WINETECH Technical Yearbook 2019

winemaking process. The type of soil, the climate and the different field treatments of the grape vines (such as benzothiadiazole) can largely increase the levels of melatonin in the skins of vine grapes, although most of melatonin’s production seems to occur during the fermentation process (Iriti et al ., 2006). At the Hatter Institute, we have been able to demonstrate that the presence of melatonin in wine contributes to the cardioprotective effect of regular and moderate consumption of wine. Indeed, a chronic treatment of melatonin, given at the concentration equivalent to the concentration found in 2-3 glasses of red wine, was able to protect against the cellular damage observed in a simulated heart attack model (Lamont et al ., 2011; Lamont et al ., 2015). Melatonin is a strong antioxidant and it exerts most of its physiological function via melatonin receptors. When a chronic and moderate treatment of wine was given together with an inhibitor of the melatonin receptors, the cardiovascular benefit of wine was largely attenuated, therefore suggesting that melatonin in wine plays a key role for

cardioprotection (above) (Lamont et al ., 2015). Recently, the presence of mel atonin isomers has been discovered in wine at concentrations even higher than melatonin itself (Tan et al ., 2012). In partnership with our colleagues in Italy (who have been able to isolate these melatonin isomers), we are currently exploring whether these isomers may present any health benefits for wine drinkers. CONCLUSION The presence of melatonin in the vine and in wine may present benefits to grow a healthy vine, to improve the quality of the wine and to protect the heart of wine drinkers. Although melatonin is known to have very little side effects, its interaction with the other thousand components in wine, including with the different melatonin isomers, still remains to be understood. SUMMARY Numerous population studies suggest the health benefit of chronic and moderate consumption of wine. Wine contains over a thousand different components and the

exact components that may contribute to its health benefit still remain unclear. REFERENCES Norrie, P., 2005. Wine and health through the age with specific references to Australia. PhD thesis, University of Western Sydney. http: //www.drnor r i e. info/downloads/ drnorriethesis/DrNorrieThesis.pdf . Renaud, S. & De Lorgeril, M., 1992. Wine, alcohol, platelets, and the French paradox for coronary heart disease. Lancet 339(8808): 1523-6. Opie, L.H. & Lecour, S., 2007. The red wine hypothesis: From concepts to protective signalling molecules. European Heart Journal 28(14): 1683-93. Lamont, K., Blackhurst, D., Albertyn, Z., Marais, D. & Lecour, S., 2012. Lowering the alcohol content of red wine does not alter its cardioprotective properties. South African Medical Journal 102(6): 565-7. Lamont, K.T., Somers, S., Lacerda, L., Opie, L.H. & Lecour, S., 2011. Is red wine a safe sip away from cardioprotection? Mechanisms involved in resveratrol- and melatonin-

induced cardioprotection. Journal of Pineal Research 50(4): 374-80. Lamont, K. & Lecour, S., 2011. Natural polyphenols and cardioprotection. Mini- Reviews in Medicinal Chemistry 11(14): 1191-9. Arnao, M. & Hernandez-Ruiz, J., 2015. Functions of melatonin in plants. Journal of Pineal Research 59: 133-50. Iriti, M., Rossoni, M. & Faoro, F., 2006. Melatonin content in grape: Myth or panacea? Journal of the Science of Food and Agriculture 86(10): 1432-38. Lamont, K., Nduhirabandi, F., Adam, T., Thomas, D.P., Opie, L.H. & Lecour, S., 2015. Role of melatonin, melatonin receptors and STAT3 in the cardioprotective effect of chronic and moderate consumption of red wine. Biochemical and Biophysical Research Communications 465(4): 719-24. Tan, D.X., Hardeland, R., Manchester, L.C., Rosales-Corral, S., Coto-Montes, A., Boga, J.A. & Reiter, R.J., 2012. Emergence of naturally occurring melatonin isomers and their proposed nomenclature. Journal of Pineal Research 53(2): 113-21.

– For more information, contact Prof. Sandrine Lecour at Sandrine.lecour@uct.ac.za.