a. The effect on heart function: Ginseng has the effects of excitement first and then inhibition on the hearts of various animals, a small amount of excitement, and a large amount of inhibition. Its effect on the heart is similar to that of cardiac glycosides, which can improve myocardial contractility. Larger doses weaken contractility and slow the heart rate. Experiments have shown that the alcohol extract and water infusion of red ginseng can strengthen the contraction of the isolated frog heart, and finally stop at the systolic period; it can also strengthen the contraction and reduce the heart rate of the in-situ heart of dogs, rabbits, and cats. slow. These effects are mainly due to the direct excitation of the myocardium. For animals with massive blood loss and acute circulatory failure (slow heart rate and weak heart power), ginseng can make the heart rate increase abnormally and the heart rate significantly increase. Ginsenosides have a strong anti-arrhythmia effect induced by barium chloride, have a strong corrective effect on the resulting tachycardia, and can make the heart rate return to a normal level. There are reports that ginseng fruit or ginseng root saponins can counteract experimental arrhythmias induced by adrenaline. Ginsenosides have a two-way regulation effect on the content of cAMP and cGMP in cardiomyocytes, so maintaining the balance of cAMP and cGMP is also a factor against arrhythmia under stress. Total saponins from ginseng stems and leaves have a protective effect on experimental sinus node dysfunction in rabbits.
The effect of ginseng on heart function is mainly to increase myocardial contractility, slow down heart rate, increase cardiac output and coronary blood flow. Studies suggest that the mechanism of ginseng's cardiotonic effect may be related to its inhibition of Na+, K+-ATPase activity, promotion of catecholamine release or increase of myocardial cAMP/cGMP ratio. There are also reports that the cardiotonic effect of ginseng is related to the metabolism of cyclic nucleotides in the myocardium. Ginseng can increase the content of cAMP in cultured cardiomyocytes. The total saponins of the aerial part of ginseng can increase the content of cAMP in toad myocardium, significantly reduce cGMP, and significantly increase the ratio of cAMP/cGMP.
b. The effect on the myocardium: Ginseng has a protective effect on the myocardium. Ginsenosides can reduce the lactic acid content of the brain and myocardium in mice under severe hypoxia, restore the myocardial cAMP/cGMP ratio during hypoxia, protect myocardial capillary endothelial cells and reduce mitochondrial damage. The saponins extracted from ginseng stems and leaves, reed heads, fruits and main roots, etc., have obvious myocardial protective effects on rat myocardial necrosis caused by isoproterenol, and can reduce the damage, especially the effect of ginseng fruit saponins better. Saponins from different parts of ginseng have similar effects to propranolol. The total saponins of ginseng and reed head can promote the DNA synthesis of cardiomyocytes cultured in vitro, and have a certain protective effect on the cardiomyocytes cultured by hypoxia and glucose deficiency. Studies suggest that the mechanism of total ginseng saponins against myocardial ischemia and reperfusion injury is to promote myocardial production and release of prostaglandins, inhibit the generation of thromboxane A2, and protect cardiomyocytes through anti-oxygen free radicals and anti-lipid peroxidation .
c. Effect on blood vessels: The effect of ginseng on blood vessels is generally considered as a vasodilator, but there are also reports of contraction in small doses, expansion in large doses, or first contraction and then expansion. The effect of ginseng on blood vessels is different because of the different types of blood vessels or the state of the body. Ginseng has a contraction effect on rabbit ear blood vessels and rat hind limb blood vessels. However, it has a dilating effect on the coronary arteries, cerebral blood vessels, and fundus blood vessels of the whole animal. Intravenous injection of total saponins can reduce hindlimb vascular and cerebrovascular resistance in dogs, but increase renal vascular resistance in rats. Ginsenosides Rg1 and Re also have an expansion effect on canine blood vessels, and the effects are 1/20 and 1/50 of that of papaverine respectively. The effects of Rc and Rb2 are very weak, while Rb1 is ineffective. Studies on the active ingredients and mechanism of action of ginseng affecting vascular function have shown that ginsenosides Rb1 and R0 are non-selective in dilating blood vessels, while Rg1 is only selective against Ca++-induced vasoconstriction, and its mechanism of action remains to be further studied. Some people think that the different regulatory effects of ginseng on blood vessels of different types and different physiological states may be the reason why ginseng regulates blood pressure in both directions.
d. Effects on blood pressure: most of the data show that: in normal or hypertensive animals, ginseng has the effect of lowering blood pressure, but there are also reports of raising blood pressure. Ginseng can increase blood pressure in small doses and lower blood pressure in large doses on the blood pressure of anesthetized animals. The therapeutic dose had no significant effect on the patient's blood pressure. The boosting effect of ginseng may be related to the shrinkage of the kidneys and spleen, and the contraction of visceral blood vessels. The lowering of blood pressure is due to the release of histamine. Anesthetized dogs have tachyphylaxis to the antihypertensive effect of ginseng. Ginsenosides Rb1, Rb2, Rc, Rd, Re, and Rf have a bidirectional effect on blood pressure, which first increases slightly and then decreases, and Rg1 is the strongest, and high doses of Rb1 increase blood pressure. However, its effect on blood pressure was not affected by atropine, diphenhydramine, phenazoline and propranolol. Intravenous injection of ginseng ether extract 40mg/kg can slow down the heart rate and central venous pressure of dogs under mild halothane anesthesia. It is worth noting that: intravenous injection of ginseng extract can revive cats whose breathing has stopped, blood pressure has dropped, and reflexes have completely disappeared.
It is generally believed that the mechanism of ginseng's antihypertensive effect is: ginseng has a cholinergic effect; the short-term antihypertensive effect of red ginseng ether extract is related to the release of histamine, and then the long-lasting antihypertensive effect is due to other reasons; It can lead to a decrease in intravascular Ca++, and its antihypertensive effect is the result of the effect of ginseng on vascular smooth muscle. Ginsenoside Rb1 has a lasting antihypertensive effect; because the antihypertensive effect of ginseng can be eliminated after removing the animal brain or using ganglion blockers, Therefore, the antihypertensive effect of ginseng may be involved in the central nervous system and reflex mechanism.