Blueberry Leaves Extract:Diabetes & More - Diabetes and Blueberry Leave

Blueberry Leaves Extract:Diabetes & More
Annie Appleseed Project

Blueberry leaves extract: For Treatment of Diabetes and Prevention of Neurodegenerative diseases

By Dr. Miguel Jimenez del Rio

President Natural Polyphenols SA Las Palmas, Canary Islands, Spain Fax: +34-928-13-42-49

Introduction

Blueberry (Vaccinium arctostaphylos L) plant inhabiting the elevations of 3,000-5,000 feet high in the Perinea Peninsula has a legendary reputation as aid to diabetics. The Europeans have used the leaves blueberry for diabetes successfully for many decades. In the East European countries tea of blueberry leaves known as "Chai Cherniki" used in tinctures for gastric colitis and diabetes and other digestive problems.

Phytochemistry of Blueberry Leaves

The key compounds responsible for pharmacological and medicinal properties of blueberry leaves extract are caffeoylquinic acid (CA) and hydroxycinnamic acids (HA) (Durmishidze 1981).

Phytochemical composition of Blueberry leaves extract: Caffeoylquinic + Hydroxycinnamic acid (20% dry weight), Salidroside and its aglycon Tyrosol (0,2-0.4%), Arbutin (0.2%), Coumaric acid (0.4%), Quercetin and Rutin (0,7%) and Malvidine-3-glycoside (0.15%)

Blueberry leaves extract and blood sugar

Glucose is a double-edged sword. On the one hand, we cannot live without it - it is the bodies preferred fuel, and the energy we receive from burning it allows us to wake up in the morning and keep moving all day long. The overabundance of glucose in the blood of individuals suffering from diabetes causes some of the most deleterious effects of any disease known. The enzyme glucose-6-phosphatase plays a major role in the homeostatic regulation of blood glucose, which is responsible for the formation of glucose originating from gluconeogenesis and glycogenolysis.

CA was identified as a specific inhibitor of this enzyme in microsomes of liver (Arion et al. 1997; Hemmerle et al. 1997). Inhibition of glucose-6-phosphatase activity in the liver is expected to result in a reduction of hepatic glucose production and may be useful for the reduction of high rates of hepatic glucose output often found in non-insulin-dependent diabetes.

Pharmaceutical companies have synthesized caffeoylquinic acid derivatives with glucose-6-phosphatase inhibiting properties in human liver microsomes (Arion et al. 1997) and these synthetic compounds also reduce blood glucose. CA derivative produced concentration-dependent inhibition of glucose synthesis in isolated rat liver (Herling et al. 1998).

The recent discovery that blueberry leaves extract reduce blood sugar level by 26% is not surprising and somewhat expected results. The blueberry leaves extract also reduce plasma triglyceride by 39%, indicating its usefulness in treatment of high blood sugar and plasma triglyceride level (Cirnarella et al. 1996).

Another evidences for blueberry leaves effectiveness in diabetes arrives from human study of Prof of Medicine Abidoff MD (Moscow Center for Modern Medicine, Russian Ministry for National Defense Industries, 1999).

Seventy-five healthy volunteers age between 37-66 years were randomly assigned to receive 150mg/three times/day of standardized blueberry leaves standardized extract (BlueberinÙ) or placebo, to be taken with in 200 ml of water before meals. After meal concentration of blood glucose increased from average 102mg/dl±8md/dl (baseline) to 142mg/dl ±7mg/dl in placebo group, while plasma glucose level in BlueberinÙ group increase from 109mg/dl ± 9 mg /dl to 121mg/dl±6mg/dl, indicating that the blueberry leaves extract possess physiologically significant glucose-reducing property.

In another clinical trial twenty-nine patients average age 50 years with type II diabetes were selected to participate in double-blind placebo-controlled 60 days trial (Abidoff 1999). Subjects were randomly assigned to receive 200mg/three times/day of standardized blueberry leaves extract or placebo with 200 ml of water before meals. Those individuals taking the blueberry leaves extract showed the reduction of plasma glucose levels from approximately 169 mg/dl to 136 mg/dl (p < 0.01), while no such reduction was observed in placebo group.

Furthermore, by the end of the clinical study, those taking BlueberinÙ showed a reduction triglyceride and LDL values from 179 ± 95 mg/L to 130 ± 53 mg/L (p < 0.005) and 141 ± 47 mg/cU to 115 ± 34 mg/dl (p < 0.01) respectively. All patients tolerated well blueberry leaves extract at even 400mg/ three times a day (1200mg/day). It is interesting to note that the HA is also involved in the regulation of blood glucose level. Cheng & Liu (2000) demonstrated that the administration of hydroxycinnamic acid reduced blood glucose level. In animal model Hsu et al. (2000) provided evidences that HA lower plasma glucose in diabetic rats

CA-HA and Neurodegenerative Diseases

Elevated level of reactive nitrogen species such as 3-nitrotyrosine is associated with neurodegenerative diseases, such as Parkinson's, Alzheimer's, and amyotrophic lateral sclerosis. Yet, reactive nitro species promote the dopamine and serotonin oxidation. HA is structural analog of dopamine prevents peroxynitrite-mediated oxidation of this key brain neuro-compound (Kerry & Rice-Evans, 1999).

Neuronal 5-lipoxigenase (5-LO) is the key enzyme in the synthesis of leukotrienes, inflammatory eicosanoids that are capable of promoting neuro-degeneration. Aging process increases neuronal 5-LO expression that might play a significant role in the patho-biology of aging-associated neurodegenerative diseases (Uz et al. 1998) and HA - key compound in Blueberry leaves extract- was shown to inhibit the neuronal 5-LO activity (Koshihara et al. 1984).

Dietary supplementation of CA and HA resulted in a statistically significant increase of vitamin E both in plasma and lipoprotein Laranjinha JA et. al (1994). Oxidized low-density lipoproteins (LDL) are toxic to endothelial cells. Toxic concentrations of mildly oxidized LDL induce apoptosis (programmed cell death) of endothelial cells. The presence of CA and HA prevents the apoptosis of endothelial cells induced by oxidized LDL.

In addition, HA acts as a cytoprotective agent. CA and HA inhibit platelet aggregation and biosynthesis of thromboxane- a mediator causing broncho-constriction in allergy-related disorders (Koshihara et al. 1984).

For many decades scientists were wondered what is so special in health beneficial properties of Blueberry leaves extract, if it is became so popular among large population on the planet so quickly. Our brief pharmacological over-review of Blueberry leaves extract provides more answer than questions.

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