In vitro genotoxicity assessment of Matrine and Oxymatrine

Introduction Matrine and Oxymatrine, known constituents in Sophora ssp., may be detected in trace amounts in liquorice root preparations. Their presence is caused by technically unavoidable co-harvesting of minute portions of Sophora ssp. roots during collection of licorice roots (Glycyrrhiza ssp.) from wild habitats, the predominat source of liquorice [1]. According to the opinion of different authorities, currently available data are not sufficient to exclude a genotoxic potential. Here we present in vitro genotoxicity studies aiming to fill the data gaps.

Methods Guideline-conform genotoxicity tests were conducted with the pure test substances Matrine (99%) and Oxymatrine (92%) under GLP conditions. Mutagenicity was investigated in a bacterial reverse mutation assay (OECD guideline 471), using Salmonella Typhimurium strains TA 1535, TA 1537, TA 98, TA100 and E. coli WP2 uvra (pKM101) with and without mammalian metabolic activation [2] [3]. Subsequently, micronucleus tests (OECD guideline 487) were conducted to investigate the clastogenic and/or aneugenic potential [4] [5]. Human primary lymphocytes were used in the presence and absence of metabolic activation, using CytoB as cytokinesis blocker. For assessment of the cytotoxicity, the CBPI was determined. Experiment I was conducted as short -term experiment in presence and absence of S9-mix. Concentrations up to the limit dose of 2000 µg/ml were evaluated for micronuclei. Experiment II was conducted with long-term exposure without metabolic activation, up to the limit dose or cytostasis.

Results No biologically relevant increases in revertant colony numbers were observed in any of the five bacterial tester strains following treatment with Matrine or Oxymatrine at concentrations up to 5,000 µg/plate, neither in the presence nor absence of metabolic activation. In the micronucleus test, no statistically significant or biological relevant increases of micronuclei frequency were noted after treatment with Matrine or Oxymatrine in neither of the experiments.

Conclusion Based on the studies presented here, there is no concern for a genotoxic potential for Matrine and Oxymatrine from available bacterial reverse mutation assay and micronucleus test.

AcknowledgementThe studies were funded by the Association of the German Confectionery Industry (BDSI), Tea & Herbal Infusions Europe (THIE) and Drug and Chemical Association (VDC).

Publication History

Article published online:
14 June 2023

• References

• 1 [1] Schultz J et al. Food Additives & Contaminants 2022; Part A 39.2: 351–361
• 2 Eurofins. Reverse Mutation Assay using Bacteria (Salmonella typhimurium and Escherichia coli) with Matrine. Eurofins BioPharma Product Testing Munich GmbH, Planegg, Germany; Report STUGC22AA1441-2, 2022-11-24
• 3 Eurofins. Reverse Mutation Assay using Bacteria (Salmonella typhimurium and Escherichia coli) with Oxymatrine. Eurofins BioPharma Product Testing Munich GmbH, Planegg, Germany; Report STUGC22AA1440-2, 2022-11-24
• 4 Eurofins. In vitro Mammalian Micronucleus Assay in Human Lymphocytes with Matrine. Eurofins BioPharma Product Testing Munich GmbH, Planegg, Germany; Report STUGC22AA1441-3, 2023-04-27
• 5 Eurofins. In vitro Mammalian Micronucleus Assay in Human Lymphocytes with Oxymatrine; Eurofins BioPharma Product Testing Munich GmbH, Planegg, Germany; Report STUGC22AA1440-3, 2023-04-27