Genotoxicity and mutagenicity of Echinodorus macrophyllus (chapéu-de-couro) extracts

Leonardo S Vidal,Ricardo M Kuster,Adriana M Alves,Alvaro C Leitão,Claudia Lage

doi:10.1590/s1415-47572010005000060

Leonardo S Vidal, Ricardo M Kuster + Show 3 more

Open Access

https://doi.org/10.1590/s1415-47572010005000060

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Abstract

Echinodorus macrophyllus, commonly known as chapéu-de-couro, is a medicinal plant used in folk medicine to treat inflammation and rheumatic diseases. In this work, we used short-term bacterial assays based on the induction of SOS functions to examine the genotoxicity and mutagenicity of an aqueous extract of E. macrophyllus leaves. Whole extract and an ethyl acetate fraction showed similar genotoxicity and caused an ~70-fold increase in lysogenic induction. The extract also gave a positive result in the SOS chromotest with an increase of 12-fold in β-Galactosidase enzymatic units. There was a strong trend towards base substitutions and frameshifts at purine sites in the mutations induced by the extract in Escherichia coli (CC103 and CC104 strains) and Salmonella typhimurium test strains (22-fold increase in histidine revertants in TA98 strain). Since reactive oxygen species may be implicated in aging process and in degenerative diseases, we used antioxidant compounds as catalase, thiourea and dipyridyl in the lysogenic induction test. All this compounds were able to reduce the induction factor observed in the treatment with chapéu-de-couro, thus suggesting that the genotoxicity and mutagenicity were attributable to the production of reactive oxygen species that targeted DNA purines.

Highlights

In recent years, there has been a widespread increase in the use of medicinal plants or natural products because of their potentially beneficial effect on human health
The results obtained with the Chromotest reinforced those of the inductest assay and indicated that chapéu-de-couro extract was genotoxic to bacterial cells
To examine the mechanism by which chapéu-decouro extract exerts its genotoxicity, different antioxidant agents were added to the bacterial cultures simultaneously with the extract (150 mg/plate)

Summary

Introduction

There has been a widespread increase in the use of medicinal plants or natural products because of their potentially beneficial effect on human health. There is little information on the mutagenic effects of most of the active principles found in these medicinal plants. Many plants may be effective phytomedicines but need to be exhaustively investigated to detect any toxic side effects. This is important because many plants synthesize toxic substances for defense against viruses, bacteria and fungi and these compounds could have potentially deleterious effects in humans. The biological effects of medicinal plant extracts are complex because of the presence of additional substances generated during processing and/or through the use of additives (Sugimura, 1982). Since many constituents found in industrial food/phytomedicine preparations may be muta-

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