Antinociceptive, genotoxic and histopathological study of Heliopsis longipes S.F.Blake in mice

Ethnopharmacological relevance: H. longipes S.F. Blake (Asteraceae) is a Mexican plant, whose roots aretraditionally used as a condiment, as a mouth anesthetic, and as an antiparasitic. Affinin is the alkamidepresent in higher amounts in the roots of H. longipes.Aim of the study: To date, there are no published studies regarding the relation between the analgesicproperties, in vivo cytotoxicity, and DNA-damaging potential of H. longipes ethanol extract (HLEE).Materials and methods: The HLEE was chromatographically fingerprinted to validate its affinin contents.Biological evaluation was conducted in sets of 6?8 CD1+ mice. Antinociceptive effect was evaluated usingthe writhing and hot-plate tests, and mutagenic and cytotoxic effects were evaluated with micronucleoustest in CD1+ mice. For histopathological studies, biological samples from liver, heart, kidneys, spleen, lung,and brain were collected and stained.Results: Oral administration of HLEE (3?100 mg/kg) produced a dose-dependent antinociceptive effectin both assays. In micronucleus assay, the variability in the number of micronucleated polychromaticerythrocytes (MNPE) induced, and PE/NE index, the ratio of polychromatic erythrocytes with respect tothe number of normochromatic erythrocytes induced by HLEE in the evaluated schedule, were small andnonsignificant. After histopathological results, HLEE showed polioencephalomalacia with 1000 mg/kgdose.Conclusions: This work provides evidence that HLEE exerts analgesic effects, with no genotoxic effectsin vivo. These findings would be an important contribution to explain the use of H. longipes root as aneffective analgesic in traditional medicine, and to establish for the first time the absence of genotoxic andcytotoxic effects of the root in bioactive doses in vivo.