Curcumin, the yellow ingredient, rejuvenates cancer-fighting immune cells

India’s wonder spice turmeric just doesn’t appear to stop surprising scientists. It’s been found to combat cancer, fight inflammation and infections. Now, Calcutta biochemists Gaurisankar Sa and Tanya Das have discovered yet another trait of this traditional medicinal herb.

The Bose Institute researchers have shown that curcumin, the yellow ingredient of turmeric, rejuvenates a class of immune cells that fight cancer, strengthening the immune system by restoring key immune cells destroyed by tumours.

While studies over the past decade have helped scientists establish that curcumin can fight tumours, its effects on the immune system in cancer have been unclear. Patients with advanced cancer have poor immunity, because of the weakening effect of tumours. This allows the cancer to progress even faster and makes the patients susceptible to infections.

“Our work shows that curcumin is a double-edged sword,” Sa said. “On the one hand, it can help kill tumour cells and on the other, replenish the weakened immune system in cancer,” he told KnowHow.

The findings, published recently in the Journal of Biological Chemistry, suggest that curcumin may be used in the treatment of cancer by itself or in combination with standard anti-tumour drugs used in chemotherapy.

The researchers, in their studies on mice, have shown how curcumin increases the production of proteins that allow a set of immune cells called the CD4 and CD8 cells to proliferate and reduces the production of proteins that help destroy these cells.

“Curcumin thus blocks the tumour-induced destruction of immune cells,” Sa said. “One of the roles of the immune cells is to destroy tumours. This happens in the earliest stages of the disease,” he said.

But tumours also release chemicals that destroy these immune cells, and advanced cancers simply overwhelm the cells. The studies by the Calcutta team have shown how curcumin interferes with the production of these chemicals by tumours and restores the immune cells.

However, scientists unconnected with the study have cautioned that curcumin has not become part of standard anti-cancer treatment as it is poorly absorbed into the bloodstream. Most of the curcumin consumed orally is thus excreted.

“Curcumin is one of the most attractive among emerging anti-cancer agents because it’s been consumed through food for centuries,” said Anirban Maitra, associate professor at the Johns Hopkins School of Medicine, US. “But its poor solubility prevents it from widespread testing against human cancers,” said Maitra, who’s trying new ways to deliver curcumin into the body.