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Possible Biochemical Mechanism of Action of Petroleum‐Ether Extract of Calotropis procera leaves (Asclepiadaceae) in Gravid Pregnant Sprague Dawley Rats
Author(s) -
James Ayorinde Babatunde,
Magbagbeola Olubunmi Adeola,
Saibu Gbemisola Morounke,
Oloyo Ahmed
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.879.4
Subject(s) - calotropis procera , petroleum ether , endocrinology , protein kinase a , chemistry , medicine , muscarinic acetylcholine receptor , receptor , atropine , adrenergic receptor , mechanism of action , uterus , pharmacology , kinase , traditional medicine , biochemistry , chromatography , in vitro , extraction (chemistry)
Calotropis procera (Asclepiadaceae) is one of the traditionally used antifertility plants in Nigeria. Previous studies have shown that this antifertility plant has abortifacient property but none of them has reported its possible biochemical mechanism of action. Organ bath experiments using cumulative doses of the extract on rat uterine rings in Dejalon's solution aerated with 95% O 2 + 5% CO 2 produced a non significant ( P>0.05 ) increase in tension (% response). An EC 50 value of 0.1059 mg/ml was obtained and the intrinsic activity was found to be above 1 in comparison with oxytocin. Blocking muscarinic receptors with 35µg/ml atropine caused the dose‐response curve to shift to the right with a non‐significant ( P>0.05 ) decrease in maximal tension (% Response). However, the ? 2 ‐adrenergic blocker (1µM propanolol) caused a significant ( P<0.05 ) shift in the dose‐response curve. The extract also exhibited its effect on cAMP modulation of β 2 ‐adrenergic receptors by causing a significant ( P<0.05 ) decrease in cAMP level after treatment of cultured uterine cells with the extract. In conclusion, this study suggests that pet‐ether extract of Calotropis procera (Asclepiadaceae) exerts its abortifacient effect by inducing myometrial contractions of the uterus by binding to β2‐adrenergic receptors thereby causing a decrease in the level of cAMP. cAMP reduction may reduce the activation of protein kinase A (PKA) preventing PKA from inactivating myosin light chain kinase (MLCK).