Studies conducted in the 1960s showed that extracts from the root had a positive effect in protecting laboratory animals from cold, radiation, and heavy physical excursive, as well as having antioxidant activity. Further studies showed that rhodiola extracts increased work capacity and resistance to irradiation and poisoning by various toxins. Other animal studies have shown it produces an improvement in memory tests, increases learning behavior, decreases fatigue, and helps improve brain function.
Interest in the West was sparked by German scientists, who brought the pharmacological and clinical literature on the herb to an English-reading scientific audience. Notable among them was Hildebert Wagner, Ph.D. from the University of Munich, a leading European medicinal plant researcher well known for his work on adaptogenic and immunostimulatory phytomedicines. In a review of plant adaptogens published in 1994, he highlighted the plant and suggested that clinical studies have shown that salidroside can improve mental ability. In a study designed to measure accuracy of work, called “correction tests,” error rates were reduced by as much as 50 percent.
A recent double-blind, crossover, placebo-controlled study on a standardized extract of R.rosea was performed to assess the effects of the extract for stress-induced fatigue. It was conducted by Armenian and German researchers. The test population included fifty-six young, healthy physicians (including men and women, ages twenty-four to thirty-five) working night duty. The test method calculated overall mental performance, including mental fatigue, associative thinking, short-term memory, calculation and concentration ability, and speed of audio-visual perception. These factors were measured in three test periods of two weeks each. Perceptive and cognitive cerebral functions used five different tests. A statistically significant improvement was seen in the first two weeks, and no side effects were reported. Each tablet taken contained 170 mg of rhodiola extract, containing 4.5 mg of salidroside.
Another recently published clinical study looked at the effect of rhodiola extract on fatigue of students stressed during the examination period. Significant improvements (but barely so) in physical fitness, mental fatigue, and neuro-motor tests were observed, along with a subjective “feel good” assessment by the volunteers. The researchers, in this case from Russia, felt that the dose level was below optimal levels for the best benefits, so the question of what is the best dose remains.
Look for rhodiola to assume its position next to other well-known adaptogens such as Asian ginseng (Panax ginseng), eleuthero (Eleutherococcus senticosus), and ashwaganda (Withania somnifera). It is not an obscure new herbal medicine from Russia, but one that occurs throughout cooler regions of the Northern Hemisphere and has a long and diverse history of use.
It seems that over the past two years, many popular herbs have been scrutinized for possible adverse reactions. Kava is the most recent victim. As of November 29, 2001, Merck’s German division withdrew two kava products from store shelves. The two products sold by Merck in Germany, Kavadura 120 mg and Kytta-Kava, were permanently withdrawn from the market following a notification by the German Federal Institute of Drugs and Medical Devices (BfArM). The move followed a November 8, 2001, notice to all manufacturers of kava products in Germany informing them of the reports of liver toxicity documented in Germany and Switzerland. The notice sought opinions as to whether kava should be discontinued as a drug or relabeled. Merck was apparently the first manufacturer to withdraw its products from the market.
The German health authorities may decide to remove kava from the market as a drug in that country, or to require manufacturers to place a label on products warning consumers of potential liver complications. At press time, no action has been taken. Various scientific reviews of kava published in recent years have concluded that kava appears to be effective in the treatment of anxiety and as a muscle relaxant at normal and appropriate dosage levels. In all but five of the twenty-four reported cases of liver toxicity associated with kava, patients were also taking prescription drugs.
According to Mark Blumenthal, executive director of the American Botanical Council, “In the public interest the American Botanical Council is working with the American Herbal Products Association on this issue. Both organizations are investigating the BfArM’s concerns and are considering the establishment of an independent scientific evaluation of the case reports. ABC is also prepared to work with other interested parties (e.g., researchers, trade groups, FDA, etc.) on this important matter.” Stay tuned. (1)
Eat your berries!
For more than a decade, researchers have focused on berries (such as bilberries, blackberries, cranberries, elderberries, raspberries, and others) for their potential antioxidant activity and other health benefits. The presence of high levels of anthocyanins in the fruits—the pigments responsible for colors such as orange, red, and blue in fruits, flowers, and vegetables—prompted the research. Because specific anthocyanin profiles are unique to different types or varieties of fruits and vegetables, their presence can also be used to determine a product’s authenticity. Researchers at the Michigan State University’s Department of Food Science and Human Nutrition, the Department of Horticulture, and National Food Safety and Toxicology Center have taken a closer look at the presence of and effects of various anthocyanins in fruits and have discovered some interesting results.
The researchers recently published results of antioxidant and cyclooxygenase (COX I and COX II) inhibitory effects from tart cherries (Prunus cerasus), sweet cherries (Prunus avium), bilberries (Vaccinium myrtillus), blackberries (Rubus spp.), blueberries (Vaccinium corymbosum), cranberries (Vaccinium macrocarpon), elderberries (Sambucus nigra), raspberries (Rubus idaeus), and strawberries (Fragaria spp.). COX I and COX II inhibitory activity is related to anti-inflammatory activity. Selective COX II inhibitors are believed to be responsible for anti-inflammatory activity.
After isolating various anthocyanins from the fruits, comparing their chemical test results with previously published scientific reports, the researchers focused on interesting activity from cherries and raspberries. The antioxidant activity of anthocyanins from cherries was found to be comparable to three commercial antioxidants (used as food preservatives)—BHT, BHA, and TBHQ. In addition they were found to be superior to vitamin E as antioxidant compounds. The researchers also found that the best COX I and COX II inhibitory activity was from raspberries and sweet cherries. They concluded that the antioxidant and anti-inflammatory activity of these fruits in particular would be beneficial to human health. In addition, the high levels of anthocyanins in raspberries and cherries make them suitable as part of a regular diet for helping to alleviate arthritis and gout-related pain. (2)
(1) Blumenthal, M. “Perspectives on Safety of Kava.” Personal correspondence with author, 2001. American Botanical Council, Austin, Texas.
(2) Seeram, N. P., et al. “Cyclooxygenase inhibitory and antioxidant cyanidin glycosides in cherries and berries.” Phytomedicine 2001, 8(5): 362–369.
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