The aqueous calyx extract of Hibiscus sabdariffa (HS) is widely consumed as a beverage in Northern Nigeria and other parts of the world. HS has been reported to lower blood pressure (BP) in animals and man. However, not much is known about the effect of HS on BP in different postures. We tested the hypothesis that HS may lower BP, heart rate (HR) and heart rate-pressure product or double product (DP) by attenuating the discharge of the autonomic nervous system in different postures. Experiments were performed in accordance with the Principles of the Declaration of Helsinki. Following ethical approval and informed consent, BP and HR were measured in different postures (supine, sitting and standing) in apparently healthy human subjects (n=20) before and after (+HS) the oral administration of 15mg/Kg HS. Mean arterial pressure (MAP; taken as representative BP) and DP were calculated. Results are expressed as mean ±SEM. Paired t test and ANOVA with a post hoc Bonferroni test were used for statistical analyses. P<0.05 was considered significant. In the supine position MAP, HR and DP were significantly (P<0.0001 each) reduced in the presence of HS (85.6±1.7mmHg, 72.1±1.1/min and 8716±320mmHg.bpm) compared to its absence (89.6±2.0mmHg, 73.7±1.6/min and 8921±444mmHg.bpm). Similar trends were observed in the sitting position in the presence of HS (85.4±2.7mmHg, 73.7±1.8/min and 9098±345mmHg.bpm vs its absence: 91.4±2.3mmHg, 77.1±1.9/min and 9388±478mmHg.bpm; P<0.0001, P<0.0001 and P=0.007 respectively) and in the standing position (+HS: 89.3±2.0mmHg, 78.1±1.8/min and 10164±230mmHg.bpm vs its absence: 94.3±2.1mmHg, 81.8±2.3/min and 10742±268mmHg.bpm; P<0.0001, P<0.0001 and P=0.007 respectively). In the absence of HS, HR and DP were significantly higher in the standing posture (81.8±2.3/min, 10742±268mmHg.bpm) compared to the sitting (77.1±1.9/min, 9388±478mmHg.bpm; P<0.05 and P<0.0001 respectively) and the supine (73.7±1.6/min, 8921±444mmHg.bpm; P<0.001 each) postures while the BP remained similar. A similar trend was observed across the three postures in the presence of HS although the parameters were significantly lower. It is concluded that HS lowered BP, HR and DP by modulating autonomic mechanisms through the inhibition of both parasympathetic withdrawal and sympathetic nervous system discharge across the postures. Also the standing posture is associated more with a higher sympathetic nervous system discharge and a higher cardiac oxygen demand and workload than the sitting and supine postures in the absence or presence of HS.
Abubakar. S. M., Ukeyima, M. T., Spencer, J. P. E. and Lovegrove, J. A. (2019). Acute Effects of Hibiscus sabdariffa Calyces on Postprandial Blood Pressure, Vascular Function, Blood Lipids, Biomarkers of Insulin Resistance and Inflammation in Humans. Nutrients 11:341 doi:10.3390/nu11020341
Adegunloye, B. J., Omoniyi, J. O, Owolabi., O. A., Ajagbona, O.P., Sofola, O.A. and Coker, H.A. (1996). Mechanisms of blood pressure lowering effects of the calyx extract of Hibiscus sabdariffa in rats. Afr. J. Med. Med. Sci. 25: 235-238
Ajay, M., Chai, H. J., Mustafa, A. M., Gilani, A. H. and Mustafa, M. R (2007). Mechanism of antihypertensive effect of Hibiscus sabdariffa L. calyces. J. Ethnopharmacol. 109:338-393
Alarcon-Alonso, J., Zamilpa, A., Aguilar, F.A., Herrera-Ruiz, M., Tortoriello, J. and Jimenez-Ferrer, E., (2012). Pharmacological characterization of the diuretic effect of Hibiscus sabdariffa Linn (Malvaceae) extract. J. Ethnopharmacol. 139(3): 751-756.
Aliyu, B., Oyeniyi, Y.J., Mojiminiyi, F.B.O., Isezuo, S.A. and Alada, A.R.A. (2014). The Aqueous Calyx Extract of Hibiscus sabdariffa Lowers Blood Pressure and Heart Rate via Sympathetic Nervous System Dependent Mechanisms. Niger. J. Physiol. Sci. 29: 131-136
Alsayed, A.M.A., Zhang, B.L., Bredeloux, P., Boudesocque-Delaye, L., Yu, A., Peineau, N., Enguehard-Gueiffier, C., Ahmed, E.M., Pasqualin, C. and Maupoil, V. (2020). Aqueous Fraction from Hibiscus sabdariffa Relaxes Mesenteric Arteries of Normotensive and Hypertensive Rats through Calcium Current Reduction and Possibly Potassium Channels Modulation. Nutrients. 12(6):1782. doi: 10.3390/nu12061782. PMID: 32549326; PMCID: PMC7353181.
Ganong, W. F. (1991). Review of Medical Physiology. 15th Ed. Appleton & Lange, Norwalk, CA, USA
Guyton, A. C. and Hall JE. (2011). Textbook of Medical Physiology 11th edition. W.B. Saunders, Philadelphia, PA, USA
Hermida, R. C., Fernández, J. R., Ayala, D. E., Mojon, A., Alonso, I., and Smolensky, M. (2001). Circadian Rhythm of Double (Rate- Pressure) Product in Healthy Normotensive Young Subjects. Chronobiol. Int. 18(3): 475–489
Hopkins, A.L., Lamm, M.G., Funk, J.L. and Ritenbaugh, C. (2013). Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: a comprehensive review of animal and human studies. Fitoterapia. 85:84-94.
Jaja, S. I., Kehinde M. O., Gbenebitse, S., Mojiminiyi, F. B. O. and Ogungbemi A. I. (2000). Effect of Vitamin C on Arterial Blood Pressure, Irreversibly Sickled Cells and Osmotic Fragility in Sickle Cell Anemia Subjects. Niger. J. Physiol. Sci. 16(1- 2): 14-18
Katz, L. N. and Feinberg, H. (1958). The relation of cardiac effort to myocardial oxygen consumption and coronary flow. Circ. Res. 6: 656–669.
Kitamura, K., Jorgensen, C. R., Gobel, F. L., Taylor, H.L. and Wang, Y. (1972). Hemodynamic correlates of myocardial oxygen consumption during upright exercise. J Appl. Physiol. 32: 516– 522.
Mojiminiyi, F. B. O., Adegunloye, B. J., Egbeniyi, Y. A. and Okolo, R. U. (2000). An investigation of the diuretic effect of an aqueous extract of the petals of Hibiscus sabdariffa. J. Med. Sci. 2:77-80
Mojiminiyi, F.B.O., Audu, Z., Etuk, E. and Ajagbonna, O. P. (2012). Attenuation of salt-induced hypertension by aqueous calyx extract of Hibiscus sabdariffa. Niger. J. Physiol. Sci. 27(2): 195-200
Mojiminiyi, F.B.O., Dikko, M., Muhammad, B.Y., Ojobor, P.D., Ajagbonna, O.P., Okolo, R.U., Igbokwe, U.V., Mojiminiyi, U.E., Fagbemi, M.A., Bello, S.O. and Anga, T.J. (2007). Antihypertensive effect of an aqueous extract of the calyx of Hibiscus sabdariffa. Fitoterapia, 78(4): 292-297.
Nardo, C.J., Chambless, L.E., Light, K.C., Rosamond, W.D., Sharrett, A.R., Tell, G.S. and Heiss, G., (1999). Descriptive epidemiology of blood pressure response to change in body position. The ARIC study. Hypertension, 33(5): 1123-1129.
Norsk P. (1992). Gravitational stress and volume regulation. Clin. Physiol.12: 505–526
Ochani, P. C. and D’Mello, P. (2009). Antioxidant and antihyperlipidemic activity of Hibiscus sabdariffa Linn. leaves and calyces extract in rats. Indian J. Exp. Biol. 47:276-282
Ojeda, D., Jimenez-Ferrer, E., Zamilpa, A., Herrera-Arellano, A., Tortoriello, J. and Alvarez, L. (2010). Inhibition of angiotensin converting enzyme (ACE) activity by the anthocyanins delphinidin and cyanidin-3-O-sambubiosides form Hibiscus sabdariffa. J. Ethnopharmacol. 127(1):7-10
Olufsen, M. S., Ottesen, J.,T,, Tran, H.T., Ellwein, L..M., Lipstiz, L. A. and Novak, V. (2005). Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation. J. Appl. Physiol. 99(4):1523-1537
Pump, B., Talleruphuus, U., Christensen, N. J., Warberg, J., Norsk, P. (2002). Effects of supine, prone, and lateral positions on cardiovascular and renal variables in humans. Am. J. Physiol. Regul. Integr. Comp. Physiol. 283: R174−R180.
Sarr, M., Ngom, S., Kane, M.O., Wele, A., Diop, D., Sarr, B., Gueye, L., Andriantsitohaina, R. and Diallo, A.S. (2009). In vitro vasorelaxation mechanisms of bioactive compounds extracted from Hibiscus sabdariffa on rat thoracic aorta. Nutr. Metab. (Lond). 6(1): 45. doi: 10.1186/1743-7075-6-45. PMID: 19883513; PMCID: PMC2777910.
Silvani, A., Calandra-Buonaura, G., Johnson, B.D., van Helmond, N., Barletta, G., Cecere, A.G., Joyner, M.J. and Cortelli, P. (2017). Physiological mechanisms mediating the coupling between heart period and arterial pressure in response to postural changes in humans. Front. Physiol. 8: 163. doi: 10.3389/fphys.2017.00163. PMID: 28396638; PMCID: PMC5366337.
Smith, J. J. and Kampine, J. T. (1990). Circulatory Physiology, the Essentials (3rded). Baltimore, MD: Williams and Wilkins.
Tabara, Y., Tachibana-Iimori, R., Yamamoto, M., Abe, M., Kondo, I., Miki, T. and Kohara, K., (2005). Hypotension associated with prone body position: a possible overlooked postural hypotension. Hypertens. Res. 28(9): 741-746.
Wang, H., Cao, G., Prior, R. L. (1997). The oxygen radical absorbing capacity of anthocyanins. J. Agric. Food Chem. 45: 304-9
Watanabe, N., Reece, J., Polus, B.I. (2007). Effects of body position on autonomic regulation of cardiovascular function in young, healthy adults. Chiropr. Osteopat. 15:19 doi:10.1186/1746-1340-15-19
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