Hoodia P57. Enough to put you off your food

The story goes that, when the San tribe of southern Africa felt hungry but had no food around, they would chew on a plant called the hoodia gordonii. A few mouthfuls of this bitter-tasting succulent later, their hunger pangs would mysteriously disappear. Very soon, the plant will begin its journey to a plate near you. The remarkable appetite-suppressing quality of hoodia has attracted the attention of Unilever and, early next year, a clinical trial will begin on the active ingredient, a combination of molecules codenamed p57.

According to research carried out by Cambridge-based pharmaceutical company Phytopharm, the company that owns the worldwide patent on the extract, p57 suppresses hunger so well that it can make people eat 1,000 fewer calories per day compared to their usual diets. For a society facing the burden of a growing obesity epidemic, hoodia gordonii is a mouth-watering prospect.

Anyone with a body mass index of greater than 30 is classed as obese, and the World Health Organisation estimates there are 300 million such adults worldwide. In the UK, more than a fifth of the adult population is obese, and a further half of men and a third of women are classified as overweight. Obesity is a major risk factor linked to heart disease, diabetes and premature death.

"Looking for chemicals from plants is a fantastic domain of opportunity," said John Blundell, director of the Institute of Psychological Sciences at the University of Leeds who specialises in the study of obesity.

The search for the physiological reasons behind excessive weight gain and for a way to mitigate it occupies teams of scientists and public health officials worldwide. Much of the research has focused on working out which chemicals in the bloodstream control hunger.

There are two class of anti-obesity drugs coming onto market. One type, such as rimonabant, targets the areas of the brain which regulate how we feel, so that we end up eating less. The other type, such as xenical, prevents fat from being absorbed by the intestines. Hoodia seems to do neither of these things. According to Phytopharm, it seems to work as a genuine appetite suppressant. Behavioural studies on animals showed that even those which had their appetite severely suppressed by p57 seemed to show no change in mood or behaviour.

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