Neuromuscular effects and acute toxicity of an ethyl acetate extract of Spigelia anthelmia Linn

• Published in: Journal of ethnopharmacology 2004-06, Vol.92 (2), p.257-261
• Main Authors: Camurça-Vasconcelos, A.L.F., Nascimento, N.R.F., Sousa, C.M., Melo, L.M., Morais, S.M., Bevilaqua, C.M.L., Rocha, M.F.G.
• Format: Article
• Language: English
• Subjects: Acetates - chemistry; Administration, Oral; Animals; Anthelmintics - isolation & purification; Anthelmintics - toxicity; bioactive properties; Biological and medical sciences; Bufonidae; Chickens; General pharmacology; In Vitro Techniques; Injections, Intramuscular; Injections, Intraperitoneal; Lethal Dose 50; Loganiaceae - chemistry; Male; Medical sciences; medicinal plants; Mice; Muscle Contraction - drug effects; Muscle Spasticity - chemically induced; Muscle, Skeletal - drug effects; Neuromuscular; Paralysis - chemically induced; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Components, Aerial - chemistry; plant extracts; Plant Extracts - isolation & purification; Plant Extracts - toxicity; Sciatic; Solvents - chemistry; Spigelia anthelmia; Toxicity Tests, Acute
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2004.03.005

An ethyl acetate extract of Spigelia anthelmia (EASa), with validated anthelmintic activity, was evaluated for its acute toxicity and general effects in albino Swiss mice and for neuromuscular relaxant activity in the frog sciatic-gastrocnemius and rectus abdominis preparation. The extract induced a dose-related myotonia and muscular paralysis of rapid onset at higher doses. The calculated LD 50 after oral and intraperitoneal administration was 345.9 [241.4–484.7] mg/kg and 60.8 [47.4–80] mg/kg, respectively. In broilers, intramuscullar injection of EASa-induced spastic paralysis qualitatively similar to that obtained after succinylcholine administration and contrasting to the flaccid paralysis induced by d-tubocurarine. The contraction elicited by direct stimulation of the gastrocnemius was blocked by EASa by 54.3±4.7% (IC 50 = 21.4 [11.2–35.8] μg/ml) and the twitches evoked by stimulation of the sciatic nerve were blocked by 69.1±7.4% (IC 50 = 17.9 [4.5–34.23] μg/ml). EASa also blocked acetylcholine-induced contractions in the frog rectus abdominis by 58.6±7.4% (IC 50 = 7.4 [1.7–15.28] μg/ml) but did not decrease tonic contractions induced by a high-potassium Ringer solution. In summary, the ethyl acetate extract of Spigelia anthelmia induces tonic paralysis in vivo, and decreases amplitudes of twitches and increases tonus of skeletal muscle in vitro.