HONOLULU - Known to herbalists for its healing powers, the native Hawaiian noni plant has been found to kill the bacterium that causes tuberculosis. The finding could lead to new drugs to fight the disease, according to the latest research. Tuberculosis has resurfaced recently due to the emergence of drug-resistant strains, and is particularly prevalent in Hawaii.
Noni, also known as Indian mulberry or its scientific name, Morinda citrifolia, is an evergreen plant that is recognized by its foul-smelling, green-skinned fruit. It is found throughout the world, particularly in Asia and northern Australia. Hawaii is the major source of noni in the United States.
While traditional Hawaiian healers have long used the plant to treat patients afflicted with tuberculosis (TB), this study represents the first report identifying the compounds that may be responsible for this action, according to researchers at the University of Santo Tomas (UST), Manila, Philippines.
The researchers randomly screened a group of native plants for potential activity against Mycobacterium tuberculosis, the bacterium that causes TB. In laboratory tests, a concentration of extracts from the leaves of the noni showed a significant inhibitory rate, killing 89 percent of the pathogens, they say. This compares favorably with rifampicin, a drug commonly used to treat TB, which has an inhibition rate of 97 percent at the same concentration, according to the
The active compounds were isolated from the extract and found to be
phytosterols (plant steroids). The compounds are structurally different from those drugs that are typically used to treat TB, indicating that the compounds may act under a different mechanism that could be useful
for building an alternative drug to fight resistant bacterial strains, the researchers say. An additional drug source could also provide cheaper alternatives to more expensive drugs for treating TB, they add.
"I hope that pharmaceutical companies will pay attention to this research and explore the noni plant as a potential source of drugs," says Jonel Saludes, who was the lead researcher on the study.
Saludes declined to speculate how much of the extract is needed to achieve a therapeutic effect in humans, as the extract has not yet been tested in animals. Also unknown is whether the active chemicals are found in other parts of the plant, including the fruit, stems and roots. Studies on the fruit are ongoing, he says.
The noni plant has been used for hundreds of years to treat a variety of other illnesses, including heart disease, diabetes and cancer. The plant's popularity has recently surged in the United States and Southeast Asia. The noni's fruit has been processed into juices, pills and other products that are sold in health food stores and over the
Like other herbal remedies, the curative powers of noni remain largely unproven, while its potential health risks are unknown. Still, the plant has become the target of a growing number of studies.
The incidence of tuberculosis is increasing worldwide, due largely to the emergence of drug- resistant bacteria. In 1999, Hawaii had the highest rate of TB in the nation, according to the Centers for Disease Control and Prevention. Unless improved efforts are undertaken to stem the growing threat worldwide, the disease will continue to rise,
health officials warn.