Recent studies in the herbal world.
Everyone knows that cayenne pepper (Capsicum annuum) is hot stuff. However, when its active compound, capsaicin, is applied to the skin, it relieves pain rather than producing it. Unlike many pain relievers, capsaicin doesn’t work by reducing inflammation. Instead, the compound blocks production and transport of “substance P,” a chemical that carries pain messages from nerve endings in your skin to control headquarters in your central nervous system. Double-blind clinical studies indicate that it helps relieve the nerve and muscle pain caused by conditions such as osteoarthritis and fibromyalgia, whether or not there is inflammation. To test the efficiency of capsaicin on back pain, a double-blind, parallel-group, placebo study applied a capsicum plaster on the backs of 154 volunteers who had been dealing with chronic back pain for at least three months. Nearly one-third of them found that their pain was quickly reduced. After three weeks, another 31 percent were feeling less pain, and it was easier for them to get around and to function in general. Tolerating the treatment was actually easier for those using capsicum rather than the placebo group because it provided so much pain relief, although some volunteers reported discomfort. Previous studies have shown that a burning sensation can last for up to three days in some people. In another recent study, when an analgesic balm made with capsaicin and methyl salicylate (aspirin) was applied on the skin, it decreased muscle contraction and the resulting discomfort. This suggests that capsaicin relieves pain by signaling muscle receptors. While a capsaicin or cayenne plaster is effective, an easier way to treat back pain is with the over-the-counter capsaicin cream sold to treat shingles. In clinical trials, it gave 75 percent of the people with shingles who tried it complete or substantial pain relief and it is also being tested on other painful skin problems, such as diabetic neuropathy, psoriasis, and pain after surgery.
Selected sources: Ichiyama, R. M., et al. “Effects of topical analgesics on the pressor response evoked by muscle afferents.” Medicine and Science in Sports and Exercise 2002, 34(9): 1440–1445.
Surh, Y. J. “More Than Spice: Capsaicin in Hot Chili Peppers Makes Tumor Cells Commit Suicide.” Journal of the National Cancer Institute 2002, 94(17): 1263–1265.
The hawthorn tree (Crataegus spp.) is admired throughout its native Europe for its attractive spring blossoms and its deep-red berries in the fall. Preparations made from its leaves, flowers, and berries are also a favorite of many European doctors as a nontoxic remedy to relieve symptoms of congestive heart failure. In Germany, some doctors prescribe hawthorn instead of drugs such as digitalis for mild cases of heart disease. It is also used there to reduce the dose of prescription heart medications. (Don’t take hawthorn with prescription drugs without the guidance of a health practitioner—hawthorn can make the drugs you’re taking too potent.) Most modern studies have been conducted with hawthorn flowers, leaves, or twigs, although traditionally, herbalists use the berry. A recent German study of eighty-eight people with congestive heart failure gave participants a standardized extract made from the fresh berries. The berry extract not only decreased their difficulty in breathing while exercising 11 percent (compared to only 4 percent with a placebo), it also improved their energy level and quality of life. The three-month randomized, double-blind placebo study showed that exercise time on a stationary bicycle went up nearly 50 percent in those taking hawthorn compared to the placebo. The study’s researchers declared hawthorn is an effective and safe treatment. Long-term use may also lower blood pressure, according to a British study. Thirty-six people with mildly high blood pressure took a hawthorn extract (500 mg) or magnesium supplements (600 m.), a combination of both, or a placebo. Blood pressure dropped in all of the groups, including those taking a placebo, but resting diastolic pressure fell the most with hawthorn after ten weeks of use. The extract was also found to reduce feelings of anxiety.
Sources: Rietbrock, N., et al. “Actions of Standardized Extracts of Crataegus Berries on Exercise Tolerance and Quality of Life in Patients with Congestive Heart Failure.” Arzneimittelforschung 2001, 51(10): 793–798.
Walker, A. F., et al. “Promising Hypotensive Effect of Hawthorn Extract: A Randomized Double-blind Pilot Study of Mild, Essential Hypertension.” Phytotherapy Research 2002, 16(1): 48–54.
There’s increasing interest in herbs that provide a natural way to regulate hormones and to prevent estrogen-based cancers. Rather than resulting in an oversupply of hormones, researchers are discovering that many plant-based hormones gently signal the body’s responses while blocking the more carcinogenic forms of hormones such as estrogen. The Pusan National University in Korea decided to test out one of the most potent sources of plant estrogens: pomegranate (Punica granatum). Researchers there found that the fermented juice, seed oil, and a water extract of the seed covering may help prevent breast cancer by inhibiting estrogen receptors in breast cancer cells. Pomegranate seed oil was particularly effective. Pomegranate’s estrogen-modifying action is thought to be caused by compounds called polyphenols, which inhibited estrogenic activity 55 percent and cancerous lesions by 47 percent in mammary glands. These compounds also reduced oxidation by decreasing enzyme activity up to 79 percent. Plus, pomegranate fruit is a strong antioxidant that is also good for the heart. During a three-and-a-half month Israeli study, cholesterol dropped 20 percent in volunteers who drank pomegranate juice. It increased factors that protect against lipid oxidation 29 percent in only two weeks and greatly reduced the size of lesions associated with hardening of the arteries and produced less clumping of blood cells compared to a control group.
Sources: Kim, N. D., et al. “Chemopreventive and Adjuvant Therapeutic Potential of Pomegranate (Punica granatum) for Human Breast Cancer.” Breast Cancer Research and Treatment 2002, 71(3): 203–217.
Aviram, M., et al. “Pomegranate Juice Consumption Reduces Oxidative Stress, Atherogenic Modifications to LDL, and Platelet Aggregation.” American Journal of Clinical Nutrition 2000, 71(5): 1062–1076.
Irritable Bowel Syndrome (IBS) can be very bothersome, causing chronic, sometimes severe diarrhea, pain, spasms, belching, nausea, heartburn, and loss of appetite. It is estimated that 10 percent to 25 percent of the U.S. population suffers from it, although the cause and cure eludes doctors. Researchers now suspect that the symptoms may be caused by free radicals produced by the colon’s inflamed lining. Five herbs often used to treat the condition—slippery elm (Ulmus rubra), fenugreek (Trigonella foenum-graecum), devil’s claw (Harpagophytum procumbens), Mexican yam (Dioscorea villosa), and tormentil (Potentilla erecta)—were all found helpful in easing the symptoms. Except for Mexican yam, all five herbs proved to be strong antioxidants. The study’s researchers, who worked with the Academic Department of Adult and Pediatric Gastroenterology and Queen Mary’s School of Medicine and Dentistry in London, England, feel that herbs may provide “novel” remedies to treat IBS. In another study, an extract of artichoke leaf (Cynara scolymus) also relieved the symptoms of irritable bowel syndrome when 279 volunteers who had at least three of the typical symptoms of IBS took two capsules of a standardized extract (320 mg each) per day for six weeks. The treatment was rated as good or excellent by 84 percent of the participants and there were no serious side effects reported.
Sources: Langmead, L., et al. “Antioxidant Effects of Herbal Therapies Used by Patients with Inflammatory Bowel Disease.” Alimentary Pharmacology & Therapeutics 2002 16(2): 197–205.
Walker A. F., et al. “Artichoke Leaf Extract Reduces Symptoms of Irritable Bowel Syndrome in a Post-marketing Surveillance Study.” Phytotherapy Research 2001, 15(1): 58–61.
Antioxidant herbs reduce free radical production, which results in less destruction of cells. They are also suspected of slowing down the aging process. Even using small amounts of these herbs seems to have beneficial results. Because the essential oils found in many herbs tend be antioxidants, researchers at the University of California at Davis conducted two independent assays to evaluate them. Of the plants they tested, the most potent antioxidants were from thyme (Thymus vulgaris), basil (Ocimum basilicum), rosemary (Rosmarinus officinalis), chamomile (Matricaria recutita), lavender (Lavandula angustifolia), and cinnamon (Cinnamomum verum), in that order. Thyme and basil were so strong that they inhibited oxidation for forty days. A previous study at the University of Illinois, Chicago, found that thyme contains forty different antioxidants and that basil contains more than thirty! Thyme’s potency was comparable to the common food preservative BHT and vitamin E. Rosemary’s antioxidant properties help heal stomach ulcers, apparently by increasing protective mucus in the digestive tract lining and lowering levels of substances that produce inflammation. Rosemary was investigated for use as a natural food preservative and now researchers in Italy think it could be a good addition to skin creams or lotions. They found it protects the complexion from cellular damage by minimizing free radical damage to skin cells and may even help cells tolerate stress from oxidation and slow deterioration of their DNA.
Selected sources: Lee, K. G. and T. Shibamoto. “Determination of Antioxidant Potential of Volatile Extracts Isolated from Various Herbs and Spices.” Journal of Agricultural Food Chemistry 2002, 50(17): 4947–4952.
Calabrese, V., et al. “Biochemical Studies of a Natural Antioxidant Isolated from Rosemary and its Application in Cosmetic Dermatology.” International Journal of Tissue Reactions 2000, 22(1): 5–13.
Kathi Keville is director of the American Herb Association (www.jps.net/ahaherb) and the author of eleven herb and aromatherapy books including Herbs for Health and Healing (Rodale, 1996). She teaches seminars throughout the United States.
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