Pharmacological Effects of Ginkgo Biloba Extract on Cardiovascular and Cerebrovascular Diseases

Pharmacological Effects of Ginkgo Biloba Extract on Cardiovascular and Cerebrovascular Diseases

Time:2018-06-07 Hits:
Ginkgo biloba has been widely used as the preferred plant drug for the treatment of cardiovascular and cerebrovascular diseases, especially in Europe and America in the 1960s and 1970s. This is because Ginkgo biloba extract has the effects of scavenging oxygen free radicals, platelet aggregation and thrombosis caused by antagonizing platelet activating factor, and it also has the functions of reducing blood fat, enhancing central nervous system, regulating neurotransmitters and hormone levels, and improving blood rheology, anti-inflammatory and anti-allergic.

As a traditional Chinese medicine, ginkgo biloba leaf has the effect of regulating the lungs, moistening and promoting blood circulation, which has been recognized by traditional Chinese medicine since ancient times. Since Ginkgo biloba contains natural ingredients such as active flavonoids and ginkgolide that are beneficial to human health, it has the functions of dissolving cholesterol, dilating blood vessels, improving brain dysfunction, having obvious effects for arteriosclerosis, hypertension, dizziness, tinnitus, headaches, and senile dementia, memory loss, etc. It’s value of prevention, treatment, and fitness has been recorded in the "Compendium of Materia Medica" of the Ming Dynasty.
Modern pharmacological studies have shown that it can reduce blood lipids, prevent arteriosclerosis and improve cardiac and brain circulation. With the in-depth clinical study of ginkgo biloba leaf extract, various preparations have been widely used in cardiovascular and cerebrovascular diseases. Ginkgo biloba leaf is more and more widely used in clinical practice and five mechanisms of action in medicine of this extract has been proved by Chinese medicine.
TCM Confirmation: Five Roles of Ginkgo Biloba
Improvement of cerebral circulatory system

1. Effects on cerebral circulation and hemodynamics
Intravenous injection of ginkgo biloba extract can selectively expand cerebral blood vessels, significantly increase cerebral blood flow and reduce cerebral vascular resistance, decrease the fibrinogen (PFC) content, enhance the capacity of deformation of red blood cells, improve hemodynamics, antagonize platelet aggregation (BPC) caused by platelet activating factors (PAF), lower blood viscosity, improve microcirculation, thus increasing tissue blood perfusion and improving brain function.
2. Effects on free radical generation and scavenging system
It was found that ginkgo biloba leaf extract has free radical scavenging and anti-lipid peroxidation effects on various experimental pathological models.
3. Anti-cerebral ischemia
Improve energy metabolism disorders and fight against acidosis; antagonizes excitatory amino acid (EAA) toxicity and free radical damage; prevent post-ischemic inflammatory response; reduce neuronal apoptosis; inhibit intracellular calcium overload; improve hemodynamics.
Effects on the central nervous system

1. Effects on free radical generation and scavenging system
It was found that ginkgo biloba leaf extract has free radical scavenging and anti-lipid peroxidation effects on various experimental pathological models.
2. Improve learning and memory
The increase of nerve fiber projection in hippocampal CA3 region may be related to improvement of learning and memory function of ginkgo biloba extract to the decline of aged animals. Oral administration of Ginkgo biloba extract for 4 or 8 weeks can promote the learning and memory process of mice and improve the memory reproducibility. Both ethanol extract and water extract of ginkgo biloba can significantly improve the memory damage caused by NaNO2 and scopolamine.
3. Improvement of aging, dementia, and brain dysfunction
Ginkgo biloba flavonoid glycosides have a strong antioxidant effect, which can promote microcirculation, dilute blood, block platelet activating factor (PAF), and thus can improve Alzheimer's and delay the development of dementia.
Effects on the cardiovascular system

1. The protective effects on the heart
Studies have found that Ginkgo biloba extract can significantly reduce the arrhythmia induced by reperfusion of isolated rat hearts, decrease the occurrence of premature ventricular, reduce the duration of ventricular tachycardia and ventricular fibrillation, and reduce the grade of arrhythmia, thereby it is considered that ginkgo biloba extract has protective effects on myocardial ischemia-reperfusion injury. Another experiment found that ginkgo biloba total flavonoids can obviously reduce the total abnormal elevation of ST segment in myocardial infarction rabbits and the frequency of pathological Q wave, significantly inhibit myocardial tissue creatine phosphate kinase release.
2. The protective effects on blood vessels
By stimulating endothelial cells to release of endogenous relaxation factors, ginkgo biloba extract can antagonize adrenaline-induced artery contraction and inhibit the activity of angiotensin converting enzyme, which may be one of the mechanisms for the expansion of blood vessels; the vasoconstriction effect of norepinephrine can be enhanced can be enhanced at low concentrations. The vasoconstrictive effect of norepinephrine enhances physiological vascular regulation through the adrenergic nervous system; it can also reduce the permeability of capillaries and has a good therapeutic effect on edema and hypovolemic shock.
3. Hypotension
Inject the 150-200 mg · kg-1 intravenously once to rats of total flavonoids of Ginkgo biloba (0.1 g · ml-1) extracted by 75% ethanol, and observe the blood pressure changes of normal anesthetized rats, hypertensive rats and spontaneous hypertension rats (SHR) by carotid artery intubation. Changes in blood pressure in rats and spontaneously hypertensive rats (SHR). The results showed that 75% ethanol extract of total flavonoids had significant hypotensive effect on various hypertensive rats (P<0.01), in addition, the urinary protein, NO content and ET activity of patients with pregnancy-induced hypertension were also decreased (P<0.01).
4. Inhibition of platelet function
Vitro experiments have shown that ginkgo biloba extract can dissolve thrombus, inhibit platelet aggregation and reduce blood viscosity.
5. Hypolipidemic effect
After administration of ginkgo biloba extract for 4 weeks, cholesterol and triacylglycerol in the serum of the experimental mice were significantly decreased, indicating that ginkgo biloba extract have significant lipid lowering effect.
Improve microcirculation and enhance human immunity

Human microcirculation is closely related to health. If the microcirculatory disturbance occurs in the nervous system, it will lead to insufficient blood and oxygen supply of brain cells, causing headaches, dizziness, insomnia, dreaminess, poor memory and even stroke; if this occurs in the cardiovascular system and myocardial cell malnutrition, it will cause chest tightness, palpitation, arrhythmia, angina, and even myocardial infarction; and occurs in the respiratory system, there will be shortness of breath, suffocation, cough, asthma and severe respiratory arrest; occurs in the digestive system, gastrointestinal function is weakened and  disordered, causing the gastrointestinal diseases; the diseases will also occur if microcirculation disorders in other organs, muscles and bones, joints and so on.
To improve microcirculation, the premise is that the blood viscosity can not be too high, and ginkgo biloba extract has a very obvious effect on reducing blood viscosity. The basic function of microcirculation is to supply cells with blood, oxygen, energy and nutrients, and take away the harmful substances produced by human metabolism: creatine, lactic acid, carbon dioxide and other wastes. If the microcirculation is not good, the immune system will be weakened and will suffer from all kinds of diseases. Microcirculation also acts as the "second heart," because it is impossible to deliver the blood in the heart to the tissue cells if just rely on the contractile force of the heart, and blood must be re-adjusted by capillary then can be perfused into the cells.
Other clinical effects
1. Liver protection
Experimental studies have shown that ginkgo flavonoids significantly inhibited the production of malondialdehyde (MDA), the liver lipid peroxidation end-product induced by liver homogenate cream, Fe2+ and H2O2, and was dose-dependent. It is suggested that ginkgo biloba leaf extract has certain anti-hepatic damage effect.  
2. The protective effect on gastric mucosa
Ginkgo biloba leaf extract has protective effect on gastric mucosal and synergistic effect with cimetidine in the treatment of gastric ulcers. Studies have shown that ginkgo biloba extract can inhibit the gastric mucosal injury caused by binding freeze stress and anhydrous ethanol in a dose-dependent manner. It also enhances the protective effect of cimetidine on gastric mucosa. However, there was no significant effect on gastric secretion, gastric acidity and pepsin activity in rats.
3. Treatment of diabetic nephropathy
Flavonoids lactones of ginkgo biloba are anti-PAF, can lower blood viscosity and erythrocyte aggregation, reduce vascular permeability, improve blood rheology and kinetics, and improve the urine protein, fasting blood glucose, urea nitrogen and creatinine clearance rate in patients with diabetic nephropathy.
4. Hearing recovery of sudden deafness
Curative effect of clinical use of ginkgo biloba injection treatment for 46 patients with sudden deafness was compared with conventional energy mixture on hearing loss of sudden deafness. The results showed that effective rate of ginkgo biloba group was 88%, which proved that of ginkgo biloba leaf extract preparation has a remarkable hearing restoring effect for sudden deafness.