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International Journal of Pharmaceutical Sciences Research Volume 2 (2015), Article ID 2:IJPSR-106, 11 pages
http://dx.doi.org/10.15344/2394-1502/2015/106
Research Article
Facts and Artifacts in the Evaluation of the Anti-diabetic Activity of Spent Hop Extract in Rat Hearts in the“Experimental Model of Diabetes”

Magdalena Labieniec-Watala1*, Tomasz Przygodzki2, Karolina Siewiera2, Anna Podsedek3 and Cezary Watala2

1Faculty of Biology and Environmental Protection, Department of Thermobiology, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
2Department of Hemostasis and Hemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, Mazowiecka 6/9, 92-215 Lodz, Poland
3Institute of Technical Biochemistry, Lodz University of Technology, Stefanowskiego 4/10, 90-924 Lodz, Poland
Dr. Magdalena Labieniec-Watala, Faculty of Biology and Environmental Protection, Department of Thermobiology, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland, Tel: (48) 42 635 44 81, Fax: (48) 42 635 44 73; E-mail: magdalab@biol.uni.lodz.pl
10 November 2014; 13 January 2015; 15 January 2015
Labieniec-Watala M, Przygodzki T, Siewiera K, Podsedek A, Watala C (2015) Facts and Artifacts in the Evaluation of the Anti-diabetic Activity of Spent Hop Extract in Rat Hearts in the “Experimental Model of Diabetes”. Int J Pharma Sci Res 2: 106. doi: http://dx.doi.org/10.15344/2394-1502/2015/106
This work was supported by the grant "Production of polyphenol extracts of plant origin with antiplatelet and cardioprotective properties -FLAWOPIRYNA" UDA-POIG.01.03.01-10-129/08-00, co-financed by European Union from the European Regional Development Fund within the frame of the Innovative Economy Operational Program. The authors sincerely thank Agata Rucinska (University of Lodz) for her excellent technical assistance and Prof. Jan Oszmianski (Wroclaw University of Environmental and Life Science) for the identification of low molecular weight phenolics using the UPLC-MS method.

Abstract

Background: The present study was undertaken to demonstrate the anti-diabetic mode of action of Humulus lupulus L. extract and its protective influence against changes in the respiratory capacity and coronary flow of the heart in experimental diabetes.
Methods: The study was performed in non-diabetic and streptozotocin-diabetic rats. The rats were administered the plant extract at the dose of 5 mg/kg b.w. in drinking water, once daily for a maximum of 20 weeks, while another group received pure drinking water as a vehicle. Twenty animals from each group were randomly selected after the period of 1, 2.5 and 5 months, and the effects of plant polyphenolrich extract on: body weight, blood glucose level, HbA1c level, heart mitochondria respiratory activity and coronary flow were evaluated. The heart mitochondria respiratory activity and coronary blood flow were monitored using high-resolution respirometry and the retrograde perfusion Langendorff system.
Results: There was a statistically significant decrease in body weight and increase in the level of glucose and glycated hemoglobin in diabetic subjects compared to non-diabetic ones. The plant extract did not affect any of the measured parameters in the diabetic animals compared to those not treated with the extract. The majority of the heart mitochondria parameters remained at a similar level to those recorded in the cardiomyocytes isolated from healthy rats. Multiple parameters of coronary flow were also not affected by the extract supplementation. The NO-independent coronary vessel blood flow was significantly improved only after the 5th month treatment.
Conclusion: Regardless of well evidenced development of diabetes, both the heart mitochondrial function and coronary flow in rats with STZ-induced diabetes were not significantly affected. Consequently, it was not possible to prove the scientific hypothesis that the extract of spent hops improves heart mitochondrial bioenergetics-impaired by the excessive glucose.