Fighting cancer with plant molecules: Indian scientists show the way

What do tea, turmeric and broccoli have in common? A lot, when it comes to an arsenal of certain chemicals found in them, called phytochemicals, that can be harnessed to combat cancer therapy side-effects in synergy with conventional anti-cancer drugs.

Chemotherapy is fraught with side-effects. Now Indian scientists have shown how certain naturally-occurring plant chemicals when used in combination with routine cancer drugs can actually lower the dosage of the medication, thereby minimising the after-effects.

Moreover, phytochemicals (plant chemicals) may increase the efficiency of the drugs, said Madhumita Roy, head of the Environmental Carcinogenesis and Toxicology Department at Chittaranjan National Cancer Institute (CNCI) here, who led the study.

"Our data suggest that treatment of cells with these phytochemicals in conjunction with chemotherapeutic drugs resulted in the same extent of cell killing at a much lower concentration of the drug," Roy told IANS.

Some examples of the plant-derived chemicals include curcumin found in turmeric, polyphenols found in tea - both green and black - and isothiocyanates that are common in cauliflowers, cabbages, broccoli and Brussels sprouts, among others.

These agents, in tandem with anti-cancer drugs, Roy explained, reduce the levels of certain proteins (called tumour markers) which are elevated in cancer. This, in turn, sensitises the deadly cancer cells to opt for suicide - a process called apoptosis.

Besides fighting cancer, there is another side to these natural molecules: Phytochemicals can also play a key role in cancer prevention.

With arsenic in groundwater posing a "big problem" in West Bengal, prolonged exposure to the toxic substance may lead to cancer by damaging the DNA hereditary molecule.

Curcumin has been shown to be particularly beneficial in this aspect.

"These phytochemicals showed their efficiency to counter DNA damage caused by arsenic. This DNA damage initiates the process of cancer development; therefore reduction of such damage may pave a way to cancer prevention. Apart from this, phytochemicals also play a role in repair of DNA damage. We conducted a field study where curcumin has been found to be of great value in combating the problem with arsenic at the genetic level," said Roy.

This furthers the fact that the traditional Indian diet, encompassing a wide range of vegetables, fruit and spices, scores over the Western approach to diet, said cancer scientist Sukta Das, member of the Cancer Foundation of India.

Another facet of these phytochemicals is that they are non-toxic to the human body.

According to CNCI director Jaydip Biswas, since the treatment protocols for cancer are not only expensive but also cause severe side-effects, "plant derived products with anti-cancer potential may come to the rescue. They may improve the efficacy of chemotherapy and radiotherapy."

The next step of the preliminary study, said Biswas, would be to go for "further clinical research" which is necessary to "prove the role of phytochemicals. Once established it will open a new avenue (for cancer prevention and treatment)."

(Sahana Ghosh can be contacted at sahana.g@ians.in)