Diketopiperazines in wines

This study describes the identification of cyclic dipeptides known as diketopiperazines in red, white and sparkling wines from Greek market. Diketopiperazines have been isolated from bottled wines after liquid–liquid extraction and identified using gas chromatography coupled with mass spectrometry. Cyclo (Leu–Leu), cyclo (Leu–Pro), cyclo (Phe–Pro), cyclo (Leu–Phe), cyclo (Val–Phe) and cyclo (Ala–Phe) were the six diketopiperazines that were identified in bottled wines made from local and international plant varieties. The varieties tested were agiorgitiko, malagouzia, xinomauro, roditis, muscat, athiri, mandilari, vidiano, cabernet sauvignon, syrah and merlot. The cyclo (Leu–Pro) was identified in eighteen bottled wines while the cyclo (Phe–Pro), cyclo (Leu–Phe), cyclo (Leu–Leu), cyclo (Ala–Phe) and cyclo (Val–Phe) were identified in a small number of samples. The analysis of some wine samples showed that the values of cyclo (Leu–Pro) ranged from 0.1 to 1?mg/L. These cyclic dipeptides have biological properties and may contribute to the beneficial health effects of wine.