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© 2001 Alternative Medicine Review
Pulbisher, Thorne Research, Inc. used by permission
Rhodiola rosea:
A Possible Plant Adaptogen
Gregory S. Kelly, ND
Abstract
Rhodiola rosea is a popular plant in traditional medical
systems in Eastern Europe and Asia with a reputation
for stimulating the nervous system, decreasing depression,
enhancing work performance, eliminating fatigue, and
preventing high altitude sickness. Rhodiola rosea
has been categorized as an adaptogen by Russian researchers
due to its observed ability to increase resistance
to a variety of chemical, biological, and physical
stressors. Its claimed benefits include antidepressant,
anticancer, cardioprotective, and central nervous
system enhancement. Research also indicates great
utility in asthenic conditions (decline in work performance,
sleep difficulties, poor appetite, irritability, hypertension,
headaches, and fatigue) developing subsequent to intense
physical or intellectual strain. The adaptogenic,
cardiopulmonary protective, and central nervous system
activities of Rhodiola rosea have been attributed
primarily to its ability to influence levels and activity
of monoamines and opioid peptides such as beta-endorphins.
(Altern Med Rev 2001;6(3):293-302)
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Introduction
Rhodiola rosea ("golden root" or "rose root") is widely
distributed at high altitudes in Arctic and mountainous
regions throughout Europe and Asia. It is a popular
plant in traditional medical systems in Eastern Europe
and Asia, with a reputation for stimulating the nervous
system, decreasing depression, enhancing work performance,
eliminating fatigue, and preventing high altitude
sickness.1 In addition to Rhodiola rosea, over 200
different species of Rhodiola have been identified
and at least 20 are used in traditional medical systems
in Asia, including R. alterna, R. brevipetiolata,
R. crenulata, R. kirilowii, R. quadrifida, R. sachalinensis,
and R. sacra.
Rhodiola rosea has been intensively studied in Russia
and Scandinavia for more than 35 years. Although the
majority of this research on Rhodiola rosea is unavailable
for review, available literature is supportive of
its adaptogenic properties. Similar to other plant
adaptogens investigated by Russian researchers, such
as Eleutherococcus senticosus (Siberian ginseng) and
Panax ginseng (Korean ginseng), extracts of this plant
produce favorable changes in a variety of diverse
areas of physiological function, including neurotransmitter
levels, central nervous system activity, and cardiovascular
function.
Rhodiola rosea has been categorized as an adaptogen
by Russian researchers due to its observed ability
to increase resistance to a variety of chemical, biological,
and physical stressors. Origination of the term adaptogen
has been dated to 1947 and credited to a Russian scientist,
Lazarev. He defined an "adaptogen" as an agent that
allows an organism to counteract adverse physical,
chemical, or biological stressors by generating non-specific
resistance. Inherent in his definition is the concept
that administration of the adaptogenic agent allows
an organism to pre-adapt itself in a manner that allows
it to be more capable of responding appropriately
when diverse demands are eventually placed on it.
In 1969, Brekhman and Dardymov proposed specific criteria
that need to be fulfilled in order for a substance
to qualify as an adaptogen.
Subjecting animals and humans to a period of stress
produces characteristic changes in several hormones
and parameters associated with the central nervous
system and the hypothalamic-pituitary-adrenal axis
(HPA). HPA changes include an increase in cortisol,
a reduced sensitivity of the HPA to feedback down-regulation,
and a disruption in the circadian rhythm of cortisol
secretion. Central nervous system changes include
the stress-induced depletion of catecholamine neurotransmitters
such as norepinephrine and dopamine. An acute increase
in beta-endorphin levels is also observed under stressful
conditions.
To successfully combat stress and stressful situations,
adaptation is required. Adaptation might be best thought
of as the ability to be exposed to a stressor, while
responding with either decreased or no characteristic
hormonal perturbations. Adaptation also implies being
prepared to and capable of rapidly reassuming homeostasis
after the stressor is withdrawn. As an example, a
well-trained athlete can participate in an event that
would induce a large HPA perturbation (stress response)
in a sedentary person, and yet the athlete will be
relatively unaffected. This is a result of adaptation
that has occurred during the athlete's training process.
Additionally, if athletes are exposed to stressors
they were not trained for, hormonal perturbations
characteristic of a stress response would be expected;
however, this response might not be as great as that
found in less fit individuals. Furthermore, after
the stress ended, their physiology would be expected
to re-establish homeostasis rapidly. This is a result
of non-specific resistance to stress gained by virtue
of a training-induced higher level of fitness.
The utility of plant adaptogens is analogous to the
training an athlete undergoes in order to prepare
for competition. Plant adaptogens cause our physiology
to begin the adaptation process to stress. When a
stressful situation occurs, consuming adaptogens generates
a degree of generalized adaptation (or non-specific
resistance) that allows our physiology to handle the
stressful situation in a more resourceful manner.
As an example of this process, Rhodiola rosea administration
promotes a moderate increase in the amount of serum
immunoreactive beta-endorphin in rats under basal
conditions. This moderate increase is similar to that
found when rats are adapted to exercise. When Rhodiola
rosea-treated rats were subjected to a 4-hour period
of non-specific stress, the expected elevation in
beta-endorphin was either not observed or substantially
decreased. Consequently, the characteristic perturbations
of the HPA were decreased or totally prevented.3 In
these rats administration of Rhodiola rosea appears
to have generated non-specific resistance and prepared
the rats to respond more appropriately to the eventual
stressful situation.
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Chemical Composition
The chemical composition and physiological properties
of Rhodiola species are to a degree species-dependent,
although some overlap in constituents and physiological
properties does exist in many Rhodiola species.
Twenty-eight compounds have been isolated from the
roots and above-ground parts of Rhodiola rosea, including
12 novel compounds. The roots contain a range of biologically
active substances including organic acids, flavonoids,
tannins, and phenolic glycosides. The stimulating
and adaptogenic properties of Rhodiola rosea were
originally attributed to two compounds isolated from
its roots, identified as p-tyrosol and the phenolic
glycoside rhodioloside. Rhodioloside was later determined
to be structurally similar to the known glycoside
salidroside found in several other plant species.
Salidroside, rhodioloside, and occasionally rhodosin
are used to describe this compound and are considered
to be synonyms. Additional glycoside compounds isolated
from the root include rhodioniside, rhodiolin, rosin,
rosavin, rosarin, and rosiridin. These glycoside compounds
are also thought to be critical for the plant's observed
adaptogenic properties.1,4
A range of antioxidant compounds have been identified
in Rhodiola rosea and related species, including p-tyrosol,
organic acids (gallic acid, caffeic acid, and chlorogenic
acid), and flavonoids (catechins and proanthocyanidins).5,6
Significant free-radical scavenging activity has been
demonstrated for alcohol and water extracts of Rhodiola
sp. and is attributed to the variety of antioxidant
compounds.5,6 p-Tyrosol has been shown to be readily
and dose-dependently absorbed after an oral dose,7,8
and appears to produce a significant antioxidant8
and modest 5-lipoxygenase inhibitory activity9 in
vivo.
Salidroside (rhodioloside), the additional salidroside-like
glycoside compounds (rhodiolin, rosin, rosavin, rosarin,
and rosiridin), and p-tyrosol are thought to be the
most critical plant constituents needed for therapeutic
activity.1,2 The contents of salidroside and p-tyrosol
in root samples gathered from various areas in China
have been shown to range from 1.3-11.1 mg/g and 0.3-2.2
mg/g, respectively.4 These two compounds have been
found in all studied species of Rhodiola; however,
the other active glycosides, including rosavin, rosin,
and rosarin, have not been found in all examined Rhodiola
species.5,6 Because of this variation within the Rhodiola
genus, verification of Rhodiola rosea by high performance
liquid chromatography (HPLC) is dependent on the content
of the additional glycosides (rather than salidroside
and p-tyrosol); rosavin is the constituent currently
selected for standardization of extracts.10
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Proposed Mechanisms of Action
The adaptogenic properties, cardio-pulmonary protective
effects, and central nervous system activities of
Rhodiola rosea have been attributed primarily to its
ability to influence levels and activity of monoamines
and opioid peptides such as beta-endorphins.
Oral administration of a water extract of Rhodiola
rosea to rats for 10 days modulated biogenic monoamines
in the cerebral cortex, brain stem, and hypothalamus.
In the cerebral cortex and brain stem, levels of nor-epinephrine
and dopamine decreased, while the amount of serotonin
increased substantially. In the hypothalamus, the
results were reversed with a 3-fold increase in the
amount of norepinephrine and dopamine, and a trend
toward reduced serotonin levels. It is believed these
changes in monoamine levels are a result of Rhodiola
rosea inhibiting the activity of the enzymes responsible
for monoamine degradation, monoamine oxidase and catechol-O-methyltransferase.
It is also believed Rhodiola rosea facilitates the
transport of neurotransmitters within the brain.11
In addition to these central effects on monoamines,
Rhodiola rosea has been reported to prevent both catecholamine
release and subsequent cAMP elevation in the myocardium,
and the depletion of adrenal catecholamines induced
by acute stress.12
Abstracts of untranslated Russian research indicate
that a great deal of the activity of Rhodiola rosea
might be secondary to an ability to induce opioid
peptide biosynthesis and through the activation of
both central and peripheral opioid receptors.3,13-15
Lack of current availability of the complete text
of these articles make verification of these effects
impossible.
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Experimental Studies
Adaptogenic Activity
Rhodiola rosea appears to offer generalized resistance
against physical, chemical, and biological stressors
in rats and other animals studied. Evidence also suggests
cardioprotective and anticancer benefits in animals.
In the test of swimming "to the limit," Rhodiola rosea
administration increased the swimming time of rats
135-159 percent. Working capacity of the rats consistently
improved throughout the supplementation period.16
Eggs from the freshwater snail Lymnaea stagnalis were
incubated in water extracts of Rhodiola rosea and
subsequently exposed to a variety of environmental
stressors, including heat shock (43°C for four minutes),
oxidative stress (600 µM menadione for two hours),
and heavy metal-induced stress (one-hour exposure
to 150 µM copper sulphate or 20 µM cadmium chloride).
Exposure to these environmental stressors kills 80-90
percent of larvae within four days post-exposure.
Pre-incubation with Rhodiola rosea extract afforded
a significant degree of non-specific resistance against
each of these environmental stressors as measured
by rate of survival. While only nine percent of the
control population survived exposure to heat shock,
approximately 90 percent of snail larvae pre-incubated
with Rhodiola rosea (40.5 µg/ml) survived. Pre-incubation
with Rhodiola resulted in non-specific resistance
to oxidative stress (survival of approximately 68
percent) and heavy metal stress (approximately 28-35
percent of larvae survived depending on the metal
exposure).10
Two experiments have suggested possible benefit on
various aspects of learning and memory in rats under
certain experimental conditions. Rhodiola rosea extract
administered orally at a dose of 0.1 mL/day for 10
days resulted in a non-significant trend toward protection
against impairments in memory, as assessed by step-down
passive avoidance, induced by electroshock in rats.17
Rhodiola rosea extract was administered in a single
dose of 0.10 mL. Improvements in both learning and
memory retention, as determined by using a maze test
with negative reinforcement, were observed. Repeated
dosing with the same quantity of the extract over
a 10-day period generated significant improvement
in long-term memory as assessed by the maze test with
negative enforcement and the "staircase" method with
positive enforcement. However, in this experiment
two other doses were tested (0.02 and 1.0 mL) and
were found to have no substantial effect on learning
and memory.1
This suggests the possibility of an efficacious dose
of Rhodiola rosea administration, above and below
which beneficial physiological effects might be less
likely. In the other experimental conditions investigated
(active avoidance with negative reinforcement using
a "shuttle box" and passive avoidance using "step
down" and "step through") no beneficial effects on
either learning or memory were observed with any of
the administered doses of Rhodiola rosea.1
Cardioprotective Activity
Rhodiola rosea has been shown to moderate against
stress-induced damage and dysfunction in cardiovascular
tissue. Treatment with Rhodiola rosea extract prevents
the decrease in cardiac contractile force secondary
to environmental stress in the form of acute cooling
and contributes to stable contractility. In animals,
acute cooling leads to a decrease in myocardial contractile
activity that partially recovers during the first
18 hours after the cold-stress is removed. This recovery
is viewed as only partial, since the heart tissue
is incapable of stable contractility during perfusion.
Pretreatment with Rhodiola rosea extracts appears
to create a beneficial adaptive response in this type
of stress. When Rhodiola pretreated rats were exposed
to acute cooling, the decrease in contractility was
prevented and stable contractility of heart tissue
occurred during perfusion.18
Other reports suggest administration of Rhodiola rosea
protects cardiovascular tissue from stress-induced
catecholamine release12 and mitigates against adrenaline-induced
arrhythmias in rats.13,14,19 The antiarrhythmic effect
of Rhodiola rosea is suggested to be secondary to
an ability to induce opioid peptide biosynthesis13
and related to the stimulation of peripheral kappa-opioid
receptors.14
Anticancer Activity
Administration of Rhodiola rosea appears to have potential
as an anticancer agent, and might be useful in conjunction
with some pharmaceutical antitumor agents. In rats
with transplanted solid Ehrlich adenocarcinoma and
metastasizing rat Pliss lymphosarcoma, supplementation
with Rhodiola rosea extract inhibited the growth of
both tumor types, decreased metastasis to the liver,
and extended survival times.20 Administration of Rhodiola
rosea extract also directly suppressed the growth
of and the extent of metastasis from transplanted
Lewis lung carcinomas.21 When Rhodiola rosea extract
was combined with the antitumor agent cyclophosphamide
in these same tumor models, the antitumor and antimetastatic
efficacy of drug treatment was enhanced. The authors
also commented that, "complete abrogation of the haematotoxicity
of cyclophosphamide" was observed.21 The chemotherapeutic
drug Adriamycin is known to induce pronounced liver
dysfunction, generally reflected by an increase in
transaminase levels. In animal experiments, adding
Rhodiola rosea extract to a protocol with Adriamycin
resulted in an improved inhibition of tumor dissemination
(as compared to that found with Adriamycin alone),
and the combined protocol prevented liver toxicity.22
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Clinical Studies
Although Rhodiola rosea has been studied in the former
Soviet Union for more than 35 years, this research
is presently unavailable for review. This makes it
impossible to verify the Russian claims of its antidepressant,
anticancer, cardioprotective, and central nervous
system enhancing properties.23 Available animal evidence
seems supportive of a possible role for this plant
adaptogen in many of these conditions. Table 2 outlines
the conditions suggested to benefit from Rhodiola
supplementation.
TABLE 2
There have also been claims that this plant has great utility as a therapy in asthenic conditions (decline in work performance, sleep disturbances, poor appetite, irritability, hypertension, headaches, and fatigue) developing subsequent to intense physical or intellectual strain, influenza and other viral exposures, and other
illness. 23 Two randomized, double-blind, placebo-controlled trials of the standardized extract of Rhodiola rosea root (SHR-5) provide a degree of support for these claimed adaptogenic properties and indicate possible utility in asthenic conditions induced by overwork or over study. SHR-5 is standardized to contain rosavin (3.6%), salidroside (1.6%), and p-tyrosol (<0.1%).10
Darbinyan et al evaluated the effect of chronic administration of 170 mg of SHR-5 for 14 days on aspects of mental performance and fatigue on 56 healthy male and female physicians (age 24-35) on night duty. Mental performance was evaluated using tests to determine speed of visual and auditory perception, attention capacity, and short-term memory. Based on the results of the battery of tests used, a Fatigue Index was calculated. The trial was divided into three periods: (1) a two-week test period of one SHR-5 or placebo tablet daily; (2) a two-week washout period; and (3) a third two-week cross-over period of one placebo or SHR-5 tablet daily.
A statistically significant improvement in Fatigue Index was observed during the first two-week period in the SHR-5 group, and the improved mental performance reverted toward baseline values during the washout period. Administration of SHR-5 for the final two weeks of the six-week night duty period was unable to significantly offset declines in mental performance.24
Spasov et al investigated the effects of SHR-5 on male medical students during an exam period. Forty students were randomized to receive either 50 mg SHR-5 or placebo twice daily for a period of 20 days. The students receiving the standardized extract of Rhodiola rosea demonstrated significant improvements in physical fitness, psychomotor function, mental performance, and general wellbeing. Subjects receiving the Rhodiola rosea extract also reported statistically significant reductions in mental fatigue, improved sleep patterns, a reduced need for sleep, greater mood stability, and a greater motivation to study. The average exam scores between students receiving the Rhodiola rosea extract and placebo were 3.47 and 3.20,
respectively. 25
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Dosage and Toxicity
In the two double-blind clinical trials, the dose of a standardized Rhodiola rosea extract ranged from 100-170 mg per day. The content of rosavin consumed in these daily doses is approximately 3.6-6.14 mg. The therapeutic dose of available Rhodiola rosea preparations will vary depending on degree of standardization; however, for chronic administration rosavin content within the above range seems prudent. This would suggest a dose of approximately 360-600 mg Rhodiola rosea daily of an extract standardized for one-percent rosavin, 180-300 mg of an extract standardized for two-percent rosavin, or the dose of between 100-170 mg for an extract standardized for 3.6-percent rosavin. As an adaptogen, chronic administration is normally begun several weeks prior to a period of expected increased physiological, chemical, or biological strain, and continued throughout the duration of the challenging event or activity. When using Rhodiola rosea as a single dose for acute purposes (e.g., for an exam or athletic competition), the suggested dose is three times the dose used for chronic supplementation.
The Russian approach to long-term supplementation with adaptogens generally calls for repeating cycles characterized by short periods of adaptogen administration, followed by an interval with no supplementation.26 Rhodiola rosea has been administered for periods ranging from as little as one day (acute administration) up to four months. Until more specific information is available, a dosing regime following the established patterns used with other plant adaptogens, with periodic intervals of abstinence, seems warranted when Rhodiola rosea is being used chronically.
At the doses administered in the clinical trials, a complete absence of all side effects has been reported. However, preliminary clinical feedback indicates that at doses of 1.5-2.0 grams and above of Rhodiola rosea extract standardized for two-percent rosavin, some individuals might experience an increase in irritability and insomnia within several days. It is possible that other physiological parameters that benefit from a lower dose of Rhodiola rosea extract might be exacerbated by a dose that is inappropriately high and/or sustained for prolonged periods of time.
Evidence on the safety and appropriateness of Rhodiola rosea supplementation during pregnancy and lactation is currently unavailable.
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Conclusion
Consistent with benefits found with other adaptogenic substances, Rhodiola rosea appears to offer generalized resistance to physical, chemical, and biological stressors. Available evidence suggests it can be a suitable substitute in conditions where other adaptogens might be considered. However, Rhodiola rosea also appears to be unique among the currently available adaptogenic herbs and might offer an advantage in some clinical conditions and stressful circumstances. Unlike Korean and Siberian ginseng, which are thought to exert their adaptogenic activity primarily at the level of HPA function,27-29 Rhodiola rosea appears to exert its adaptogenic effects by working centrally and peripherally on monoamine and opioid synthesis, transport, and receptor activity. If this is in fact the case in humans, it suggests the potential for therapeutic utility of Rhodiola rosea in conditions not particularly responsive to administration of ginseng products. It also suggests the possibility of potential synergistic interactions among Rhodiola rosea and other plant adaptogens.
Based on the proposed mechanism of action and available experimental data, Rhodiola rosea appears to offer an advantage over other adaptogens in circumstances of acute stress. A single dose of Rhodiola rosea prior to acute stress produces favorable results and prevents stress-induced disruptions in function and performance. Acute stress tends to initially impact monoamine levels and endorphins, while chronic stress places greater demands on the HPA axis. While this is a generalization and there is obvious overlap in the stress response, Rhodiola does seem to exert a pronounced effect on aspects of the acute stress response. Since many stressful situations are acute in nature, and sometimes unexpected, an adaptogen that can be taken acutely in these circumstances, rather than requiring chronic advance supplementation, could be very useful.
Rhodiola rosea also offers some cardioprotective benefits not associated with other adaptogens. Its proposed ability to moderate stress-induced damage and dysfunction in cardiovascular tissue might make Rhodiola rosea the adaptogen of choice among patients at higher risk for cardiovascular disease.
Since Rhodiola rosea administration appears to impact central monoamine levels, it might also provide benefits and be the adaptogen of choice in clinical conditions characterized by an imbalance of central nervous system monoamines. This is consistent with Russian claims for improvements in depression and schizophrenia. It also suggests that research in areas such as seasonal affective disorder, fibromyalgia, and chronic fatigue syndrome, to name a few clinical conditions, is warranted.
Administration of Rhodiola rosea appears to have potential as an anticancer agent, and might be useful in conjunction with some pharmaceutical antitumor agents. While available evidence is limited to animal models, results appear promising. This is an area that would benefit from additional research.
The clearest indication for Rhodiola rosea administration is for the asthenic condition resulting from acute or chronic overwork, which may manifest as decline in work performance, sleep disturbances, poor appetite, irritability, hypertension, headaches, and fatigue.
Some animal and preliminary clinical evidence suggests the need for a narrow range of therapeutic dosage of Rhodiola rosea, above and below which beneficial physiological effects might be less likely. Because of this, it seems prudent to keep doses at a moderate level both in terms of the quantity and duration of supplementation. While Rhodiola rosea appears to be a promising plant medicine, and has been investigated intensively in Russia, additional research is required before any conclusions with respect to its therapeutic utility can be made.
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References
1. Petkov VD, Yonkov D, Mosharoff A, et al. Effects of alcohol aqueous extract from Rhodiola rosea L. roots on learning and memory. Acta Physiol Pharmacol Bulg 1986;12:3-16.
2. Brekhman II, Dardymov IV. New substances of plant origin which increase nonspecific resistance. Ann Rev Pharmacol 1969;9:419-430.
3. Lishmanov IB, Trifonova ZV, Tsibin AN, et al. Plasma beta-endorphin and stress hormones in stress and adaptation. Biull Eksp Biol Med 1987;103:422-424. [Article in Russian]
4. Linh PT, Kim YH, Hong SP, et al. Quantitative determination of salidroside and tyrosol from the underground part of Rhodiola rosea by high performance liquid chromatography. Arch Pharm Res 2000;23:349-352.
5. Lee MW, Lee YA, Park HM, et al. Antioxidative phenolic compounds from the roots of Rhodiola sachalinensis A. Bor. Arch Pharm Res 2000;23:455-458.
6. Ohsugi M, Fan W, Hase K, et al. Active-oxygen scavenging activity of traditional nourishing-tonic herbal medicines and active constituents of Rhodiola sacra. J Ethnopharmacol 1999;67:111-119.
7. Visioli F, Galli C, Bornet F, et al. Olive oil phenolics are dose-dependently absorbed in humans. FEBS Lett 2000;468:159-160.
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10. Boon-Niermeijer EK, van den Berg A, Wikman G, Wiegant FA. Phyto-adaptogens protect against environmental stress-induced death of embryos from the freshwater snail Lymnaea stagnalis. Phytomedicine 2000;7:389-399.
11. Stancheva SL, Mosharrof A. Effect of the extract of Rhodiola rosea L. on the content of the brain biogenic monamines. Med Physiol 1987;40:85-87.
12. Maslova LV, Kondrat'ev BI, Maslov LN, Lishmanov IB. The cardioprotective and antiadrenergic activity of an extract of Rhodiola rosea in stress. Eksp Klin Farmakol 1994;57:61-63. [Article in Russian]
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15. Lishmanov IB, Naumova AV, Afanas'ev SA, Maslov LN. Contribution of the opioid system to realization of inotropic effects of Rhodiola rosea extracts in ischemic and reperfusion heart damage in vitro. Eksp Klin Farmakol 1997;60:34-36. [Article in Russian]
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19. Maimeskulova LA, Maslov LN. The anti-arrhythmia action of an extract of Rhodiola rosea and of n-tyrosol in models of experimental arrhythmias. Eksp Klin Farmakol 1998;61:37-40. [Article in Russian]
20. Udintsev SN, Shakhov VP. The role of humoral factors of regenerating liver in the development of experimental tumors and the effect of Rhodiola rosea extract on this process. Neoplasma 1991;38:323-331.
21. Udintsev SN, Schakhov VP. Decrease of cyclophosphamide haematotoxicity by Rhodiola rosea root extract in mice with Ehrlich and Lewis transplantable tumors. Eur J Cancer 1991;27:1182.
22. Udintsev SN, Krylova SG, Fomina TI. The enhancement of the efficacy of adriamycin by using hepatoprotectors of plant origin in metastases of Ehrlich's adenocarcinoma to the liver in mice. Vopr Onkol 1992;38:1217-1222. [Article in Russian]
23. Germano C, Ramazanov Z, Bernal Suarez M. Arctic Root (Rhodiola Rosea): The Powerful New Ginseng Alternative. New York, NY: Kensington Publishing Corp; 1999.
24. Darbinyan V, Kteyan A, Panossian A, et al. Rhodiola rosea in stress induced fatigue a double blind cross-over study of a standardized extract SHR-5 with a repeated low-dose regimen on the mental performance of healthy physicians during night duty. Phytomedicine 2000;7:365-371.
25. Spasov AA, Wikman GK, Mandrikov VB, et al. A double-blind, placebo-controlled pilot study of the stimulating and adaptogenic effect of Rhodiola rosea SHR-5 extract on the fatigue of students caused by stress during an examination period with a repeated low-dose regimen. Phytomedicine 2000;7:85-89.
26. Baranov AI. Medicinal uses of ginseng and related plants in the Soviet Union: recent trends in the Soviet literature. J Ethnopharmacol 1982;6:339-353.
27. Hiai S, Yokoyama H, Oura H, Yano S. Stimulation of pituitary-adrenocortical system by ginseng saponin. Endocrinol Jpn 1979;26:661-665.
28. Fulder SJ. Ginseng and the hypothalamic-pituitary control of stress. Am J Chin Med 1981;9:112-118.
29. Golotin VG, Gonenko VA, Zimina VV, et al. Effect of ionol and eleutherococcus on changes of the hypophyseo-adrenal system in rats under extreme conditions. Vopr Med Khim 1989;35:35-37. [Article in Russian]
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