Probable mechanisms involved in the antiepileptic activity of Clerodendrum polycephalum Baker (Labiatae) leaf extract in mice exposed to chemical-induced seizures.

The leaves of Clerodendrum polycephalum Baker (Labiatae) are used as a dietary legume supplement and applied ethnomedicinally for the management of epilepsy, convulsion, and spasms. This study is aimed at evaluating the effects of Clerodendrum polycephalum (CP) leaf extract on chemical-induced seizures in mice and the possible mechanisms of action. Swiss albino mice were pretreated with CP (50, 100, or 500 mg/kg, p.o.) prior to intraperitoneal injection of picrotoxin (PTX) or pentylenetetrazole (PTZ). However, the most effective dose was used to elucidate the role of GABAergic and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling mechanisms in mice brains. Accordingly, we evaluated the preventive and reversal effects of CP on kainic acid (KA)-induced temporal lobe epilepsy (TLE), oxidative stress, and neuroinflammatory in mice. The pretreatment of mice with CP delayed the latencies to PTX and PTZ-induced seizures and decrement in the period of tonic-clonic attacks. Interestingly, CP (100 mg/kg) completely prevented PTZ-induced tonic-clonic seizures. Contrastingly, flumazenil (benzodiazepine receptor antagonist), NG -nitro-L-Arginine (L-NNA) (10 mg/kg., neuronal nitric oxide synthase inhibitor), and methylene blue (MB) (2 mg/kg, a soluble guanylyl cyclase inhibitor) but not L-arginine (150 mg/kg., nitric oxide precursor) reversed CP-induced anticonvulsant-like effect in PTZ model. Furthermore, KA-elicited TLE was prevented by CP treatment. CP also attenuated KA-induced oxidative stress, cyooxygenase-2 (COX-2), and nuclear factor kappa-B (NF-κB) elevated expressions in the hippocampus. The study revealed that the ethanolic leaf extract of CP produced anticonvulsant actions through enhancement of antioxidant defense, GABAergic, and NO-cGMP signaling pathways as well as attenuation of inflammatory processes. PRACTICAL APPLICATIONS: The leaves of Clerodendrum polycephalum Baker (Labiatae) are used as a dietary legume supplement and applied ethnomedicinally for the management of epilepsy, convulsion, and spasms. For this reason, we believe that supplementation of the Clerodendrum polycephalum leaf extract would prevent epileptic-related disorders in mice induced with epileptic conditions using kainic acid and other behavioral phenotypic models. Here, our findings clearly revealed that Clerodendrum polycephalum leaf extract protects against conditions of epileptic-related disorders and thus might be relevant as a dietary supplement in the prevention or delay of the onset of seizures and epileptic behavior.

Cnestis ferruginea Vahl ex DC (Connaraceae) downregulates expression of immediate early genes in kainic acid-induced temporal lobe epilepsy in mice.

OBJECTIVES: This study investigates the influence of Cnestis ferruginea (CF) on kainic acid (KA)-induced immediate early genes (IEGs) associated with hippocampal sclerosis in temporal lobe epilepsy (TLE) in mice. METHODS: Animals were randomly divided into preventive treatment; vehicle (10 mL/kg, p.o.) or CF (400 mg/kg, p.o.) for three consecutive days before KA (5 mg/kg, i.p.) on days 4 and 5. In the reversal model, KA (5 mg/kg, i.p.) was administered on days 1 and 2 before CF (400 mg/kg) administration on days 3-5. Animals were euthanized on day 5, 6 h after KA exposure in preventive model and 1 h after CF administration in reversal model to estimate markers of IEGs. RESULTS: KA upregulated the expression of c-Fos protein by 3.32-, 9.45-, 8.13-, and 8.66-fold in the hippocampal CA1, CA2, CA3, and DG regions, respectively. Also, KA elevated inducible nitric oxide synthase protein expression by 10.9-, 10.6-, 9.78-, and 9.51-fold. Besides, mRNA expression of brain-derived neurotrophic factors and heat shock protein was increased by 2.38- and 1.39-fold, respectively, after exposure to KA which were attenuated by CF. CONCLUSIONS: CF attenuated KA-induced IEGs and could be used as an adjunct in TLE.

Evaluation of the toxicity potential of acute and sub-acute exposure to the aqueous root extract of Aristolochia ringens Vahl. (Aristolochiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia ringens Vahl. (Aristolochiaceae) is used traditionally in Nigeria for managing a number of ailments including gastrointestinal disturbances, rheumatoid arthritis, pile, insomnia, oedema, and snake bite venom. Some studies in our laboratory have demonstrated a scientific justification for some of such uses. This study aims at investigating the toxicological actions of the aqueous root extract of Aristolochia ringens (AR). MATERIALS AND METHODS: Brine shrimp lethality assay was carried out using 10, 100 and 1000 µg/ml of the extract. Oral and intraperitoneal acute toxicity tests were carried out using mice. The effect of sub-acute (30 days) repeated oral exposure to the extract at 10, 50 and 250 mg/kg in rats was also evaluated via weekly assessments of body weights and general observations as well as end of exposure haematological, biochemical and histological examinations of blood and tissue samples of treated rats. Phytochemical analyses to determine the presence of aristolochic acid I in the extract was also carried out using high performance liquid chromatography (HPLC). RESULTS: The aqueous root extract of A. ringens showed potential for biological activity and cytotoxicity with an LC50 of 175 µg/ml in brine shrimps. AR was found to be relatively safe on acute oral exposure with LD50 estimated to be greater than 10 g/kg, while its LD50 on intraperitoneal administration was 407.38 mg/kg. Upon 30 days sub-chronic exposure, AR induced significant weight loss in female rats, enlargement of male rats' stomach, oxidative stress in male and female rats' kidney and liver tissues and disruption of leukocytes level in female rats. It also showed evidence of kidney and liver injuries inducible by oxidative damage and the potential to cause male sterility. HPLC revealed the presence of 0.003 mg/1 g of aristolochic acid in AR. CONCLUSION: These results show that AR contains detectible aristolochic acid I and has potential to induce toxic responses. Caution must therefore be exercised in its medicinal application especially when required for a prolonged use.

Ameliorative influence of Cnestis ferruginea vahl ex DC (Connaraceae) root extract on kainic acid-induced temporal lobe epilepsy in mice: Role of oxidative stress and neuroinflammation.

ETHNOPHARMACOLOGY RELEVANCE: the root decoction of Cnestis ferruginea Vahl ex DC (Connaraceae) is widely used in traditional African medicine for the treatment of various ailments including pain, inflammation and epilepsy. We have earlier reported anticonvulsant effect of Cnestis ferruginea root extract in mice. AIM OF THE STUDY: to evaluate the effect of ethanolic root extract of Cnestis ferruginea (CF) on kainic acid (KA)-induced temporal lobe epilepsy (TLE) in mice as well as the involvement of inflammatory mediators and oxidative stress. MATERIALS AND METHODS: mice were randomly divided into preventive treatment (vehicle (normal saline) or CF (400 mg/kg, p.o.) for 3 consecutive days before KA (5 mg/kg, i.p.) on days 4 and 5. In the reversal model, KA (5 mg/kg, i.p.) was administered on days 1 and 2 before vehicle or CF (400 mg/kg) administration on days 3-5. The effect of treatments on seizure severity was recorded using Racine scale. Animals were euthanized on day 5, 6 h after last KA exposure in preventive model and 1 h after CF administration in reversal model to estimate markers of oxidative stress and neuroinflammation. RESULTS: exposure of mice to KA induced TLE evidenced in increased severity of seizures which was significantly reduced by the pre- and post-treatment of mice with CF. Moreso, KA-induced malondialdehyde/nitrite generation and GSH deficit in the brain were attenuated by CF treatments. KA-induced up-regulation of inflammatory transcription factors; cyclooxygenase-2 (COX-2) and nuclear facor-kappaB (NF-κB) in the CA1, CA2, CA3 and dentate gyrus (DG) regions of the hippocampus regions were attenuated by CF treatments. CONCLUSION: findings from this study showed that Cnestis ferruginea root extract ameliorated KA-induced TLE through enhancement of antioxidant defense mechanism and attenuation of neuro-inflammatory transcription factors. Thus, could possibly be a potential phytotherapeutic agent in the management of temporal lobe epilepsy.