INHIBITORY EFFECT OF ZIZYPHUS SPINA-CHRISTI LEAF EXTRACT ON RAT ISOLATED UTERUS

The Zizyphus spina-christi from Rhamnaceae grows in south of Iran and its leaf powder is used for hair washing. Its antifungal, antimicrobial activities have been also reported. The sweet fruit of that is eaten fresh or dried. We have previously demonstrated that, the Zizyphus spina-christi hydroalcoholic leaf extract reduces the ileum and stomach muscles tone in rats. The aim of present study was to investigate the effect of Zizyphus spina christi leaf hydroalcoholic extract on isolated rat uterus. To achieve this aim, uterine horns of adult virgin rats were placed in an organ bath containing 10 ml either standard Tyrode’s or De Jalon's solution (30 ° C) with 0.5 g initial tension, which bubbled with pure O2. The uterine contractility was recorded by an isometric transducer in presence of either KCl (40 mM), oxytocin (100 μU/ml) or performance of electrical stimulation (30 Hz, 20 V, 1ms for 10 seconds). Rats for oxytocin experiments were treated with single estrogen (Premarin) injection (1mg/Kg, s.c.) 24 hr prior the experiments. Contraction forces were calculated as gram for 100 mg of uterine weight. Extract was prepared using percolation method with 70% alcohol for 72 hr. After equilibrium period (45-60 min), the tissue was exposed to three above uterus stimulants in presence and absence of extract with final concentrations in the organ bath: 0.125, 0.25, 0.5, 1, 2, 4 and 8 mg/ml for 1 to 3 min. The results indicated that, the extract significantly reduced uterine contractions induced by KCl, electrical stimulation and oxytocin (P < 0.001) in a dose-dependent manner. In conclusion, it is postulated that the extract may contain voltage dependent calcium channel blocker. However, further work is required to determine the mechanisms of action.