Mawoza Tariro, Tagwireyi Dexter, Nhachi Charles
Department of Clinical Pharmacology, University of Zimbabwe College of Health Sciences, P.O. Box A178, Avondale, Harare, Zimbabwe.
Department of Clinical Pharmacology, University of Zimbabwe College of Health Sciences, P.O. Box A178, Avondale, Harare, Zimbabwe.
J Ethnopharmacol. 2015 Apr 22;164:129-35. doi: 10.1016/j.jep.2015.02.006. Epub 2015 Feb 9.
Sclerocarya birrea (Anacardiaceae), popularly known as "marula", is used as a traditional remedy for allegedly treating dysmenorrhoea and a host of other ailments such as malaria, fever, diarrhoea, dysentery, stomach disorders, headaches and to facilitate childbirth. This study investigated the pharmacological effects of S. birrea extract (SBE) on isolated, spontaneously-contracting uterine horns of healthy, young adult, female Wistar rats.
One kilogramme of S. birrea fresh stem bark was identified and authenticated. The bark was air-dried at room temperature (26 ± 1°C) for two weeks. The dried stem bark was milled and macerated in 2.5l of distilled water for 48 h and filtered. A rotary evaporator was used to concentrate the aqueous extract by drying it at 60 ± 1°C. Freeze-drying gave 61.3g/kg (i.e., 6.13% yield) of a dark-brown, powdery, crude extract. Rat isolated uterine horns were mounted in 25-ml Iworx tissue organ-baths containing De Jalon׳s physiological solution, and exposed to graded concentrations of SBE (25, 50, 100, 200, 300, 400mg/ml/kg). The effects of SBE and atropine, oxytocin, verapamil, indomethacin, acetylcholine, serotonin, cimetidine and histamine on the isolated uterine muscles, were recorded using LabScribe2 software.
The aqueous stem bark extract of S. birrea produced significant (p<0.05) concentration-dependent contractions of the uterine horn muscle preparation reaching a maximum at the 300 mg/ml dose. SBE mimicked and potentiated uterine muscle contractile effects of oxytocin (0.5-5 µU/ml) and acetylcholine (0.1-3 µg/ml). Pre-incubation of tissues with atropine (1-3 µg/ml), non-significantly (p>0.05) inhibited SBE-induced contractions on uterine muscles. Verapamil (2 µg/ml), indomethacin and -p-tosyl-l-phenylalanine-chloromethyl-ketone (TPCK) inhibited the contractile effects of SBE (25-400mg/ml/kg), suggesting possible calcium-mediated mechanism of action for SBE and possible COX-enzyme inhibition. Pre-incubating tissues with histamine (10(-8)-10(-5)M) resulted in relaxation of the uterus, while cimetidine potentiated the contractile effects of SBE. Serotonin potentiated the contractile effects of SBE.
These results indicate that SBE causes contraction on uterine smooth muscles possibly through its effects on oxytocin, acetylcholine and serotonin receptors. As a result SBE should not be used by patients suffering from dysmenorrhoea as it can worsen it or pregnant patients as it can result in miscarriage/abortion.
刺桫椤（漆树科），俗称“马鲁拉树”，被用作一种传统药物，据称可治疗痛经以及许多其他疾病，如疟疾、发烧、腹泻、痢疾、胃部疾病、头痛，并有助于分娩。本研究调查了刺桫椤提取物（SBE）对健康、年轻成年雌性Wistar大鼠离体自发收缩子宫角的药理作用。
鉴定并验证了1千克刺桫椤新鲜茎皮。将树皮在室温（26±1°C）下风干两周。将干燥的茎皮研磨并在2.5升蒸馏水中浸泡48小时，然后过滤。使用旋转蒸发仪在60±1°C下干燥浓缩水提取物。冷冻干燥得到61.3克/千克（即产率6.13%）深褐色粉末状粗提取物。将大鼠离体子宫角安装在含有德贾隆氏生理溶液的25毫升Iworx组织器官浴槽中，并暴露于不同浓度的SBE（25、50、100、200、300、400毫克/毫升/千克）。使用LabScribe2软件记录SBE以及阿托品、催产素、维拉帕米、吲哚美辛、乙酰胆碱、5-羟色胺、西咪替丁和组胺对离体子宫肌肉的影响。
刺桫椤茎皮水提取物对子宫角肌肉制剂产生显著（p<0.05）的浓度依赖性收缩，在300毫克/毫升剂量时达到最大值。SBE模拟并增强了催产素（0.5 - 5微单位/毫升）和乙酰胆碱（0.1 - 3微克/毫升）对子宫肌肉的收缩作用。用阿托品（1 - 3微克/毫升）对组织进行预孵育，对SBE诱导的子宫肌肉收缩无显著（p>0.05）抑制作用。维拉帕米（2微克/毫升）、吲哚美辛和对甲苯磺酰-L-苯丙氨酸氯甲基酮（TPCK）抑制了SBE（25 - 400毫克/毫升/千克）的收缩作用，提示SBE可能通过钙介导的作用机制，且可能存在COX酶抑制作用。用组胺（10⁻⁸ - 10⁻⁵摩尔）对组织进行预孵育导致子宫松弛，而西咪替丁增强了SBE的收缩作用。5-羟色胺增强了SBE的收缩作用。
这些结果表明，SBE可能通过对催产素、乙酰胆碱和5-羟色胺受体的作用导致子宫平滑肌收缩。因此，痛经患者不应使用SBE，因为它可能会加重痛经，孕妇也不应使用，因为它可能导致流产。
