Influence of fructooligosaccharides and garlic on formation of heterocyclic amines in fried ground beef patties

The effects of fructooligosaccharide (FOS) and garlic on the formation of 15 heterocyclic amines (HCAs) were evaluated in fried beef patties. The HCAs were extracted from the fried meat samples and purified using a solid-phase extraction method and then analyzed on a liquid chromatography-mass spectrometry. Among the 15 HCAs, 3-amino-1, 4-dimethyl-5H-pyrido-[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), 2-amino-6-methyldipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-1), 2-aminodipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-2), 9H-pyrido [3,4-b]indole (norharman), 1-methyl-9H-pyrido [3,4-b]indole (harman), 2-amino-9H-pyrido [2,3-b]indole (AαC), 2-amino-3,8 dimethylimidazo [4,5-f]-quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP) were detected in all of the cooked beef patties. Analysis of variance revealed that the addition of 1 or 3 g of FOS significantly reduced the formation of total amino-carboline type HCAs in the cooked beef patties, and adding the 1 or 3 g of FOS to ground beef patties reduced levels of PhIP and MeIQx (amino-imidazo-azaarenes; AIAs) in the patties. When it is compared with the HCA formation in control, additions of minced garlic (5.0, 10.0, and 15.0 g) to the ground beef patties (100 g) reduced HCA formation in the range of 14 to 100%.     

Quantitation of heterocyclic aromatic amines in ready to eat meatballs by ultra fast liquid chromatography

Heterocyclic aromatic amines (HCAs) in meatballs ready to eat and sold in restaurants in Turkey were determined. A solid phase extraction method was used to isolate HCAs from meatballs. Various HCAs analysed by ultra fast liquid chromatography (UFLC) were varying levels of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) (up to 1.59 ng/g), 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx) (up to 3.81 ng/g), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) (up to 0.66 ng/g), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (not detected or not quantified), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (not detected or not quantified), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx) (up to 0.43 ng/g), 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) (up to 1.93 ng/g), 2-amino-9H-pyrido[2,3-b]indole (AαC) (up to 0.35 ng/g), and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) (up to 0.43 ng/g) in cooked meatballs which are consumed in Turkey. Overall average of total HCA amount was 5.54 ng/g. The present study is to prove that HCAs can be isolated in a very short time (5 min) by using UFLC.     

Influence of natural food ingredients on the formation of heterocyclic amines in fried beef patties and chicken breasts

The effects of natural food ingredients including Korean bramble, onion, and marinade sauce with water extracts of olive and lotus leaf on the formation of 15 heterocyclic amines (HCAs) were evaluated in fried beef patties and chicken breasts. The patties and chicken breasts containing natural food ingredients were fried at 230 and 200°C for 8 min on each side. Addition of 4 g Korean bramble to beef patties reduced the formation of 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 9H-pyrido [3,4-b]indole (Norharman), and 2-amino-6-methyldipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-1) by 74, 62, and 39%, respectively. Also, when 2 g onion was added to beef patties, the formation of 2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline (4,8-DiMeIQx), Glu-P-1, MeIQ, Norharman, and 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine (PhIP) was inhibited by 100, 96, 88, 74, and 79%, respectively. When marinade sauce containing 2% water extracts of olive and lotus leaf was added to chicken breasts, most HCAs formation was inhibited. Especially, the formation of Glu-P-1, 2-aminodipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-2), and MeIQ were reduced by 100%.     

Determination of Heterocyclic Aromatic Amines in Cooked Commercial Frozen Meat Products by Ultrafast Liquid Chromatography

This paper describes a method for the determination of nine heterocyclic aromatic amines (HCAs) in commercial frozen meat products, which were sold in Turkey by ultrafast liquid chromatography (UFLC) with ultraviolet visible detection. HCAs are separated on a Shim-pack XR-ODS (7.5?×?3 mm, 2.2 μm). Varying levels of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) (up to 1.95 ng/g), 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx) (up to 4.17 ng/g), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) (up to 0.69 ng/g), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (up to 0.83 ng/g), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (up to 0.22 ng/g), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx) (up to 0.94 ng/g), 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) (up to 4.58 ng/g), 2-amino-9H-pyrido[2,3-b]indole (AαC) (up to 0.57 ng/g), and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) (up to 3.51 ng/g) were detected in these commercial frozen meat products of Turkey. The data obtained show clearly that HCAs could be isolated in a very short time (5 min) by using UFLC.     

Analysis of heterocyclic amines and β-carbolines by liquid chromatography–mass spectrometry in cooked meats commonly consumed in Korea

Heterocyclic amines (HAs), which form in meats during heating and cooking, are recognized as mutagenic and carcinogenic compounds. In this study, 13 HAs and 2 β-carbolines (BCs) were analyzed in cooked Korean meat products, including griddled bacon, griddled pork loin, boiled pork loin, boiled chicken meat, chicken meat stock, chicken breast for salad and chicken patty. The samples were either cooked in the laboratory or purchased from local fast-food restaurants. The HAs and BCs in the samples were separated using solid-phase extraction and were analyzed by high performance liquid chromatography–mass spectrometry (HPLC–MS). The most frequently detected HAs and BCs in the cooked meats were harman (1-methyl-9H pyrido[4,3-b]indole; 990.9 ng g^?1), norharman (9H-pyrido[4,3-b]indole; 412.7 ng g^?1) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine; 258.2 ng g^?1). The griddled pork loin and bacon contained higher levels of norharman, harman and PhIP than the other cooked meats. PhIP, which is classified as a Group 2B carcinogen by the International Agency for Research on Cancer, had levels of 258.2 and 168.2 ng g^?1 in the griddled pork loin and griddled bacon, respectively. The griddled bacon was the only sample containing TriMeIQx (2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline; 79.9 ng g^?1). IQ (2-amino-3-methyl imidazo[4,5-f]quinoline), 7,8-DiMeIQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline), 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline) and AαC (2-amino-9H-pyrido[2,3-b]indole) were detected at trace levels in all samples.     

Development of a New Extraction Method for Heterocyclic Aromatic Amines Determination in Cooked Meatballs

Heterocyclic aromatic amines (HCAs) are mutagenic and carcinogenic compounds that are produced in meats cooked at high temperature. In this study, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 9H-pyrido[3,4-b]indole (norharman), and 1-methyl-9H-pyrido[3,4-b]indole (harman) were studied. A new extraction method was developed for the determination of heterocyclic amines with high-performance liquid chromatography (HPLC). Linearity for each HCA was observed with a high regression coefficient (r?=?0.9999, P?<?0.01 for IQ; r?=?0.9990, P?<?0.01 for MeIQx; r?=?0.9989, P?<?0.01 for 4,8-DiMeIQx; r?=?0.9934, P?<?0.05 for PhIP; r?=?1.000, P?<?0.01 for norharman; r?=?0.9991, P?<?0.01 for harman). Limits of detection for various HCAs were found between 0.04 and 1.40 ng/g. Limits of quantification were found in the range of 0.13–4.40 ng/g. Recovery rates varied from 68.9 % to 87.8 %. This method was compared with two different common HCA extraction methods in literature. The optimized new extraction method and the other two methods were used for the determination of HCAs in ten different cooked meatball samples. Sample extraction procedures of HCAs were investigated in more detail, and a rapid, accurate, precise, and reliable extraction method was developed.     

Formation of heterocyclic amine–amino acid adducts by heating in a model system

Although mutagenic and carcinogenic heterocyclic amines (HCAs) are known to be formed in cooked meat and fish, human HCA exposure and carcinogenic risk have not been elucidated in sufficient detail. In this work, we investigated the formations of HCA–amino acid adducts in a model system by using a liquid chromatography–mass spectrometry to elucidate another source of human HCA exposure. The 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) adduct with glycine was formed easily by heating at 200 °C within 5 min, which is probably based on the dehydration condensation of the amino group of PhIP and carboxyl group of glycine. PhIP and other HCAs such as 2-amino-3-methyl-3H-imidazo[4,5-f]quinolone, 2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline and 3-amino-1,4-dimethyl-5H-pyrido[3,4-b]indole, also bound with various amino acids by heating. Among these amino acids, proline tends to form adducts with HCAs, but serine, cysteine and lysine hardly bound with HCAs. These results provided a basic understanding of the formation of HCA adducts with amino acids during cooking.     

Formation of amino-imidazo-azaarenes and carbolines in fried beef patties and chicken breasts under different cooking conditions in Korea

The effect of cooking temperature and time on amino-imidazo-azaarenes (AIAs) and carbolines in fried ground beef patties and chicken breast under different cooking conditions in Korea was evaluated. Beef patties were fried at different temperatures (150, 180, and 230°C) for 4, 8, 12, and 16 min per each side and then the amount of AIAs and carbolines was evaluated by solid-phase extraction and HPLC-MS analysis. In fried ground beef patties, formations of 9H-pyrido [3,4-b]indole (Norharman) and 1-methyl-9H-pyrido [3,4-b]indole (Harman) were dramatically increased at 230°C for 16 min. Concentrations of Norhanrman and Harman formed at 230°C for 16 min/side were 12 and 40 times greater than level those of Norharman formed at same cooking condition. In fried chicken breasts, 2-amino-3,7,8-trimethylimidazo[4,5-f] quinoxaline (7,8-DiMeIQx) and 2-amino-3,4,7,8-tetramethylimidazo[ 4,5-f]quinoxaline (Tri-MeIQx) were not found at 150 and 180°C. Norhanrman formed at 230°C for 16 min was approximately 4 times higher than fried chicken breasts at 180°C. These results suggest that increase of cooking temperature and time was directly affected on AIAs and carbolines formation in Korean cooked meat.     

Heterocyclic aromatic amines in cooked hamburgers and chicken obtained from local fast food outlets in the Ottawa region

Heterocyclic aromatic amines (HAAs) are formed in protein-rich foods during high temperature cooking such as frying and grilling. Since most HAAs are potent mutagens and almost all are carcinogenic to laboratory animals, their formation in cooked foods is a health concern. In the present study, 31 cooked hamburgers and six chicken preparations were obtained from various fast food outlets in the Ottawa area and analyzed for HAAs. In the developed procedure, ground-up samples were extracted under both acidic and alkaline conditions, cleaned on SPE cartridges, and the concentrations of various HAAs determined using electrospray ionization LC/MS/MS. Deuterium-labelled internal standards of the three most commonly found HAAs (IQ, MeIQx, and PhIP) in such foods were used for quantitation and recovery correction. Varying levels of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (0.2–6 μg/kg), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) (0.1–3.5 μg/kg), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (0.3–6.9 μg/kg), and 7,8-dimethyl-IQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline) (0.1–2.9 μg/kg) were detected in most hamburgers, whereas our limited data on the chicken samples (wings, drumsticks, and nuggets) indicated the presence of mainly PhIP (0.1–2.1 μg/kg) and MeIQx (0.1–1.8 μg/kg). Traces of 4,7,8-trimethyl-IQx (<0.1 μg/kg), 3-amino-1,4-dimethyl-5H-pyrido[3,4-b]indole (Trp-P-1) (<0.1–0.3 μg/kg), and 3-amino-1-methyl-5H-pyrido[3,4-b]indole (Trp-P-2) (<0.1–0.8 μg/kg) were also detected in some samples of hamburgers but not in any of the chicken analyzed thus far. Since hamburger is a popular meal among Canadians, regular consumption of such items may contribute substantially to one's dietary intake of HAAs.     

Heterocyclic amine formation during frying of frozen beefburgers

The formation of heterocyclic amines (HCAs) was studied during frying of beefburgers with different fat contents (6.7%, 16.1% and 39%). Beefburgers were fried from the frozen state for 60, 90, 120 s, and until the centre temperature had reached 72 °C (approximately 150 s) in a double‐sided pan fryer. The beefburgers were analysed for HCAs with solid‐phase extraction and LC/MS detection, and 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline (MeIQx), 2‐amino‐3,4,8‐trimethylimidazo[4,5‐f]quinoxaline (4,8‐DiMeIQx), 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP), 1‐methyl‐9H‐pyrido[3,4‐b]indole (Harman) and 9H‐pyrido[3,4‐b]indole (Norharman) were detected in all samples. The concentrations of HCAs ranged between 0 and 2.3 ng g^?1. The HCAs concentrations were fitted to a first‐order reaction model. The amounts of HCAs in beefburgers fried from the frozen state were in the same range as in beefburgers that have reached room temperature before frying. Furthermore, it was found that the formation of HCAs is not only concentration‐controlled but also mass transport‐controlled and that kinetic models stated in earlier studies fit relatively well our analysed values on HCAs in fried beefburgers.     

Effects of cooking methods and levels on formation of heterocyclic aromatic amines in chicken and fish with Oasis extraction method

Heterocyclic aromatic amines (HCAs) are potent mutagenic and carcinogenic compounds formed during heat processing of proteinaceous food such as beef, poultry, and fish. The objective of this study was to measure nine HCAs in chicken chops and fish fillets cooked by various methods (microwave, oven, hot plate, pan-frying, and barbecuing) to different degrees of doneness (rare, medium, well done, and very well done). Total HCA amount in chicken changed between 0.24 and 8.21 ng/g, and not only the highest total amount but also the lowest total HCA amount was found in microwave cooked chicken samples. The highest total HCA amount found in fish for microwave, oven, hot plate, pan-frying, and barbecuing were 18.09, 4.28, 3.12, 6.98, and 5.22 ng/g, respectively. The results show that microwave cooking alone is found to possess the highest total HCA amount, followed by pan-frying, and barbecuing of meat samples, and the total HCA amount in cooked samples is low if cooked to rare and medium degrees of doneness. 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole (AαC), and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) were not detected in any samples.     

Occurrence of heterocyclic amines in cooked meat products

Heterocyclic amines (HCAs), potent mutagens and a risk factor for human cancers, are produced in meats cooked at high temperature. The aim of this study was to determine the HCA content in cooked meat products (beef, chicken, pork, fish) prepared by various cooking methods (pan frying, oven broiling, and oven baking at 170 to 230 °C) that are preferred by U.S. meat consumers. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (1.49-10.89 ng/g), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-4.0 ng/g), and DiMeIQx (2-amino-3,4,8-trimethyl-imidazo [4,5-f]quinoxaline) (not detected-3.57 ng/g). Type and content of HCAs in cooked meat samples were highly dependent on cooking conditions. The total HCA content in well-done meat was 3.5 times higher than that of medium-rare meat. Fried pork (13.91 ng/g) had higher levels of total HCAs than fried beef (8.92 ng/g) and fried chicken (7.00 ng/g). Among the samples, fried bacon contained the highest total HCA content (17.59 ng/g).     

Content of heterocyclic amines and polycyclic aromatic hydrocarbons in pork,beef and chicken barbecued at home by Danish consumers

It is a well-known fact that, when meat is barbecued, several harmful components, including heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH), may be formed. The aim of this study was to determine the HCA and PAH content in meat (pork, chicken and beef) when barbecued at home by Danish consumers according to their normal practice. With regard to HCA, beef contained the highest concentrations of 9H-pyrido[3,4-b]indole (norharman) and 2-methyl-β-carboline (harman), while chicken contained more 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) than pork and beef. The analysis of PAH showed a markedly higher concentration of PAH in beef compared with pork and chicken. In general, a correlation between the HCA content and the surface colour of the meat was found, the darker the colour the higher the HCA concentrations.     

Effects of precursor composition and water on the formation of heterocyclic amines in meat model systems

Model systems based on pressed meat from ox, pork and chicken were used to study the formation of carcinogenic/mutagenic heterocyclic amines (HAs). The composition of precursors (free amino acids, creatine and glucose) was examined and samples were heated in test-tubes under wet and dry conditions at 175 and 200°C for 30 min. Several HAs were detected, and the formation of DMIP (2-amino-1,6-dimethylimidazo[4,5-b]-pyridine), TMIP (2-amino-1,5,6-trimethyl-imidazo[4,5-b]-pyridine), IFP (2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]-pyridine) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine) was found to be favoured by dry heating conditions. Highest amounts of PhIP and IFP were detected in heated meat juice from chicken breast, while more MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline) was found in heated meat juices from roast beef and pork chop. Norharman (9H-pyrido[3,4-b]-indole) and Harman (1-methyl-9H-pyrido[3,4-b]-indole) were also detected at high levels.     

Lack of formation of heterocyclic amines in fumes from frying French fries

The formation of heterocyclic amines (HAs) in the fumes from frying French fries in soybean oil or lard was studied. A high-pressure liquid chromatography method was used to determine the various HAs in fumes. Results showed that the yields of fumes produced from soybean oil when heated alone for 2 or 4 h were higher than from lard; however, a reversed trend was found when frying French fries in soybean oil and lard. Most fumes from soybean oil and lard while frying French fries were adsorbed onto the condensation apparatus, while the other portions were adsorbed onto the wool and glass beads, which were incorporated in our experimental design for collecting the fumes. The fumes from soybean oil when heated alone were found to contain three HAs, namely, 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx), 2-amino-3-methylimidazo[4,5-f ]quinoline (IQ), and 1-methyl-9H-pyrido[4,3-b ]indole (Harman), whereas two more HAs, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b ]indole (Trp-P-1), were generated in lard. Lard was more susceptible to the formation of HAs than soybean oil when both were heated alone. No HAs were detected in the fumes from French fries fried in soybean oil and lard.     

Binding of mutagens by fractions of the cell wall skeleton of lactic acid bacteria on mutagens

The binding effect of cells and cell fractions, cell wall skeleton, cytoplasm, whole cells, and cell wall skeleton treated by lysozyme and alpha-amylase at 37 degrees C for 5 h, on Trp-P-1 (3-amino-1,4-dimethyl-[5H]pyrido [4,3-b]indole) and Trp-P-2 (3-amino-1-methyl-[5H]-pyrido[4,3-b]indole) were investigated. The cell and cell wall skeleton of Streptococcus cremoris Z-25 had greater binding activity, but cytoplasm and extract of cell wall skeleton did not bind Trp-P-1 and Trp-P-2. When the cells or cell wall skeleton were treated with lysozyme and alpha-amylase, unbound Trp-P-1 and Trp-P-2 concentrations were greater than that of the untreated control. It is possible that cell walls may be involved in the binding of mutagenic pyrolyzates to lactic acid bacteria. The cell wall skeleton of S. cremoris Z-25, Lactobacillus acidophilus IFO 13951, and Bifidobacterium bifidum IFO 14252 showed binding of Trp-P-1, 2-amino-6-methyldipyrido(1,2-a:3',2'- d)imidazole, 2-amino-5-phenylpyridine, 2-amino-3-methylimidazo(4,5-f)quinoline, 2-amino-3,4-dimethylimidazo(4,5-f) quinoline, and 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline. The cell wall skeleton of S. cremoris group and Streptococcus lactis also showed the binding activity with A N-nitrosodimethylamine. The binding of Trp-P-1 to cell walls was very high, and the binding of mutagenic pyrolyzates was variable with different bacterial species. The peptidoglycan complex and polysaccharides liberated from cell wall skeleton of S. cremoris Z-25 showed strong binding of Trp-P-2. Peptidoglycans has a binding effect of about 19.86 micrograms/mg; polysaccharides had a binding effect of 14 micrograms/mg.     

Inhibition of Heterocyclic Amine Formation in Beef Patties by Ethanolic Extracts of Rosemary

ABSTRACT: Heterocyclic amines (HCAs) are mutagenic compounds formed during cooking muscle foods at high temperature. Inhibition of HCAs by rosemary extracts were evaluated with beef patties cooked at 191 °C (375 °F) for 6 min each side and 204 °C (400 °F) for 5 min each side. Five rosemary extracts extracted with different solvents were used in this study: extract 100W (100% water), 10E (10% ethanol), 20E (20% ethanol), 30E (30% ethanol), and 40E (40% ethanol). The 5 extracts were directly added to beef patties at 3 levels (0.05%, 0.2%, and 0.5%) before cooking and HCA contents were extracted and quantified. All of the patties contained 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP). There was no statistical difference in the inhibition of HCAs in the 0.05%, 0.2%, and 0.5% rosemary extracts. All rosemary extracts significantly decreased the levels of MeIQx and PhIP at both cooking conditions. When cooking at 204 °C (400 °F) for 5 min each side, rosemary extracts 10E and 20E were superior to rosemary extracts 100W, 30E, and 40E in inhibiting HCA formation. Rosemary extract 20E showed the greatest inhibition of MeIQx (up to 91.7%) and PhIP (up to 85.3%). The inhibiting effect of rosemary extracts on HCA formation corresponded to their antioxidant activity based on a DPPH scavenging assay. Rosemary extract 10E and 20E contain a mixture of rosmarinic acid, carnosol, and carnosic acid. It is possible that these compounds might act synergistically in inhibiting the formation of HCAs.     

Effects of various additives on the formation of heterocyclic amines in fried fish fibre

The effects of various additives on the formation of heterocyclic amines (HAs) in fried fish fibre (Trachinooephlus myops) were studied. Fried fish fibre was prepared by boiling raw snake fish, followed by deboning, eviscerating, separating of fish meat and pressing. The fish meat was subjected to frying, during which treatment the additives, such as sugar, monosodium glutamate (MSG), antioxidants and edible oil, were added. The HAs were analyzed by high-performance liquid chromatography (HPLC) with diode-array detection. Results showed that the formation of HAs was retarded after the addition of a high level of sugar (19%), and the amount of 9H-pyrido-[4,3-b]indole (Norharman), 1-methyl-9H-pyrido-[4,3-b]indole (Harman), 2-amino-9H-pyrido[2,3-b]indole (AαC) or 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) also decreased to a minimum. The total amount of HAs rose with increasing levels of MSG, and the individual HAs, Norharman, Harman, AαC and MeAαC showed the same trend. Antioxidants, such as vitamin C, α-tocopherol and BHT (Butylated hydroxytoluene), did not show any consistent effect of concentration on HAs formation. Coconut oil contributed to the highest levels of HAs formation, followed by lard and soybean oil.     

The inhibition by naphthoquinones and anthraquinones of 2-amino-3-methylimidazo[4,5-f ]quinoline metabolic activation to a mutagen: a structure-activity relationship study

 Nine naphthoquinones, 19 anthraquinones, and nine structurally related monoketonic compounds such as anthrone, xanthone, etc., inhibited mutagenicity induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Salmonella typhimurium TA 98 in the presence of rat liver S9 with distinct structure-activity relationships. A carbonyl function was a prerequisite for antimutagenicity while, in general, anthraquinones (IC₅₀ values: 2.3–>213 nmol/ml top agar) were more potent antimutagens than structurally related monoketonic compounds (IC₅₀ values: 25.3–94.9 nmol/ml top agar) and naphthoquinones (IC₅₀ values: 3.7–90.7 nmol/ml top agar). The parent compounds and methyl substituted derivatives were already the most potent while introduction of polar substituents such as COOH and SO₃H considerably reduced antimutagenicity. Introduction of OH functions had equivocal effects: with increasing numbers, antimutagenic potencies were concomitantly reduced; however, anthraflavic acid, chrysazin, quinizarin, and especially 5,8-dihydroxy-1,4-naphthoquinone were more potent than the parent compounds. The patterns of inhibition by quinones of 7-ethoxyresorufin-O-dealkylase activities in rat liver microsomes, linked to cytochrome P-450-dependent oxidation of IQ to N-hydroxy-IQ (N-OH-IQ), were in general identical with those obtained in the Salmonella/reversion assay except for chrysophanic acid, emodin, and some naphthoquinones which were very potent in this assay (IC₅₀: 0.20–45.0 μM). On the other hand, mutagenicity of N-OH-IQ in S. typhimurium TA 98NR was not inhibited by nonpolar quinones (except 1,4-naphthoquinone) but rather by polar compounds and especially by hydroxyquinones (IC₅₀ values: 5.3–106.7 nmol/ml top agar or not reached). Inhibition of mutagenic activities of IQ, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-6-methyldipyrido[1,2-a:3′,2′-d]imidazole, and 3-amino-1-methyl-5H-pyrido[4,3-b]indole by chrysazin, chrysophanic acid, physicon, and purpurin varied, but no clearcut structure-activity relationships of the mutagens were observed. Received: 29 May 1998     

The inhibition by naphthoquinones and anthraquinones of 2-amino-3-methylimidazo[4,5-f?]quinoline metabolic activation to a mutagen: a structure-activity relationship study

 Nine naphthoquinones, 19 anthraquinones, and nine structurally related monoketonic compounds such as anthrone, xanthone, etc., inhibited mutagenicity induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Salmonella typhimurium TA 98 in the presence of rat liver S9 with distinct structure-activity relationships. A carbonyl function was a prerequisite for antimutagenicity while, in general, anthraquinones (IC₅₀ values: 2.3–>213 nmol/ml top agar) were more potent antimutagens than structurally related monoketonic compounds (IC₅₀ values: 25.3–94.9 nmol/ml top agar) and naphthoquinones (IC₅₀ values: 3.7–90.7 nmol/ml top agar). The parent compounds and methyl substituted derivatives were already the most potent while introduction of polar substituents such as COOH and SO₃H considerably reduced antimutagenicity. Introduction of OH functions had equivocal effects: with increasing numbers, antimutagenic potencies were concomitantly reduced; however, anthraflavic acid, chrysazin, quinizarin, and especially 5,8-dihydroxy-1,4-naphthoquinone were more potent than the parent compounds. The patterns of inhibition by quinones of 7-ethoxyresorufin-O-dealkylase activities in rat liver microsomes, linked to cytochrome P-450-dependent oxidation of IQ to N-hydroxy-IQ (N-OH-IQ), were in general identical with those obtained in the Salmonella/reversion assay except for chrysophanic acid, emodin, and some naphthoquinones which were very potent in this assay (IC₅₀: 0.20–45.0 μM). On the other hand, mutagenicity of N-OH-IQ in S. typhimurium TA 98NR was not inhibited by nonpolar quinones (except 1,4-naphthoquinone) but rather by polar compounds and especially by hydroxyquinones (IC₅₀ values: 5.3–106.7 nmol/ml top agar or not reached). Inhibition of mutagenic activities of IQ, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-6-methyldipyrido[1,2-a:3′,2′-d]imidazole, and 3-amino-1-methyl-5H-pyrido[4,3-b]indole by chrysazin, chrysophanic acid, physicon, and purpurin varied, but no clearcut structure-activity relationships of the mutagens were observed. Received: 29 May 1998