Quantification of PAH4 in roasted cocoa beans using QuEChERS and dispersive liquid-liquid micro-extraction (DLLME) coupled with HPLC-FLD.

Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (p < 0.05) increase of PAH4 (0.19-7.73 ng/g) with an increase in temperatures (110-190 °C) and duration (10-50 min). The PAHs content in whole cocoa bean roasting was detected even at the lowest temperature (110 °C) compared to nib roasting detected at 150 °C which indicates that PAHs was transferred from dried shells to roasted cocoa beans during the roasting process. The data obtained may help to control and minimize PAH4 formation during cocoa processing.

Polycyclic aromatic hydrocarbons in teas using QuEChERS and HPLC-FLD.

Polycyclic aromatic hydrocarbons (PAHs) are food-processing contaminants considered to be carcinogenic and genotoxic. Due to its drying process stage, teas may be contaminated with PAHs. The aim of the study was to validate an analytical method involving QuEChERS and HPLC-FLD for the determination of PAH4 in teas and evaluate the contamination levels in 10 different types of teas from Brazil. Recoveries varied from 54% to 99% and relative standard deviations from 1% to 21%. Limits of detection and quantification were from 0.03 to 0.3 µg/kg and 0.1 to 0.5 µg/kg, respectively. Mate tea presented the highest PAH levels, with PAH4 varying from 194 to 1795 µg/kg; followed by black (1.8-186 µg/kg), white (24-119 µg/kg), and green teas (3.1-92 µg/kg). Teas with lowest PAH4 were strawberry, lemongrass, peppermint, and boldo. Only trace levels of PAHs were detected in tea infusions, so apparently it would not affect PAH intake by Brazilian population.

Discrimination between naphthacene and triphenylene using cellulose tris(4-methylbenzoate) and cellulose tribenzoate: A computational study.

The mechanisms of naphthacene and triphenylene discrimination using commercially available cellulose tris(4-methylbenzoate) (CMB) and cellulose tribenzoate (CB) chiral stationary phases were investigated using molecular mechanics calculations. Naphthacene and triphenylene could be separated by liquid chromatography on CMB and CB, with triphenylene being eluted earlier than naphthacene on both phases. However, the corresponding separation factor is much larger for CMB than for CB. The docking of these polycyclic aromatic hydrocarbons to the above polymers suggested that the most important sites of CMB and CB for interacting with these hydrocarbons are located at equivalent positions, featuring a space surrounded by main chain glucose units and benzoyl side chains. The difference of hydrocarbon stabilization energies with CMB and CB agreed well with the observed chromatographic separation factors.

Amhezole, A Novel Fungal Secondary Metabolite from Aspergillus terreus for Treatment of Microbial Mouth Infection.

Bio-guided fractionation of Aspergillus terreus extract leads to isolation of a novel terpenoidal secondary metabolite. The isolated compound and the total alcoholic extract of Aspergillus terreus showed a remarkable activity against microbial mouth infections; namely, Candida albicans, Lactobacillus acidophilus, Streptococcus gordonii, and S. mutan. Moreover, the Minimum Inhibitory Concentration of the isolated compound was determined and showed low values. The combination of each of the alcoholic extract of A. terreus and the isolated compound Coe-Comfort tissue conditioner inhibited the growth of Candida albicans at concentrations of 500 and 7.81 µg/mL, respectively, Lactobacillus acidophilus at concentrations of 250 and 7.81 µg/mL, respectively, Streptococcus gordonii at concentrations of 1000 and 62.50 µg/mL, respectively, and S. mutans at concentrations of 1000 and 125 µg/mL, respectively. The oral dosing of the extract and the isolated compound did not show any significant effect on the activity of alanine aminotransferase, aspirate aminotransferase, and the levels of blood urea and serum creatinine. Copyright © 2017 John Wiley & Sons, Ltd.

Nanoparticle Self-Assembled Grain Like Curcumin Conjugated ZnO: Curcumin Conjugation Enhances Removal of Perylene, Fluoranthene, and Chrysene by ZnO.

Curcumin conjugated ZnO, referred as Zn(cur)O, nanostructures have been successfully synthesized, these sub-micro grain-like structures are actually self-assemblies of individual needle-shaped nanoparticles. The nanostructures as synthesized possess the wurtzite hexagonal crystal structure of ZnO and exhibit very good crystalline quality. FT-Raman and TGA analysis establish that Zn(cur)O is different from curcumin anchored ZnO (ZnO@cur), which is prepared by physically adsorbing curcumin on ZnO surfaces. Chemically Zn(cur)O is more stable than ZnO@cur. Diffuse reflectance spectroscopy indicates Zn(cur)O have more impurities compared to ZnO@cur. The solid-state photoluminescence of Zn(cur)O has been investigated, which demonstrates that increase of curcumin concentration in Zn(cur)O suppresses visible emission of ZnO prepared through the same method, this implies filling ZnO defects by curcumin. However, at excitation wavelength 425 nm the emission is dominated by fluorescence from curcumin. The study reveals that Zn(cur)O can remove to a far extent high concentrations of perylene, fluoranthene, and chrysene faster than ZnO. The removal depends on the extent of curcumin conjugation and is found to be faster for PAHs having smaller number of aromatic rings, particularly, it is exceptional for fluoranthene with 93% removal after 10 minutes in the present conditions. The high rate of removal is related to photo-degradation and a mechanism has been proposed.

Metabolism of an Alkylated Polycyclic Aromatic Hydrocarbon 5-Methylchrysene in Human Hepatoma (HepG2) Cells.

Exposure to polycyclic aromatic hydrocarbons (PAHs) in the food chain is the major human health hazard associated with the Deepwater Horizon oil spill. C1-chrysenes are representative PAHs present in the crude oil and have been detected in contaminated sea food in amounts that exceed their permissible safety thresholds. We describe the metabolism of the most carcinogenic C1-chrysene regioisomer, 5-methylchrysene (5-MC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 5-MC-tetraol, a signature metabolite of the diol-epoxide pathway, was identified as reported previously. Novel O-monosulfonated-5-MC-catechol isomers and O-monomethyl-O-monosulfonated-5-MC-catechol were discovered, and evidence for their precursor ortho-quinones was obtained. The identities of O-monosulfonated-5-MC-1,2-catechol, O-monomethyl-O-monosulfonated-5-MC-1,2-catechol, and 5-MC-1,2-dione were validated by comparison to authentic synthesized standards. Dual metabolic activation of 5-MC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones is reported for the first time. Evidence was also obtained for minor metabolic conversion of 5-MC to form monohydroxylated-quinones and bis-phenols. The identification of 5-MC-tetraol, O-monosulfonated-5-MC-1,2-catechol, O-monomethyl-O-monosulfonated-5-MC-1,2-catechol, and 5-MC-1,2-dione supports metabolic activation of 5-MC by P450 and AKR isozymes followed by metabolic detoxification of the ortho-quinone through interception of redox cycling by COMT and SULT isozymes. The major metabolites, O-monosulfonated-catechols and tetraols, could be used as biomarkers of human exposure to 5-MC resulting from oil spills.

Ex situ slurry phase bioremediation of chrysene contaminated soil with the function of metabolic function: process evaluation by data enveloping analysis (DEA) and Taguchi design of experimental methodology (DOE).

Bioremediation of chrysene in soil matrix was evaluated in soil slurry phase bioreactor in conjugation with metabolic functions (aerobic, anoxic and anaerobic), microenvironment (single and mixed) conditions and nature of mixed consortia (native/resident mixed microflora and bioaugmented inoculum). Twelve experiments were operated independently in agitated-batch reactor keeping all other operating conditions constant (substrate loading rate--0.084 g chrysene/kg soil-day; soil loading rate--10 kg soil/m(3)-day (3:25 soil water ratio); operating temperature--35+/-2 degrees C). Data envelopment analysis (DEA) procedure was employed to analyze the performance of experimental variations in terms of chrysene degradation and pH. The efficacy of anoxic metabolism over the corresponding aerobic and anaerobic metabolic functions was documented. Aerobic metabolic function showed effective degradation capability under mixed microenvironment after augmentation with anaerobic inoculum. Anaerobic metabolic function showed lowest degradation potential. Application of bioaugmentation showed positive influence on the chrysene degradation rate. Design of experimental methodology (DOE) by Taguchi approach was applied to evaluate the effect of four selected factors (native soil microflora, microenvironment, metabolic function and bioaugmentation) on the chrysene degradation process. The optimized factors derived from analysis depicted the requirement of native soil microflora under anoxic metabolic function using mixed microenvironment after augmenting with anaerobic inoculum for achieving effective chrysene degradation efficacy.

Semi-preparative gas chromatographic separation of all-trans-perhydrotriphenylene enantiomers on a chiral cyclodextrin stationary phase.

Enantiomers of all-trans-perhydrotriphenylene (PHTP) were separated by gas chromatography using heptakis(6-O-tert.-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin (TBDMS-beta-CD) as the chiral selector. Conditions for semi-preparative separations were established using a 2 m x 2 mm I.D. packed column and subsequently extended to a 1.8 m x 4 mm I.D. column which enabled separations on a mg scale. The column packing was TBDMS-beta-CD dissolved in SE-54 coated on Chromosorb P AW-DMCS 80-100 mesh. Optimization of the chromatographic conditions (oven temperature, carrier gas flow, and column load) with respect to better efficiency and peak retention resulted in a system capable of separating up to 10 mg of the racemate per day. Purities of separated enantiomers were determined by capillary gas chromatography. Yields and purities of the fractions obtained by single- and double-step separations are compared. Highly enriched enantiomers with purities of up to 99.6% (99.2% ee) were obtained by a single separation step.

WF11605, an antagonist of leukotriene B4 produced by a fungus. I. Producing strain, fermentation, isolation and biological activity.

WF11605, a new antagonist of leukotriene B4 (LTB4) was isolated as a product of fungal strain F11605. The molecular formula of WF11605 was determined to be C38H60O11. WF11605 inhibited LTB4-induced chemotaxis of rabbit polymorphonuclear leukocytes (PMNLs) with an IC50 value of 1.7 x 10(-7) M and blocked 3H-LTB4 binding to PMNL membranes at 5.6 x 10(-6) M (IC50). WF11605 also inhibited LTB4-induced degranulation of rabbit PMNLs at 3.0 x 10(-6) M (IC50). However, WF11605 did not show any inhibitory effect on platelet activating factor (PAF)- and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced degranulation at concentrations up to 10(-4) M. These results suggest that WF11605 is a specific antagonist of LTB4.

WF11605, an antagonist of leukotriene B4 produced by a fungus. II. Structure determination.

The structure of WF11605, a novel tetracyclic triterpene glucoside, was determined to be 1. The plane structure of deacetyl-WF11605 aglycone was elucidated as 2 through the concerted application of a series of 2D NMR techniques. The relative configurations were established by X-ray crystallographic analysis of bis(p-bromobenzoyl) derivative 3 and absolute stereochemistry by CD exciton chirality method.

Selective covalent binding of the active sulfate ester of the carcinogen 5-(hydroxymethyl)chrysene to the adenine residue of calf thymus DNA.

5-(Hydroxymethyl)chrysene (5-HCR) sulfate, an active metabolite of the carcinogen 5-HCR, bound significantly in a covalent manner to the purine bases of calf thymus DNA through its 5-methylene carbon with loss of a sulfate anion when incubated at pH 7.4 and 37 degrees C. From the DNA were isolated two purine base adducts by high-pressure liquid chromatography, and they were identified as N6-[(chrysen-5-yl)methyl]adenine and N2-[(chrysen-5-yl)methyl]guanine with the corresponding synthetic specimens. The purine base adducts, appearing in the ratio 1 to 27 for guanine to adenine in the chromatogram, accounted for about 60% of the total covalent binding of 5-HCR sulfate to the DNA. 5-HCR sulfate also reacted specifically with the exocyclic amino groups of the purine bases of 2'-deoxyadenosine 5'-phosphate and 2'-deoxyguanosine 5'-phosphate at much lower rates than did with those of calf thymus DNA. Denaturing the DNA by heating followed by rapid cooling, covalent binding of 5-HCR sulfate to it markedly decreased with the increasing ratio of N2-guanine to N6-adenine adducts (1:3.6). These results strongly suggest that secondary structure of DNA has an influence on the covalent binding of 5-HCR sulfate and that intercalation of the sulfate ester into DNA base pairs plays an important role in its preferential binding to N6 of the adenine residue of native DNA.

Reversed-phase high-performance liquid chromatographic separation of phenolic derivatives of benzo[a]pyrene, benz[a]anthracene, and chrysene with monomeric and polymeric C18 columns.

The separation of monohydroxylated derivatives (phenols) of benzo[a]pyrene, benz[a]anthracene, and chrysene was studied by reversed-phase high-performance liquid chromatography using a monomeric Zorbax ODS column and a polymeric Vydac C18 column. The Vydac C18 column resolved the phenols of each hydrocarbon with a wide range of retention times than the Zorbax ODS column. Four K-region phenols of benzo[a]pyrene are either not separated or marginally separated on both monomeric and polymeric columns. Other K-region and non-K-region phenols of all three hydrocarbons can be separated by using the monomeric and polymeric columns in combination.

Direct separation of non-K-region mono-ol and diol enantiomers of phenanthrene, benz[a]anthracene, and chrysene by high-performance liquid chromatography with chiral stationary phases.

The direct separation of 26 bay region and non-bay region mono-ol and diol enantiomers of phenanthrene, benz[a]anthracene, and chrysene was compared by high-performance liquid chromatography on commercially available columns, packed with gamma-aminopropylsilanized silica to which either (R)-N-(3,5-dinitrobenzoyl)phenylglycine(R-DNBPG) or (S)-N-(3,5-dinitrobenzoyl)leucine(S-DNBL) was either ionically or covalently bonded. In general, enantiomers of bay region mono-ols and diols are more efficiently resolved than those of non-bay region derivatives. Elution orders of enantiomers on either chiral stationary phase are the same, regardless of whether the chiral stationary phase is ionically or covalently bonded. Except for the enantiomers of 4-hydroxy-4-methyl-1,2,3,4-tetrahydrobenz[a]anthracene, 1,2,3,4-tetrahydrobenz[a]anthracene trans-1,2-diol, and benz[a]anthracene trans-1,2-dihydrodiol, elution orders of resolved enantiomers on R-DNBPG are reversed on S-DNBL. The enantiomers are generally more efficiently resolved on R-DNBPG than on S-DNBL. With the exception of the elution order of the enantiomeric 4-hydroxy-1,2,3,4-tetrahydrochrysene, the results of this study are consistent with the chiral recognition mechanisms proposed by Pirkle and co-workers, who developed the chiral stationary phases used in this study.