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Dr. Pan's Clinic of TCM
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Pu huang
Common name: typha pollen / cattail pollen/ bulrush Species: Typha angustifolia by Stephanie Curran TCM properties ¨C sweet, acrid, neutral
Channels entered ¨C Liver, Heart, Spleen
TCM Actions & Indications
- stops bleeding - invigorates blood and dispels blood stasis - promotes urination and stops bleeding
Chemical Composition
Flavonoids: typhaneoside, quercetin, quercetin-3-0-neohesperidoside, kaempferol, kaempferol-3-0rhamnosylglucoside, isorhamnetin, naringenin
Volatile oil: 2,6,11,14-tetramethyl-nonadecane, methyl palmitate, palmitic acid, 2-octadecenol, 2-pentylfuran, B-pinene, 7-methyl-4-triacontanone, 6-triacontanol, pentacosane, methyloctadeca-8, 11-dienoate, 1,2-dimethoxtbenzene, 1-methylnaphthalene, 2,7-dimethylnaphthalene
Steroles: B-sitosterol, B-sitosterol glucoside, B-sitosterol palmitate
Other constituents: polysaccharides, organic acids, amino acids
Pharmacology
1. Effects on the Cardiovascular System
Low concentrations of the ethanol extract of puhuang increased the contractility of isoluated toad hearts, but high concentrations had the opposite effect. The ethanol extract also decreased the rate of isolated hearts of rabbits and guinea pigs, large doses of it inhibited the heart, precipitating cardiac arrest at the diastolic phase. At doses slightly smaller than that required to inhibit the myocardium, the ethanol extract increased the coronary flow in isolated rabbit hearts with or without electrically induced fibrillation, by 43 and 35% respectively. This effect which was accompanied by ECG improvement was especially prominent when coronary constriction was induced by pituitrin injection; the coronary flow was increased by 76%. Intramuscular injection of puhuang fluidextract 0.6g (crude drug) increased the Rb uptake of the mouse myocardium by 27.9% (P<o.o1), but reducing the dose to one-half or orally administering 2.5 times this dose for 10 days produced no significant influence on the myocardial microcirculation of the animals. The proportion of the alcohol-precipitated aqueous extract absorbed onto the strong acid cation exchange resin (heretofore called the absorbed agent) had significant cardiovascular effects. In the lung-heart specimen of dogs, the absorbed agent increased the cardiac output per unit time, increased the aortic pressure, lowered the central venous pressure, accelerated the heart beat, improved T wave on the ECG and increased the index of cardiac function, but it did not significantly change the stroke volume. Blockage of the B-receptors by alpronolol, however, abolished the effect of the absorbed agent on the heart rate of the lung-heart preparation of dogs; the stroke volume was markedly increased while the other effects remained unchanged. These findings indicate a possible connection between the positive chronotropic action and B-receptor stimulation. Nevertheless, the absorbed agent injected intravenously was found to decrease the heart rate of anesthetized dogs, and this negative chronotropic effect could be annulled by atropine or hexamethonium bromide, suggesting that the drug inhibits the heart of intact animals through the vagus nerve ganglion or vagus centre. It was also shown that the negative chronotrpoic action of the drug overcame its direct positive chronotropic effect; thus, it is inferred that the drug has diametrically opposed effects in intact animals and isolated hearts. Puhuang extract has vasodilatory effect on the rabbit ear. Intraperitoneal injection of the fluidextract increased the arteriorlar blood flow and the number of open capillaries in the hamster cheek pouches but did not significantly alter the caliber of arterioles. The ethanol extract 30mg/kg injected into the femoral artery of anesthetized dogs increased the femoral artery blood flow by 75-570% and decrease the peripheral resistance coefficient by a mean of 62.7%. Likewise, the absorbed agent caused vasodilation which was not blocked by alprenolol, implying no relationship with B-recptors. The alcohol-fractionated aqueous extract directly caused weak peripheral vasodilation. Intravenous injection of the puhuang decoction, ethanol extract, or the absorbed agent to anesthetized cats, rabbits and dogs decreased the blood pressure and heart rate; intraperitoneal injection of these agents also caused mild hypotension in dogs. Hypotension, bradycardia and decreased vascular resistance of hind limbs elicited by pu huang were partially or completely abolished by blocking the muscarinic receptors or nerve ganglions with atropine or hexamethonium bromide injection. It is postulated that the hypotension and lowering of vascular resistance were probably linked to the cholinergic receptor and central reflex regulation, and that vasodilation might be the chief cause of acute hypotension. Within the range of therapeutic dosages, however, the orally administered puhuang showed no clinical effect on normal blood pressure. Moreover, intraperitoneal injection of large doses of the puhuang preparation increased the tolerance of mice to hypobaric hypoxia. The injection of ˇ°Shi Xiao Powerˇ± (equal amounts of Pollen Typhae and Faeces Trogopterori) increased the tolerance of miceto hyobaric hypoxia, antagonizing pituitrin-induced acute myocardial ischemia in rats, suppressed the spontaneous activity of mice and lowered the blood pressure of conscious rabbits which was weaker and shorter than that induced by hexamethonium bromide.
2. Hypocholesterolemic and Antiatherosclerotic Effects
In studies where rabbits were fed initially with high fat feed plus puhuang 16g/animal/day for 12 weeks and then with ordinary feed plus puhuang for another 4 weeks, it was discovered that the treatment group had markedly lower serum cholesterol level and milder aortic plaque formation and coronary atherosclerosis lesions than the control group. Electron microscopy revealed that the majority of the animals in the treatment group had intact and smooth aortic endothelium, normal subendothelium, and occasionally marginal cellular infiltration and lipid deposition. In contrast, most of the animals in the control group had markedly thickened aortic subendothelium, large amounts of intracellular and extracellular lipid deposits, and large numbers of foam cells and smooth muscle cells penetrating the subendothelium through the cracks of the internal elastic lamina. Further studies revealed that in the treatment groups, the fecal cholesterol was greatly increased and the absorption of the orally administered I-cholesterol was rather slow, but they had no correlation with the serum cholesterol level. Consequently, the hypolipemic mechanism is believed to involve the inhibition of intestinal absorption of exogenous cholesterol, and reabsorption of cholic acid and endogenous cholesterol, thus promoting the excretion of cholesterol and cholic acid into the bile and intestinal lumen. Active studies are on-going to determine whether or not puhuang influences cholesterol synthesis in the liver.
3. Anti-inflammatory Effect
External application with concentrated puhuang decoction produced a striking anti-inflammatory effect on scalds of rat hind limbs and also hastened the resolution of the intradermally injected Evans blue in rats. A detumescent effect was also achieved by intraperitineal injection of the alcohol-fractionated decoction of the herb in rats with egg white-induced paw swelling; it reduced vascular permeability increased by local injection of histamine in rats and mice. In summing up the effects of puhuang including that on the microcirculation of the hamster cheek pouch, it is preliminarily held that the detumescent effect was due to improvement of local circulation, fascilitation of reabsorption, and lowering of the capillary permeability (13).
4. Coagulant effect
The puhuang decoction was proved in vitro to promote the coagulation of human blood (14). Intragastric administration of the aqueous extract or the50% ethanol extract of this herb to rabbits significantly shortened the clotting time (6). The clotting time was also shortened following intragstric administration of the herb decoction to rabbits, especially on the first day (15). The crude puhuang by mouth also reduced the clotting time in rabbits and the bleeding time in mice. Oral administration of carbonized puhuang was even more effective than administration of the crude drug (16,17) Subcutaneous injection of puhuang extract to rabbits increased the platelet count and shortened the prothrombin time (6). Homeostasis was achieved by external application of the puhuang powder to experimental bleeding from femoral artery of anesthetized dogs (18). The bioactive principle responsible for shortening the clotting time and initiating homeostasis is thought to be isorhamnetin (19).
5. Effect on Uterus
The decoction, tincture and ether extract of puhuang had stimulant effect on isolated uteri of guinea pigs, rats and mice, and at large doses caused spastic contraction. More pronounced effect was achieved on non-pregnant than on pregnant uteri (2,6,8). The ethanol extract also caused rhythmic contraction of the isolated uterus of pregnant rabbits and increased the tonicity of the isolated uterus of the non-pregnant animals (3). Experiments on in situ uteri of anesthetized dogs and rabbits and uterine fistulae of rabbits showed that the puhuang decoction, tincture or ether extract at doses of 0.05-0.2g/kg IV produced uterine excitation (2). The herb increased uterine contractility or tonicity in postpartum women (8).
6. Effect on Intestinal Tract
The puhuang extract enhanced peristalsis of the isolated rabbit intestine, increased the tone and its rhythmic contraction of the isolated duodenum of rats or guinea pigs. These effects can be blocked by atropine (3,6). On the other hand, with potency of 57% of that of papaverine, isohamnetin isolated from this herb produced a spasmolytic effect on the isolated intestine of mice (20).
7. Miscellaneous Actions
Intravenous injection of the ethanol extract of puhuang to anesthetized dogs produced a choleretic effect (21). Crude or carbonized puhuang was proved to be inactive against hemolytic Staphylococcus aureus and various dysentery bacilli in vitro (17). An early paper reported that the 1:100 puhuang decoction inhibited growth of mycobacterium tuberculosis in vitro and the intragastrically administered decoction had definite effectiveness in guinea pigs with experimental tuberculosis (22). In addition, clinical observation showed that puhuang has diuretic and antiasthmatic effects (13).
8. Toxicity
No death of mice occurred after injection of the ethanol extract of puhuang 500 mg/kg IV (6). In experiments with the lung-heart specimen of dogs, myocardial inhibition or arrhythmia were not observed in 2 hours after perfusion with 152 g (crude drug) / 800ml (blood volume) of the absorbed agent. The results indicated that the herb has a low toxicity and a wide safety range (5).
Indications
- coronary diseases and hyperlipidemia - postpartum blood retention and abdominal cramping - functional uterine bleeding, hematuria, bloody stool, etc - eczema - fungal infection of the oral cavity
Adverse effects
No significant side effects have been reported with the therapeutic dosage of puhuang. However, it is contraindicated in pregnant women because it contracts the uterus. Extra-amniotic administration of the sterile solution of the herb was reported to produce transient chilliness and elevated body temperature (<39ˇăC) in some patients, which recovered spontaneously. ECG shows that the herb does not aggravate the condition of patients with severe heart disease.
References
Bensky, Dan et al, Materia Medica 3rd Edition, Eastland Press Inc, 2004; pg 563-4
Chang, Hson-Mou et al, Pharmacology and Applications of Chinese Materia Medica: V.2 World Scientific 1987; pg 1267-1272
Research
http://www.wipo.int/pctdb/en/wo.jsp?wo=2004009575&IA=CN2003000577&DISPLAY=STATUS
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Last modified: 12/13/10 |