Evaluation of in vitro Cholesterol esterase inhibitory and in vivo Anti-hyperlipidemic activity of aqueous extract of Plukenetia conophora Mull. Arg. (Euphorbiaceae)
Keywords:Hyperlipidemia, pancreatic cholesterol esterase, Tyloxapol, High Cholesterol diet, Plukenetia conophora, Simvastatin
Hyperlipidemia is a condition of abnormally high lipids levels in the blood which has been ranked as one of the greatest risk factors contributing to prevalence and severity of coronary heart disease. The available antihyperlipidemic drugs have been associated with some side effects however, herbal management of hyperlipidemia are relatively safe, cheap and readily available. P. conophora is an edible plant consumed in Nigeria as snack and speculated to have beneficial effect on blood lipid profile. The present study evaluates anti-hyperlipidemic effect of aqueous extract of cooked P. conophora nut using in vivo and in vitro experimental models. The anti-hyperlipidemic activity was evaluated using tyloxapol induced-hyperlipidemic rats by intraperitoneal injections of Tyloxapol at a dose of 300 mg/kg body weight and high cholesterol-diet induced rats by oral administration of high cholesterol diet for 60 days. Cholesterol esterase enzyme inhibition was used for the in vitro evaluation. Aqueous extract of P. conophora at varying doses, reduced the elevated lipid parameters in both models; the dose of 500 mg/kg showed comparable hypolipidemic effects with standard drug (Simvastatin) at 10 mg/kg (P<0.01). The extract also inhibited cholesterol esterase enzyme with IC50 value of 129.30±0.10μg/ml while Simvastatin with IC50 value of 51.42±0.13μg/ml. Preliminary phytochemical analysis revealed the presence of; Flavonoids, saponin, cardiac glycoside, alkaloids, tannins, steroids and reducing sugar. P. conophora extract exhibited strong hypolipidemic activity and the dose of 500mg/kg demonstrated equipotent activity as the standard drug; Simvastatin 10mg/kg. The extract also showed inhibitory activity against pancreatic cholesterol esterase enzyme; hence can be used to limit absorption of dietary cholesterol, prevent and treat hyperlipidemia.
Amuamuta, A. A review on risk factors/Indicators and effects Of Hyperlipidemia. Middle-east journal of Scientific Research 2014; 22(6):886-893.  Sivaelango, G., Kumaran, P., Kumaravel, P., Revathi, P. and Jaswant, A. Antihyperlipidaemic Activity of Spermacoce Hispida Ethanolic Extract in Triton WR-1339 Induced Hyperlipidaemic Rats. Journal of Applied Pharmaceutical Science 2012; 2 (2): 95-98.  Tekes-Manova, D., Israeli, E., Shochat, T., Swartzon, M., Gordon, S., Heruti, R. The Prevalence of Reversible Cardiovascular Risk Factors in Israelis aged 25-55 years. Isreal Medical Association Journal 2006; 8:527- 531.  Adisakwattana, S., Moonrat, J., Srichairat, S., Chanasit, C., Tirapongporn, H., Chanathong, B., Ngamukote, S., Mäkynen, K. and Sapwarobol, S. Lipid-Lowering mechanisms of grape seed extract (Vitis vinifera L) and its antihyperlidemic activity. Journal of Medicinal Plants Research, 2010; 4(20): 2113-2120.  Siddiqi, H., Mehmood, M., Rehman, N. and Gilani, A. Studies on the antihypertensive and antidyslipidemic activities of Viola odorata leaves extract. Lipids in Health and disease; 2012; 11(1): 6 –18  Pandit, K., Karmarkar, S. and Bhagwat, A. Evaluation of Antihyperlipidemic Activity Of Ficus Hispida Linn Leaves In Triton Wr-1339 (Tyloxapol) Induced Hyperlipidemia In Mice. International Journal of Pharmacy and Pharmaceutical Science 2011;3(5): 188-191.  Adisakwattana, S., Intrawangso, J., Hemrid, A., Chanathong, B. and Mäkynen, K. Extracts of edible plants inhibit pancreatic lipase, cholesterol esterase and cholesterol micellization, and bind bile acids. Food Technol. Biotechnol. 2012; 50 (1):11–16.  Hutchinson, J. and Dalziel, J. Flora of West Tropical Africa. Vol. I. Part 2. 2 Ed. Revised by Keay, R. W. J. Crown Agents for Overseas Governments and Administrations: London. 1958;533pp  Burkill, H. Entry for Plukenetia conophora. The Useful Plants of West Tropical Africa, 2nd Ed; 1985; 241-250.  Iwu, M., Duncan, A. and Okunji, C. New antimicrobials of Plant origin. In: Janick J (ed); Perspective on new crops and the new uses. ASHS Press, Alexandra, VA; 1999; 457-462.  Evans, W. C. Trease and Evans Pharmacognosy. 15th edition W. R. Saunders, London 2002; p. 199 - 203.  Sofowora, E. Medicinal Plants and Traditional Medicine in Africa, 3rd Edition, Nigeria: Spectrum books Ltd, 2008; p. 150-153.  American Physiological Society: Guiding principles for research involving animals and human beings. Am. J. Physiological Regul/Integr Comp physiol. 2002; 283: R281 – R283, . Tamer, A., Mohamed, M., Mohamed, N., Dalia, I. Antihypercholesterolemic Effects of Mushroom, Chrysin, Curcumin And Omega-3 in Experimental Hypercholesterolemic Rats. Journal of Food and Nutrition Research, 2015; 3(2): 77-87.  Varsha, D., Shubhangi, S., Mangesh, P., Naikwade, N. Antihyperlipidemic Activity of Cinnamomum tamala Nees on High Cholesterol Diet Induced Hyperlipidemia. International Journal of PharmTech Research, 2010; 2(4): 2517-2521. . Kumar, A., Sivashanmugam, A., Umamaheswari, M., Subhadradevi, V. and Jagannath, P. Cholesterol Esterase Enzyme Inhibitory and Antioxidant Activities of Leaves of Camellia sinensis (L.) Kuntze. Using In Vitro Models. International Journal of Pharmaceutical Science Research 2011; 2 (10): 2675-2680.  Ojeda, D., Ferrer, E., Zamilpa, A., Arellanob, A., Tortoriello, J. and Alvarez, L. Inhibition of angiotensin convertin enzyme (ACE) activity by the anthocyanins delphinidin and cyanidin-3-O-sambubiosides from Hibiscus sabdariffa. Journal of Ethnopharmacology; 2010; 127: 7-10.  Grundy, S., Cleeman, J. and Merz, C. Implication of recent clinical trials for the National Cholesterol Education Program Adult Panel on Detection, Evaluation and Treatment of high blood cholesterol in adults. JAMA 2004; 285: 2486-2497  Davidson, M. and Tooth, P. Comparative effect of lipid lowering therapies. Prog. Cardiovasc. Dis. 2004; 47:173-204.  Wang, H. and Ng, T. Natural products with hypoglycaemic, hypotensive, hypocholesterlemic, antiathero-sclerotic and antithrombotic activities. Life Sci; 1999; 65:2663-2677  Schurr, P., Schultz, J. and Parkinson, T. Triton induced hyperlipidemia in rats as an animal model for screening of hypolipideamic drugs. Lipids; 1972; 7:68–74.  Otway, S. and Robinson, D. The effect of nonionic detergent (Triton WR 1339) on the removal of triglyceride fatty acids from the blood of the rats. J. Physiol ; 1967; 19: 309-319.  Pankaj, G. and Sanjay, J. Evaluation of Antihyperlipidemic potential of Prosopis cineraria extract against high fat diet induced hyperlipidemia in laboratory rat. Pharmacologia, 2015; 7:44-52.  Khanna, A., Rizvi, F. and Chander, R. Lipid lowering activity of Phyllanthus niruri in hyperlipemic rats. J. Ethnopharmacology; 2002; 82: 19-22.  Brodt-Eppley, J., White, P., Jenkins, S. and Hui, D. Plasma cholesterol esterase level is a determinant for an atherogenic lipoprotein profile in normolipidemic human subjects. Biochim.Biophys. Acta, 1995; 1272: 69-72.  Myers-Payne, S., Hui, D., Brockman, H. and Schroeder, F. Cholesterol esterase: a cholesterol transfer protein. Biochem 1995; 34: 3942-3947.  Nwaoguikpe, R., Ujowundu, C. and Wesley, B.. Phytochemical and biochemical compositions of African Walnut (Tetracarpidium conophorum). J Pharm Biomed Sci. 2012; 20(9): 1-5.  Apeh, V., Agu, C., Ogugua, V., Uzoegwu, P., Anaduaka, E., Rex, T. and Agbalu, I. Effect of Cooking on Proximate, Phytochemical Constituents and Hematological Parameters of Tetracarpidium conophorum in Male Albino Rats. European Journal of Medicinal Plants; 2014; 4(12): 1388-139.  Elke, A., Guus, S., Yuguang, L., Sergey, M., Henri, O. and Fady, Y. Proposed mechanisms of cholesterol lowering action of plant sterol. Eur. J. Lipid Sci. Technol. 105: 2003; 171-185.  Ostlund, R., Racette, S., Okeke, A., Stenson, W. Phytosterol that are naturally present in commercial corn oil significantly reduce cholesterol absorption in human. Am J clin. Nutr. 2002; 75(6):1000-1004.  Heynekamp J, Hunsaker L, Vander J, Royer R, Decka M and Vander J. Isocoumarin-based inhibitors of pancreatic cholesterol esterase. Bioorganic & Medicinal Chemistry 2008; 16: 5285–5294.  Kirana, C., Rogers, P., Bennett, L., Abeywardena, M. and Patten, G.Naturally derived micelles for rapid in vitro screening of potential cholesterol-lowering bioactives. J.Agric. Food Chem. 2005: 53: 4623–4627.