Phytotherapy in the Management of Diabetes and Hypertension, Volume 1* by Mohamed Eddouks and Debprasad Chattopadhyay, eds. Dubai, UAE: Bentham Science; 2012. E-book, 249 pages. ISBN: 978-1-60805-014-7. $59.00.
From the onset, the editors of this compilation of research papers set an ambitious goal: “to [provide] success in the management of diabetes and hypertension through plant-based therapeutics and dietary intervention.”
Chapter 1 accounts for almost a quarter of the e-book and presents an overview of what the authors of this section call cellular nutrition and nutritional medicine, as they relate to diabetes and its complications. Initially, there is an interesting historical overview of major discoveries related to diabetes, which is presented in a standard and concise way. General symptoms and diagnostic guidelines for the disease are also provided. The authors then describe the biochemical pathophysiology of diabetes in simple terms, and cover the broad mechanisms of glucose handling and insulin action. The rest of the chapter focuses primarily on nutrition and nutritional medicine. The authors’ approach to nutritional medicine, however, is a bit haphazard and somewhat opinionated.
The first chapter also includes informative, general tables on minerals and vitamins, but the authors then highlight alpha-lipoic acid, omega-3 fatty acids, and chromium without clearly establishing the rationale for their selections. One table presents graded evidence for the beneficial actions of omega-3 fatty acids in diabetes, yet it fails to provide references or the rationale for the grading. Another table details nutrition requirements and sources of “major” phytonutrients, vitamins, and minerals, but, there too, the selections are not justified and thus appear random. Similarly, the last table in the chapter lists “Symptoms and Solutions for Some Health Problems with Nutritional Medicine” that leaves the reader wondering how and why the listed components were chosen.
Chapter 2 explores the intimate relationship between diabetes and hypertension. It begins by repeating the classifications of the two types of diabetes and then provides the general biochemistry of carbohydrate metabolism and insulin action. A significant portion of this chapter is devoted to reactive oxygen species (ROS), their sources, and their role in the pathogenesis of diabetes and atherogenesis (the formation of plaques in the arteries). Hypertension is then discussed with a focus on nutritional factors, such as sugar and salt as contributors to the condition. A number of botanicals and natural products that can be useful for treating hypertension are then described, but, again, without a rationale for the selections or references supporting the claims.
Chapter 3 continues exploring the relationships among diabetes, hypertension, and cardiovascular diseases. After statements about diabetes statistics and gene-environment interactions, the chapter presents concise paragraphs that address the influence or involvement of stress, aging, sedentary lifestyle, obesity, dyslipidemia (an abnormal amount of blood lipids), and microalbuminuria (an elevated amount of the protein albumin in urine). The prominent biomarkers for atherosclerosis and hypertension in people with diabetes are then discussed. Surprisingly, the chapter also focuses on the dynamic and electrokinetic parameters of red blood cell membranes — a topic that includes references to the authors’ own work. Lastly, lifestyle modifications and genetic susceptibility (gene polymorphisms) are briefly covered.
The first three chapters make up more than half of the book and provide useful background on nutrition, diabetes, hypertension, and cardiovascular diseases, though the material is somewhat simplistic and the selected topics are sometimes a bit random.
The remainder of the book covers the main subject matter, namely phytotherapy for diabetes and hypertension. Chapter 4 is written by Nigerian reserachers and begins with concise, yet redundant sections on the classification, epidemiology, pathophysiology, and treatment of diabetes. The authors then describe 18 plants as useful monoherbal antidiabetic therapies. These stem mostly from Indian (several from Ayurveda) and Arabic traditional medicine, with a few plants from West Africa, Asia, and Latin America also included. Among the better-known plants mentioned in this chapter are fenugreek (Trigonella foenum-graecum, Fabaceae), Asian ginseng (Panax ginseng, Araliaceae), bitter melon (Momordica charantia, Cucurbitaceae), and prickly pear (Opuntia ficus-indica, Cactaceae). Unfortunately, many of the references are out-dated and some are of questionable scientific quality. In the last portion of the chapter, the authors present several interesting polyherbal preparations originating principally from India/Ayurveda. References are more recent, but, in one case, the only citation refers to the website of an Indian pharmaceutical company.
In Chapter 5, the e-book’s editors review the transition of blood sugar-regulating plants from folkloric to modern, science-based applications. After discussing ethnobotany and different worldviews of various traditional medicine systems, the reader is again presented with brief definitions and classifications of diabetes. The chapter then surveys botanicals used for the treatment of diabetes around the world. The selections were apparently based on the number of citations for the plants’ antidiabetic effects, though a clear description of the actual parameters used is not provided. Again, “classical” hypoglycemia-mitigating plants, such as ginseng and bitter melon, are described with more updated references, considering the publication date of the e-book (2012). The author then covers several classes of compounds with references to their biodiversity, mechanisms of action, and potential toxicity. The chapter concludes with a review of in vivo (animal-based) and in vitro (cell-based) methods that will be helpful for students and new researchers in the field.
Chapter 6, “Phytotherapy of Hypertension in Morocco,” was also written by the editors. After a concise introduction of hypertension, its causes, and general pathophysiology, the chapter systematically discusses plants used for hypertension, as identified in a Moroccan ethnobotanical survey. The plants are organized alphabetically in their respective families, and information about their botanical properties, ethnobotanical studies, and hypotensive activities is clearly presented.
Unfortunately, for several plants, studies on their uses for hypertension are either lacking or solely based on preclinical experiments. It is surprising that, even for the plants with the most compelling evidence, certain crucial references are missing. In the case of garlic (Allium sativum, Amaryllidaceae), for example, the authors list a Cochrane review concerning garlic and the common cold, but fail to cite a meta-analysis for garlic and hypertension that was published around the same time.1 Similarly, for olive (Olea europaea, Oleaceae) products, the authors concentrate on olive leaf extracts but do not detail the well-described benefits of olive oil (e.g., a reduced risk of developing cardiovascular conditions such as hypertension) as a crucial part of the Mediterranean diet.
In the final chapter, the editors present a general overview of processes involved in the discovery of plant-derived drug leads, from extraction to structure elucidation.
The contents of the e-book are unfortunately already a bit outdated, given that this field is evolving so rapidly. Nevertheless, the book can be useful for students and researchers with a new interest in herbals who are looking for an overview of diabetes and hypertension in the realm of phytotherapy, as well as general approaches to research in this field. However, contemporary researchers will be left somewhat disappointed if they want an updated and well-documented review of the most prominent herbs used for diabetes and hypertension around the globe, notably those supported by more recent clinical evidence.
* Volume 2 of Phytotherapy in the Management of Diabetes and Hypertension was published in December 2015.
—Pierre S. Haddad, PhD
Department of Pharmacology
Université de Montréal
Montreal, Canada
Reference
- Reinhart KM, Coleman CI, Teevan C, Vachhani P, White CM. Effects of garlic on blood pressure in patients with and without systolic hypertension: a meta-analysis. Ann Pharmacother. 2008;42(12):1766-1771.