Genotoxicity assessment of the flavouring agent, perillaldehyde

Abstract

Perillaldehyde, a natural monocyclic terpenoid found most abundantly in the herb perilla, has a long history of use as a flavouring ingredient to add spiciness and citrus taste to foods. Previously, it was judged to be safe by several international expert panels. To confirm the safety of flavourings placed on the European Union list of flavourings, perillaldehyde was selected by the European Food Safety Authority as a representative of a subgroup of alicyclic aldehyde flavouring substances to be evaluated for genotoxic potential. Perillaldehyde was tested in a bacterial reverse mutation assay, an in vitro micronucleus assay in human lymphocytes, an HPRT assay in mouse lymphoma cells, and a micronucleus/comet assay in Han Wistar rats. In contrast to previously published results, perillaldehyde induced mutation in Salmonella typhimurium strain TA98 in the absence of metabolic activation. The comet assay was negative for duodenum and weakly positive for liver but only at a hepatotoxic dose of perillaldehyde. All other genotoxicity assays were negative. These data do not provide an indication of any genotoxic potential for perillaldehyde, and they provide the primary basis for recent scientific opinions regarding perillaldehyde genotoxicity announced by several international organizations responsible for safety assessment of food additives and flavourings.

Induced cell death in Ceratocystis fimbriata by pro‐apoptotic activity of a natural organic compound, perillaldehyde, through Ca2+ overload and accumulation of reactive oxygen species

“…Perillaldehyde (PAE), a secondary metabolite in perilla plants, has been used extensively as a flavouring ingredient to add spice and citrus tastes to foods (Wang et al, 2008). Moreover, since 1948, PAE has been designated as unlikely to harm human health by the Japanese Ministry of Health, Labour and Welfare under the Food Sanitation Act (Hobbs et al, 2016). PAE exhibits antioxidant, antidepressant and other biological properties (Ito et al, 2011;Jin et al, 2012).…”

Scientific Opinion on Flavouring Group Evaluation 208 Revision 3 (FGE.208Rev3): consideration of genotoxicity data on alicyclic aldehydes with α,β‐unsaturation in ring/side‐chain and precursors from chemical subgroup 2.2 of FGE.19

“…The Panel noted that on the basis of OECD TG 489, the evaluation should be based on a comparison between treatment-induced values and the concurrent vehicle control, the consideration of a potential dose-response relationship and on a comparison of treatment-induced values with (appropriate) historical negative control data, not primarily on a comparison between vehicle/positive control experimental data and historical controls. Hobbs et al (2016) report three different ranges of historical control, two of the reported ranges are new and not overlapping. However, the range of historical negative control is still wide and no justification on the overlapping range is provided.…”

“…‘The international effort to validate the in vivo comet assay for the detection of genotoxic carcinogens, coordinated by the Japanese Center for the Validation of Alternative Methods (JaCVAM), concluded that histopathology remains the “gold standard” for assessing tissue cytotoxicity, and changes in % tail DNA require careful interpretation when measured in conjunction with severe histopathological changes (Uno et al., ). (..) The perillaldehyde comet findings (both the group mean and individual animal data) are well within this upper limit for acceptable vehicle control values further supporting the conclusion that the small increase in tail intensity observed in the liver following administration at 700 mg/kg per day was not biologically relevant and was most likely an artefact of the observed hepatic cytotoxicity’ (Hobbs et al., ).…”

“…(..) In that regard, it is useful to consider the perillaldehyde positive % tail intensity value in the context of broadened historical datasets collated by the testing laboratory, in which the vehicle and positive control reference ranges are clearly distinct (Supplemental Data Table II) (2016). Comparison of the positive % tail intensity value (2.20%) to historical data that included the studies performed immediately prior to the perillaldehyde study (n = 230) or historical data spanning the period immediately prior and subsequent to the perillaldehyde study (n = 400) confirms that the perillaldehyde data are close to the means of both vehicle control data sets (2.31% and 1.60%, respectively), supporting the arguments that the positive comet result for perillaldehyde is not biologically relevant (Hobbs et al., )’.…”

“…Appendix G -Publications on the evaluation of genotoxicity studies on p-Mentha- 1, p-Mentha ] was evaluated by the Panel as genotoxic in vivo and, accordingly, there is a safety concern for the use of p-mentha .117] as a flavouring substance (FGE.208Rev1). After the publication of this opinion (EFSA CEF Panel, 2015), two articles on the genotoxicity of p-mentha .117] were published (Cohen et al, 2016;Hobbs et al, 2016) if the positive test in the liver, the major site of metabolism in vivo, is assumed to reflect a biologically relevant result, then it is surprising that in vitro mutagenicity and chromosome damage tests performed in the presence of metabolic activation did not provide any indication of genotoxic effects' (Hobbs et al, 2016).…”