Uterotonic effect of methanol extract and fractions of <i>Psidium guajava L.</i> (Myrtaceae) stem bark on female white albino rats

Abstract

Background and aim: Psidium guajava L. (Myrtaceae), commonly known as the guava tree, has many medicinal  properties which include anti-microbial, and inflammatory and healing properties, in addition to  its folkloric usage in  facilitating childbirth.

Methods: This study evaluated the effect of methanol (MeOH) crude extract, aqueous (AQ) and  dichloromethane (DCM)  fractions of P. guajava stem bark on isolated uterus of non-pregnant estrogenized  female rats at varying doses  to determine on uterine contractility in the spontaneous, oxytocin-induced and  high KCL-induced contractions models, and also in calcium-free physiological salt solution.

Results: Concentration-dependent increases in amplitude and frequency of contractions were observed for  extract and  AQ fraction in the spontaneous contraction experiment. For the oxytocin pre-contracted uterus, only the fractions gave  concentration-dependent decreases in contraction. Moreover, only extract and AQ  fraction potentiated KCL-induced  contraction at 10 mg/mL. In addition, all three samples at 10 mg/mL,  increased amplitude of uterine contraction in  calcium-free PSS by 15.25-15.41%. 

Conclusion: Although not as active as oxytocin, crude MeOH extract of P. guajava was  more potent than the two fractions in eliciting oxytocic effects on isolated rat uterus by a different mechanism, thereby Justifying the folkloric usage of P. guajava stem bark in inducing labour.