaptogens
It can be difficult to determine which constituents are active ingredients in plants with as diffuse an effect as adaptogens.  According to adaptogen researcher Panossian and medical botanist and herbalist Robyn Klein, adaptogens tend to have the following consitituents:
Triterpenes (mevalonate pathway)
- Triterpenoid saponins:       dammarane triterpene saponins, cucurbitacins
- Phytosterols:      beta-sitosterol
- Phytoecdysteroids:       20-ecdysone, turkesterone
Phenylpropanes (shikimate pathway)
- Flavonoids:      glucopyranosides, prenylated flavonoids, flavan glycosides
- Lignans:     schizandrin, sesamin, syringaresinol
Oxylipins (acetate pathway)
- Hydroxylated fatty acids:      octadecadienoic acid
Triterpenoid saponins have been the focus of most studies of adaptogen constituents.  Saponins include ginsenoside from Panax ginseng, gypenosides from Gynostemma and eleutherosides from Eleutherococcus. The lipophilic properties of ginsenosides, for instance, favor binding to intracellular steroid hormone receptors.  Triterpenes also include phytosterols and phytoecdysteroids, both of which are thought to have adaptogenic roles in mammals.  Phytosterols have been studied more in food science than phytotherapy but are known to have immune function. Phytoecdysteroids are in common use by athletes and weight lifters for the anabolic effects they produce.  Rhaponticum carthamoides is notable for these compounds.  Oxylipins are fatty acids that have been oxidized and display prostaglandin-like activity due to a shape similar to leukotrienes. Examples are the hydroxylated fatty acids in licorice, Glycyrrhiza glabra.
In addition to the above constituents, many adaptogens contain polysaccharides that have been reported to stimulate immune system components and have immune system enhancing benefits. Polysaccharide-rich plants have a long history of use in traditional practices such as Chinese medicine. In addition to stimulating the immune system, they are used to increase vital energy and considered qi tonics. Adaptogens that contain polysaccharides include: American ginseng, Asian ginseng, astragalus, cordyceps, eleuthero, licorice, lycium, prince seng, reishi, rhaponticum, and shatavari.

# Notes
-  Jump up to: 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Winston, David & Maimes, Steven. Adaptogens: Herbs for Strength, Stamina, and Stress Relief, Healing Arts Press, 2007.
-  Robyn Klein."Allostasis Theory and Adaptogenic Plant Remedies" 2004
-  Saleeby, J. P. "Wonder Herbs: A Guide to Three Adaptogens", Xlibris, 2006. (Three chapters on adaptogens Rhodiola rosea, Eleuthero & Jiaogulan.)
-  Hobbs, Christopher "Medicinal mushrooms: The history, chemistry, pharmacology and folk uses for modern times" Botanica Press, 1987.
-  April 2005 MMS Newsletter
"PubMed Home". www.ncbi.nlm.nih.gov. Retrieved 2008-03-06..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
-  Search term "licorice" instead of scientific name.  The search term also brought up some other similar species.
-  It seems there may be more papers under a synonym for the plant.
-  0 PubMed results listed under the name Ashphaltum bitumen + 0 under "Shilajit"
-  44 PubMed results found under the name Asparagus racemosus + 0 results under synonym Asparagus rigidulus + 0 results under synonym Protasparagus racemosus
-  342 PubMed results under the name Astragalus membranaceus + 151 under the synonym Radix astragali = 493.  This is assuming both terms do not appear in the same paper
-  30 PubMed results listed under the name Bacopa monnieri
-  96 results for PubMed search under the name Phyllanthus emblica + 122 results under the name Emblica officinalis = 218.  This is assuming bother terms do not appear in the same paper
-  0 PubMed results found
-  12 results under the name Pfaffia paniculata
-  66 PubMed results under the name Polygonum
multiflorum
-  17 PubMed results under the name Pseudostellaria
heterophylla
-  17 PubMed results under the name Rhaponticum carthamoides
-  Panossian, Alexander G., 2003. Adaptogens: a historical overview and perspective. Natural Pharmacy, 7(4), 1, 19-
-  Robyn Klein Masters Thesis Paper, May 2004, Montana State University, Dept Plant Sciences & Plant Pathology: Phylogenetic and phytochemical characteristics of plant species with adaptogenic properties
-  Bouic, Patrick J.D., 2002. Sterols and sterolins: new drugs for the immune system? Drug Discovery Today, 7(14),
-  Panossian, Alexander G., 2003. Adaptogens: a historical overview and perspective. Natural Pharmacy, 7(4), 1, 19-
-  Robyn Klein Masters Thesis Paper, May 2004, Montana State University, Dept Plant Sciences & Plant Pathology: Phylogenetic and phytochemical characteristics of plant species with adaptogenic properties

# Further reading
- Adaptogens.org
- David Winston & Steven Maimes. Adaptogens: Herbs for Strength, Stamina, and Stress Relief, Healing Arts Press, 2007. The definitive guide to adaptogenic herbs. Includes overview, history, actions, health benefits, 21 monographs; and chapters on adaptogens as food and adaptogens for animals.
- Adaptogens in America
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