Assessment of the genotoxic and mutagenic properties of Himatanthus articulatus bark extracts used as phytotherapeutic drug in the Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE: Himatanthus articulatus (Apocynaceae) is a plant native to the Amazon, popularly used to treat external ulcers, tumors, inflammations, cancer, syphilis and malaria. AIM OF THE STUDY: To investigate the in vivo genotoxic and mutagenic potential of this plant, using the comet assay and the micronucleus test. MATERIAL AND METHODS: Female and male adult mice were treated with 500 mg/kg, 1000 mg/kg or 2000 mg/kg of Himatanthus articulatus aqueous or ethanolic bark extracts by gavage for two consecutive days. In addition, blood slides were exposed to hydrogen peroxide (ex vivo) to evaluate the anticlastogenic effect using the comet assay. The HPLC analyses indicated plumieride as the main constituent of both extracts from Himatanthus articulatus barks. RESULTS: No differences between genders were observed. Micronuclei were observed only in the group treated with the highest dose of both extracts. Conversely, lower doses of these extracts showed protective effects to DNA against damage induced by hydrogen peroxide, indicating an important antigenotoxic effect. CONCLUSIONS: The toxicological evaluation indicated that the extracts are non-genotoxic and reduce the clastogenic damage induced by hydrogen peroxide. In part, this result can be atributted to the phytochemical profile of Himatanthus articulatus, which presents iridoids and phenolic compounds.

The antigenotoxic activity of latex from Himatanthus articulatus

Himatanthus articulatus (Vahl) Woodson (Apocynaceae) is a native plant to the Amazon popularly used to treat ulcers, tumors, inflammations, cancer, syphilis and malaria. The aim of the present study was to investigate the in vivo genotoxic/antigenotoxic and mutagenic potential of this plant, using the comet and the micronucleus assays in mice. Female and male adult mice were treated with different doses of H. articulatus latex by gavage for two consecutive days. For the experiments, the latex was serially diluted with water to 1:2 (D1); 1:4 (D½) and 1:8 (D») and administered to the animals. The blood slides were exposed to hydrogen peroxide (ex vivo) to evaluate antigenotoxic effect. Under the experimental conditions used in this study, the latex of H. articulatus did not increase the frequency of DNA damage as measured by the comet assay and micronucleus test in treated mice, indicating a non-genotoxic and non-mutagenic activity. In relation to the antigenotoxicity, latex exerted protective effect against DNA damage induced by hydrogen peroxide. Therefore, our results add new information about the antigenotoxic potential of H. articulatus latex, which is popularly used in the Amazon to treat different pathologies.