A recent laboratory study at the University of Iowa has identified two compounds from clove oil that show strong activity against Porphyromonas gingivalis and Prevotella intermedia, bacteria associated with cavities, plaque formation, and swollen gums, as well as periodontal disease.
Cloves, the buds of a tropical tree, Syzygium aromaticum, are a familiar culinary spice. Their essential oil, long used in dental products and as a home remedy to relieve toothaches, is mildly antiseptic and antibacterial. Eugenol, which comprises 60 to 90 percent of the oil, contributes to cloves’ flavor, fragrance, and pain-numbing property.
Of eight antibacterial compounds in clove oil, the Iowa study found kaempferol and myricetin to be the most potent. The remaining six compounds were less effective.(1)
Lemongrass (Cymbopogon citratus) oil from local sources shows promise as an inexpensive remedy for ringworm, a fungal skin infection that is especially prevalent in the Third World Tropics, where many people can’t afford Western antifungal medications.
Researchers in Bangkok, Thailand, searching for cheaper alternatives have been testing lemongrass, a traditional remedy for fungal diseases. They tested a lemongrass-oil cream and citral (a major constituent of the oil and the source of its fragrance) against strains of four fungal organisms known to cause skin disease. A preparation containing 2.5 percent lemongrass oil was effective in a laboratory study and will be used in a clinical trial.
The cream was also found to be more effective than four commercial creams containing clotrimazole, isoconazole nitrate, ketoconazole, benzoic acid, and salicylic acid. Further tests are planned.
Lemongrass is a favorite flavoring of Southeast Asian cooks. The oil also scents cosmetics, soaps, and detergents, and teas have been used traditionally to treat colds, upset stomach, and headaches.(2)
The anticancer potential of poppy seeds (Papaver somniferum), sacred basil leaves (Ocimum sanctum), and cumin seeds (Cuminum cyminum) resides in their essential oils, an Indian study has found.
Previous research had shown that something in these herbs inhibits the growth of some kinds of cancer cells and that the essential oils of other herbs are responsible for preventing cancer development.
Pure essential oils prepared from poppy and cumin seeds and sacred basil leaves purchased at local markets were evaluated by studying their interaction with glutathione-S-transferase, an enzyme that inhibits cancer development, and by examining their effect on the development of squamous-cell carcinomas (cancers) induced in the stomachs of laboratory mice. The oils significantly increased the enzyme activity by more than 87 percent and also significantly inhibited the development of stomach cancers in the mice. Further research is needed to identify the active compounds in the oils.(3)
Aromatherapists recommend inhaling the vaporized oil of chamomile (Matricaria recutita) to relieve nervous disorders, including anxiety and depression associated with menopause. Although the treatment reportedly is effective, how it works is unknown.
Researchers in Tokyo compared the effectiveness of chamomile vapor with the conventional tranquilizer diazepam (Valium) in relieving anxiety and depression in menopause. Stressed female laboratory rats whose ovaries had been removed were assigned to three groups. One group was exposed to the vapors twice each day for three days; the second received diazepam, and the third received both chamomile vapors and diazepam. Three groups of stressed rats with intact ovaries received the same treatments.
Stress hormone levels in the intact stressed rats exposed to chamomile vapor decreased significantly, but the decrease was 15 percent greater in intact rats on diazepam. By contrast, the combination of diazepam and chamomile vapor was about 15 percent less effective than the vapors alone.
In rats whose ovaries had been removed, exposure to chamomile vapors lowered stress hormone levels by some 40 percent, about 32 percent more than diazepam. But the combination of diazepam and chamomile vapors decreased levels by about 88 percent, more than twice as much as the vapor alone and far more than the combined treatment produced in intact stressed rats.
Whether sniffing chamomile oil can replace taking conventional tranquilizers in the treatment of menopausal anxiety and depression in humans requires further study. The Tokyo study does, however, indicate that persons taking diazepam or similar sedatives should seek professional advice before trying aromatherapy with chamomile.(4)
The medicinal vine known as “cat’s-claw” has two species that grow in Peru: Uncaria tomentosa and U. guianensis. Typically, the stalk bark, root, or root bark is removed to prepare teas, decoctions, or simple extracts made with a sugarcane rum called “aguardiente”. Recently, ethnobotanists noted that the Yanomani Indians of Brazil treat diarrhea and stomachaches with a tea made from pieces of the U. guianensis stem steeped in hot water. They also use the plant topically for the same conditions by beating the stems until soft and applying them to affected areas. Beating the stems releases plant juices, raising the possibility that active constituents of the plants may be absorbed through the skin as well as by the lining of the stomach.
In the Amazon area of northeastern Peru, U. guianensis, known as “uña de gato”, is used as a tonic for liver problems, tumors, and cancer. In most of Peru, the root or inner bark of the stalk is used, but here the locals use every part of the vine to prepare a tea by macerating the vine or steeping the parts in hot water.
Austrian researchers recently distinguished two types, or “modifications”, of U. tomentosa by identifying the predominant alkaloids. The seventeen different alkaloids present in the vine are either pentacyclic oxindole alkaloids, which have shown anti-inflammatory and immune-strengthening activities, or tetracyclic oxindole alkaloids, which “exhibit activity on the central nervous system”. Some researchers suggest the plants should be identified either as U. tomentosa tetracyclica or as U. tomentosa pentacyclica because the tetracyclic alkaloids may cause unwanted side effects.(5),(6),(7), and (8)
(1) Cai, Lining, and C. D. Wu. “Compounds from Syzygium aromaticum Possessing Growth Inhibitory Activity Against Oral Pathogens”. Journal of Natural Products 1996, 59:987–990.
(2) Wannissorn, B., S. Jarikasem, and T. Soontorntanasart. “Antifungal Activity of Lemon Grass Oil and Lemon Grass Oil Cream”. Phytotherapy Research 1996, 10:551–554.
(3) Aruna, K., and V. M. Sivaramakrishnan. “Anticarcinogenic Effects of the Essential Oils from Cumin, Poppy and Basil”. Phytotherapy Research 1996, 10:577–580.
(4) Yamada, K., et al. “Effect of Inhalation of Chamomile Oil Vapour on Plasma ACTH Level in Ovariectomized Rats under Restriction Stress”. Biological and Pharmaceutical Bulletin 1996, 19:1244–1246.
(5) Jones, Kenneth. Cat’s Claw. Healing Vine of Peru. Seattle, Washington: Sylvan Press, 1995.
(6) Milliken, W., and B. Albert. “The Use of Medicinal Plants by the Yanomani Indians of Brazil”. Economic Botany 1996, 50(1):10–25.
(7) Jovel, E. M., “An Ethnobotanical study of the traditional medicine of the Mestizo people of Suni Mirano, Loreto, Peru”. Journal of Ethnopharmacology 1996, 53:149–156.
(8) Keplinger, K., et al. “Uncaria tomentosa—Two Natural Modifications.” 2nd International Congress on Phytomedicine, Munich, Germany (September 11–14, 1996) Poster presentation.
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