Moringa emerges to prevent cancer

Moringa  emerges to prevent Cancer

by Upali Rupasinghe in New Delhi

Indian scientists have discovered an even more tantalising application of Moringa oleifera, the drumstick plant "murunga", liquid extracted from its leaves can prevent lethal radiation damage to living tissues.

The discovery by radiobiologists at the Jawaharlal Nehru Cancer Hospital and Research Centre, Bhopal, raises fresh hopes that compounds from medicinal plants might emerge a major source of natural drugs that could prevent the harmful effects of radiation damage to living tissues.

The drumstick now joins a growing list of medicinal plants that researchers believe might one day find use in improving the efficiency of cancer treatment with radiation because it can reduce the severe side-effects of radiotherapy. Radiation damage to normal tissues in the body lead to the adverse effects associated with radiotherapy. Compounds that protect normal tissues from damage from radiation exposure could increase the tolerance of patients to radiation therapy and thus increase the efficiency of radiation treatment.

"This the first study that demonstrates that Moringa oleifera has a radioprotective effect", P. Uma Devi and her colleagues, formerly at the Kasturba Medical College (KMC), Manipal, said reporting their findings in the Indian Journal of Experimental Biology.

Over the past five years, the researchers have established the radio-protective effects of another traditional Indian backyard plant - tulsi. The new findings suggest that tulsi and drumstick may have similar mechanisms of action against radiation.

The only pharmaceutical drug approved for use in radio-protection is a synthetic chemical that by itself leads to side-effects like nausea, vomiting, and low blood pressure. Several research teams in India and elsewhere have been searching the plant world for efficient radioprotective agents.

"The radio-protective effect of plants is nor surprising," says a senior radiation biologist. "Radiation leads to oxidative damage to living tissues, and many plants contain anti-oxidants which can prevent this damage", the biologist said.

In the mid-1990s, Uma Devi and her colleagues showed that extracts of the tulsi plant have a radioprotective effect. They demonstrated this through cells maintained in tissue culture as well as through experiments on animals that were administered the tulsi extracts and then exposed to radiation.

The KMC researchers showed that aswagandha might also play a role in radiation therapy, but in an opposite way. The ashwagandha extract serves as a 'radiosensitiser,' making tumour cells more susceptible to radiation.

In radiation therapy, tumour cells located relatively far from blood vessels have low oxygen levels and survive the radiation. This can often lead to a resurgence of cancer.

"The way a radio-sensitizer makes cells more susceptible to radiation is interesting," says a radiobiologist in a national research laboratory. "The trick is to find a radiosensitising agent that electively makes only tumour cells more susceptible to radiation while leaving normal cells alone. Whether ashwagandha does this kind of differential sensitisation is till an open question,".

Several medicinal properties of drumstick plant had already been established when the Mainpal research team picked it for radiobiological investigations. Researchers in Japan and elsewhere had shown that Moringa Oleffera extracts had antitumour and anti-inflammatory agents.

The KMC scientists crushed leaves into a powder and extracted a liquid. Then in a series of experiments, they injected the extracts into mice and exposed them to radiation to determine whether and at what concentration the extract had any protective effect.

The studies revealed that a single dose of Moringa oleifera administered prior to whole body radiation can significantly decrease chromosome damage caused by radiation. The best results were obtained when mice were given 150 mg of the extract per kg body weight. The scientists called this the "optimum protective dose".

The scientists also found that giving the mice that dose in five equal fractions actually enhanced the protective effect. These findings are similar to what the KMC researchers had observed earlier with extracts from the tulsi plant where five divided doses distributed over time before exposure to radiation had better protective effect than a single dose.

Examinations of tissues of the mice that received radiation alone and no injections revealed severe chromosomal abnormalities in the bone marrow that could be attributed to radiation damage. The bone marrow of the mice that received injections were protected from chromosomal damage and their survival was higher.

Drumstick leaves are widely used across South Asia in a variety of foods Their high vitamin C content might be responsible for their radio Potective effect, says Uma Devi who moved to the Jawaharlal Nehru Cancer Research centre in Bhopal earlier this year and is currently at a Japanese research centre studying radiobiological effects of ashwagandha. Her team urges detailed follow-up investigations aimed at exploiting the radioprotective effects of medicinal plants to save humans from radiation damages.

There are indications that other plants might yield even more powerful radioprotective agents. At the Institute of Nuclear Medicine and Allied Sciences, new Delhi, for instance, a research team led by harsh Goel has shown that a plant called Hip-pophear, popularly called the seabuck thorn and found in the Himalayan region, can also serve as a radioprotective agent.

Presenting his findings at an international conference on the seabuck thorn held in New Delhi earlier this year, Goel reported that administration of 25 to 35 mg per kg body weight of the extract protected mice from potentially lethal doses of radiation.