Ameliorative effects of Matricaria chamomilla L. hydroalcoholic extract on scopolamine-induced memory impairment in rats: A behavioral and molecular study

Background: Matricaria chamomilla L. is a medicinal herb traditionally used as the anti-inflammatory, anti-microbial, antiviral, anxiolytic and antidepressant agent. Nevertheless, supporting evidence demonstrated its memory enhancing activity and antioxidant properties. Purpose: To investigate the effects of the hydroalcoholic extract of M. chamomilla L. on memory processes in a scopolamine-induced a rat model of amnesia and to reveal its underlying mechanism of action. Methods: The hydroalcoholic extract (25 and 75 mg/kg) was intraperitoneally administered to rats once daily for 7 days, and scopolamine (0.7 mg/kg) was injected 30 min before the behavioral testing to induce memory impairment. The phytochemical composition of the extract was quantified by HPLC/DAD analysis. Y-maze and radial arm-maze tests were employed for memory assessing. Acetylcholinesterase activity was measured in the rat hippocampus. Superoxide dismutase, glutathione peroxidase, and catalase specific activities along with the total content of reduced glutathione and protein carbonyl and malondialdehyde levels were also measured in the rat hippocampus. qRT-PCR was used to quantify BDNF mRNA and IL1 beta mRNA expression in the rat hippocampus. Results: We first identified the chlorogenic acid, apigenin-7-glucoside, rutin, cynaroside, luteolin, apigenin and derivatives of apigenin-7-glucoside as the extract major components. Furthermore, we showed that the extract reversed the scopolamine-induced decreasing of the spontaneous alternation in the Y-maze test and the scopolamine-induced increasing of the working and reference memory errors in the radial arm maze test. Also, the scopolamine-induced alteration of the acetylcholinesterase activity and the oxidant-antioxidant balance in the rat hippocampus was recovered by the treatment with the extract. Finally, we demonstrated that the extract restored the scopolamine-decreased BDNF expression and increased IL1 beta expression in the rat hippocampus. Conclusion: These findings suggest that the extract could be a potent neuropharmacological agent against amnesia via modulating cholinergic activity, neuroinflammation and promoting antioxidant action in the rat hippocampus.