Assessment of the Cytotoxicity, Mutagenicity, and Genotoxicity of Two Traditional Chinese Herbs: Aristolochia baetica and Magnolia officinalis

Herbal remedies used in traditional medicine often contain several compounds combined in order to potentiate their own intrinsic properties. However, herbs can sometimes cause serious health troubles. In Belgium, patients who developed severe aristolochic acid nephropathy ingested slimming pills containing root extracts of an Aristolochia species, as well as the bark of Magnolia officinalis. The goal of the study was to evaluate, on a human renal cell line, Aristolochia and Magnolia extracts for their cytotoxicity by a resazurin cell viability assay, and their genotoxicity by immunodetection and quantification of the phosphorylated histone γ-H2AX. The present study also sought to assess the mutagenicity of these extracts, employing an OECD recognized test, the Ames test, using four Salmonella typhimurium strains with and without a microsomial fraction. Based on our results, it has been demonstrated that the Aristolochia–Magnolia combination (aqueous extracts) was more genotoxic to human kidney cells, and that this combination (aqueous and methanolic extracts) was more cytotoxic to human kidney cells after 24 and 48 h. Interestingly, it has also been shown that the Aristolochia–Magnolia combination (aqueous extracts) was mutagenic with a TA98 Salmonella typhimurium strain in the presence of a microsomial liver S9 fraction. This mutagenic effect appears to be dose-dependent.