Qat, the plant chewed for the euphoria-inducing properties of its leaves, may increase the potency of men's sperm, scientists said yesterday.
Qat has been widely used in east Africa and the Arabian peninsula for centuries, and as people from those regions have come to live in the UK, they have brought the chewing habit with them. Some seven tonnes of the leaves, categorised as a vegetable, are legally imported into the UK every week.
Men who chew qat are not known to be more fertile than those who do not, for all that its aficionados believe it improves their sex drive and ability to maintain an erection. In fact, some scientists have questioned whether a serious qat habit might not damage men's reproductive system.
But researchers at King's College London have now found that immersing sperm in chemicals extracted from qat stimulates them to become more active more quickly, and thus more likely to fertilise an egg.
While they are not suggesting chewing qat as an aid to conception, they say it may be possible to make an over-the-counter pill that the infertile or indeed anyone else hoping for a baby may be able to take.
"A pill a day or a pill every two days would be quite enough for the fertility effect," said Lynn Fraser, professor of reproductive biology at King's. "We certainly wouldn't advocate anyone going out and chewing qat leaves, because you need a measured dose."
Chewing the leaves releases a stimulant called cathinone, which is not very stable and quickly breaks down into cathine and norephedrine. These chemicals belong to a group called the phenylpropanolamines (PPAs), which are structurally similar to amphetamines and adrenaline.
The researchers at the centre for reproduction, endocrinol ogy and diabetes at King's looked at the effect in the lab of the exposure of mouse and human sperm to PPAs.
They told the European Society on Human Reproduction and Embryology conference in Berlin that they found cathine stimulated sperm to mature and released enzymes that allow it to enter the egg. When mouse sperm was treated with cathine, it fertilised eggs much more quickly than untreated sperm.
More work has to be done in animal tests - and also tests to ensure there is no harm to the ovaries, testes and sperm - but Prof Fraser believes there is potential for a qat pill. Other PPAs have already been used in over-the-counter ephedrine medication.
Work is now under way to establish whether qat chemicals can also encourage men to produce more sperm. If that proves successful, the pill might be taken by both sexes - by men initially to encourage sperm production and then by women to help the sperm become more potent while they are in the female reproductive tract.
