MDMA (ecstasy) and its two mirror-image forms (enantiomers) cause distinct toxic effects in zebrafish embryos and larvae at concentrations as low as 0.02 μg/L, which are found in polluted waters. (S)-MDMA increases mortality and birth defects and disrupts the startle-habituation response, while (R)-MDMA suppresses general activity and avoidance behavior. The racemic mixture produces greater DNA damage than either enantiomer alone. Although MDMA does not accumulate in zebrafish tissues, these developmental, behavioral, and genetic effects could reduce larval survival and increase predation risk, raising concerns for wild fish populations. The findings demonstrate that enantioselective toxicity should be included in environmental risk assessments for MDMA.
An experimental study in rats found that an alcoholic extract of the ayahuasca mixture (Banisteriopsis caapi and Psychotria viridis) produced neuropathological changes in the hippocampus. At a low dose (0.7 mL), the number of granule cells increased significantly relative to pyramidal cells. At a medium dose (3.5 mL), granule cells decreased and both large and small pyramidal cells appeared. At the highest dose (7.0 mL), cellular disorganization occurred alongside large and small pyramidal cells and an increase in granule cells. Phytochemical screening revealed alkaloids, anthraquinones, triterpenoids, steroids, phenols, flavonoids, and saponins. The authors conclude the extract has a neuropathological effect on the rat hippocampus.