DNA damaging potential of Ganoderma lucidum extracts

Abstract

Ethnopharmacological relevance: Ganoderma lucidum (Lingzhi or Reishi) is a medicinal mushroom historically used in Asian countries to treat a wide variety of diseases and prolong life. In the last years, G. lucidum has been internationally recognized as an effective adjuvant in cancer treatment. Among active components, the most recent research indicates that polysaccharides modulate the immune response favoring the recovery from toxicity of chemo and radiotherapy while triterpenes are cytotoxic to tumoral cells mainly by altering gene expression. Beyond this body of evidence on the efficacy of G. lucidum in cancer treatment, it is not yet understood whether these extracts exert the same mechanisms of action than current antitumoral drugs. Aim of the study: In this study, we tested the DNA damaging potential of G. lucidum extracts by the β-galactosidase biochemical prophage induction assay (BIA) using doxorubicin, a DNA intercalating agent, as a positive control. This assay was traditionally used to screen microbial metabolites towards antitumoral agents. Here, we used this bacterial assay for the first time to assess DNA damage of herbal drugs. Results: After a bioguided assay, only a purified fraction of G. lucidum containing a mixture of C16 and C18:1 fatty acids exerted weak activity which could not be attributed to direct interaction with DNA. At the same concentrations, the induction observed for doxorubicin was clearly contrasting. Conclusions: The micro BIA assay could be successfully used to demonstrate differences in cellular effects between G. lucidum extracts and doxorubicin. These results showed that G. lucidum extracts display weak DNA damaging potential. Since DNA injury promotes aging and cancer, our results substantiate the traditional use of this mushroom to prolong life.