Chinese Herbs in treatment of Diabetes
Diabetes mellitus is one of the chronic non-communicable diseases. Over the last few decades, it has maintained a rise in prevalence with increasing morbidities that have negative impact on quality of life. In the United States, 25.8million people are suffering from diabetes mellitus with another 7million people presumed to be undiagnosed. Diabetes mellitus was responsible for deaths of 3.4million people in the year 2004. This figure, according to the WHO, will double by the year 2030.
With increase in lifespan, rising incidence of obesity and increase in the number of young children diagnosed of diabetes mellitus, a global epidemic is approaching, thus, necessitating the need for better therapeutic measures. Chinese herbs in the treatment of diabetes are currently showing great potentials and may soon revolutionize the therapeutic management of diabetes mellitus.
Diabetes mellitus is a disorder of carbohydrate, protein and fat metabolism with a major underlying factor of relative or absolute insulin deficiency (a hormone produced by the β-cells of the pancreas). The inadequate insulin or resistance to circulating insulin results in persistent increase in blood sugar (hyperglycemia) which serves as the initiating factor for all complications associated with diabetes namely; heart failure, eye disease, lower limb amputation, kidney disease, etc. Types 1 and 2 diabetes mellitus are the major types, however, gestational diabetes (seen in pregnant women) and other rare forms also exist. 90% of patients with diabetes mellitus have the type 2.
Mechanism of action
Pharmacological treatment of type 2 diabetes mellitus involves the use of drugs that either increases the secretion of insulin from the pancreas or the sensitivity of body tissues to the available insulin. In extreme cases, a patient may require insulin injection to keep the blood sugar low and reduce the progression of complications. However, these medications are not without unwanted side effects such as weight gain, bone loss, and increase risk of cardiovascular events. The costs of these medications are often not sustainable for most patients.
The Chinese have been using herbal medication for prevention and treatment of type 2 diabetes mellitus for centuries. Many of these herbal medicines have been subjected to trials and were found to be effective with fewer and tolerable side effects and may therefore be an adjunct to the current pharmacological treatment modalities.
Because herbal medications contain more than one active ingredient, multiple mechanisms of action can be seen with a single herbal medicine as opposed to conventional pharmacological agents where one drug is directed towards a particular target. The mechanisms of action of Chinese herbal medicine include enhancement of insulin sensitivity, stimulation of insulin secretion, or reduction of carbohydrate absorption, reducing cell death due to their antioxidant properties, inhibiting the production of glucose by the liver and enhancing the conversion of excess glucose to glycogen.
Examples of Chinese herbs with great potentials in the treatment of diabetes
The root of Rehmannia glutinosa Libosch, Radix rehmanniae has many bioactive components such as catalpol, rehmannioside A, B, C, and D, phenethyl alcohol derivatives such as leucosceptoside A and purpureaside C, monocyclic sesquiterpenes as well as their glycosides. When prepared with other herbs such as Radix ginseng, Radix scutellariae, the effect was that of improvement in insulin secretion, proliferation of insulin-secreting β–cell in the pancreas, improvement in diabetic foot ulcer in rats.
Stephania tetrandra Moore
Stephania tetrandra Moore has numerous applications due to its analgesic, anti-inflammatory, anti-allergic and hypotensive effects. Experiment in mice has shown that Stephania tetrandra Moore stimulates insulin secretion from the pancreas and therefore increased blood insulin with subsequent reduction in blood glucose.
Isoquinoline alkaloid and berberine are the major components of Rhizoma coptidis. They are used in the treatment of cancer, infections, Alzheimer’s disease and malaria. The berberine has been found to decrease blood glucose and serum cholesterol levels in high fat diet-fed mice through mechanisms similar to those of sulfonylureas and biguanides.
Radix astragali also known as Huang Qi, is the dried root of Astragalus spp grown in northern China with many active ingredients. A rat with diabetes treated for two months with extracts of this herb had improvement in insulin sensitivity and amelioration of fatty liver disease. The polysaccharide of Radix astragali reduces hyperglycemia with preservation of insulin-secreting β-cells (through its immunomodulatory properties).
Eriobotrya japonica Lindl
This fruit tree is found in central and south China. Extracts from the dried leaves enhance the secretion of insulin and reduce blood glucose in mice and also lower blood triglyceride levels.
Human clinical trials have been conducted to determine the effectiveness of extracts from the leaves of Ginkgo biloba tree in many diseases such as cerebrovascular disease, tinnitus, sexual dysfunction, intermittent claudication, migraine prophylaxis, and alleviating symptoms of the common cold. It has also been used for the treatment of Alzheimer’s disease. When administered to a rat, increase in the uptake of glucose by the liver and muscle was observed. The risk of artherogenesis (deposition of fat inside the wall of blood vessels) also reduced. However, clinical trials in diabetic patients have yielded mixed results.
Other examples of Chinese herbs with anti-diabetic effects include Radix ginseng, Fructus schisandrae (five-flavor berry) and Pueraria lobata.
In conclusion, many Chinese herbs are been employed in the management of type 2 diabetes mellitus and its complications. They contain many agents with multiple mechanisms of action and have fewer side effects as compared to the conventional anti-diabetic drugs. They also serve as nutritional supplements and are easily accessible at low costs. Although more clinical researches are needed to conclusively establish their efficacy in human subjects, Chinese herbs such as ginseng, mulberry etc. have shown great potential in the prevention and treatment of type 2 diabetes.
Wang Z, Wang J, Chan P. Treating Type 2 Diabetes Mellitus with Traditional Chinese and Indian Medicinal Herbs. Evidence-based Complementary and Alternative Medicine : eCAM. 2013;2013:343594. doi:10.1155/2013/343594.