harman and 2-amino-1-methyl-6-phenylimidazo(4-5-b)pyridine

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is a major public health concern due in part to prevalence, debilitating symptoms, and links to environmental exposures. Much research has focused on environmental factors that may lead to dopaminergic neurotoxicity that occurs in PD. In the study of neuronal uptake and neurotoxicity, critical species differences have been observed. For example, neuromelanin is a molecule formed in part by the breakdown products of dopamine metabolism, along with lipid and protein components. Interestingly, human catecholaminergic neurons contain readily detectable amounts of neuromelanin, while rodent models form far lower levels of neuromelanin that is barely detectable. This discrepancy is potentially an important translational weakness. Recently, we showed that neuromelanin formation modulates heterocyclic aromatic amine (HAA)-induced neurotoxicity in cellular models. HAAs are dietary toxins that have primarily been studied as carcinogens, with emergent literature on selective neurotoxicity. The goal of the present study was to identify whether mitochondria in neuromelanin forming cells may be especially sensitive to HAAs. Here, we exposed galactose-supplemented SH-SY5Y cells to HAAs and tested mitochondrial function and mitophagy. The ectopic formation of neuromelanin was found to increase mitochondrial oxidative stress, decrease membrane potential, increase mitochondrial bioenergetic impairments, and impair mitophagy relative to HAA-treated cells that do not form neuromelanin. These results suggest that neuromelanin has a critical role in HAA toxicity and adverse effects on mitochondria. The data also further cement the need to conduct both mechanistic and risk assessment studies on PD-relevant neurotoxicity in models that form neuromelanin.

Topics: Cell Line, Tumor; Energy Metabolism; Harmine; Humans; Imidazoles; Melanins; Membrane Potential, Mitochondrial; Mitochondria; Mitophagy; Neurons; Oxidative Stress; Parkinsonian Disorders

Data from National Health and Nutrition Examination Survey for US population aged ≥ 6 years for 2013-2014 were used to analyze data for four heterocyclic aromatic amines (HCAA), namely 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhlP), harman, and norharman. Data were analyzed separately for children aged 6-11 years (N = 416), adolescents aged 12-19 years (N = 475), adults aged 20-64 years (N = 1913), and seniors aged ≥ 65 years (N = 458). Adult males had lower concentrations of AαC and harman than adult females (1.44 vs. 2.22 pg/mL for AαC, p < 0.01 and 136.8 vs. 163.2 pg/mL for harman, p = 0.04). Racial/ethnic differences were observed in the adjusted concentrations of HCAAs. For adults, adjusted concentrations of HCAAs were lower for non-Hispanic Asians and Hispanics as compared to non-Hispanic blacks and whites. For example for AαC, the adjusted concentrations for non-Hispanic Asians, Hispanics, non-Hispanic blacks and whites were 1.16, 2.00, 2.37, and 2.16 pg/mL respectively. Adjusted concentrations of AαC were found to be lower among nonsmokers as compared to smokers for adolescents (0.34 vs. 1.32 pg/mL, p < 0.01), adults (0.40 vs. 7.91 pg/mL, p < 0.01), and seniors (0.30 vs. 4.29 pg/mL, p < 0.01). For both harman and norharman, adult nonsmokers had lower adjusted concentrations than smokers (125.7 vs. 177.6 pg/mL, p < 0.01 for harman, 296.1 vs. 421.6 pg/mL, p < 001, for norharman). Exposure to environmental tobacco smoke was found to be associated with higher concentrations of AαC among adolescents (p = 0.01) and adults (p = 0.01) and for harman (p = 0.01) and norharman (p = 0.01) among seniors. In conclusion, concentrations of selected HCAAs can be several fold higher among smokers as compared to nonsmokers and gender as well as race/ethnicity also affect the observed concentrations of HCAA.

Topics: Adolescent; Adult; Aged; Air Pollution, Indoor; Carbolines; Child; Environmental Exposure; Female; Harmine; Humans; Imidazoles; Male; Middle Aged; Nutrition Surveys; Racial Groups; Tobacco Smoke Pollution; United States; Young Adult

The effects of tissue antioxidant levels on formation of heterocyclic amines (HAs) and their mutagenicity in grilled lean beef were studied. Meat from 54 feedlot steers fed different levels of vitamin E (340, 690, 1040 and 1740 IU/animal/day) for 120-days was used to provide beef with different levels of antioxidants (α-tocopherol). Prevalent HAs were then analyzed by HPLC using UV/Fluorescence detection. Five major HAs were found: 2-amino-3,8-dimethyl-imidazo(4,5-F)Quinoxaline (MeIQx), 2-amino-3,4,7,8-tetramethyl-imidazo(4,5-F)Quinoxaline (TriMeIQx), ß-Carboline-9H-Pyrido[3,4-b]indole (Norharmane), 1-Methyl-9H-pyrido[3,4-b]indole (Harmane) and 2-amino-1-methyl-6-phenylimidaza(4,5-B)pyridine (PhIP). Total content of HAs in grilled lean beef ranged from 9.57 ng/g to 11.59 ng/g. There was, however, a trend (P=0.097) found for reduced mutagenicity with increasing tissue levels of α-tocopherol. The increasing dietary vitamin E significantly increased the α-tocopherol level in lean beef (P<0.001), but it had no significant (P>0.05) inhibitory effects on the content of individual and total HAs.

Topics: Amines; Animals; Antioxidants; Cattle; Chromatography, High Pressure Liquid; Cooking; Diet; Harmine; Imidazoles; Meat; Muscle, Skeletal; Mutagens; Quinoxalines; Salmonella; Vitamin E

Heterocyclic amines (HAs) are formed as Maillard reaction products in the crust of meat products during heating processes. Two typical pizza toppings--salami and cooked ham--were analyzed for the presence of HAs after baking frozen pizzas at top and bottom temperatures of 250 and 230 °C, respectively. After baking pizza slices for 12 min, MeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline; 0.2 ng/g), 4,8-DiMeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline; 0.5 ng/g), PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine; 0.2 ng/g), norharman (4.5 ng/g), and harman (2.5 ng/g) were found in the ham toppings, whereas only the comutagenic norharman (107.4 ng/g) and harman (11.4 ng/g) were found in the salami toppings. The content of MeIQx and 4,8-DiMeIQx in ham increased from 0.3 to 1.8 ng/g and 0.8 to 1.6 ng/g, respectively, when the recommended baking time was increased from 15 min (manufacturer's specification) to 18 min at 230 °C. MeIQx was formed in salami when the heating time was extended to 18 min. Moreover, higher concentrations of PhIP in salami or ham slices were found when baking temperatures were 250 °C rather than 230 °C (baking time of 12 min). However, sensory tests showed that panelists preferred longer-baked pizzas due to an increased crispiness. Thus, results show that a substantial formation of HAs may occur in pizza toppings such as ham and salami, with ham being particularly susceptible when compared to salami. Formation of HAs increases with increasing baking time and temperature. The occurrence of the cupping of ham or salami slices during baking may also increase the formation of HAs.

Topics: Amines; Animals; Carbolines; Chromatography, High Pressure Liquid; Color; Consumer Behavior; Cooking; Freezing; Harmine; Hot Temperature; Humans; Imidazoles; Maillard Reaction; Meat Products; Quinoxalines; Swine; Taste

Heterocyclic amines (HAs) are an important class of food mutagens and carcinogens produced in meat cooked at high temperature. In the present study, the effects of various cooking methods: boiling, microwave cooking, charcoal-grilling, roasting, deep-frying and pan-frying on the formation of HAs in duck breast were studied. The various HAs formed during cooking were isolated by solid-phase extraction and analysed by HPLC. Results showed that both the varieties and contents of HAs and the cooking loss of duck breast increase along with increasing cooking temperature and time. Pan-fried duck breasts contained the highest amount of total HAs, followed by charcoal-grilling, deep-frying, roasting, microwave cooking and boiling. 9H-pyrido[3,4-b]indole (norharman) and 1-methyl-9H-pyrido[3,4-b]indole (harman) were detected in all of the cooked duck meat, with levels in the range of 0.1-33 ng g⁻¹. 2-Amino-1-methyl-6-phenylimidazo[4,5-f]pyridine (PhIP) was formed easily in duck meat cooked by pan-frying and charcoal-grilling in the range of 0.9-17.8 ng g⁻¹. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was identified in duck meat cooked by charcoal-grilling and pan-frying, in the range of 0.4-4.2 ng g⁻¹. 2-Amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx) was detected in amounts below 4.5 ng g⁻¹ in duck meat cooked by charcoal-grilling, roasting, deep-frying and pan-frying. The other HAs were detected in amounts below 10 ng g⁻¹. Colour development increased with cooking temperature, but no correlation with HAs' content was observed.

Topics: Amines; Animals; Carbolines; China; Chromatography, High Pressure Liquid; Cooking; Ducks; Food Contamination; Harmine; Heterocyclic Compounds; Hot Temperature; Imidazoles; Maillard Reaction; Meat; Microwaves; Mutagens; Quinolines; Quinoxalines; Solid Phase Extraction; Time Factors

A recently developed HPTLC/UV-FLD method was compared to the routinely used HPLC/UV-FLD method for the quantification of heterocyclic aromatic amines (HAA) formed at trace levels during the heating process of meat. For formation of these process contaminants under normal cooking conditions, beef patties were fried in a double-contact grill at 230 degrees C for five different frying times and extracted by solid-phase extraction. The HAAs most frequently found, that is, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5- f]quinoxaline (4,8-DiMeIQx), 9 H-pyrido[3,4- b]indole (norharman), and 1-methyl-9 H-pyrido[3,4- b]indole (harman), were quantified by two chromatographic methods, which were orthogonal to each other (normal versus reversed phase system). Both methods showed a similar performance and good correlation of the results ( R (2) between 0.8875 and 0.9751). The comparison of running costs and run time in routine analysis proved HPTLC/UV-FLD to be more economical (factor of 3) and faster (factor of 4) due to its capability of parallel chromatography. The HAA findings calculated by standard addition increased with the heating time from <1 to 33 microg/kg related to 3-6 min of frying time. The precision (RSD) was between 7 and 49% (HPTLC) and between 5 and 38% (HPLC) at these very low HAA levels formed.

Topics: Amines; Animals; Carbolines; Carcinogens; Cattle; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Harmine; Heterocyclic Compounds; Hot Temperature; Imidazoles; Meat; Mutagens; Quinoxalines

Reversed phase ion-pair chromatography (RP-IPC) of seven heterocyclic aromatic amines encompassing quinoline (IQ, MeIQ), quinoxaline (MeIQx), pyridine (PhIP) and carboline derivatives (AalphaC, Harman, Norharman) was carried out with formate as counter ion in an aqueous eluent with acetonitrile as organic modifier. TSKgel ODS-80TS was used as the stationary phase. With the aim of acquiring a better insight into the mutual influence of ion-pair reagent and the organic modifier upon solute retention, the study was performed by using an experimental design approach able to evidencing the effect of the simultaneous variation of the two factors. A model for the chromatographic behavior of the amines is proposed that includes classical ion-pair mechanism involving formate in the case of MeIQx, PhIP, Harman and Norharman. A competitive ion-exchange mechanism was hypothesized to govern retention of quinoline compounds, whereas electrostatic interactions and hydrogen bond formation with the silanols of the stationary phase were judged to be responsible for the retention of AalphaC. Further, the chromatographic behavior of the analytes using the formic acid-ammonium formate buffer in the mobile phase was compared with that observed using acetic acid-ammonium acetate buffer. The method based on the use of RP IPC with tandem mass spectrometry when the eluent contained formate buffer at pH 2.8 exhibited higher detectability with respect to that achieved using the acetate buffer.

Topics: Acetonitriles; Amines; Buffers; Carbolines; Chromatography, Liquid; Formates; Harmine; Heterocyclic Compounds; Hydrogen-Ion Concentration; Imidazoles; Quinolines; Quinoxalines; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization

Pig meat shows natural variations in the concentrations of precursors of heterocyclic amines (HCAs), which may affect formation of HCAs in cooked pig meat. To study this, 26 pigs with an inherent genetic variation (carriers and noncarriers of the RN(-) allele) were subjected to different feeding regimes (conventional feed compared with feed composed according to organic standards). In addition, the effect of sex (castrated males or females) was considered when assessing chemical and technological meat quality parameters. Concentrations of precursors of HCAs, i.e., creatine, residual glycogen, dipeptides, and free amino acids, were analyzed in the raw meat, and the levels of some HCAs (4,8-DiMeIQx, MeIQx, PhIP, harman, and norharman) were then determined in fried meat patties prepared from these pigs. The RN genotype most affected technological meat quality parameters and the level of precursors of HCAs, especially the level of residual glycogen, where carriers of the RN(-) allele showed levels four times as high as those of noncarriers (75.3 +/- 2.6 compared with 17.2 +/- 2.4 micromol/g meat, least-squares means +/- SE). The increased level of residual glycogen resulted in about 50% lower amounts of total mutagenic HCAs in cooked meat compared with cooked meat from normal pigs. Fried meat from carriers of the RN(-) allele obtained darker crust color than meat from noncarriers. Feeding regime and sex did not significantly affect the chemical composition of the meat or the formation of HCAs.

Topics: Animals; Carcinogens; Eating; Female; Genotype; Harmine; Hot Temperature; Imidazoles; Male; Meat; Mutagens; Quinoxalines; Sex Characteristics; Swine