Although shepherd's purse is a wild vegetable, its nutritional value is by no means inferior to that of expensive medicinal herbs. Shepherd's purse has many health benefits, which are documented in detail in traditional Chinese medical works such as "Qian Jin Fang Shi Zhi", "Ming Yi Bie Lu", and "Dian Nan Ben Cao".
1. Effect on the Uterus
Shepherd's purse has an effect similar to ergot. Its extract, when tested on isolated animal uteri or intestinal tubes, showed significant contraction. The alcohol extract of the whole plant has an oxytocin-like uterine contraction effect. The active ingredients of the whole plant can cause contraction of the isolated uteri of mice and rats. It can also enhance the contraction of isolated uteri in rats (non-pregnant), in vivo uteri in rabbits (both pregnant and non-pregnant), and in vivo uteri in cats (non-pregnant). Intravenous injection into rabbits with a uterine fistula (equivalent to 0.08-0.8g/kg of the crude drug) resulted in strengthened uterine contractions, with a slight increase in muscle tension and frequency; the same effect was observed with a decoction administered by gavage (equivalent to 5.263g/kg of the crude drug). The active ingredient responsible for the uterine excitement is soluble in water and aqueous alcohol, but insoluble or very difficult to dissolve in pure alcohol, petroleum ether, anhydrous ether, or anhydrous chloroform. The extract of shepherd's purse also has a strong effect on the uterus of unmated guinea pigs (fresh juice and dried herb are similar in effect).
2. Hemostatic Effect
Shepherd's purse contains bursic acid, which has a hemostatic effect. The extract of shepherd's purse (containing oxalic acid), when administered intravenously or intramuscularly (2-3ml each time, every 2-4 hours, with a maximum of 15ml per day) to patients with various types of bleeding, shows a significant hemostatic effect. For patients with hemophilia, it can increase the resistance of blood clots. When a decoction of shepherd's purse was administered to mice by gavage, a small dose (equivalent to 0.02g of crude drug per 10g of body weight) shortened the bleeding time in more than half of the mice, while a larger dose (equivalent to 0.06g of crude drug per 10g of body weight) prolonged the bleeding time in most mice. Intraperitoneal injection of the liquid extract's volatile fraction into mice shortened the bleeding time (more significant with larger doses). Intravenous injection of the volatile fraction of the liquid extract into rabbits shortened the clotting time. However, there are also contradictory reports. Shepherd's purse grown in hot climates and in the dry soil conditions of Samarkand, when made into a 10% infusion and injected subcutaneously into rats, significantly prolonged blood coagulation time and instead caused bleeding. A 0.1ml dose of 10% shepherd's purse extract had no effect on rabbit coagulation.
3. Effect on the Heart and Blood Vessels
The alcohol extract of shepherd's purse, when administered intravenously to dogs, cats, rabbits, and rats, produces a transient drop in blood pressure, an effect that is not antagonized by 80μg/kg of atropine. The active ingredients of the whole plant also cause a transient drop in blood pressure in mice, cats, rabbits, and dogs, which also cannot be antagonized by atropine but can be inhibited by pronethanol; there were no changes in the electrocardiogram, and it had a dilating effect on the coronary vessels of the in vivo dog heart and the isolated guinea pig heart. It can also inhibit fibrillation of the isolated cat heart caused by ouabain. Intravenous injection of shepherd's purse extract into rabbits lowers blood pressure but does not reverse the effect of adrenaline. The decoction or volatile fraction of the liquid extract of shepherd's purse has a transient blood pressure-lowering effect in anesthetized dogs, which can be counteracted by pre-administering atropine. Intravenous injection of the dried extract of shepherd's purse can rapidly lower a dog's blood pressure to 40-50% of its original level. It can also lower the blood pressure of chicks. Perfusion of the frog's hind limb blood vessels with the alcohol extract of shepherd's purse (20%-0.5ml) had no effect; the dried extract of shepherd's purse, at high concentrations (10%), caused vasoconstriction, while at low concentrations (below 2%), it caused vasodilation. The alcohol extract had a vasodilatory effect on the hind limb vessels of dogs. It was previously thought that its blood pressure-lowering effect was related to its contained choline and acetylcholine, but these two substances were not found in the alcohol extract of shepherd's purse; instead, a quaternary ammonium compound different from acetylcholine was discovered.
4. Other Effects
The extract of shepherd's purse can prolong the sleeping time of hexobarbital. Intravenous injection of the decoction or volatile fraction of the liquid extract of shepherd's purse into anesthetized dogs excites respiration; this effect is not even influenced by pre-administering atropine. However, there are also reports that the dried extract of shepherd's purse can reduce the dog's respiratory movement to 20-50% of its original level, and sometimes even more. The active ingredients of the whole plant of shepherd's purse can cause contraction of the trachea and small intestine smooth muscles. After first causing mild inhibition of the guinea pig's small intestine with atropine, the alcohol extract of shepherd's purse can then cause the intestine to contract and then return to its original state. Furthermore, intraperitoneal injection of the alcohol extract of shepherd's purse can inhibit dextran-induced, carrageenan-induced edema in the rat's hind limb, and the increase in capillary permeability caused by 5-hydroxytryptamine; it has a 90% inhibition rate on Shay ulcers and can accelerate the healing of stress ulcers. It has a diuretic effect in mice. For rabbits with artificial fever, shepherd's purse has a slight antipyretic effect.