Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Vol. 15, No. 12, 2016, pp. 2557-2562
Bioline Code: pr16336
Full paper language: English
Document type: Research Article
Document available free of charge
Tropical Journal of Pharmaceutical Research, Vol. 15, No. 12, 2016, pp. 2557-2562
© Copyright 2016 - Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria.
In vitro inhibitory effect of methanol leaf extract of Stachytarpheta jamaicensis (Verbenaceae) on non-pregnant rat uterus|
Amaechina, Fabian C & Bafor, Enitome E
Purpose: To investigate the effect of the methanol extract of the plant, Stachytarpheta jamaicensis
(Verbenaceae) (SJ) on uterine smooth muscles of non-pregnant female rats, with the aim of examining
the oxytocic or otherwise effect of the extract.
Methods: In the first phase of experiments, the effects of SJ (0.41 and 4.01 mg/ml) on oxytocin (OT)
induced uterine contractions were determined and repeated after addition of salbutamol (SBL) (41.7
nM). In the second phase, verapamil (VER) (2.03 μM), SBL (41.7 nM), and SJ (0.41 and 4.01 mg/ml)
were applied to the tissues after pre-contraction with K+ (80 mM). In the third phase, the effects of VER,
SBL, and SJ on CaCl2-induced contractions (0.03 – 10.83 mM) were examined. In the fourth and final
phases, the second phase experiments were repeated in a calcium-free medium and in the absence
and presence of propranolol (1.54 mM) respectively.
Results: SJ exhibited significant inhibitory effects on OT and CaCl2 induced uterine contractions (p <
0.05). The EC50 for OT increased from 1.92 ± 0.12 to 7.16 ± 0.16 nM and that for CaCl2 increased from
0.19 ± 0.09 to 0.76 ± 0.11 mM in the presence of the extract. SJ also significantly inhibited KCl- induced
contraction by 39.15 ± 2.13 and 53.23 ± 1.58 % for 0.41 and 4.01 mg/ml of the extract, respectively (p <
0.01); this inhibition was unaffected by propranolol. On the other hand, SBL and VER showed inhibition
of 77.25 ± 1.85 and 79.44 ± 2.27 %, respectively.
Conclusion: SJ exerts uterine inhibitory effects in rats which appear unrelated to β2-adrenergic
receptor stimulation but possibly through inhibition of calcium entry into the cytoplasm.
Oxytocin; Calcium-free; Uterine contraction; β2-Adrenergic receptor stimulation; verapamil; salbutamol; Propranolol; S. jamaicensis
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