In vitro hepatotoxicity of Petasites hybridus extract (Ze 339) depends on the concentration, the cytochrome activity of the cell system, and the species used.

Kristina Forsch,Verena Schöning,Christin Moser,Greta Marie Assmann,Beate Siewert,Veronika Butterweck,Jürgen Drewe

doi:10.1002/ptr.6516

Abstract

Ze 339, a CO2 extract prepared from the leaves of Petasites hybridus, possesses antispasmodic and anti‐inflammatory effects and is proven to be effective in the treatment of allergic rhinitis. To study possible hepatotoxic effects of Ze 339, its main constituents and metabolites, a series of in vitro investigations were performed. Furthermore, different reconstituted fractions of extract (petasins and fatty acid fraction) were examined in three in vitro test systems using hepatocytes: Two human cell lines, with lower and higher activity of cytochrome P450 enzymes (HepG2, HepaRG) as well as a rodent cell line with high cytochrome P450 activity (H‐4‐II‐E), were used. Metabolic activity, assessed by the WST‐1 assay, was chosen as indicator of cytotoxicity. To assess potential bioactivation of Ze 339 compounds, metabolic experiments using S9 fractions from rats, dogs, and humans and isolated cytochromes (human/rat) were performed, and the formation of reactive metabolites was assessed by measuring cellular concentrations of glutathione and glutathione disulphide.Our data revealed that the cytotoxicity of Ze 339, its single constituents, and main metabolites depends on the concentration, the cytochrome activity of the cell system, and the species used.

Highlights

Petasites hybridus (L.) GAERTN., B.MEY. & SCHERB. is an herbaceous perennial plant belonging to the Asteraceae family
The analysis focused on three different in vitro test systems of hepatocytes: two human hepatic cell lines, with lower and higher activity of cytochrome P450 enzymes (HepG2 and HepaRG, respectively, (Andersson, Kanebratt, & Kenna, 2012; Guillouzo et al, 2007)) and a rat cell line (H-4-II-E [Fujimura, Murakami, Miwa, Aruga, & Toriumi, 2012; Westerink, Stevenson, & Schoonen, 2008]) were used
The cytotoxicity of Ze 339 and its single constituents petasin, isopetasin, neopetasin, isopetasol, and petasol was shown to be dependent on the concentration used, the cytochrome activity, and species

Summary

| BACKGROUND

Petasites hybridus (L.) GAERTN., B.MEY. & SCHERB. (common name: butterbur) is an herbaceous perennial plant belonging to the Asteraceae family. Nine cases of severe clinical hepatotoxicity of a medicinal product containing P. hybridus root extract (Petadolor/Dolomed) for migraine prophylaxis occurred between November 2001 and February 2002 using therapeutic doses (Evers, 2009). This led to the subsequent withdrawal of the Marketing Authorization of medicinal products containing the root extract in Switzerland in 2004 (Swissmedic, 2004). Up to now, no evidence is available regarding the hepatotoxicity of the leaf extract Ze 339 It was the aim of this study to determine possible in vitro hepatotoxic effects of Ze 339, the petasin isomers petasin, isopetasin, and neopetasin as well as the metabolites petasol and isopetasol. The formation of reactive metabolites was indirectly assessed by measuring the cellular concentrations of glutathione and glutathione disulphide levels after treatment with Ze 339

| METHODS

| RESULTS

Findings

| DISCUSSION