Anti-epileptic/pro-epileptic effects of sodium channel modulators from Buthus martensii Karsch.

The East Asian scorpion Buthus martensii Karsch (BmK) is one of the classical traditional Chinese medicines for treating epilepsy for over a thousand years. Neurotoxins purified from BmK venom are considered as the main active ingredients, acting on membrane ion channels. Voltage-gated sodium channels (VGSCs) play a crucial role in the occurrence of epilepsy, which make them become important drug targets for epilepsy. Long chain toxins of BmK, composed of 60-70 amino acid residues, could specifically recognize VGSCs. Among them, α-like neurotoxins, binding to the receptor site-3 of VGSC, induce epilepsy in rodents and can be used to establish seizure models. The ß or ß-like neurotoxins, binding to the receptor site-4 of VGSC, have significant anticonvulsant effects in epileptic models. This review aims to illuminate the anticonvulsant/convulsant effects of BmK polypeptides by acting on VGSCs, and provide potential frameworks for the anti-epileptic drug-design.

Antitussive, expectorant, and bronchodilating effects of quinazoline alkaloids (±)-vasicine, deoxyvasicine, and (±)-vasicinone from aerial parts of Peganum harmala L.

BACKGROUND: The aerial parts of Peganum harmala L. (APP) is a well-known and effective herbal medicine in China, and has been commonly used for treating various ailments, including cough and asthma. OBJECTIVES: To evaluate the antitussive, expectorant, and bronchodilating effects of the quinazoline alkaloids (±)-vasicine (VAS), deoxyvasicine (DVAS) (both isolated from the alkaloid fraction of APP) and (±)-vasicinone (VAO) (synthesized from VAS). METHODS: The three quinazoline alkaloids were tested as antitussive on cough models in mice and guinea pigs. VAO was synthesized from VAS via the oxidation of hydrogen peroxide. VAS, VAO, and DVAS were orally administered at dosages of 5, 15, and 45 mg/kg. Cough in these models was induced by ammonia, capsaicin, and citric acid. Phenol red secretion experiments in mice were performed to evaluate the expectorant activity of the alkaloids. Bronchodilating effects were evaluated by using a bronchoconstrictive induced by acetylcholine chloride and histamine in guinea pigs. RESULTS: In antitussive tests, VAS, VAO, and DVAS significantly inhibited coughing frequency and prolonged the cough latency period in animals. At the highest doses tested (45 mg/kg), they showed antitussive activities similar to codeine phosphate (30 mg/kg) in mice and guinea pigs. Expectorant evaluation showed that VAS, VAO, and DVAS could significantly increase phenol red secretion in mice by 0.54-, 0.79- and 0.97-fold, by 0.60-, 0.99-, and 1.06-fold, and by 0.46-, 0.73-, and 0.96-fold, respectively, at dosages of 5, 15, and 45 mg/kg compared with the control (0.5% CMC-Na, 20 ml/kg). Ammonium chloride at 1500 mg/kg increased phenol red secretion in mice by 0.97-fold compared with the control. Bronchodilation tests showed that VAS, VAO, and DVAS prolonged the pre-convulsive time for 28.59%, 57.21%, and 29.66%, respectively, at a dose of 45 mg/kg in guinea pigs, whereas aminophylline prolonged the pre-convulsive time by 46.98% compared with pretreatment. CONCLUSIONS: Quinazoline alkaloids VAS, VAO, and DVAS have significant antitussive, expectorant, and bronchodilating activities. VAS, VAO, and DVAS are the active ingredients in APP, which can be used to treat respiratory disease.