RESUMO
Kainic acid (KA) has been used to study the neurotoxicity induced after status epilepticus (SE) due to activation of excitatory amino acids with neuronal damage. Medicinal plants can protect against damage caused by KA-induced SE; in particular, organic extracts of Heterotheca inuloides and its metabolite quercetin display antioxidant activity and act as hepatoprotective agents. However, it is unknown whether these properties can protect against the hyperexcitability underlying the damage caused by KA-induced SE. Our aim was to study the protective effects (with regard to behavior and antioxidant activity) of administration of natural products methanolic (ME) and acetonic (AE) extracts and quercetin (Q) from H. inuloides at doses of 30 mg/kg (ME30, AE30, and Q30 groups), 100 mg/kg (ME100, AE100, and Q100 groups), and 300 mg/kg (ME300, AE300, and Q300 groups) against damage in brain regions of male Wistar rats treated with KA. We found dose-dependent effects on behavioral and biochemical studies in the all-natural product groups vs. the control group, with decreases in seizure severity (Racine's scale) and increases in seizure latency (p < 0.05 in the ME100, AE100, Q100, and Q300 groups and p < 0.01 in the AE300 and ME300 groups); on lipid peroxidation and carbonylated proteins in all brain tissues (p < 0.0001); and on GPx, GR, CAT, and SOD activities with all the treatments vs. KA (p ≤ 0.001). In addition, there were strong negative correlations between carbonyl levels and latency in the group treated with KA and in the group treated with methanolic extract in the presence of KA (r = -0.9919, p = 0.0084). This evidence suggests that organic extracts and quercetin from H. inuloides exert anticonvulsant effects via direct scavenging of reactive oxygen species (ROS) and modulation of antioxidant enzyme activity.