Welcome to the third part of Rhodiola Rosea: A Phytomedicinal Overview. You may find studying Rhodiola Rosea online confusing and frustrating. Many people simply refer to it as rhodiola, which is a mistake because several different rhodiola plants exist and only R. rosea features both the safety record and the rhodiola benefits we often look for in an herbal supplement. You may also find it difficult to determine where to find the plant growing, as some people mistake R. rhodantha or R. crenulata for R. rosea.
In this third part of Dr. Brown, Dr. Gerbarg and Dr. Ramazanov’s research, they discuss the various members of the genus Rhodiola and where you might find them in the world.
Rhodiola Rosea Taxonomy and Rhodiola Geographical Distribution
While Rhodiola as a genus may have originated in the mountainous regions of Southwest China and the Himalayas,18 botanists have established that various species of the genus Rhodiola naturally display a circumpolar distribution in mountainous regions in the higher latitudes and elevations of the Northern Hemisphere. In Central and Northern Asia, the genus is distributed from the Altai Mountains across Mongolia into many parts of Siberia.19 According to Hegi, its distribution in Europe extends from Iceland and the British Isles across Scandinavia as far south as the Pyrenees, the Alps, the Carpathian Mountains and other mountainous Balkan regions. Several varieties of Rhodiola species have also been identified across Alaska, Canada, and the northern mountains of the continental United States.20 In fact, the world database of botanical literature shows many citations identifying a broad range of species of the genus Rhodiola, in some cases including R. rosea, in many diverse locations in northern latitudes (see Table 1).
Table 1: Distribution of Plants In the Genus Rhodiola
| Asia | Europe | North America |
|---|---|---|
| Gansu, China | Austria | British Columbia, Canada |
| Hebei, China | Bulgaria | Northwest Territory, Canada |
| Jilin, China | Czechoslovakia | Yukon Territory, Canada |
| Shanxi, China | Finland | Alaska, USA |
| Sichuan, China | France | California, USA |
| Xinjiang, China | Greenland | Colorado, USA |
| Mongolia | Iceland | Idaho, USA |
| Kazakhstan | Ireland | Minnesota, USA |
| Uzbekistan | Italy | Montana, USA |
| Altai, Russia | Norway | Nevada, USA |
| Siberia, Russia | Poland | New Mexico, USA |
| Kamchatka, Russia | Romania | New York, USA |
| Khabarovsk, Russia | Spain | Oregon, USA |
| Magadan, Russia | Sweden | Tenessee, USA |
| United Kingdom | Utah, USA | |
| Yugoslavia | Virginia, USA | |
| Washington, USA | ||
| Wyoming, USA |
The current taxonomical status of the genus Rhodiola has become quite complex. Before World War II, some taxonomists separated different species of Rhodiola into an independent genus, belonging to the subfamily Sedoidae.20 Then Rhodiola was reclassified as a subgenus of the larger genus Sedum, which contained about 10 species. In 1963 Hegi identified more than 50 species of Rhodiola and re-established them as a separate genus.20 Due to their morphological similarities, they form a distinct Rhodiola group.21 There are still differing opinions among specialists about which new species should or should not be included in the genus Rhodiola. The rationale and defining criteria for the boundaries of the genus remain somewhat controversial. This is not, in itself, necessarily counterproductive, since the acquisition of botanical knowledge inevitably stimulates new understanding and insight, creating the need for revised systems of classification. In the case of R. rosea, however, this taxonomic ambiguity may have unexpected and potentially negative consequences.
Popularizing a phytomedicinal plant like R. rosea can create confusion when the public is offered a variety of “Rhodiola” products using the general plant family name instead of the full botanical name of the particular species. For example, products called “Rhodiola spp., Tibetan Rhodiola or Indian Rhodiola” may incorrectly imply equivalence with R. rosea extract. Because of significant species-dependent variation in phytochemistry and pharmacology, the use of “Rhodiola” as a general term is inaccurate and misleading. The correct identification of all Rhodiola species according to precise and generally accepted botanical, phytochemical, and genetic taxonomic criteria is not merely an abstract intellectual exercise. It is critical for both scientific and phytopharmacological accuracy, as well as for product labeling for the public. Consumers may need professional guidance to avoid purchasing ineffective brands, particularly those that do not provide full information, including the complete botanical name of the plant species. Companies may change their suppliers over time. Therefore, consumers should periodically check independent sources of product evaluation, as well as requesting information about quality control and content from manufacturers.
Table 2: Comparison of Human and Animal Studies of Plants in the Genus Rhodiola *
| Species Name | Animal Studies | Human Studies |
|---|---|---|
| R. rosea | 32 | 17 |
| R. alterna | 0 | 0 |
| R. brevipetiolata | 0 | 0 |
| R. coccinea | 1 | 0 |
| R. crenulata | 4 | 1 |
| R. ellipticum | 0 | 0 |
| R. fastigita | 2 | 0 |
| R. gelida | 0 | 0 |
| R. henryi | 0 | 0 |
| R. heterodonta | 1 | 0 |
| R. kirilowii | 6 | 0 |
| R. pinnatifida | 1 | 0 |
| R. quadrifidia | 1 | 0 |
| R. sachalinensis | 6 | 0 |
| R. sacra | 5 | 0 |
| R. wolongensis | 1 | 0 |
| R. yunnanensis | 0 | 0 |
The pharmacological and medicinal properties of Rhodiola are species-dependent phenomena. 22 Of all the Rhodiola species, R. rosea has been the predominant subject of phytochemical, animal, and human studies.2,18,23,24 Table 2 compares the research record of R. rosea with all other species of the genus Rhodiola. Approximately 51 percent of all animal studies and 94 percent of all human studies conducted on plants in the genus Rhodiola are on the species R. rosea. Only R. rosea has passed extensive toxicological studies and has been certified safe for both animals and humans.25
Previous Section: Rhodiola Rosea In Traditional Medicine
Next Section: Phytochemistry of Rhodiola Rosea
Table of Contents: Rhodiola Rosea: A Phytomedicinal Overview
Credits and References
Supplemental Reading:
- Rhodiola for Herbal Stress Relief
- Rhodiola Supplements for Muscle Development and Athletic Performance
- Rhodiola Rosea Pharmacology, Phytochemistry and Standardization