After 50 Years of Hepatic Clearance Models, Where Should We Go from Here? Improvements and Implications for Physiologically Based Pharmacokinetic Modeling.

There is overwhelming preference for application of the unphysiologic, well-stirred model (WSM) over the parallel tube model (PTM) and dispersion model (DM) to predict hepatic drug clearance, CLH , despite that liver blood flow is dispersive and closer to the DM in nature. The reasoning is the ease in computation relating the hepatic intrinsic clearance ( CLint ), hepatic blood flow ( QH ), unbound fraction in blood ( fub ) and the transmembrane clearances ( CLin and CLef ) to CLH for the WSM. However, the WSM, being the least efficient liver model, predicts a lower EH that is associated with the in vitro CLint ( Vmax / Km ), therefore requiring scale-up to predict CLH in vivo. By contrast, the miniPTM, a three-subcompartment tank-in-series model of uniform enzymes, closely mimics the DM and yielded similar patterns for CLint versus EH , substrate concentration [S] , and KL / B , the tissue to outflow blood concentration ratio. We placed these liver models nested within physiologically based pharmacokinetic models to describe the kinetics of the flow-limited, phenolic substrate, harmol, using the WSM (single compartment) and the miniPTM and zonal liver models (ZLMs) of evenly and unevenly distributed glucuronidation and sulfation activities, respectively, to predict CLH For the same, given CLint ( Vmax and Km ), the WSM again furnished the lowest extraction ratio ( EH,WSM = 0.5) compared with the miniPTM and ZLM (>0.68). Values of EH,WSM were elevated to those for EH, PTM and EH, ZLM when the Vmax s for sulfation and glucuronidation were raised 5.7- to 1.15-fold. The miniPTM is easily manageable mathematically and should be the new normal for liver/physiologic modeling. SIGNIFICANCE STATEMENT: Selection of the proper liver clearance model impacts strongly on CLH predictions. The authors recommend use of the tank-in-series miniPTM (3 compartments mini-parallel tube model), which displays similar properties as the dispersion model (DM) in relating CLint and [ S ] to CLH as a stand-in for the DM, which best describes the liver microcirculation. The miniPTM is readily modified to accommodate enzyme and transporter zonation.

Scientific Opinion of Flavouring Group Evaluation 411 (FGE.411): 2-(4-methylphenoxy)-N-(1H-pyrazol-3-yl)-N-(thiophen-2-ylmethyl)acetamide from chemical group 30 (miscellaneous substances).

EFSA was requested to deliver a scientific opinion on the implications for human health of the flavouring substance 2-(4-methylphenoxy)-N-(1H-pyrazol-3-yl)-N-(thiophen-2-ylmethyl)acetamide [FL-no: 16.133], in the Flavouring Group Evaluation 411 (FGE.411), according to Regulation (EC) No 1331/2008 of the European Parliament and of the Council. The substance has not been reported to occur in natural source materials of botanical or animal origin. It is intended to be used as a flavouring substance in specific categories of food but not intended to be used in beverages, except for milk and dairy based beverages that are opaque. The chronic dietary exposure to the substance estimated using the added portions exposure technique (APET), is calculated to be 225 µg/person per day for a 60-kg adult and 142 µg/person per day for a 15-kg 3-year-old child. A 90-day oral gavage study in rats showed no adverse effects at doses up to 100 mg/kg body weight (bw) per day, providing an adequate margin of safety. Developmental toxicity was not observed in a study with rats at the dose levels up to 1,000 mg/kg bw per day. The Panel concluded that there is no safety concern for [FL-no: 16.133], when used as a flavouring substance at the estimated level of dietary exposure calculated using the APET approach and based on the recommended uses and use levels as specified in Appendix  B. This conclusion does not apply for use in beverages where the substance can be subject to phototransformation.

Scientific Opinion of Flavouring Group Evaluation 406 (FGE.406): (S)-1-(3-(((4-amino-2,2-dioxido-1H-benzo[c][1,2,6]thiadiazin-5-yl)oxy)methyl)piperidin-1-yl)-3-methylbutan-1-one.

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of EFSA was requested to deliver a scientific opinion on the safety of the use of the substance (S)-1-(3-(((4-amino-2,2-dioxido-1H-benzo[c][1,2,6]thiadiazin-5-yl)oxy)methyl)piperidin-1-yl)-3-methylbutan-1-one [FL-no: 16.129], as a flavouring substance. The substance is intended to be used in the form of its sodium salt as a flavour modifier in beverages. The Panel concluded that [FL-no: 16.129] would not raise a concern with respect to genotoxicity under conditions where it remains stable and does not undergo photodegradation. However, the data provided do not rule out genotoxicity for the degradation products. A 90-day toxicity study with [FL-no: 16.129] in rats showed no adverse effects at exposure up to 100 mg/kg body weight (bw) per day. No developmental toxicity was observed in rats at dose levels up to 1,000 mg/kg bw per day. An adequate margin of safety was calculated for [FL-no: 16.129]. The Panel concluded that [FL-no: 16.129] and its sodium salt are not expected to be of safety concern at the estimated levels of intake. This conclusion applies only to the use of the substance as a flavour modifier at levels up to those specified in beverages, but not to the degradation products that may be formed upon exposure to ultraviolet-A (UV-A) light. The conditions protecting [FL-no: 16.129] from photodegradation have not been adequately investigated. It is also unclear if degradation occurs in the absence of UV light. Based on the data provided, the Panel cannot conclude on the safety of [FL-no: 16.129] when used as a flavour modifier.

Scientific Opinion on Flavouring Group Evaluation 74, Revision 4 (FGE.74Rev4): Consideration of aliphatic sulphides and thiols evaluated by JECFA (53rd and 61st meeting) structurally related to aliphatic and alicyclic mono-, di-, tri- and polysulphides with or without additional oxygenated functional groups from chemical group 20 evaluated by EFSA in FGE.08Rev5.

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present revision of this FGE is on the assessment of recently submitted toxicity data on methyl propyl trisulfide [FL-no: 12.020], being the representative for a group of seven additional flavouring substances: diallyl trisulfide [FL-no: 12.009], dimethyl trisulfide [FL-no: 12.013], dipropyl trisulfide [FL-no: 12.023], methyl allyl trisulfide [FL-no: 12.045], diallyl polysulfides [FL-no: 12.074], methyl ethyl trisulfide [FL-no: 12.155] and diisopropyl trisulphide [FL-no: 12.280]. Specifications have been provided for all substances. The Panel decided that the 90-day study submitted for [FL-no: 12.020] can be considered only once it is clearly demonstrated that the material tested is representative of the material of commerce and that potential reaction products of the components are not of safety concern. Therefore, no conclusion on the safety of the eight flavouring substances [FL-no: 12.009, 12.013, 12.020, 12.023, 12.045, 12.074, 12.155 and 12.280] can be reached. For 2-methyl-4-oxopentane-2-thiol [FL-no: 12.169] and 2-mercapto-2-methylpentan-1-ol [FL-no: 12.241], additional subchronic toxicity data are required. The remaining nine substances [FL-no: 12.088, 12.179, 12.198, 12.212, 12.238, 12.239, 12.255, 12.257 and 12.291] in this FGE are not considered of safety concern under the intended conditions of use.

Scientific opinion on flavouring group evaluation 77, revision 3 (FGE.77Rev3): consideration of pyridine, pyrrole and quinoline derivatives evaluated by JECFA (63rd meeting) structurally related to pyridine, pyrrole, indole and quinoline derivatives evaluated by EFSA in FGE.24Rev2.

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the EFSA was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of 22 pyridine, pyrrole and quinoline derivatives evaluated by JECFA (63rd meeting). The revision of this consideration is made since additional genotoxicity data have become available for 6-methylquinoline [FL-no: 14.042]. The genotoxicity data available rule out the concern with respect to genotoxicity and accordingly the substance is evaluated through the Procedure. For all 22 substances [FL-no: 13.134, 14.001, 14.004, 14.007, 14.030, 14.038, 14.039, 14.041, 14.042, 14.045, 14.046, 14.047, 14.058, 14.059, 14.060, 14.061, 14.065, 14.066, 14.068, 14.071, 14.072 and 14.164] considered in this Flavouring Group Evaluation (FGE), the Panel agrees with the JECFA conclusion, 'No safety concern at estimated levels of intake as flavouring substances' based on the Maximised Survey-derived Daily Intake (MSDI) approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been evaluated, and the information is considered adequate for all the substances. For the following substances [FL-no: 13.134, 14.001, 14.030, 14.041, 14.042, 14.058, 14.072], the Industry has submitted use levels for normal and maximum use. For the remaining 15 substances, use levels are needed to calculate the modified Theoretical Added Maximum Daily Intakes (mTAMDIs) in order to identify those flavouring substances that need more refined exposure assessment and to finalise the evaluation.

Scientific Opinion of Flavouring Group Evaluation 407 (FGE.407): 4-amino-5-(3-(isopropylamino)-2,2-dimethyl-3-oxopropoxy)-2-methylquinoline-3-carboxylic acid.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) was requested to deliver a scientific opinion on the implications for human health of the flavouring substance 4-amino-5-(3-(isopropylamino)-2,2-dimethyl-3-oxopropoxy)-2-methylquinoline-3-carboxylic acid [FL-no: 16.130], in the Flavouring Group Evaluation 407 (FGE.407), according to Regulation (EC) No 1331/2008 of the European Parliament and of the Council. The substance has not been reported to occur in natural source materials of botanical or animal origin. It is intended to be used as both the parent compound and its hemisulfate monohydrate salt as a flavouring substance with modifying properties in specific categories of food. The chronic dietary exposure to the substance estimated using the added portions exposure technique (APET), is calculated to be 882 µg/person per day for a 60-kg adult and 547 µg/person per day for a 15-kg 3-year-old child. There is no concern with respect to genotoxicity. A 90-day dietary administration study in rats showed no adverse effects for doses up to 100 mg/kg body weight (bw) per day, providing an adequate margin of safety. Developmental toxicity was not observed in a study with rats at the dose levels up to 1,000 mg/kg bw per day. The Panel concluded that [FL-no: 16.130] and its hemisulfate monohydrate salt are not expected to be of safety concern at the estimated levels of dietary exposure calculated using the APET approach. This conclusion applies only to the use of the substance as a flavour modifier as requested and when used at the levels as specified for foods from different food categories.

Scientific Opinion on Flavouring Group Evaluation 63, Revision 3 (FGE.63Rev3): aliphatic secondary alcohols, ketones and related esters evaluated by JECFA (59th and 69th meetings) structurally related to saturated and unsaturated aliphatic secondary alcohols, ketones and esters of secondary alcohols and saturated linear or branched-chain carboxylic acids evaluated by EFSA in FGE.07Rev4.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of 29 aliphatic secondary alcohols, ketones and related esters evaluated by JECFA at the 59th and 69th meetings in 2002 and 2008. This revision is made due to the inclusion of nine additional substances cleared for genotoxicity concern in FGE.205 Revision 1. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern and available data on metabolism and toxicity. The Panel agrees with the application of the Procedure as performed by JECFA for all 29 substances considered in this FGE. For all substances, the Panel concludes that there is 'no safety concern at the estimated levels of intake as flavouring substances based on the MSDI approach'. For all 29 substances, the specifications for the materials of commerce have also been considered and found adequate. Ten out of the 14 substances for which use levels became available exceed the modified theoretical added maximum daily intake (mTAMDI) and more reliable exposure data are required to finalise their evaluation. On the basis of such data, additional toxicological data might become necessary. For 15 substances, use levels are needed to calculate the mTAMDIs in order to identify those flavouring substances that need more refined exposure assessment to finalise the evaluation.

Scientific Opinion on Flavouring Group Evaluation 73, Revision 4 (FGE.73Rev4): consideration of alicyclic alcohols, aldehydes, acids and related esters evaluated by JECFA (59th and 63rd meeting) structurally related to primary saturated or unsaturated alicyclic alcohols, aldehydes, acids and esters evaluated by EFSA in FGE.12Rev5.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present revision of FGE.73 concerns the inclusion of four additional flavouring substances (p-mentha-1,8-dien-7-ol [FL-no: 02.060], myrtenol [FL-no: 02.091], p-mentha-1,8-dien-7-yl acetate [FL-no: 09.278] and myrtenyl acetate [FL-no: 09.302]) evaluated by JECFA at the 59th meeting. The substances were evaluated through a stepwise approach integrating information on structure-activity relationships, intake from current uses, toxicological thresholds of concern (TTC), and available data on metabolism and toxicity. In agreement with JECFA, the Panel evaluated 22 and one candidate substances via the A and the B-side of the Procedure, respectively, and concluded for all substances 'No safety concern at estimated levels of intake as flavouring substances' based on the maximised survey-derived daily intake (MSDI) approach. The specifications for the materials of commerce have also been considered. Adequate specifications, including complete purity criteria and identity data, are available for 22 out of the 23 JECFA substances evaluated in this FGE. For [FL-no: 09.278], the stereoisomeric composition is not specified. For the six substances with [FL-no: 02.060, 02.091, 09.034, 09.278, 09.302 and 09.712] evaluated in this FGE, use levels have become available and the modified theoretical added maximum daily intakes (mTAMDIs) were estimated. For two substances [FL-no: 09.034, and 09.712], the mTAMDI estimates were above the TTC for their structural class and more detailed information is needed to finalise their evaluation. For the remaining 17 substances evaluated through the Procedure, use levels are needed to calculate the mTAMDIs in order to identify those flavouring substances that need more refined exposure assessment in order to finalise the evaluation.

Safety of ethyl acrylate to be used as flavouring.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) was requested by the European Commission according to Art. 29 1(a) of the Regulation (EC) No 178/2002 to carry out a review of existing literature on the safety of ethyl acrylate [FL-no: 09.037] when used as a flavouring substance. Ethyl acrylate [FL-no: 09.037] was evaluated in 2010 by EFSA in FGE.71 as a flavouring substance, based on the 2006 JECFA evaluation. The Panel concluded that ethyl acrylate was of no safety concern at estimated level of intake as flavouring substance based on the Maximised Survey-Derived Daily Intake (MSDI) approach. The Panel has evaluated the new literature available and any previous assessments performed by JECFA (2006) and EFSA (2010). Moreover, new data on the use levels of ethyl acrylate as flavouring substance have been provided. For use as flavouring substance, the chronic dietary exposure estimated using the added portions exposure technique (APET), is calculated to be 3,545 µg/person per day for a 60-kg adult and 2,233 µg/person per day for a 15-kg 3-year-old child. Exposure from food contact materials may be up to 6,000 µg/person per day. The Panel considered that based on the available data, which covers all relevant genetic endpoints (i.e. gene mutations, structural and numerical chromosomal aberrations) there is no concern with respect to genotoxicity of ethyl acrylate. The Panel evaluated the available carcinogenicity studies conducted in rats and mice and agreed with the NTP evaluation (1998) concluding that the forestomach squamous cell papilloma and carcinoma observed in rodents were not relevant to humans. Additionally, there was no evidence of systemic toxicity in short-term and subchronic toxicity studies. Therefore, the Panel concluded that there is no safety concern for the use of ethyl acrylate as a flavouring substance, under the intended conditions of use.

Safety of benzophenone to be used as flavouring.

Benzophenone [FL-no: 07.032] has been evaluated as a flavouring substance, in FGE.69, by the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food in 2008. Benzophenone was evaluated also by JECFA (2011) and by IARC (2013) based on studies that were not considered in the EFSA opinion on FGE.69. Therefore, the Commission requested the CEF Panel to carry out a review of existing literature on the safety of this flavouring substance. In the framework of the evaluation of benzophenone as a food contact material, the CEF Panel established a tolerable daily intake (TDI) of 0.03 mg/kg body weight (bw) per day (2009). In the present Opinion, the Panel considered the already existing evaluations by EFSA, JECFA, IARC and available literature data on benzophenone toxicity. Moreover, new data on the use levels of benzophenone as a flavouring substance have been provided. The Panel considers that there is no concern with respect to genotoxicity. The Panel considers the endocrine activities of benzophenone and its metabolite 4-hydroxybenzophenone as weak and not directly related to the observed toxic effects including the neoplastic effects in rodents. The Panel confirms that the conservative approach taken by EFSA (2009) to derive a TDI of 0.03 mg/kg bw for benzophenone is appropriate to cover the non-neoplastic effects in the chronic toxicity studies and the neoplastic effects induced in the rodent carcinogenicity studies. The TDI is in the same order of magnitude as the chronic dietary exposure of adults and children to benzophenone (10-20 µg/kg bw per day) for the amount of added flavouring substance. The Panel considers that the calculated TDI and exposure estimate are based on conservative assumptions. The Panel concludes that there is no safety concern for benzophenone under the current condition of use as a flavouring substance.

Scientific Opinion on Flavouring Group Evaluation 7, Revision 5 (FGE.07Rev5): saturated and unsaturated aliphatic secondary alcohols, ketones and esters of secondary alcohols and saturated linear or branched-chain carboxylic acids from chemical group 5.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids was requested to evaluate 53 flavouring substances attributed to the Flavouring Group Evaluation 07, including four new substances but-3-en-2-ol, non-1-en-e-ol, hex-1-en-3-one and 1-nonene-3-one [FL-nos: 02.131, 02.187, 07.161 and 07.210] in this Revision 5, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the 53 substances was considered to have genotoxic potential. The substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that all 53 substances do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the 'Maximised Survey-derived Daily Intake' (MSDI) approach. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been considered and found adequate. For 50 substances, further information is required based on comparison of the 'modified Theoretical Added Maximum Daily Intakes' (mTAMDIs) with the TTCs. This would include more reliable intake data and then, if required, additional toxicological data.

Scientific Opinion on Flavouring Group Evaluation 302 (FGE.302): N-(2-methylcyclohexyl)-2,3,4,5,6-pentafluoro-benzamide from Chemical Group 30.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids was requested to evaluate N-(2-methylcyclohexyl)-2,3,4,5,6-pentafluoro-benzamide [FL-no: 16.119] in the Flavouring Group Evaluation 302, using the Procedure in Commission Regulation (EC) No 1565/2000. The substance is intended to be used as a flavour modifier and the current evaluation is only applicable to this use. Information on the ratios of diastereoisomers of the substance has been provided (cis 20-40% and trans 60-80%). Information on the ratio of enantiomers is lacking. The available data on genotoxicity do not preclude the evaluation of the candidate substance [FL-no: 16.119] through the Procedure. The substance was evaluated through the B-side of the Procedure. A 'No Observed Adverse Effect Level' (NOAEL) of 55 mg/kg body weight (bw) per day could be derived for [FL-no: 16.119] from a 90-day subchronic toxicity study in rats. This NOAEL provides an adequate margin of safety of 1.4 × 106, based on the 'Maximised Survey-Derived Daily Intake' (MSDI) of 2.4 µg/capita per day. Based on the 'modified Theoretical Added Maximum Daily Intake' (mTAMDI) approach, the Panel concluded that more information is needed on use and use levels. Besides the safety assessment of this flavouring substance, the specifications for the material of commerce have also been considered. Additional information on the stereoisomeric composition of the flavouring substance is required.

Scientific Opinion on Flavouring Group Evaluation 57, Revision 1 (FGE.57Rev1): consideration of isopulegone and three flavouring substances evaluated by JECFA (55th meeting).

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of four flavouring substances consisting of isopulegone and three other substances evaluated by JECFA at the 55th meeting. This revision is made due to additional toxicity data available for (1R,2S,5R)-isopulegol [FL-no: 02.067]. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. p-Mentha-1,4(8)-dien-3-one [FL-no: 07.127] is no longer supported by the flavour industry and was not evaluated. In agreement with JECFA, the Panel evaluated the candidate substances in this Flavouring Group Evaluation (FGE) via the B-side of the Procedure. Based on a no observed adverse effect level (NOAEL) from a 90-day oral toxicity study on [FL-no: 02.067], adequate margins of safety for the three candidate substances could be calculated. Therefore, the Panel agrees with the JECFA conclusion, 'No safety concern at estimated levels of intake as flavouring substances' based on the maximised survey-derived daily intake (MSDI) approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and found adequate. For the three substances evaluated in this FGE, use levels have become available and the modified theoretical added maximum daily intakes (mTAMDIs) were estimated. For [FL-no: 02.067 and 07.067], the mTAMDI exceeds the toxicological threshold of concern for their structural classes and need more refined exposure assessment to finalise the evaluation.

Scientific Opinion on Flavouring Group Evaluation 49, Revision 1 (FGE.49Rev1): xanthine alkaloids from the priority list.

Following a request from the European Commission, the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) was requested to deliver a scientific opinion on the safety assessment of the flavouring substances caffeine [FL-no: 16.016] and theobromine [FL-no: 16.032] in the Flavouring Group Evaluation 49, Revision 1. Consequent to the 2015 scientific opinion from the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) on the safety of caffeine from all dietary sources, the CEF Panel considered it inappropriate to evaluate the two substances through the Procedure. For caffeine, the Panel based its assessment on the safety threshold of 5.7 mg/kg body weight (bw) per day for adults, except pregnant/lactating women, and 3 mg/kg bw per day for children, adolescents, pregnant and lactating women, as established by the NDA Panel. The safety evaluation of theobromine takes into account that approximately 11% of an oral dose of caffeine is metabolised to theobromine and that both substances have a similar pharmacological profile. For the exposure assessment, a brand loyalty model was chosen. In this model, it was assumed that a consumer is exposed on a long-term basis to a specific category of food (i.e. non-alcoholic beverages), containing caffeine or theobromine at their respective maximum use levels. For the rest of the categories, normal use levels applied. Daily dietary exposure to caffeine and theobromine (excluding systemic exposure) added as a chemically defined flavouring substance ranged 0-2.3 and 0-0.4 mg/kg bw, respectively, across all population groups. The Panel concluded that caffeine [FL-no: 16.016] and theobromine [FL-no: 16.032] would not be expected to present safety concern based on their estimated levels of intake from their use as flavouring substances.

Scientific Opinion of Flavouring Group Evaluation 500 (FGE.500): rum ether.

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to deliver a scientific opinion on the implications for human health of the flavouring rum ether [FL-no: 21.001] in the Flavouring Group Evaluation 500 (FGE.500), according to Regulation (EC) No 1331/2008 and Regulation (EC) No 1334/2008 of the European Parliament and of the Council. Rum ether is a complex mixture of volatile substances obtained by distillation of the reaction products of pyroligneous acid and ethyl alcohol under oxidative conditions in the presence of manganese dioxide and sulfuric acid. A total of 84 volatile constituents have been reported by the applicant. It is a colourless liquid with a rum-like odour and flavour. Its major uses are in the food categories beverages, confectionery and baked goods. The Panel decided to apply a congeneric group-based approach. The 84 reported constituents were allocated to 12 congeneric groups, based on structural and metabolic similarity. For eight of the congeneric groups, the Panel concluded that there is no safety concern at the intended conditions of use. However, the Panel concluded that substances in congeneric group 1 (ethanol and acetaldehyde) and congeneric group 12 (furan) are carcinogenic and genotoxic. The Panel also identified genotoxicity concerns for substances in congeneric group 3 (3-pentene-2-one). The exposure for congeneric group 10 (ethers of various structures) was above the Threshold of Toxicological Concern (TTC) applicable for this group, but a point of departure or health based guidance value that covers all the substances in this group could not be identified. The Panel concluded that according to the overall strategy for the risk assessment of flavouring substances, the presence of genotoxic substances as process-derived constituents of rum ether is of safety concern.

Scientific Opinion of Flavouring Group Evaluation 410 (FGE.410): 4',5,7-trihydroxyflavanone from chemical group 25 (phenol derivatives containing ring-alkyl, ring-alkoxy, and side-chains with an oxygenated functional group).

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of EFSA was requested to deliver a scientific opinion on the implications for human health of the flavouring substance 4',5,7-trihydroxyflavanone or naringenin [FL-no: 16.132], in the Flavouring Group Evaluation 410 (FGE.410), according to Regulation (EC) No 1331/2008 of the European Parliament and of the Council. The substance occurs naturally in grapefruits, oranges and tomatoes. It is intended to be used as a flavouring substance with flavour-modifying properties in specific categories of food. Information on specifications and manufacturing of [FL-no: 16.132] were considered adequate; however, data on stability in food are incomplete. The Panel noted that the available genotoxicity studies have significant shortcomings and are insufficient to conclude on the genotoxic potential of naringenin. Therefore, [FL-no: 16.132] cannot be evaluated through the Procedure. Additionally, the Panel noted that inhibition of CYP 450 by [FL-no: 16.132] has been clearly demonstrated in animal species in vivo which implies that the substance may interact with the metabolism and elimination of medicines and no convincing information is available that this does not pose a risk to humans at the estimated levels of exposure. To continue with the safety assessment of [FL-no: 16.132], a bacterial gene mutation assay and an in vitro micronucleus assay (according to OECD guidelines 471, 487 and GLP) are required. Even if these studies do not indicate a genotoxic potential, additional toxicological data are needed to finalise the evaluation.

Scientific opinion of Flavouring Group Evaluation 503 (FGE.503): grill flavour 'Grillin' CB-200SF'.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) was requested to deliver a scientific opinion on the implication for human health of the product Grillin' CB-200SF [FL-no: 21.004] in the Flavouring Group Evaluation 503, according to Regulation (EC) No 1331/2008 and Regulation (EC) No 1334/2008 of the European Parliament and of the Council. The product is derived from heat-treated high oleic sunflower oil, and intended to be used as a food flavouring with charbroiled or grilled aroma in a wide variety of food categories either in liquid or powder form. Information on manufacturing and compositional data was considered adequate to show the reproducibility of the production process. However, the Panel noted that a substantial amount of the non-volatile fraction of the product could not be identified. The chronic dietary exposure to the substance estimated using the Added Portions Exposure Technique (APET) was calculated to be 60 mg/person per day for a 60-kg adult and 37.8 mg/person per day for a 15-kg child. The data submitted for evaluating the genotoxic potential of the flavouring was considered insufficient. There are still eight substances in the flavouring for which the evaluation of genotoxic potential is pending. No toxicity studies have been provided on the final product itself. Only information on a number of constituents of the flavouring and data on toxicity of several thermally treated fats and oils were provided by the applicant. However, the Panel considered the time-temperature conditions that were applied in the preparation of the substances tested as not comparable to those applied in the course of the production of the flavouring. The Panel concluded that on the basis of the data provided by the applicant the safety of Grillin' CB-200SF cannot be established.

Scientific opinion of Flavouring Group Evaluation 502 (FGE.502): grill flavour 'Grillin' 5078'.

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) was requested to deliver a scientific opinion on the implication for human health of the product Grillin' 5078 [FL-no: 21.003] in the Flavouring Group Evaluation 502, according to Regulation (EC) No 1331/2008 and Regulation (EC) No 1334/2008 of the European Parliament and of the Council. The product is derived from heat-treated high oleic sunflower oil and intended to be used as a food flavouring with charbroiled or grilled aroma in a wide variety of food categories either in liquid or powder form. Information on manufacturing and compositional data was considered adequate to show the reproducibility of the production process. However, the Panel noted that a considerable amount of the non-volatile fraction of the product could not be identified. The chronic dietary exposure to the substance estimated using the Added Portions Exposure Technique (APET) was calculated to be 60 mg/person per day for a 60-kg adult and 37.8 mg/person per day for a 15-kg child. The data submitted for evaluating the genotoxic potential of the flavouring was considered insufficient. There are still 12 substances in the flavouring for which the evaluation of genotoxic potential is pending. No toxicity studies have been provided on the final product itself. Only information on a number of constituents of the flavouring and data on toxicity of several thermally treated fats and oils were provided by the applicant. However, the Panel considered the time-temperature conditions that were applied in the preparation of the substances tested as not comparable to those applied in the course of the production of the flavouring. The Panel concluded that on the basis of the data provided by the applicant the safety of Grillin' 5078 cannot be established.

Peptide-bond modified glutathione conjugate analogs modulate GSTpi function in GSH-conjugation, drug sensitivity and JNK signaling.

Glutathione S-transferase pi (GST, E.C.2.5.1.18) overexpression contributes to resistance of cancer cells towards cytostatic drugs. Furthermore, GSTpi is involved in the cellular stress response through inhibition of Jun N-terminal-kinase (JNK), a process that can be modulated by GST inhibitors. GSH conjugates are potent GST inhibitors, but are sensitive towards gamma-glutamyltranspeptidase (gammaGT)-mediated breakdown. In search for new peptidase stable GST inhibitors we employed the following strategy: (1) selection of a suitable (GST inhibiting) peptide-bond isostere from a series of previously synthesized gammaGT stabilized GSH-analogs. (2) The use of this peptidomimetic strategy to prepare a GSTpi selective inhibitor. Two gammaGT stable GSH conjugate analogs inhibited human GSTs, although non-selectively. One of these, a urethane-type peptide-bond is well accepted by GSTs and we selected this modification for the development of a gammaGT stable, GSTpi selective inhibitor, UrPhg-Et(2). This compound displayed selectivity for GSTpi compared to alpha and mu class enzymes. Furthermore, the inhibitor reversed GSTpi-mediated drug resistance (MDR) in breast tumor cells. In addition, short-term exposure of cells to UrPhg-Et(2) led to GSTpi oligomerization and JNK activation, suggesting that it activates the JNK-cJun signaling module through GSTpi dissociation. Altogether, we show the successful use of peptidomimetic glutathione conjugate analogs as GST inhibitors and MDR-modifiers. As many MDR related enzymes, such as MRP1, glyoxalase 1 and DNA-pk are also inhibited by GSH conjugates, these peptidomimetic compounds can be used as scaffolds for the development of multi-target MDR drugs.

Rat colon carcinoma cells that survived systemic immune surveillance are less sensitive to NK-cell mediated apoptosis.

In order to form distant metastases, cells from the primary tumor have to detach, enter the blood- or lymph-compartment and escape immune surveillance. Here, we describe the selection of rat colon carcinoma cell lines (CC531s-m1 and CC531s-m2) that escaped from systemic immune surveillance; CC531s cells were injected into the v. jugularis of Wag/Rij rats, after three weeks the lung tumors were isolated, the tumor cells were cultured, characterized and injected again. The m1- and m2-cell lines were less susceptible for killing by syngeneic NK cells. Further characterization of this cell line showed a decreased sensitivity towards TRAIL- and CD95L-, but not to granzyme B-mediated apoptosis. In the m1- and m2-cells log-phase growth started earlier as compared to the parental cell line, whereas no changes were found in anchorage-dependent or anchorage-independent growth. After subcapsular injection of the m2-cell line into the liver of rats much more lung metastases were formed in comparison to injection of the parental cell line. In conclusion, the results suggest that the resistance of the m1- and m2-cells to NK cell-mediated apoptosis was associated with their capability to survive systemic immune surveillance and form metastases in vivo.