Protective effect of methanol leaf extract of Cnidoscolus aconitifolius against lipopolysaccharides-induced cortico-hippocampal neuroinflammation, oxidative stress and memory impairment

Cnidoscolus aconitifolius contains various phenolic compounds possessing anti-inflammatory and antioxidant properties. This study aimed to evaluate the protective effect of the Methanol Extract of Cnidoscolus aconitifolius (MECA) against LPS-induced memory impairment, oxidative stress and neuroinflammation in rats. Thirty male Wistar rats were divided into 5 groups (n = 6). Group 1 served as the control and received the vehicle, group 2 was negative control, groups 3–5 received MECA (25, 50, and 100 mg/kg) for 14 days. Groups 2–5 were daily injected with LPS (250 μg/kg, i.p) from day 8–14 of treatment. Memory impairment was evaluated after the last LPS administration using the Y-Maze Test (YMT) and Novel Object Recognition Test (NORT). Brain prefrontal cortex (PFC) and hippocampus (HPC) sections were obtained and levels of reduced glutathione (GSH), malondialdehyde, catalase, nitrite, acetylcholinesterase, and TNF-α and IL-6 were determined. Oral administration of MECA significantly reversed LPS-induced memory impairment in the YMT and NORT. MECA significantly reduced LPS-induced elevated malondialdehyde and nitrite, while preventing depletion of GSH and catalase in the PFC and HPC sections of the brain. Acetylcholinesterase activity is also reduced. MECA (100 mg/kg) significantly reduced IL-6 and TNF-α levels in PFC and HPC of LPS-treated rats. This study showed that the methanol extract of Cnidoscolus aconitifolius has significant protective effect against lipopolysaccharide-induced memory impairment via mechanisms related to inhibition of neuroinflammation and oxidative stress.