A supplement to The Herb Companion from the American Botanical Council and the Herb Research Foundation.
Ginger battles cholesterol
Indian researchers report that rhizomes of ginger (Zingiber officinale), a common culinary spice and ancient herbal medicine in both Ayurvedic and Chinese traditions, may help the body reduce cholesterol levels and unclog arteries.
Researchers at the University of Rajasthan fed five groups of five healthy male rabbits either a diet high in cholesterol or a normal diet. One group received the normal diet for 120 days. Two groups received the high-cholesterol diet for 60 days. The fourth group received the high-cholesterol diet for 60 days, then the normal diet for an additional 60 days. The fifth group received the high-cholesterol diet for 60 days, then the normal diet plus an oral ginger extract for an additional 60 days.
The animals on the high-cholesterol diet had a sevenfold increase in total serum cholesterol levels, a high incidence of plaque buildup on their artery walls, and a reduction in high-density lipoprotein (HDL), or “good”, cholesterol levels. After 60 days off the high-cholesterol diet, the rabbits treated with ginger had a 79.7 percent reduction in blood cholesterol and near-normal levels of cholesterol, triglycerides, and phospholipids in their liver and aorta. The animals in the high-cholesterol groups not treated with the ginger extract had only a 23.9 percent reduction of serum cholesterol and significant increases in cholesterol, triglyceride, and phospholipid levels in their liver and aorta.
Ginger appears to work by converting low-density lipoprotein (LDL)–or “bad”–cholesterol into a form that HDL cholesterol can transport to the liver, where it can be metabolized and then eliminated from the body. The researchers concluded that several mechanisms may be involved; a constituent of ginger called 6-gingerol is known to increase the secretion of bile, which would promote the metabolism of LDL cholesterol.(1)
More than just a weed
Eclipta (Eclipta prostrata also known as E. alba)is a sunflower-family member better known in the United States as a weed than a medicinal plant. Scientific studies, however, have attributed antibacterial, astringent, anti-inflammatory, immune-stimulating, and, recently, liver-protecting activity to the plant.
In Taiwan, where the plant traditionally has been used to stop bleeding and treat itching, hepatitis, diphtheria, and diarrhea, scientists have been studying its potential to also treat liver disease. Researchers at Taipei Medical College tested whether an extract of eclipta would protect the liver of laboratory mice from injury by carbon tetrachloride, beta-D-galactosamine, or acetaminophen (the generic form of Tylenol), agents commonly used to induce acute hepatitis in experimental animals. The extract did protect against toxicity induced by carbon tetrachloride and beta-D-galactosamine but had no effect against acetaminophen. It appeared to be relatively safe. The constituent of the extract responsible for the protective effect has not been identified.(2)
Eleuthero or imposter?
A recent case report by a Canadian physician has focused attention on the problem of adulterated Siberian ginseng (Eleutherococcus senticosus), or eleuthero, and the need for accurate botanical identification.
A seventy-four-year-old man had been taking the cardiac glycoside digoxin, which is derived from foxglove (Digitalis purpurea), for many years. When a blood test showed abnormally elevated cardiac glycoside levels, his digoxin was discontinued, but his glycoside levels remained high. The physician then discovered that the patient was taking a product labeled “Siberian ginseng”. When the patient stopped taking the product, his cardiac glycosides returned to normal. Treatment with digoxin resumed. Several months later, the man started taking “Siberian ginseng” again, and his glycoside levels again rose. The effect was attributed to the “Siberian ginseng”.
Although Siberian ginseng, known as ci-wu-jia in Traditional Chinese Medicine (TCM), contains no cardiac glycosides, Periploca sepium, a vining herb of the milkweed family known in TCM as wu-jia or xiang-jia-pi, does contain cardiac glycosides similar to digoxin. The similarity of names has caused confusion among those not trained in TCM, and during the past twenty years P. sepium has on several occasions been identified as an adulterant of Siberian ginseng.
In the Canadian case, the suspected impostor tested negative for digoxin, but it was not tested for other cardiac glycosides, and its identity was never ascertained.(3)
(1) Sharma, I., et al. “Hypolipidaemic and Antiatherosclerotic Effects of Zingiber officinale in Cholesterol Red Rabbits”. Phytotherapy Research 1996, 10(6):517- 518.
(2) Lin, S. C., et al. “Hepatoprotective Activity of Taiwan Folk Medicine: Eclipta prostrata L. against Various Hepatotoxins Induced Acute Hepatotoxicity”. Phytotherapy Research 1996, 10(6):483-490.
(3) MacRae, S. “Elevated Serum Digoxin Levels in a Patient Taking Digoxin and Siberian Ginseng”. Canadian Medical Association Journal 1996, 155:293-295.
“Herbs for Health” is offered bimonthly by the American Botanical Council and the Herb Research Foundation as a supplement to The Herb Companion.
Editor, Steven Foster
American Botanical Council
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“Herbs for Health” is intended as an educational service, not a source of medical advice or a guide for self-medication. Please consult a qualified health-care professional for treatment of any serious health problems. For further information on any of the topics in “Herbs for Health”, write the American Botanical Council or the Herb Research Foundation.