Oliveira Rita de Cassia Meneses, Lima Julianeli T, Ribeiro Luciano A A, Silva Joelmir L V, Monteiro Fabio S, Assis Temilce S, Agra Maria de F, Silva Tania M S, Almeida Fernanda R C, Silva Bagnólia A
Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraíba, P.O. Box 5009, 58051-970 João Pessoa, Paraíba, Brazil.
Z Naturforsch C J Biosci. 2006 Nov-Dec;61(11-12):799-805. doi: 10.1515/znc-2006-11-1205.
Solanum asterophorum Mart. (Solanaceae) is a shrub popularly known as "jurubeba-defogo" in the northeast of Brazil. In the present work, the methanol extract (SA-MeOH, 3750 microg/mL) and isojuripidine (10(-7) - 3 x 10(-4) M), a steroidal alkaloid obtained from S. asterophorum Mart. leaves, inhibited phasic contractions induced by both 1 microM histamine [IC50 = (225.8 +/- 47.4), g/mL and (3.5 +/- 0.8) x 10(-5) M] or 1 microm acetylcholine [IC50 = (112.5 +/- 20.6) microg/mL and (2.3 +/- 0.4) x 10(-5) M] in guinea-pig ileum, respectively. The extract and isojuripidine also relaxed the ileum (SA-MeOH, 1-750 microg/mL, and isojuripidine, 10(-9) - 3 x 10(-4) M) pre-contracted with 1 M histamine [EC50 = (101.1 +/- 17.4) microg/mL and (1.2 +/- 0.3) x 10(-6) M] or 1 microM acetylcholine [EC50 = (136.8 +/- 21.1) microg/mL and (1.9 +/- 0.4) x 10(-6) M] or 40 mm KCl [EC50 = (149.4 +/- 19.5) microg/mL and (1.8 +/- 0.7) x 10(-6) M], respectively, in an equipotent and concentration-dependent manner. This effect is probably due to inhibition of calcium influx through voltage-operated calcium (Ca(v)) channels. To confirm this hypothesis, we evaluated their effect on cumulative CaCl2 curves in depolarizing medium nominally without Ca2+. SA-MeOH (27, 243, 500, and 750 microg/mL) and isojuripidine (3 x 10(-8), 10(-6), 3 x 10(-5), and 3 x 10(-4) M) inhibited the contractions induced by CaCl2, in a concentration-dependent manner. The concentration-response curves to CaCl2, in the presence of SA-MeOH and isojuripidine, were shifted downward in relation to a control curve in a non-parallel manner resulting in reduction of the maximum effect [E(max) = (71.2 +/- 9.2); (57.4 +/- 9.2); (43.8 +/- 3.4); (41.5 +/- 2.4) and (90.6 +/- 4.8); (74.7 +/- 8.7); (66.4 +/- 3.9); (31.3 +/- 4.1)%, respectively]. SA-MeOH and isojuripidine present spasmolytic action in guinea-pig ileum due to a partially blockade of calcium influx through Ca(v) channels.
星状茄（茄科）是一种灌木，在巴西东北部俗称“jurubeba - defogo”。在本研究中，甲醇提取物（SA - MeOH，3750微克/毫升）和异juripidine（10⁻⁷ - 3×10⁻⁴ M），一种从星状茄叶子中获得的甾体生物碱，分别抑制了豚鼠回肠中由1微摩尔组胺[IC50 =（225.8±47.4）微克/毫升和（3.5±0.8）×10⁻⁵ M]或1微摩尔乙酰胆碱[IC50 =（112.5±20.6）微克/毫升和（2.3±0.4）×10⁻⁵ M]诱导的相性收缩。该提取物和异juripidine还使预先用1 M组胺[EC50 =（101.1±17.4）微克/毫升和（1.2±0.3）×10⁻⁶ M]或1微摩尔乙酰胆碱[EC50 =（136.8±21.1）微克/毫升和（1.9±0.4）×10⁻⁶ M]或40 mM KCl[EC50 =（149.4±19.5）微克/毫升和（1.8±0.7）×10⁻⁶ M]预收缩的回肠松弛，且呈等效和浓度依赖性方式。这种作用可能是由于抑制了通过电压门控钙（Ca(v)）通道的钙内流。为了证实这一假设，我们评估了它们对名义上无Ca²⁺的去极化介质中累积CaCl₂曲线的影响。SA - MeOH（27、243、500和750微克/毫升）和异juripidine（3×10⁻⁸、10⁻⁶、3×10⁻⁵和3×10⁻⁴ M）以浓度依赖性方式抑制了CaCl₂诱导的收缩。在存在SA - MeOH和异juripidine的情况下，CaCl₂的浓度 - 反应曲线相对于对照曲线向下非平行移动，导致最大效应降低[E(max) =（71.2±9.2）；（57.4±9.2）；（43.8±3.4）；（41.5±2.4）和（90.6±4.8）；（74.7±8.7）；（66.4±3.9）；（31.3±4.1）%，分别]。SA - MeOH和异juripidine在豚鼠回肠中呈现解痉作用，这是由于部分阻断了通过Ca(v)通道的钙内流。
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