Informatics Publishing Limited

C. N. Uchendu , I. O. Nwankwo

Abstract

Objective: To investigate the role of calcium [Ca²⁺] on uterine muscle contraction induced by butanolic leaf extract of Spondias mombin (Anacardiaceae). Materials and methods: Dried leaves of S.mombin were exhausively extracted with n-hexane and 80% ethanol. The 80% ethanol extract was partitioned in dichloromethane, ethyl acetate, butanol, and water. The butanolic extract was tested for spasmogenicity on isolated uterine muscle strips of the rat using conventional methods. Results: The extract contracted the uterine muscle concentration-dependently (EC₅₀, 0.08 mg/ml). The responses to the extract (0.14 mg/ ml) were abolished in Ca²⁺-free media with or without EGTA and by verapamil (0.18 μg/ml). The contractions were similarly abolished by LaCl₃ but significantly (P<0.05) attenuated by amiloride ( 72 μmol). The extract altered the pattern of contraction induced by high K⁺ depolarization (20 mmol) from fast phasic to a tonic contracture. Both isoprenaline (0.1 μmol) and salbutamol (0.1 μmol) inhibited the extract induced contractions which were reversed by propranolol (0.03 μmol). Conclusion: Butanolic leaf extract of S. mombin contracts uterine muscle of the rat primarily through voltage-dependent extracellular Ca²⁺ entry channel.

Keywords

Calcium, Contraction, Extract, Spondias mombin, Uterus

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C. N. Uchendu

Abstract

Objective: To evaluate the biological activity of aqueous ischolar_main extract of Dalbergia saxatilis on isolated uterine muscle strips of the rat. Materials and methods: The plant material was subjected to cold extraction, initially in petroleum ether (60°-80°C) and subsequently in water. The dried aqueous extract was redissolved in water and tested on isolated uterine muscle strips of the rat mounted in a thermostatically controlled organ bath (37°C) containing physiological solution. Results : The extract (0.58-2.32 mg/ml) had no effect on spontaneous or carbachol (1.97 μmol) induced myometrial contractions but potentiated contractions initiated by phenylephrine (3.5 μmol). Salbutamol (0.15 μmol) abolished both spontaneous contractions and uterine motility stimulated by carbachol (1.97 μmol). These inhibitory effects of salbutamol on contractility were reversed by the extract (1.16 mg/ml). Conclusion : The aqueous ischolar_main extract of D. saxatilis contains biologically active principle that acted as a competitive inhibitor of the β₂ - selective adrenoreceptor agonist and enhanced α-adrenoreceptor function.

Keywords

Dalbergia saxatilis, Uterine Muscle, Contractility, Adrenoreceptor

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