Black pepper could provide a new treatment for the skin disease vitiligo, research suggests.
Vitiligo is relatively common
Vitiligo is a condition in which areas of skin lose their normal pigment and become white.
Researchers discovered that piperine - the compound that gives black pepper its spicy, pungent flavour - can stimulate pigmentation in the skin.
The study, by King's College London, appears in the British Journal of Dermatology.
Vitiligo is estimated to affect about one in 100 people. Current treatments include corticosteroids applied to the skin, and phototherapy using UV radiation (UVR) to re-pigment the skin
However, less than a quarter of patients respond successfully to corticosteroids.
And UVR causes a re-pigmentation that is spotted and patchy and in the long-term could lead to a higher risk of skin cancer.
The King's team examined the effects of piperine, and its synthetic derivatives, when applied to the skin of mice, either alone or followed by UVR.
Used alone, piperine and two of its derivatives stimulated pigmentation to an even, light brown colour within six weeks.
Combining the treatment with UVR the skin became darker still. The effect was achieved much faster than using UVR treatment alone, and lasted longer.
In addition, the combined therapy gave a much more even pigmentation than UVR alone, which can often result in a patchy appearance.
The researchers believe that piperine stimulates the production of the skin's pigment cells, called melanocytes.
Researcher Professor Antony Young said: "We have shown that topical treatment with piperine stimulates even pigmentation in the skin.
"Combining this with UVR significantly enhances the pigmentation with results that are cosmetically better than conventional vitiligo therapies."
Nina Goad, of the British Association of Dermatologists, said: "Vitiligo is a highly visible disease that can greatly affect patients psychologically and emotionally. Any breakthrough in treatments of this disease is most welcome."
"These findings could potentially lead to the development of treatments that not only provide improved results, but could also reduce the need for UV radiation in vitiligo treatment, in turn lowering the risk of skin cancer."