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Abstract
In this study, we report for the first time the effects of Acanthus montanus (Acanthaceae) aqueous extract, its fractions and Acanthus sulphate ester (ASE) – a newly isolated sulphate ester, on rat uterus. This in vitro research involved an organ bath containing an isolated unpregnant rat uterus suspended in De Jalons physiological solution and aerated with Carbogen (95%O2 +5% CO2). Following equilibration, the extract, fraction and ASE were individually added to the tissue in the absence and presence of standard antagonists and compared with standard uterine agonists. The responses were recorded on a 2-channel Ugo Basile recorder.
The extract had a biphasic action with an initial relaxation (IC50 =3.00 mM) of spontaneous uterine contractions followed by stimulation (IC50 =0.63 mM) of the same tissue. Its fraction showed both relaxation and contraction depending on the polarity of extraction solvent. 100% methanolic fraction (IC50 = 150.0 µM) and ASE (131.0 µM) contracted the uterus. The IC50s of the other fractions were variable. These stimulatory activities were less than those of PGF2α, acetylcholine, diazoxide, oxytocine and histamine.
The extract, methanolic fraction and ASE were inhibited by phentolamine, prazosin, pyrilamine, indomethacine, verapamil but not atropine. The extract was unaffected by propranolol while tetraethylammonium had slight stimulation. Quinacrine did not affect the extract and MeOH fraction activities. Verapamil was the most potent inhibitor. The involvement of both extracellular and intracellular ionic channels of calcium and potassium were observed; they are probably involved in the mechanism of action of ASE.
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References
- Adeyemi OO, Okpo SO, Young-Nwafor CC. The relaxant activity of the methanolic extract of Acanthus montanus on intestinal smooth muscles. J. Ethnopharmacol. 68(1-3), 169-173, 1999.
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- Anwer K, Oberti C, Perez GJ, Perez-Reyes N, McDougall JK, Monga M, Sanborn BM, Stefani E, Toro L. Calcium-activated K+ channels as modulators of human myometrial contractile activity. J. Physiol. 265(4 Pt 1): C976-85, 1993.
- Asongalem EA, Foyet, HS, Ekobo, S, Dimo T, Kamtchouing P. Antiinflammatory, lack of central analgesia and antipyretic properties of Acanthus montanus. J. Ethnopharmacol. 95(1), 63-68, 2004.
- Asongalem EA, Foyet HS, Folefoc GN, Eyong KO, Kamtchouing P. Spasmolytic properties of Acanthus montanus on rat uterus: The role of its extracts, fractions and an isolated component. J. Pharm. Pharamcol. (In Press).
- Avdonin, V, Shibata, EF, Hoshi T. Dihydropyridine Action on Voltage -dependent Potassium Channels Expressed in Xenopus Oocytes. J. Gen. Physiol. 109(2): 169 – 180, 1997.
- Burkill HM. Acanthus montanus. In: Useful Plants of West Tropical Africa. 2nd Ed. Royal Botanic Garden, Vol. 1, pp 458 – 459, 1985.
- Igoli JO, Ogaji GO, Tor-Anyim TA, Igoli NP. Traditional medicine practice amongst the Igede people of Nigeria part II. Afr. J. Trad. CAM 2(2): 134 – 152, 2005.
- Mohamed IM, Ojewole JAO. Cardiovascular effects of Harpagophytum procumbens DC [Pedaliaceae] secondary root aqueous extract in some mammalian experimental animal models. Afr. J. Trad. CAM 1(1): 30- 44, 2004
- Jacobs ER, DeCoursey TE. Mechanisms of potassium channel block in rat alveolar epithelial cells. Am. Soc. Pharmacol. Exp. Therapeut. 55(2): 459-472, 1990.
- Kutluay E., Roux B., Heginbotham L. Rapid intracellular TEA block of the KcsA potassium channel. Biophy. J. 88: 1018-1029, 2005.
- Mironneau J. Ion channels and the control if uterine contractility. In: Control of Uterine Contractility, CRC Press, Boea Raton, FL, USA, pp. 1 – 22, 1994.
- Noumi E, Fozi FL. Ethnomedical Botany of epilepsy treatment in Fongo-Tongo village, Western Province, Cameroon. Pharm. Biol. 41(5): 330-339, 2003.
- Perez GJ, Toro L, Erulkar SD, Stefani E. Characterization of large-conductance, calcium-activated potassium channels from human myometrium. Am. J. Obstet. Gynecol. 168: 652-660, 1993
- Shi M, Chang L, He G. Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus [Article in Chinese]. Zhongguo Zhong Yao Za Zhi. 20(3): 173-175 and 192, 1995
- Taggart MJ, Burdyga TH. Heaton RC, Wray S. Stimulus-dependent modulation of smooth muscle intracellular calcium and force by intracellular pH. Pflūgers Archiv 432: 803 – 811, 1996.
- Tanaka Y, Horinouchi T, Koike K. New insights into β-adrenoceptors in smooth muscle: distribution of receptor subtypes and molecular mechanisms triggering muscle relaxation. Clin. Exp.Pharmacol. Physiol. 32(7), 503, 2005
- Vanheel B, Calders P, Van den Bossche I, Van de Voorde J. Influence of some phospholipase A2 and cytochrome P450 inhibitors on rat arterial smooth muscle K+ currents. Can J Physiol Pharmacol. 77(7):481-9, 1999.Wray S, Kupittayanant S, Shmigol T. Role of the sarcoplasmic reticulum in uterine smooth muscle. Novartis Found Symp. 246: 6-25, 48-51, 2002.
References
Adeyemi OO, Okpo SO, Young-Nwafor CC. The relaxant activity of the methanolic extract of Acanthus montanus on intestinal smooth muscles. J. Ethnopharmacol. 68(1-3), 169-173, 1999.
Adjanohoun, JE, Aboubakar, N, Dramane, K, Ebot, ME, Ekpere, JA et al. OAU/STRC Traditional Medicine and Pharmacopoeia: Contribution to Ethnobotanical and Floristic Studies in Cameroon, CNPMS, Porto Novo, Benin, 1996
Anwer K, Oberti C, Perez GJ, Perez-Reyes N, McDougall JK, Monga M, Sanborn BM, Stefani E, Toro L. Calcium-activated K+ channels as modulators of human myometrial contractile activity. J. Physiol. 265(4 Pt 1): C976-85, 1993.
Asongalem EA, Foyet, HS, Ekobo, S, Dimo T, Kamtchouing P. Antiinflammatory, lack of central analgesia and antipyretic properties of Acanthus montanus. J. Ethnopharmacol. 95(1), 63-68, 2004.
Asongalem EA, Foyet HS, Folefoc GN, Eyong KO, Kamtchouing P. Spasmolytic properties of Acanthus montanus on rat uterus: The role of its extracts, fractions and an isolated component. J. Pharm. Pharamcol. (In Press).
Avdonin, V, Shibata, EF, Hoshi T. Dihydropyridine Action on Voltage -dependent Potassium Channels Expressed in Xenopus Oocytes. J. Gen. Physiol. 109(2): 169 – 180, 1997.
Burkill HM. Acanthus montanus. In: Useful Plants of West Tropical Africa. 2nd Ed. Royal Botanic Garden, Vol. 1, pp 458 – 459, 1985.
Igoli JO, Ogaji GO, Tor-Anyim TA, Igoli NP. Traditional medicine practice amongst the Igede people of Nigeria part II. Afr. J. Trad. CAM 2(2): 134 – 152, 2005.
Mohamed IM, Ojewole JAO. Cardiovascular effects of Harpagophytum procumbens DC [Pedaliaceae] secondary root aqueous extract in some mammalian experimental animal models. Afr. J. Trad. CAM 1(1): 30- 44, 2004
Jacobs ER, DeCoursey TE. Mechanisms of potassium channel block in rat alveolar epithelial cells. Am. Soc. Pharmacol. Exp. Therapeut. 55(2): 459-472, 1990.
Kutluay E., Roux B., Heginbotham L. Rapid intracellular TEA block of the KcsA potassium channel. Biophy. J. 88: 1018-1029, 2005.
Mironneau J. Ion channels and the control if uterine contractility. In: Control of Uterine Contractility, CRC Press, Boea Raton, FL, USA, pp. 1 – 22, 1994.
Noumi E, Fozi FL. Ethnomedical Botany of epilepsy treatment in Fongo-Tongo village, Western Province, Cameroon. Pharm. Biol. 41(5): 330-339, 2003.
Perez GJ, Toro L, Erulkar SD, Stefani E. Characterization of large-conductance, calcium-activated potassium channels from human myometrium. Am. J. Obstet. Gynecol. 168: 652-660, 1993
Shi M, Chang L, He G. Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus [Article in Chinese]. Zhongguo Zhong Yao Za Zhi. 20(3): 173-175 and 192, 1995
Taggart MJ, Burdyga TH. Heaton RC, Wray S. Stimulus-dependent modulation of smooth muscle intracellular calcium and force by intracellular pH. Pflūgers Archiv 432: 803 – 811, 1996.
Tanaka Y, Horinouchi T, Koike K. New insights into β-adrenoceptors in smooth muscle: distribution of receptor subtypes and molecular mechanisms triggering muscle relaxation. Clin. Exp.Pharmacol. Physiol. 32(7), 503, 2005
Vanheel B, Calders P, Van den Bossche I, Van de Voorde J. Influence of some phospholipase A2 and cytochrome P450 inhibitors on rat arterial smooth muscle K+ currents. Can J Physiol Pharmacol. 77(7):481-9, 1999.Wray S, Kupittayanant S, Shmigol T. Role of the sarcoplasmic reticulum in uterine smooth muscle. Novartis Found Symp. 246: 6-25, 48-51, 2002.