Neuroprotective and anxiolytic effects of Matricaria chamomilla ethanolic extract against harmine-induced anxiety and oxidative stress in rats exposed to forced swimming stress

An ethanolic extract of Matricaria chamomilla (EEC) counteracted harmine-induced anxiety- and depression-like behaviors in rats. In a forced swimming stress protocol, groups of Wistar rats received either harmine alone (40 mg/kg), EEC alone (200 or 500 mg/kg), or harmine combined with EEC. EEC ameliorated harmine-induced reductions in locomotor activity, exploration, and memory performance. It also lowered circulating adrenocorticotropic hormone (ACTH) levels and restored antioxidant enzyme activity, reducing brain oxidative-stress markers such as malondialdehyde. The findings suggest that oral EEC supplementation may enhance exploratory behavior and modulate oxidative stress, indicating a potential prophylactic effect against depressive states.

Study at a glance

Abstract

The global rise in anxiety and depression disorders has drawn attention to compounds like harmine, a Peganum harmala alkaloid, which induces a pronounced anxiety response. Herbal treatments exhibit the potential to relieve such symptoms with minimal or no side effects. This study aimed to investigate the behavioral, neurobiological, and protective effects of the ethanolic extract of Matricaria chamomilla (EEC) in rats previously exposed to harmine and subjected to a forced swimming stress protocol. Six groups (n=8) of Wistar rats were formed as follows: group 1 (control); group 2 that received a single injection of harmine (40 mg/kg); groups 3 and 4 received 200 mg/kg or 500 mg/kg EEC, respectively; groups 5 and 6 received an injection of harmine (40 mg/kg) with administration of 200 mg/kg or 500 mg/kg EEC). Rats underwent behavioral testing alongside biochemical and histological analyses. Oxidative-stress markers were quantified, including malondialdehyde (MDA), glutathione peroxidase (GPx), glutathione S-transferase (GST), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity. The EEC extract ameliorated depression-like behavior by counteracting harmine-induced reductions in locomotor activity, environmental exploration, and memory performance. It also lowered circulating adrenocorticotropic hormone (ACTH) levels and restored antioxidant enzyme activity, reflected by reductions in brain oxidative-stress markers. The findings indicate that oral EEC supplementation may enhance exploratory behavior, suggesting a potential neural mechanism for mitigating depressive states. Its modulation of brain oxidative-stress responses points to a possible prophylactic effect, supporting further investigation of EEC as an adjunctive therapeutic candidate.