Query: mesquite

Relevant passages:
Comparison of the cytotoxic and mutagenic potential of liquid smoke food flavourings, cigarette smoke condensate and wood smoke condensate. <=SEP=> Although products of pyrolysis are often cytotoxic and mutagenic, the relationship between the type of material pyrolysed and the toxicity of the resulting pyrolysis products is poorly understood. The objective of this study was to evaluate and compare the cytotoxicity and mutagenicity of several types of common pyrolysis products. The cytotoxicity and mutagenicity of these products were assessed by using neutral red uptake and Ames mutagenicity assays, respectively. The biological activities of four liquid smoke food flavourings (LSF) were compared with two other pyrolysis-derived materials; cigarette smoke condensate (CSC) and a wood smoke condensate (WSC). Results indicated all of the mixtures exhibited a concentration-dependent cytotoxic response. The CSC and WSC were less cytotoxic than three of the LSFs, but more cytotoxic than one of the brands. The CSC was mutagenic in two Salmonella strains; however, none of the LSFs or WSC was mutagenic using TA98, and only three of the LSFs were positive with TA100. The six pyrolysis-derived materials evaluated in this study showed differing patterns and magnitudes of cytotoxicity and mutagenicity. These results indicate that the cytotoxicity and mutagenicity of complex mixtures derived from pyrolysis products are affected by the type of material pyrolysed and/or the method used to prepare the mixture. The cytotoxic potential of some commercial smoke flavourings is greater than cigarette smoke condensate and several of the food flavourings are mutagenic in one Salmonella strain.

Mutagenicity testing in the Salmonella typhimurium assay of phenolic compounds and phenolic fractions obtained from smokehouse smoke condensates. <=SEP=> Smokehouse smoke, which is used for flavouring meat products, was investigated for its mutagenic activity in the Salmonella typhimurium assay. We were chiefly concerned with the fractions free of polycyclic aromatic hydrocarbons but containing phenol compounds, which are responsible for the preservative and aromatizing properties of the smoke. The most abundantly occurring phenol compounds (phenol, cresols, 2,4-dimethylphenol, brenzcatechine, syringol, eugenol, vanilline and guaiacol) gave negative results when they were tested for mutagenicity at five concentrations up to 5000 micrograms/plate, with and without S-9 mix, using five strains of S. typhimurium. Even when phenol was further investigated in a variety of test conditions, no induction of his+ revertants was observed. When smokehouse smoke was condensed and fractionated the majority of the various phenolic fractions also gave negative results when tested at five concentrations using five strains of S. typhimurium. However there was a slight increase in the number of revertants in a few cases. The presence in the phenolic fractions of very small amounts of mutagenic impurities, the nature of which needs further investigation, cannot be excluded. These results support the further development of non-hazardous smoke-aroma preparations, based on the phenolic components of smokehouse smoke.

Biological Clues to Potent DNA-Damaging Activities in Food and Flavoring <=SEP=> Population differences in age-related diseases and cancer could stem from differences in diet. To characterize DNA strand-breaking activities in selected foods/beverages, flavorings, and some of their constituent chemicals, we used p53R cells, a cellular assay sensitive to such breaks. Substances testing positive included reference chemicals: quinacrine (peak response, 51X) and etoposide (33X); flavonoids: EGCG (19X), curcumin (12X), apigenin (9X), and quercetin (7X); beverages: chamomile (11X), green (21X), and black tea (26X) and coffee (3 to 29X); and liquid smoke (4 to 28X). Damage occurred at dietary concentrations: etoposide near 5 μg/ml produced responses similar to a 1:1000 dilution of liquid smoke, a 1:20 dilution of coffee, and a 1:5 dilution of tea. Pyrogallol-related chemicals and tannins are present in dietary sources and individually produced strong activity: pyrogallol (30X), 3-methoxycatechol (25X), gallic acid (21X), and 1,2,4-benzenetriol (21X). From structure-activity relationships, high activities depended on specific orientations of hydroxyls on the benzene ring. Responses accompanied cellular signals characteristic of DNA breaks such as H2AX phosphorylation. Breaks were also directly detected by comet assay. Cellular toxicological effects of foods and flavorings could guide epidemiologic and experimental studies of potential disease risks from DNA strand-breaking chemicals in diets.

Polycyclic aromatic hydrocarbons in smoked food products and commercial liquid smoke flavourings. <=SEP=> Smoked foods including turkey, pork, chicken, beef and fish products were screened for the presence of carcinogenic and non-carcinogenic polycyclic aromatic hydrocarbons (PAHs). Eighteen commercial liquid smoke flavourings and seasonings were also analysed. Total PAH concentrations in smoked meat products ranged from 2.6 micrograms/kg in a cooked ham sample to 29.8 micrograms/kg in grilled pork chops, while those in fish products ranged from 9.3 micrograms/kg in smoked shrimp to 86.6 micrograms/kg in smoked salmon. Total concentrations of the carcinogenic PAHs (benzo[a]anthracene, benzo[b]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, and indeno[1,2,3-c,d]pyrene) ranged from non-detectable in several meat products to 7.4 micrograms/kg in grilled pork chops, and from 0.2 micrograms/kg in trout to 16.0 micrograms/kg in salmon. In liquid smoke flavourings and seasonings, total PAH concentrations ranged from 6.3 to 43.7 micrograms/kg, with the carcinogenic PAHs ranging from 0.3 to 10.2 micrograms/kg.

Commercial hickory-smoke flavouring is a human lymphoblast mutagen but does not induce lung adenomas in newborn mice. <=SEP=> Commercial aqueous wood-smoke flavouring induced significant increases in the 6-thioguanine resistance mutation frequency of TK6 human lymphoblasts at 0.1 microliter flavouring/ml of cell suspension. This corresponds to 6 micrograms/ml of dissolved 'solids' as determined by fully drying the aqueous flavouring in a vacuum desiccator. In AHH-1 human lymphoblasts, which contain a cytochrome P-450 monooxygenase system, mutations were induced at 0.3 microliter/ml, corresponding to 18 microliters/ml of dissolved 'solids'. The flavouring did not induce 8-azaguanine resistant mutations in Salmonella typhimurium at concentrations up to 1.5 microliter/ml. At higher concentrations the flavouring was toxic to bacteria. The flavouring did not induce lung adenomas or other tumours in newborn mice when injected ip with total doses of up to 26 microliters over a 3-wk period. Toxicity to the kidney, colon and rectum was observed in some mice at 15 wk of age.

p53: guardian of the genome and policeman of the oncogenes. <=SEP=> The process of malignant transformation universally entails genetic damage and oncogenic signaling, two stresses that are signaled to p53 through different genetic pathways. Based on this, it is possible to distinguish two jobs for p53: "guardian of the genome" that consists in sensing and reacting to DNA damage through the ATM/ATR and Chk1/Chk2 kinases, and "policeman of the oncogenes" that, correspondingly, consists in responding to oncogenic signaling through the p53-stabilizing protein ARF. Contrary to expectation, recent genetic evidence in mice indicates that the response of p53 to DNA damage has little or no impact on cancer protection. In contrast, ARF-dependent activation of p53 is critical for p53-mediated tumor suppression. Here, we discuss the mechanistic implications of these observations and their relevance for cancer therapy.