applied sciences  
The Effect of Terpenoid Compounds on the Formation of Advanced Glycation Endproducts (AGEs) in Model Systems  
[PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON],*  
1 Laboratory of Food Chemistry and Analysis, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos75, 11855 Athens, Greece; [EMAIL_ADDRESS] (A.V. ); [EMAIL_ADDRESS] (T.M. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (M.K. ); [EMAIL_ADDRESS] (A.M.)  
2 Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece; [EMAIL_ADDRESS]  
* Correspondence: [EMAIL_ADDRESS]  
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On the other hand, little is known about the impact of terpenoid compounds on other oxidative reaction in foods. Glycation is an important chemical reaction occurring mainly during food processing when a free amino group of protein interacts with the carbonyl group of glucose or other reducing sugars [6; 7; 8]. Among the complex mixture of compounds produced, several carbonyl derivatives such as Strecker aldehydes and dicarbonyls (glyoxal, methylglyoxal, 3-deoxyglucose) are formed [9; 10]. Those highly reactive carbonyl derivatives can react with the \(\varepsilon\)-amino group of lysine or the guanidino group of arginine to generate products known as Advanced Glycation End-products (AGEs). AGEs are a very heterogeneous group of compounds and can be classified into fluorescent (such as pentosidine) and nonfluorescent AGEs (such as N\(\varepsilon\)-(carboxymethyl)lysine CML) as well as cross-linking and non-cross-linking AGEs. Some AGEs exhibit both fluorescent and cross-linking properties, while others show none of the mentioned characteristics [7; 11]. Mainly produced through the thermal processing of foods, mitigation of AGEs formation in foods is often dealt through modifications in heating time and temperature [12]. Alternatively, molecules that exhibit enhanced antioxidant activity, sugar autoxidation inhibition, reactive dicarbonyls trapping, and amino group binding, could be used as AGEs inhibitors [13; 14]. Many synthetic inhibitors, have been used to control AGEs production in food systems and in humans (aminoguanidine, metformin, irbesartan, pyridoxamine, etc.) but their severe side effects highlight the need for effective and safe alternatives like natural plant extract [8]. Phenolic compounds with potent antioxidant and free radical scavenging activity and the ability to trap reactive carbonyl species are commonly studied [11; 13]. Phenolic acids such as ferulic and isoferulic acid [15; 16], cinnamic [17], chlorogenic [14], vanillic, syringic, sinapic, p-coumaric and caffeic acids [18; 19] have showed satisfactory AGEs inhibition in vitro. In food systems, flavonoids such as rutin, quercetin, genistein and narigenin, stilbenes (resveratrol) [13; 20] and tannins (punicalagin) [21] have been identified as potent AGEs inhibitors. In addition, several herbal infusions of medicinal plants have been successfully screened as inhibitors [22]. Hydroxy cytosol, the main phenolic compound in olive oil, was also recently identified as a potential AGEs inhibitor through the binding of methylglyoxal [23]. Despite their antioxidant and radical scavenging properties, EOs have not been fully studied as AGEs inhibitors. In a PatchDock study, limonene was shown to inhibit albumin glycation through hydrophobic binding of its monoterpene hydrocarbon [24]. In another study, the essential oil of caraway which consists mainly of S-carvone (a monoterpene aldehyde), prevented the formation of early Maillard intermediates. Interestingly, the antiglycative capacity of caraway oil was not linked to the carbonyl group in the S-carvone structure.