α-Dicarbonyl compounds (α-DCs) are commonly present in various foods. We conducted the investigation into concentration changes of α-DCs including 3-deoxyglucosone (3-DG), glyoxal (GO), and methylglyoxal (MGO) in fresh fruits and decapped commercial juices during storage at room temperature and 4 °C, as well as in homemade juices during storage at 4 °C. The studies indicate the presence of α-DCs in all samples. The initial contents of 3-DG in the commercial juices (6.74 to 65.61 μg/mL) are higher than those in the homemade ones (1.97 to 4.65 μg/mL) as well as fruits (1.58 to 3.33 μg/g). The initial concentrations of GO and MGO are normally less than 1 μg/mL in all samples. During storage, the α-DC levels in the fruits exhibit an initial increase followed by a subsequent decrease, whereas, in all juices, they tend to accumulate continuously over time. As expected, 4 °C storage reduces the increase rates of the α-DC concentrations in most samples. From the viewpoint of the α-DC contents, fruits and homemade juices should always be the first choice for daily intake of nutrients and commercial juices ought to be mostly avoided.

α-DCs (α-dicarbonyls) have been proven to be closely related to aging and the onset and development of many chronic diseases. The wide presence of this kind of components in various foods and beverages has been unambiguously determined, but their occurrence in various phytomedicines remains in obscurity. In this study, we established and evaluated an HPLC-UV method and used it to measure the contents of four α-DCs including 3-deoxyglucosone (3-DG), glyoxal (GO), methylglyoxal (MGO), and diacetyl (DA) in 35 Chinese herbs after they have been derivatized with 4-nitro-1,2-phenylenediamine. The results uncover that 3-DG is the major component among the α-DCs, being detectable in all the selected herbs in concentrations ranging from 22.80 μg/g in the seeds of Alpinia katsumadai to 7032.75 μg/g in the fruit of Siraitia grosuenorii. The contents of the other three compounds are much lower than those of 3-DG, with GO being up to 22.65 μg/g, MGO being up to 55.50 μg/g, and DA to 18.75 μg/g, respectively. The data show as well the contents of the total four α-DCs in the herbs are generally in a comparable level to those in various foods, implying that herb medicines may have potential risks on human heath in view of the α-DCs.

Dicarbonyls are reactive precursors of advanced glycation endproducts. They are formed endogenously and during food processing. Currently, a comprehensive database on dicarbonyls in foods that covers the entire range of food groups is lacking, limiting knowledge about the amount of dicarbonyls that is ingested via food. The aim of this study was to analyze the dicarbonyls methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG) in commonly-consumed products in a Western diet. We validated a UHPLC-MS/MS method to quantify MGO, GO, and 3-DG. We present a dietary dicarbonyl database of 223 foods and drinks. Total dicarbonyl concentrations were highest in dried fruit, Dutch spiced cake, and candy bars (>400 mg/kg). Total dicarbonyl concentrations were lowest in tea, dairy, light soft drinks, and rice (<10 mg/kg). The presented database of MGO, GO, and 3-DG opens the possibility to accurately estimate dietary exposure to these dicarbonyls, and explore their physiological impact on human health.

The antibacterial activities of the dicarbonyl compounds glyoxal (GO), methylglyoxal (MGO), 3-deoxyglucosone (3-DG) were assessed against Gram-positive and Gram-negative pathogenic and food spoilage bacteria, both in agarised and liquid assay system. The kinetics of dicarbonyls\' degradation at different antimicrobial assay conditions were studied, to determine the possible interference of the nutrient medium. In agarised assay system, GO and MGO exhibited antimicrobial activity, with higher efficacy against Gram-positive strains than Gram-negative ones. The nutrient medium reacted quickly both with GO and MGO, interfering with the antibacterial potential and the degradation kinetics indicated first-order reactions. In liquid assay system, both GO and MGO inhibited the target bacteria at concentrations significantly lower than those estimated in agarised assay system. Moreover, to the best of our knowledge, the antibacterial activity of GO and MGO against Listeria innocua, Pseudomonas fluorescens, Salmonella enterica and Bacillus cereus has not been previously reported.

The non-enzymatic glycation reaction results in the generation of free radicals which play an important role in the pathophysiology of aging, diabetes, and cancer. 3-Deoxyglucosone (3-DG) is a dicarbonyl species which may lead to the formation of advanced glycation end products (AGEs). 3-DG also reacts with free amino group of nucleic acids resulting in the formation of DNA-AGEs. While the establishment of nucleoside AGEs has been revealed before, no extensive studies have been done to probe the role of 3-DG in the generation of immunogenicity and induction of cancer auto-antibodies. In this study, we report the immunogenicity of AGEs formed by 3-DG-Arg-Fe(3+) system. Spectroscopic analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. Immunogenicity of native and 3-DG-Arg-Fe(3+) DNA was probed in female rabbits. The modified DNA was highly immunogenic eliciting high-titer immunogen-specific antibodies, while the unmodified form was almost non-immunogenic. We also report the presence of auto-antibodies against 3-DG-Arg-Fe(3+)-modified DNA in the sera of patients with different types of cancers. The glycoxidative lesions were also detected in the lymphocyte DNA isolated from selected cancer patients. The results show structural perturbations in 3-DG-Arg-Fe(3+)-DNA generating new epitopes that render the molecule immunogenic.