Evaluation of anti-amnesic effect of Conyza bonariensis in rats

OBJECTIVE: Conyza bonariensis is an ornamental medicinal weed. This experiment was planned to explore the outcome of petroleum ether extract of C. bonariensis (PECB) leaves on scopolamine-induced amnesia in rats. MATERIALS AND METHODS: For impairing memory, 0.4 mg/kg (i. p.) of scopolamine was given. Fifty to 200 mg/kg of PECB was fed orally to rats and 3 mg/kg (i. p.) of tacrine was given as a standard drug. Anti-amnesic property was evaluated in Barnes maze using ANY-maze software. Following a behavioral study, acetylcholinesterase (AChE), β-amyloid(1-41), antioxidant enzymes, and cytokine levels were measured. Furthermore, reverse transcription–polymerase chain reaction was done for expression of the marker genes such as AChE, Nrf2, NF-κB, PP2A, and HO-1, whereas BDNF, TrkB, caspase-3, and Bax were measured by Western blotting. RESULTS: PECB and tacrine significantly improved memory dysfunction by decreasing escape latency in Barnes maze. At the highest dose, treatment with PECB altered the scopolamine-induced hyperactivation of AChE and β-amyloid(1-41) activity. PECB elevated the levels of superoxide dismutase, glutathione, and catalase and decreased lipid peroxidation and nitric oxide dose dependently. PECB attenuated scopolamine-induced increase of tumor necrosis factor-α and interleukin (IL)-1β concentrations in the hippocampus with reversed diminished IL-10 level toward normal in the brain. Nrf2, HO-1, PP2A, BDNF, and TrkB were significantly upregulated with downregulation of AChE, NF-κB, Tau, Bax, and caspase-3. Different components such as beta-amyrin and alpha-amyrin were isolated from leaves of the plant. CONCLUSION: The results indicated that PECB might be a potential curative drug for the treatment of cognitive impairment.