Phyllanthus amarus protects against spatial memory impairment induced by lipopolysaccharide in mice

Phyllanthus amarus Schumach. and Thonn. is a wide spread medicinal herb with various traditional uses. It is well documented for its antioxidant, anti-inflammatory, and hepatoprotective activities. Therefore, it is of interest to evaluate the 80% ethanol extract of Phyllanthus amarus (PA) on spatial memory using the 8-radial arm maze (8-RAM) in mice after induction of neuro inflammation by lipopolysaccharide (LPS) in a 14- and 28-days treatment study. LC-MS/MS was performed to profile the chemical composition in PA extract. Mice were treated orally with 5% v/v tween 20, PA extract (100, 200 and 400 mg/kg), or ibuprofen (IBF 40 mg/kg) for 14 and 28 days. All groups were challenged with LPS (1 mg/kg) via intraperitoneal (i.p.) injection a day prior to the 8-RAM task except for the negative control group which received an i.p. injection of saline. Data obtained were analyzed with one-way ANOVA followed by post hoc Dunnett's test (comparison of all groups against vehicle control). Analysis of LC-MS/MS data revealed the presence of 16 compounds in the PA extract. Administration of PA extract at 200 and 400 mg/kg for 14 and 28 days significantly (*P<0.05) decreased the working and reference memory errors against LPS-induced spatial memory impairment. The observed protective action is possibly due to the putative antineuroinflammatory effects of PA. In conclusion, PA extract possess neuroprotective effects against spatial memory impairment mediated by LPS.