News - What a Natural Antioxidant—Ginkgo Leaf Extract!

I. Introduction

Introduction

What are the health benefits of ginkgo biloba extract powder (2)

Ginkgo leaf extract is a natural active substance extracted from ginkgo leaves. Its main components are flavonoids and ginkgo lactones. It is a specific PAF (platelet-activating factor, platelet-activating factor) receptor antagonist. Its pharmacological activities include: improving cerebral circulation and cell metabolism; increasing the activity of red blood cell superoxide dismutase (SOD) and glutathione peroxidase (GSH-px), and reducing cell membrane peroxidized lipids (MDA). production, scavenge free radicals, prevent damage to cardiomyocytes and vascular endothelial cells; selectively antagonize platelet aggregation, micro thrombosis, and lipid metabolism disorders caused by platelet PAF; improve coronary circulation of the heart and protect ischemic myocardium; Increase the deformability of red blood cells, reduce blood viscosity, and eliminate microcirculatory disorders; inhibit the synthesis of thromboxane (TXA2) and stimulate the release of prostaglandin PGI2 from vascular endothelial cells.

Plant Source

Ginkgo biloba is the leaf of Ginkgo biloba L., a plant of the Ginkgo family. Its extract (EGB) has a variety of healthcare functions and is widely used in food and cosmetics. The chemical composition of Ginkgo leaves is very complex, with more than 140 compounds isolated from it. Flavonoids and terpene lactones are the two main active ingredients of Ginkgo leaves. In addition, it also contains polyprenol, organic acids, polysaccharides, amino acids, phenols, and trace elements. According to incomplete statistics, the current international standard ginkgo leaf extract is EGb761 produced according to Germany's Schwabe patented process. It appears as a brown-yellow powder and has a slight scent of ginkgo leaf. The chemical composition is 24% flavonoids, 6% terpene lactones, less than 0.0005% ginkgo acid, 7.0% proanthocyanidins, 13.0% carboxylic acids, 2.0% catechins, 20% non-flavonoid glycosides, and 4.0 polymer compounds. %, inorganic matter 5.0%, moisture solvent 3.0%, others 3.0%.

Antioxidant Characteristics and Mechanism

Ginkgo leaf extract can directly eliminate lipid free radicals, lipid peroxidation free radicals alkane free radicals, etc., and terminate the free radical chain reaction chain. At the same time, it can also regulate and improve the activity of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase. The antioxidant effect of flavonoids in EGB exceeds that of vitamins, and it has anti-free radical attack properties in vitro.

The antioxidant effects of ginkgo extracts extracted by different methods are different, and the antioxidant effects of crude extracts and refined products are also different. Ma Xihan et al. found that petroleum ether-ethanol extract had the strongest antioxidant effect on rapeseed oil compared to Ginkgo leaf extracts obtained by different preparation methods. The antioxidant capacity of the crude Ginkgo leaf extract was slightly higher than that of the refined extract. This may be due to the crude The extract contains other antioxidant ingredients, such as organic acids, amino acids, tannins, alkaloids, and other substances that have synergistic effects.

Preparation Method

(1) Organic solvent extraction method At present, the most widely used method at home and abroad is the organic solvent extraction method. Since other organic solvents are toxic or volatile, ethanol is generally used as the extraction agent. Experiments by Zhang Yonghong and others showed that the best conditions for extracting flavonoids from ginkgo leaves are 70% ethanol as the extraction solution, the extraction temperature is 90°C, the solid-liquid ratio is 1:20, the number of extractions is 3 times, and each time refluxes for 1.5 hours.

(2) Enzyme extraction method Wang Hui et al.’s experiments showed that the yield of total flavonoids was significantly increased after the ginkgo leaf raw materials were pretreated with cellulase and extracted, and the yield could reach 2.01%.

(3) Ultrasonic extraction method After ultrasonic treatment of ginkgo leaves, the cell membrane has been broken, and the movement of leaf particles has been accelerated, which promotes the dissolution of active ingredients. Therefore, ultrasonic extraction of flavonoids has great advantages. The experimental results obtained by Liu Jingzhi et al. show that the process conditions of ultrasonic extraction are: ultrasonic frequency 40kHz, ultrasonic treatment time 55min, temperature 35°C, and standing for 3h. At this time, the extraction rate is 81.9%.

Application

The flavonoids in Ginkgo leaves have antioxidant properties and can be added to oils and pastries as antioxidants. The total flavonoids are mostly yellow and have wide solubility, both water-soluble and fat-soluble, so the total flavonoids can be used for coloring. agent effect. Ginkgo biloba is processed into ultrafine powder and added to food. Ginkgo leaves are ultra-finely pulverized and added to cakes, biscuits, noodles, candies, and ice cream at a rate of 5% to 10% to process them into ginkgo leaf foods with health care effects.
Ginkgo leaf extract is used as a food additive in Canada and has been approved as an over-the-counter drug in Germany and France. Ginkgo leaf is included in the United States Pharmacopoeia (24th edition) and can be used as a dietary supplement in the United States.

Pharmacological Effects

1. Effect on the cardiovascular system
(1) Ginkgo leaf extract can inhibit the activity of angiotensin-converting enzyme (ACE) in normal human serum, thereby inhibiting the contraction of arterioles, dilating blood vessels, and increasing blood flow.
(2) Ginkgo leaf extract can prevent a myocardial decline in male rats caused by intravenous injection of bupivacaine, inhibit coronary artery contraction in humans and pigs caused by hypoxia, and eliminate PAF (platelet-activating factor) causing arrhythmia in dogs. It can inhibit cardiac dysfunction caused by cardiac allergies in isolated guinea pigs.
(3) Ginkgo leaf extract can significantly expand the cerebral blood vessels of anesthetized cats and dogs, increase cerebral blood flow, and reduce cerebral vascular resistance. Ginkgo leaf extract can prevent the increase in mesenteric microvascular diameter caused by intravenous endotoxin. In the canine endotoxin model, Ginkgo biloba extract inhibits hemodynamic changes; in the sheep lung model, Ginkgo biloba extract inhibits hypertension and pulmonary edema caused by lymphatic flow disorder caused by endotoxin.
(4) Rats were intraperitoneally injected with 5ml/kg of ginkgo leaf flavonoids daily. After 40 days, the serum triglyceride content was significantly reduced. Ginkgo biloba extract (20 mg/kg per day) was administered orally to rabbits receiving a normal and hypercholesterolemic diet. After one month, the levels of hyper-esterified cholesterol in the plasma and aorta of the rabbits receiving an atherogenic diet were significantly reduced. However free cholesterol levels remained unchanged.
(5) Ginkgo terpene lactone is a highly specific PAF receptor blocker. Ginkgo leaf extract or ginkgo terpene lactone can inhibit platelet-activating factor (PAF) and cyclooxygenase or lipoxygenase. Ginkgo leaf extract was well tolerated and antagonized platelet aggregation caused by PAF but did not affect aggregation caused by ADP.

2. Effect on the central nervous system
(1) Ginkgo leaf extract affects the endocrine system and the interaction between the immune system and the central nervous system by inhibiting the action of PAF. It can promote brain circulation metabolism and improve memory function.
(2) Ginkgo terpene lactones have antidepressant effects, and their antidepressant effects are related to the central monoaminergic nervous system.
(3) In addition to the fact that Ginkgo leaf extract can significantly improve the deficit-type memory impairment caused by NaNO2, its anti-hypoxic effect may be related to its increase in cerebral blood flow and improvement of brain energy metabolism during hypoxia.
(4) Ginkgo leaf extract greatly improves the brain behavioral disorders of gerbils caused by ligation and recirculation of both carotid arteries and prevents brain damage in gerbils caused by ischemia and congestion; enhances the function of dogs after multi-focal brain ischemia Early neuronal recovery and reduction of neuronal damage following ischemia in the hippocampus of the gerbil brain; greatly reduces the loss of ATP, AMP, creatine and creatine phosphate in the ischemic brain of the mongrel dog. Ginkgo biloba lactone B is useful in the clinical treatment of stroke.

3. Effect on the digestive system
(1) Ginkgo leaf extract can significantly improve gastric and intestinal ulcers in mice caused by PAF and endotoxin, and can partially inhibit gastric damage caused by ethanol.
(2) In mice with liver cirrhosis caused by bile duct ligation, intravenous injection of ginkgo leaf extract significantly reduced hepatic portal venous pressure, cardiac index, blood flow of portal vein branches, and improved systemic vascular tolerance compared with placebo. This shows that ginkgo leaf extract has a potential therapeutic effect on liver cirrhosis. It can block the formation of oxygen-free radicals in mouse acute pancreatitis caused by cholecystokinin. Ginkgo terpene lactone B may have a role in the treatment of acute pancreatitis.

4. Effect on the respiratory system
(1) The ethanol extract of Ginkgo biloba has a direct relaxing effect on tracheal smooth muscle and can relieve the spasmodic effects of histamine phosphate and acetylcholine on the isolated trachea of guinea pigs, and prevent histamine-induced asthma attacks in guinea pigs.
(2) Intravenous injection of Ginkgo leaf extract can inhibit the bronchoconstriction and hyperresponsiveness of mice induced by PAF and ovalbumin, and prevent the bronchoconstriction caused by antigens, but does not affect the bronchial hyperresponsiveness caused by indomethacin.
(3) Inhalation of aerosolized Ginkgo leaf extract not only inhibits bronchoconstriction but also inhibits the reduction of white blood cells and eosinophils caused by PAF. Ginkgo leaf extract is of great significance in inhibiting and treating bronchial hyperresponsiveness.

5. Anti-aging effect
Ginkgobiflavonoids, isoginkgobiflavonoids, ginkgo biloba, and quercetin in ginkgo leaves all inhibit lipid peroxidation, especially since quercetin has stronger inhibitory activity. Experiments were conducted on rats and it was found that water-extracted ginkgo leaf total flavonoids (0.95mg/ml) could significantly reduce lipid peroxidation, and acid-extracted ginkgo leaf total flavonoids (1.9mg/ml) could increase serum copper and zinc SOD activity and reduce The effect of blood viscosity while reducing SGPT activity.

7. Role in transplant rejection and other immune reactions
Ginkgo leaf extract can prolong the survival time of skin grafts, heterotopic heart xenografts, and orthotopic liver xenografts. Ginkgo leaf extract can inhibit the body's natural killer cell activity against KC526 target cells, and can also prevent the natural killer cell activity caused by interferon.

8. Anti-tumor effect
The crude extract of the green leaves of Ginkgo biloba, the fat-soluble part, can inhibit the Epstein-Barr virus. Heptadecene salicylic acid and bilo-betin have strong inhibitory activity; the total flavonoids of Ginkgo can increase the thymus weight of tumor-bearing mice. and SOD activity levels, mobilizing the body's inherent anti-tumor ability; quercetin and myricetin can inhibit the occurrence of carcinogens.

Notes and Contraindications

Adverse reactions of Ginkgo leaf extract: Occasionally gastrointestinal discomfort, such as anorexia, nausea, constipation, loose stools, abdominal distension, etc.; there may also be increased heart rate, fatigue, etc., but these do not affect the treatment. After long-term oral administration, relevant indicators of blood rheology should be reviewed regularly. If you have gastrointestinal symptoms, you can take it after meals instead.

Drug Interactions

This product has a synergistic effect when used in combination with other blood viscosity-lowering drugs, such as sodium alginate diester, acetate, etc., which can improve efficacy.

Development Trend

Ginkgo leaves contain a small amount of proanthocyanidins and urushiolic acids, which are still toxic to the human body. When ginkgo leaves as raw materials to process food, special treatment is required to reduce the content of proanthocyanidins and urushiolic acids. However, within the currently used dose range, there is no acute or chronic toxicity and no teratogenic effects. The Ministry of Health approved Ginkgo biloba extract as a new food additive in 1992. In recent years, Ginkgo biloba total flavonoids have been widely used in the food industry, and the research and development of Ginkgo biloba has broad prospects.