Components of rosemary are already known in the food industry as antioxidants for protecting packaged foods. Researchers at Fukuyama University in Japan recently reported research on the antioxidant activity of four diterpenoids—carnosol, carnosic acid, rosmanol, and epirosmanol—isolated from rosemary leaves. The damage resulting from the oxidation of unsaturated fatty acids in cell membranes has been linked to coronary arteriosclerosis, diabetes, and cancer as well as aging. The Japanese study showed that two of the rosemary compounds, carnosol and carnosic acid, may protect tissues and cells against oxidative stresses. More research is under way.(1)
Many North Americans plant nasturtiums (Tropaeolum majus) for their vivid colors and peppery flavor, but few are familiar with their medicinal uses. In Peru, Colombia, and Brazil, where nasturtiums are native, they are traditionally used as an antispasmodic, stimulant, antimicrobial, and antiscorbutic. Moreover, the leaves and flowers contain benzyl isothiocyanate, which has been shown to inhibit and protect against various carcinogens. Scientists in Portugal and the United Kingdom recently produced benzyl isothiocyanate by tissue culture of nasturtium cells. When they tested the purified compound against various human and animal cancer cell lines, they found that within two hours it selectively killed cells of all cancer cell types tested; the effects were not reversed when the compound was removed. Although many substances will kill cultures of mammalian cancer cells in test systems, the benzyl isothiocyanate from nasturtiums is unusual in showing rapid, selective, and irreversible activity, paving the way for more intensive research on the compound.(2)
Ocimum sanctum, known variously as holy basil, sacred basil, or green tulsi, is increasingly seen in American herb gardens. The herb is one of India’s most famous medicinal plants. The leaf juice has been taken internally to treat fevers, malaria, and bronchitis, and externally to treat ringworm and other skin diseases. It is also a folk remedy for cancer. In a recent preliminary study, researchers in India found that an ethanol leaf extract of holy basil administered to mice significantly reduced the number of mice that developed tumors, as well as the mean number of tumors that each mouse developed. The extract may accelerate detoxification of carcinogens in the liver, or antioxidant components of the extract may protect against cancer. Given the positive results of this study, holy basil likely will be the subject of future research on cancer-preventive agents found in human diets.(3)
The August/September 1995 issue of “Herbs for Health” reported on four clinical trials that showed that St.-John’s-wort (Hypericum perforatum) could be an effective treatment for mild forms of depression. In a recent review of all controlled clinical trials on the use of St.-John’s-wort for depression—fourteen studies conducted using a placebo for comparison and four studies comparing St.-John’s-wort extracts to standard antidepression drugs—the author concluded that eight of the placebo-controlled studies and three of the standard drug studies met the established criteria for acceptable design and that St.-John’s-wort extract was superior to a placebo and as effective as standard medications in alleviating symptoms of depression, with far fewer adverse reactions than standard medications. This study represents the first comprehensive review of the clinical literature published in English.(4)
Feverfew (Tanacetum parthenium) is recognized for its ability to diminish the severity of migraine headaches (see “Herbs for Health”, October/November 1995), but it is also a major folk treatment for arthritis. A research group at the University of Reading in England recently identified a new flavonol in the leaves, flowers, and seeds, which they named tanetin. Biological tests showed that tanetin may inhibit compounds known to be inflammatory (anti-inflammatory activity in a number of other feverfew compounds had previously been identified). This study suggests the need for future research on possible antiarthritic applications of feverfew.(5)
(1) Haraguchi, H., et al. Planta Med. 1995, 61:333–336.
(2) Pintao, A. M., et. al. Planta Med. 1995, 61:233–236.
(3) Prashar, R., and A. Kumar. Int. J. Pharmacog. 1995, 33:181–187.
(4)Ernst, E. Phytomedicine 1995, 2(1): 67–71.
(5) Williams, C. A., et al. Phytochemistry 1995, 38(1):267–270.