An ingredient in red wine can boost a drug’s ability to combat breast cancer, research has shown.

Laboratory tests showed that the compound resveratrol enhanced the effect of the drug rapamycin.

Cancer cells resistant to rapamycin alone had their growth inhibited when they were also exposed to resveratrol.

Rapamycin is an immunosuppressant used to prevent the rejection of transplant organs which also has anti-tumour activity. But the drug’s success in clinical trials has been tempered by the fact that cancer cells quickly develop resistance to it.

Charis Eng, medical doctor, who led the new US study at the Cleveland Clinic, Ohio, said: “Our findings show that resveratrol seems to mitigate rapamycin-induced drug resistance in breast cancers, at least in the laboratory.

“If these observations hold true in the clinic setting, then enjoying a glass of red wine or eating a bowl of boiled peanuts – which has a higher resveratrol content than red wine – before rapamycin treatment for cancer might be a prudent approach.”

The findings are published in the journal Cancer Letters.

Dr Eng’s team looked at the effect of rapamycin and resveratrol, alone and in combination, on three human breast cancer cell lines. In all three, low concentrations of resveratrol and rapamycin together led to a 50 per cent growth inhibition.