Effects of a Methanol Fraction of the Leaves of Leonotis leonurus on the Blood Pressure and Heart Rate of Normotensive Male Wistar Rats
Leonotisleonurus a shrub indigenous to Southern
Africa is widely used in traditional medicine to treat a variety of
conditions ranging from skin diseases and cough to epileptic fits and
‘heart problems’. Studies on the aqueous extract of the leaves have
indicated cycloxegenase enzyme inhibitory activity and an
antihypertensive effect.
Five methanol leaf extract fractions (MLEa - MLEe) of L.
leonurus were tested on anaesthetized normotensive male Wistar rats
(AWR) and isolated perfused working rat hearts (IWH). Fraction
MLEc (0.01mg/kg – 0.05mg/kg) induced significant increases in BP
and HR in AWR and positive chronotropic and inotropic effects in
IWH (1.0mg/ml – 5.0mg/ml). Pre-administration of atenolol
(2.0mg/kg) and prazosin (60μg/kg) significantly inhibited MLEc
effect on HR and MAP respectively in vivo, while atenolol
(7.0mg/ml) pre-perfusion significantly inhibited MLEc effect in vitro.
The hypertensive effect of MLEc is probably via β1agonism.
Results also indicate the presence of multiple cardioactive
compounds in L. leonurus.
<p>[1] J. Mander, N.W. Quinn, M. Mander, Trade in wildlife medicinals in
South Africa. Investigational Report No. 157. Pietermaritzburg: Institute
of Natural Resources,1997, pp. 1-3.
[2] B. Van Wyk, B. Van Oudtshoorn, N. Gericke, Medicinal plants of South
Africa. Cape Town: Briza Publications, 2000, p. 166.
[3] J.M. Watt, M.G. Breyer-Brandwijk, Medicinal and poisonous plants of
Southern Africa. Edinburgh: E & S Livingstone, 1962, p. 1457.
[4] E. Bienvenu, G.J. Amabeoku, P.K. Eagles, G. Scott, E.P. Springfield,
“Anticonvulsant activity of aqueous extract of
Leonotisleonurus”Phytomedicine, vol. 9, 2002, pp. 217-223.
[5] A. K. Jager, A. Hutchings, J. Van Staden, “Screening of Zulu medicinal
plants for Prostaglandin - synthesis inhibitors” Journal of
Ethnopharmacology, vol. 52(2), 1996, pp. 95-100.
[6] J. A. O. Ojewole, “Hypotensive effect of Leonotis leonurus aqueous
leaf extract in rats” American Journal of Hypertension, vol. 16(5)
Supplement 1, 2003, p. A40.
[7] P. Mugabo, A. Njagi, D.L. Dietrich, J. Syce, „Cardiovascular effects of
Leonotisleonurus in the normotensive rat” Revista de fitoterapia, vol.
2(1), 2002, p. 163.
[8] F. Khan, P. Mugabo, A.P. Burger, D.L.L. Dietrich, “Effects of
Leonotisleonurus aqueous exract on the isolated perfused rat heart”
ActaPharmacologicaSinica, Supplement 1, 2006, p. 349.
[9] K. C. Obikeze, J. M. McKenzie, I. R. Green, P. Mugabo,
“Characterization and Cardiovascular Effects of (13S)-9_,13_-
epoxylabda-6_(19),15(14)diolDilactone, a diterpenoid Isolated from
Leonotis leonurus” South African journal of chemistry, vol. 61, 2008,
pp. 119–122.
[10] D.E.A. Rivett, “Lingering amongst the Labiatae” South African journal
of chemistry, 1984, pp. 368-371.
[11] J. A. Duke, Handbook of medicinal herbs. Boca Raton: CRC Press,
2001, p. 276.
[12] V.U. Livius, J. Kilo, T. Luscher, M. Gassmann, Circulation. The
handbook of experimental animals. The laboratory rat. New York:
Georg J Krinke, 2000, p. 1541.
[13] F. Sutherland, J. Hearse, “Experimental models for the study of
cardiovascular function and disease” Pharmacological Research, vol.
41(6), 2000, pp. 597-603.
[14] F. Sutherland, J. Hearse, “The isolated blood and perfusion fluid
perfused heart” Pharmacological Research, vol. 41(6), 2000, pp. 613-
647.
[15] C. Depre, “Isolated working heart: Description of models relevant to
radioisotopic and pharmacological assessments” Nuclear medicine &
Biology, vol. 25, 1998, pp. 711-713.
[16] P. Mugabo, K.C. Obikeze, A. Njagi, A.P. Burger, I. Green, D.D.
Dietrich, “Cardiovascular effects of the alkaloid hippadine on the
isolated perfused rat heart” International journal of medicinal and
aromatic plants, vol. 2(1), 2012, pp. 172-177.
[17] H.B. Chen, M.W. Islam, R. Radhakrishnan, S.A. Wahab, M.A. Naji,
“Influence of aqueous extract from Neuradaprocumbens L. on blood
pressure of rats” Journal of Ethnopharmacology, vol. 90 (2-3), 2004, pp.
191-194.
[18] E.L. McCawley, “Cardioactive alkaloids” in The alkaloids, Chemistry
and physiology, R. Manske, Ed. New York: Academic press, 1995, pp.
79-104.
[19] D.S. Bhakuni, “Chemical and pharmacological investigation of plants
with a biological action on the cardiovascular system”, in Advances in
medicinal phytochemistry, D. Barton, D.W. Ollis, Eds. London: John
Libbery, 1986, pp. 25-35.
[20] J.C. Liu, F.L. Hsu, J.C. Tsai, P. Chan, J.Y.H. Liu, G.N. Thomas, B.
Tomlinson, M.Y. Lo, J.Y. Lin, “Antihypertensive effects of tannins
isolated from traditional Chinese herbs as non-specific inhibitors of
angiotensin converting enzyme” Life Science, vol. 73(12), 2003, pp.
1543-1555.
[21] B. B. Hoffman, “Adrenoceptor-Activating & other sympathomimetic
drugs”, in Basic & Clinical pharmacology, 7th ed. B.G. Katzung, Ed.
Connecticut: Apnge, 1998, pp. 118-151.
[22] Fujitaa, D.L. Roerig, Z. J. Bosnjak, D. F. Stowe, “Effects of vasodilators
and perfusion pressure on coronary flow and simultaneous release of
nitric oxide from guinea pig isolated hearts” Cardiovascular
Research, vol. 38(3), 1998, pp. 655-667.</p>
<p>[1] J. Mander, N.W. Quinn, M. Mander, Trade in wildlife medicinals in
South Africa. Investigational Report No. 157. Pietermaritzburg: Institute
of Natural Resources,1997, pp. 1-3.
[2] B. Van Wyk, B. Van Oudtshoorn, N. Gericke, Medicinal plants of South
Africa. Cape Town: Briza Publications, 2000, p. 166.
[3] J.M. Watt, M.G. Breyer-Brandwijk, Medicinal and poisonous plants of
Southern Africa. Edinburgh: E & S Livingstone, 1962, p. 1457.
[4] E. Bienvenu, G.J. Amabeoku, P.K. Eagles, G. Scott, E.P. Springfield,
“Anticonvulsant activity of aqueous extract of
Leonotisleonurus”Phytomedicine, vol. 9, 2002, pp. 217-223.
[5] A. K. Jager, A. Hutchings, J. Van Staden, “Screening of Zulu medicinal
plants for Prostaglandin - synthesis inhibitors” Journal of
Ethnopharmacology, vol. 52(2), 1996, pp. 95-100.
[6] J. A. O. Ojewole, “Hypotensive effect of Leonotis leonurus aqueous
leaf extract in rats” American Journal of Hypertension, vol. 16(5)
Supplement 1, 2003, p. A40.
[7] P. Mugabo, A. Njagi, D.L. Dietrich, J. Syce, „Cardiovascular effects of
Leonotisleonurus in the normotensive rat” Revista de fitoterapia, vol.
2(1), 2002, p. 163.
[8] F. Khan, P. Mugabo, A.P. Burger, D.L.L. Dietrich, “Effects of
Leonotisleonurus aqueous exract on the isolated perfused rat heart”
ActaPharmacologicaSinica, Supplement 1, 2006, p. 349.
[9] K. C. Obikeze, J. M. McKenzie, I. R. Green, P. Mugabo,
“Characterization and Cardiovascular Effects of (13S)-9_,13_-
epoxylabda-6_(19),15(14)diolDilactone, a diterpenoid Isolated from
Leonotis leonurus” South African journal of chemistry, vol. 61, 2008,
pp. 119–122.
[10] D.E.A. Rivett, “Lingering amongst the Labiatae” South African journal
of chemistry, 1984, pp. 368-371.
[11] J. A. Duke, Handbook of medicinal herbs. Boca Raton: CRC Press,
2001, p. 276.
[12] V.U. Livius, J. Kilo, T. Luscher, M. Gassmann, Circulation. The
handbook of experimental animals. The laboratory rat. New York:
Georg J Krinke, 2000, p. 1541.
[13] F. Sutherland, J. Hearse, “Experimental models for the study of
cardiovascular function and disease” Pharmacological Research, vol.
41(6), 2000, pp. 597-603.
[14] F. Sutherland, J. Hearse, “The isolated blood and perfusion fluid
perfused heart” Pharmacological Research, vol. 41(6), 2000, pp. 613-
647.
[15] C. Depre, “Isolated working heart: Description of models relevant to
radioisotopic and pharmacological assessments” Nuclear medicine &
Biology, vol. 25, 1998, pp. 711-713.
[16] P. Mugabo, K.C. Obikeze, A. Njagi, A.P. Burger, I. Green, D.D.
Dietrich, “Cardiovascular effects of the alkaloid hippadine on the
isolated perfused rat heart” International journal of medicinal and
aromatic plants, vol. 2(1), 2012, pp. 172-177.
[17] H.B. Chen, M.W. Islam, R. Radhakrishnan, S.A. Wahab, M.A. Naji,
“Influence of aqueous extract from Neuradaprocumbens L. on blood
pressure of rats” Journal of Ethnopharmacology, vol. 90 (2-3), 2004, pp.
191-194.
[18] E.L. McCawley, “Cardioactive alkaloids” in The alkaloids, Chemistry
and physiology, R. Manske, Ed. New York: Academic press, 1995, pp.
79-104.
[19] D.S. Bhakuni, “Chemical and pharmacological investigation of plants
with a biological action on the cardiovascular system”, in Advances in
medicinal phytochemistry, D. Barton, D.W. Ollis, Eds. London: John
Libbery, 1986, pp. 25-35.
[20] J.C. Liu, F.L. Hsu, J.C. Tsai, P. Chan, J.Y.H. Liu, G.N. Thomas, B.
Tomlinson, M.Y. Lo, J.Y. Lin, “Antihypertensive effects of tannins
isolated from traditional Chinese herbs as non-specific inhibitors of
angiotensin converting enzyme” Life Science, vol. 73(12), 2003, pp.
1543-1555.
[21] B. B. Hoffman, “Adrenoceptor-Activating & other sympathomimetic
drugs”, in Basic & Clinical pharmacology, 7th ed. B.G. Katzung, Ed.
Connecticut: Apnge, 1998, pp. 118-151.
[22] Fujitaa, D.L. Roerig, Z. J. Bosnjak, D. F. Stowe, “Effects of vasodilators
and perfusion pressure on coronary flow and simultaneous release of
nitric oxide from guinea pig isolated hearts” Cardiovascular
Research, vol. 38(3), 1998, pp. 655-667.</p>
@article{"International Journal of Medical, Medicine and Health Sciences:52526", author = "K. Obikeze and P. Mugabo and I. Green and D. Dietrich and A. Burger", title = "Effects of a Methanol Fraction of the Leaves of Leonotis leonurus on the Blood Pressure and Heart Rate of Normotensive Male Wistar Rats", abstract = "Leonotisleonurus a shrub indigenous to Southern
Africa is widely used in traditional medicine to treat a variety of
conditions ranging from skin diseases and cough to epileptic fits and
‘heart problems’. Studies on the aqueous extract of the leaves have
indicated cycloxegenase enzyme inhibitory activity and an
antihypertensive effect.
Five methanol leaf extract fractions (MLEa - MLEe) of L.
leonurus were tested on anaesthetized normotensive male Wistar rats
(AWR) and isolated perfused working rat hearts (IWH). Fraction
MLEc (0.01mg/kg – 0.05mg/kg) induced significant increases in BP
and HR in AWR and positive chronotropic and inotropic effects in
IWH (1.0mg/ml – 5.0mg/ml). Pre-administration of atenolol
(2.0mg/kg) and prazosin (60μg/kg) significantly inhibited MLEc
effect on HR and MAP respectively in vivo, while atenolol
(7.0mg/ml) pre-perfusion significantly inhibited MLEc effect in vitro.
The hypertensive effect of MLEc is probably via β1agonism.
Results also indicate the presence of multiple cardioactive
compounds in L. leonurus.
", keywords = "Cardiovascular effect, in vitro, in vivo, isolated
perfused working heart, Leonotis leonurus, rat.", volume = "7", number = "9", pages = "539-4", }
