Single acute and repeated subacute toxicity evaluations of Annona atemoya leaf extract with in vitro anti-inflammatory potential.

The nutraceutical and biological potential of Annona atemoya, a fruiting plant, has been reported. We and others have demonstrated that A. atemoya leaf extract (AAL) has various pharmacological properties, such as antioxidant, antimicrobial, and neuroprotective effects. However, knowledge about the safety and potential toxicity of AAL remains limited. We aimed to assess the potential toxicity of AAL using acute and repeated subacute oral toxicity tests in rats. In both acute and repeated subacute toxicity test, no AAL-related behavioral abnormalities or changes in mortality, food intake, body weight were observed up to a dosage of 2000 mg/kg, indicating that the median lethal dose of AAL is higher than 2000 mg/kg. In subacute toxicity tests, no significant changes in hematological and biochemical parameters, urinalysis results, and histopathological variables were observed. Therefore, the no-observed-adverse-effect level (NOAEL) of orally administered AAL was estimated to be 2000 mg/kg/day in male and female rats. We also examined the effect of AAL on the inflammatory reaction in lipopolysaccharide (LPS)-stimulated BV-2 cells. AAL treatment significantly inhibited the LPS-stimulated increases in the levels of nitric oxide (NO) and inflammatory cytokines, implying that AAL has an anti-inflammatory effect. Quality control analysis revealed that two marker compounds, rutin and isoquercitrin, were present at 27.570 and 4.322 mg/g, respectively, in a freeze-dried AAL sample and were completely eluted within 27 min. The extraction recovery was 99.47-103.80%, and the precision was ≤2.79%. Overall, these findings suggest the safety, anti-inflammatory activity, and standardization of AAL.