Neuroprotective and anti-oxidant properties of Waltheria americana leaf in male Wistar rats

Abstract

Neurodegenerative disorders are linked with neuroinflammation in specific areas of the brain. Waltheria americana is used in folkloric medicine for the treatment of pain and inflammation. Most drugs used in managing neuroinflammation are expensive and associated with adverse effects thereby necessitating the need for safe, potent and affordable agents. This study, therefore, evaluated the neuroprotective and anti-oxidant properties of methanol extract of Waltheria americana leaf (MEWA) in laboratory rodents.

Leaves of W. americana were obtained at the College of Agriculture, Kabba, Kogi State, and authenticated at the Herbarium, Forestry Research Institute of Nigeria, Ibadan (FHI:111064). The leaves were extracted by maceration in methanol and concentrated. Neuroinflammation was induced by intra-peritoneal injection of Lipopolysaccharide (2 mg/kg) in 15 rats and were grouped (n=5) as follows: Group1 (MEWA 200 mg/kg), Group 2 (Quercetin 50 mg/kg), Group 3 received vehicle only (control 10 mL/kg) while another group (not induced) received vehicle only. The treatment was done for 30 days. Memory function was assessed using Y Maze Test (YMT). At termination, Striatum, Prefrontal cortex (PFC) and Hippocampus were sectioned. Glutathione, malondialdehyde and acetylcholinesterase were evaluated by spectrophotometry. Nissl stains were used for neuronal morphology. Data were analysed using ANOVA at α _0.05.

The MEWA (200 mg/kg) significantly increased percentage alternation. The MEWA (200 mg/kg) significantly increased glutathione level (μmol/g tissue) in PFC (67.38±7.11) and Hippocampus (105.40±4.80) compared to control PFC (39.75±8.30), Hippocampus (55.54±2.0) and significantly decreased malondialdehyde level (ηmol/g tissue), acetylcholinesterase activity (μmol/min/g tissue), in Striatum (52.69±7.95, 7.96±0.31), PFC (57.94±3.81, 23.81±0.37), Hippocampus (111.0±12.90, 68.01±0.73), compared to control Striatum (83.51±3.85, 13.21±0.78), PFC (146.30±7.71, 32.27±1.49) and Hippocampus (151.40±8.80, 73.85±1.40), respectively. The MEWA 200 mg/kg preserved neuronal morphology.

Waltheria americana leaf extract ameliorated neurodegeneration in striatum, prefrontal cortex and hippocampus by reducing levels of free radicals, acetylcholinesterase and preventing neuronal damage in laboratory rodents.