Studies on diuretic and hypouricemic effects of Orthosiphon stamineus methanol extracts in rats

AIM OF THE STUDY: Orthosiphon stamineus (Labiatae) is a traditional folk medicine widely used in Southeast Asia for the treatment of several kidney disorders, gout and as a diuretic. This study was conducted to examine the diuretic and hypouricemic effects of Orthosiphon stamineus leaf extracts. MATERIALS AND METHODS: The diuretic effect of different methanol extracts was examined by treating different groups of Sprague-Dawley rats with single (2g/kg) oral doses of methanol and methanol:water (1:1) extracts. Hydrochlorothiazide (10mg/kg) was used as positive control in acute study. Methanol and methanol water (1:1) extracts at 0.5 g/kg were administered for a period of 7 consecutive days. Cumulative urine volume and electrolytes (Na+ and K+) concentrations at different time intervals were measured. On the other hand, hypouricemic activity of methanol:water extract (1:1) was experimented using different oral single doses (0.25, 0.5, 1 and 2g/kg). Allopurinol was used as positive control. Uric acid concentration in serum was analyzed by using RP-HPLC at 280 nm. RESULTS: Sodium and potassium excretion increased significantly (p<0.05 and <0.01) in the first 8h of treatment with a single dose (2g/kg) of the extracts in a pattern comparable to that of the known diuretic hydrochlorothiazide. Meanwhile, repeated administration of 0.5 g/kg methanol:water (1:1) extract showed a significant increase in urine volume (from day 3 to day 7) (p<0.01) and electrolytes excretion (Na+ and K+) from day 2 to day 7 (p<0.05 and <0.01). On the other hand, 0.5, 1 and 2g/kg of methanol:water (1:1) extract and the standard allopurinol reduced the serum urate level in hyperuricemic rats at hour 6. CONCLUSION: These results provided an evidence of the high tendency of methanol:water (1:1) extract of Orthosiphon stamineus towards diuretic and hypouricemic effects in rats.     

Antimicrobial, anti-inflammatory, anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil

In the Moroccan traditional medicine, the ripe fruits of Carum carvi L. (Apiaceae) and the leaves of Tanacetum vulgare L. (Asteraceae/Compositae), two widely available plant materials, are used as diuretics. Since, the diuretic activity of these substances has not been investigated in scientifically controlled studies, the aim of the present study was to evaluate the diuretic potential of aqueous extracts of Carum carvi fruit (caraway) and the leaves of Tanacetum vulgare (tansy) in normal rats after acute and sub-chronic oral administration. Water extracts of Carum carvi and Tanacetum vulgare (100 mg/kg) or the reference drug, furosemide (10 mg/kg) were administrated orally to male Wistar rats and their urine output was quantitated at several intervals of time after the dose. After single doses of the extracts of both caraway seeds and tansy leaves, urine output was significantly increased at all time points, and at 24 h after the dose, the total volume of urine excreted was similar for the plant extracts and furosemide. Both extracts increased urinary levels of Na⁺ and K⁺, to about the same extent, while furosemide increased urinary levels of only Na⁺ and decreased urinary K⁺. Despite changes in urinary excretion of the electrolytes, plasma Na⁺ and K⁺ levels were not affected by any of the three substances. In the 8-day sub-chronic study, all three substances induced significant diuresis and natriuresis; only tansy increased urinary potassium excretion. The plant extracts did not appear to have renal toxicity or any other adverse effects during the study period. In conclusion, water extracts of both Carum carvi and Tanacetum vulgare have strong diuretic action confirming their ethnopharmacological use. From the pattern of excretion of water, sodium and potassium, it may be deduced that there are atleast two types of active principals present in these extracts, one having a furosemide-like activity and the other a thiazide-like activity.     

Euphorbia hirta leaf extracts increase urine output and electrolytes in rats.

Euphorbia hirta is locally used in Africa and Australia to treat numerous diseases, including hypertension and edema. The diuretic effect of the E. hirta leaf extracts were assessed in rats using acetazolamide and furosemide as standard diuretic drugs. The water and ethanol extracts (50 and 100 mg/kg) of the plant produced time-dependent increase in urine output. Electrolyte excretion was also significantly affected by the plant extracts. The water extract increased the urine excretion of Na+, K+ and HCO3-. In contrast, the ethanol extract increased the excretion of HCO3- decreased the loss of K+ and had little effect on renal removal of Na+. Acetazolamide, like the water extract, increased urine output and enhanced the excretion of Na+, K+ and HCO3-. The high-ceiling diuretic, furosemide, increased the renal excretion of Na+ and Cl-; but had no effect on K+ and HCO3- loss. This study suggests that the active component(s) in the water extract of E. hirta leaf had similar diuretic spectrum to that of acetazolamide. These results validate the traditional use of E. hirta as a diuretic agent by the Swahilis and Sukumas.     

Diuretic activity of some Smilax canariensis fractions

Ethnopharmacological relevance

Smilax canariensis is an endemic species of the Canary Islands, popularly known as “Zarzaparrilla sin espinas”. The rhizome, leaves and stem of this species has wide use in folk medicine practice on the islands, where they are habitually employed as diuretic.

Aim of the study

In this paper we report on the diuretic activity in experimental animals of several fractions of the methanol extract of this species.

Materials and methods

Four fractions of the methanol extract of the rhizomes, leaves and stem of Smilax canariensis (50 and 100 mg/kg), Furosemide and Hydrochlorotiazide (10 mg/kg), were orally administered to laboratory animals to evaluate their diuretic activity. Water excretion rate, pH, conductivity, and content of Na⁺, K⁺ and Cl⁻ were measured in the urine of saline-loaded mice.

Results

All the studied extracts showed an interesting increase of the diuresis, although the n-buthanol (27%; p < 0.05) and ethyl acetate extract (35%; p < 0.01), at 100 mg/kg p.o., showed the most interesting diuretic activity, which suggested that this diuretic effect is associated with the compounds contained in the fractions of intermediate polarity (ethyl acetate and n-butanol), decreasing in the most extreme apolar and polar sub-extracts (dichloromethane and methanol: water respectively). The increase in diuresis produced by these two extracts was very close to the values of Hydrochlorothiazide (32%) or Furosemide (39%), used as reference diuretics.

Conclusions

These data, together with previous results on the aqueous and methanol extracts, reaffirm assertions made regarding the effectiveness of the extracts of this plant against urinary pathologies in the Canary Islands folk medicine.     

Diuretic activity of the stem-bark extracts of Steganotaenia araliacea hochst [Apiaceae

The diuretic activity of the stem-bark extracts of Steganotaenia araliacea (SbESa) and effects on urine electrolytes in rats was studied. Furthermore, a toxicological effect of the SbESa on several tissues was investigated. Groups of male Wister albino rats (170 +/- 0.77 g) were employed. Four doses of 20mg/kg body weight (b.w.), of SbESa (water, methanol, ethanol) and furosemide were administered intraperitoneally (IP). The control group received normal saline alone by oral administration. The 24-h urine outputs per day (in ml) were: normal saline (1.57 +/- 0.11); water extract (3.18 +/- 0.24); methanol extract (3.22 +/- 0.29); ethanol extract (3.62 +/- 0.27) and furosemide (4.22 +/- 0.23). The urine output among the extracts (water, methanol, ethanol) and the furosemide against the control was statistically significant, (P < 0.05), (P < 0.05), (P < 0.02), and (P < 0.01), respectively. The ethanol preparation gave the highest diuretic activity among the extracts. There was marked increase in K(+) ion excretion (122 +/- 7.3 mMol/l) in the ethanol extract as compared to control (95.8 +/- 1.2 mMol/l) and furosemide (standard) (90.05 +/- 0.1 mMol/l). The LD(50) of 1.75 g/kg body weight was observed and the histopathological examination reveals damage to vital organs. The authors conclude that though there are compelling evidence of diuretic potentials in the use of the stem-bark of Steganotaenia araliacea, the toxic effects on vital organs is a drawback to its recommendation for use as a diuretic agent.     

Antispasmodic and blood pressure lowering effects of Valeriana wallichii are mediated through K+ channel activation

Crude extract of Valeriana wallichii rhizome (Vw.Cr) and its fractions were studied for possible antispasmodic and blood pressure lowering activities to rationalize some of the folkloric uses. In rabbit jejunum preparations, Vw.Cr (0.1–3.0 mg/mL) caused relaxation of spontaneous contractions. When tested against high K⁺ (80 mM)-induced contractions it produced weak inhibitory effect, while caused complete relaxation of the contractions induced by low K⁺ (20 mM). In the presence of glibenclamide (3 μM), the inhibitory effect of low K⁺ was shifted to the right, similar to that produced by cromakalim while, verapamil caused no differentiation in its inhibitory effect against low and high K⁺-induced contractions. In guinea pig ileum, the plant extract produced similar results as in rabbit jejunum. Intravenous administration of Vw.Cr, produced fall in arterial blood pressure in normotensive anaesthetized rats and this effect was partially blocked by glibenclamide. In rabbit aortic preparations, plant extract also caused a selective and glibenclamide-sensitive relaxation of low K⁺ (20 mM)-induced contractions. Activity-directed fractionation studies revealed that the observed activity was distributed both in the chloroform and aqueous fractions. These results indicate that the antispasmodic and hypotensive effects of Valeriana wallichii are mediated possibly through K_ATP channel activation, which justify its use in gastrointestinal and cardiovascular disorders.     

Diuretic effect of the aqueous extract of Bidens odorata in the rat

The aerial part of Bidens odorata Cav., are used in Mexican Folk Medicine to treat renal diseases. The aim of this study is to measure the diuretic response to aqueous extract of this plant at doses of 41 and 166 mg/kg and to compare it with that induced by furosemide at 2 mg/kg. Aqueous extracts, furosemide or vehicle were administered orally to adult rats and the effects on sodium, potassium and water balance were assessed. Aqueous extracts at both doses and furosemide produced important and significant increments in urinary excretion of sodium, potassium and water in rats with respect to control group. This increase was dose dependent and aqueous extract at the highest dose induced a more marked sodium and water excretion than furosemide, potassium excretion increased but it was less than the one induced by furosemide. These results suggest that the aqueous extract of Bidens odorata induce diuretic response.     

Chronic diuretic effect of the water extract of Spergularia purpurea in normal rats

The purpose of this study was to examine the chronic diuretic effect of the water extract of the whole plant of Spergularia purpurea (SP) at different doses (100, 200 and 400 mg/kg) in normal rats. Daily oral administration of the water extract was tested for 4 weeks. Urinary water and electrolytes excretion were determined weekly. Oral administration of the water extract at different doses produced a significant and dose-dependent diuresis and increase in electrolytes excretion. The highest dose (400 mg/kg) of the water extract of SP enhanced urine output from 7.15 +/- 0.42 ml/24 h at the start to 23.01 +/- 0.75 ml/24 h after 4 weeks (p < 0.001). It also produced significant increase in urinary excretion of Na+ (P < 0.01), K+ (P < 0.01) and Cl(-) (P < 0.01). Chronic treatment with SP decreased significantly urine osmolality (P < 0.01 vs. control), while a slight increase in glomerular filtration rate was also observed (P < 0.05) for both doses of water extract (100 and 400 mg/kg). It is concluded that the water extract of whole plant of SP has a significant diuretic effect in rats.     

Diuretic effect of the crude extracts of Carissa edulis in rats

Carissa edulis (forssk) vahl (Apocynaceae) is used traditionally for the treatment of headache, chest complaints, rheumatism, gonorrhoea, syphilis, rabies and as a diuretic. In the present study, the diuretic activity of different extracts of Carissa edulis was investigated. The diuretic activity of the different extracts of Carissa edulis in a dose range of 50-1000 mg/kg was assessed orally in rats using hydrochlorothiazide as a standard drug. The root bark maceration extract showed no effect on the urine output up to a dose of 1000 mg/kg, while the root bark soxhlet extract produced a significant increase (P < 0.05) in urine output at a dose of 1000 mg/kg. The root wood maceration and root wood soxhlet extracts produced a significant increase in urine output at a dose of 50 mg/kg, with a P-value of <0.05. Urinary electrolyte excretion was also affected by the extracts: the root bark soxhlet extract increased urinary excretion of sodium, potassium and chloride ions; root wood maceration extract increased excretion of sodium and potassium, while root wood soxhlet extract increased excretion of potassium ion. These findings support the traditional use of Carissa edulis as a diuretic agent.     

Diuretic activity of Withania aristata: an endemic Canary Island species

This study reports on the pharmacological evaluation of the diuretic activity of an infusion and a methanol extract of Withania aristata Ait. in laboratory rats. Water excretion rate, pH, density, conductivity, and content of Na(+), K(+) and Cl(-) were measured in the urine of rats subjected to hypersaline conditions. Both the infusion and the methanol extract showed a significant diuretic effect compared with non-treated controls, with notable increases in the rates of water and sodium excretion. There was also a potassium retention effect. The diuretic effect did not appear to be related to the potassium content in the material tested, but did have some relation to its content of active polar compounds. The results justify the use of Withania aristata as a diuretic agent in folk medicine of the Canary Islands.     

Diuretic activity of some fractions of the epidermis of Poria cocos

Ethnopharmacological relevance

Poria cocos Wolf (Polyporaceae) is a well-known medicinal fungus, the epidermis (“Fu-Ling-Pi” in Chinese) of the sclerotia is used as a diuretic for treating oedema and promoting the diuretic process. In this paper we report on the diuretic activity in rats of petroleum ether, ethyl acetate, n-butanol and the remaining fractions of the ethanol extract from the epidermis of Poria cocos.

Materials and methods

Petroleum ether, ethyl acetate, n-butanol and the remaining fractions of the ethanol extract of Fu-Ling-Pi were orally administered to rats. The urinary excretion rate and the pH and electrolyte excretion were measured in the urine of saline-loaded rats.

Results

In this study, all the tested fractions of Fu-Ling-Pi increased the urinary excretion rate. The three doses of the ethyl acetate fraction all produced remarkable urinary output in 6 h, and all produced a remarkable increase in Na⁺ excretion and Cl⁻ excretion. The Na⁺/K⁺ value in the experimental group was significantly enhanced compared with that of the control group, but the three doses of the ethyl acetate fraction had no effect on the K⁺ excretion. The 25-mg/kg and 50-mg/kg doses of the n-butanol fraction showed notable urinary output and produced a remarkable increase of Na⁺ excretion and Cl⁻ excretion, but the two doses did not produce a remarkable effect on the Na⁺/K⁺ value. The petroleum ether and remaining fractions did not show remarkable diuretic activities compared with the control group.

Conclusions

This study confirmed that the ethyl acetate and n-butanol fractions present a remarkable diuretic effect, showing that they are the diuretic bioactive fractions of Fu-Ling-Pi. This finding appears to indicate at least two mechanisms for the observed diuretic activity, and the K⁺-saving diuretic effect may be related to the triterpenoid components of intermediate polarity contained in this fungus, particularly the lanostanes tetracyclic triterpenoids.     

Experimental diuretic effects of Rosmarinus officinalis and Centaurium erythraea

Herbal remedies are widely used in Moroccan pharmacopoeia. We assessed the diuretic effect of two medicinal plants: Rosmarinus officinalis L., Labiatae, and Centaurium erythraea L., Gentianaceae, both reputed for the treatment of urinary ailments. To determine the action of these herbs on urinary volume (UV) and the excretion of sodium (U(Na)V), potassium (U(K)V), and chloride (U(Cl)V), the aqueous extracts of both plants were administered daily to Wistar rats for 1 week. The concentration of electrolytes and urea in plasma and creatinine clearance were also investigated. Daily oral administration of the aqueous extracts of R. officinalis and C. erythraea at the dose of 10 ml/kg of 8 or 16% extract in distilled water significantly enhanced diuresis in rats compared to the control group from the fifth day of treatment. For R. officinalis at the dose of 8% the peak of urinary excretion of sodium, potassium and chloride was reached after 6 days of treatment (P<0.001). The aqueous extract of of R. officinalis at the dose of 16% did not significantly affect the excretion of water and electrolytes over a similar period but slight increases in urinary excretion of sodium and chloride on the seventh day and of potassium on the sixth day (P<0.05) were observed. No increase was recorded for 24 h urinary excretion of Na+, K+ and Cl- during the first 4 days of treatment for the groups treated with C. erythraea at the doses of 8 and 16% whereas their effects on the same parameters were highly significant thereafter. No change was observed in plasma electrolytes and urea in any group, except for a decrease in sodium and chloride concentration in the group treated with 16% of R. officinalis. A decrease in creatinine clearance was demonstrated after treatment with 8% of R. officinalis and C. erythraea. Our findings demonstrate a diuretic effect of aqueous extracts of R. officinalis L. and C. erythraea L. with the most effective dose for water and electrolyte excretion being 8% for both plants.     

Diuretic activity of Smilax canariensis, an endemic Canary Island species

ETHNOPHARMACOLOGICAL RELEVANCE: Smilax canariensis is an endemic species of the Canary Islands, popularly known as "Zarzaparrilla sin espinas". This species has wide use in folk-medicine practice on the islands, especially as diuretic. So the aim of our study is to evaluate the diuretic activity of an aqueous and a methanol extract of this species. MATERIAL AND METHODS: Three infusions doses (250, 500 and 750mg/kg) and two methanol extract doses (100 and 200mg/kg) were orally administered to laboratory rats. Water excretion rate, pH, density, conductivity, and content of Na(+) and K(+) were measured in the urine of saline-loaded rats. RESULTS: Water excretion rates were significantly increased in a dose-dependent manner by both hot water infusions and the alcohol extract. The electrolytic excretion was also dose-dependent, although potassium excretion was markedly reduced when using the alcohol extract compared with that observed for the infusion. CONCLUSIONS: Smilax canariensis presents a notable diuretic effect which appeared to be related both to its potassium content and to the presence of polar organic compounds. The present results provide a quantitative basis explaining the traditional folk-medicine use of Smilax canariensis as a diuretic agent by the Canary Island population.     

The skeletal muscle relaxant action of Portulaca oleracea: role of potassium ions

An aqueous extract of the stems and leaves of Portulaca oleracea abolishes the twitch contraction of the directly stimulated rat hemidiaphragm preparation. The effects of the extract mimic qualitatively the action of potassium oxalate — a known constituent of Portulaca oleracea — on the diaphragm. Removal of K⁺ ions from the methanol extract by passing it through a cation exchange resin reduced the inhibitory effect of the extract. There was a positive correlation between the concentration of K⁺ ions in the extract and the effects of potassium chloride of similar molarity. It is concluded that the K⁺ ion content of Portulaca oleracea is at least partly responsible for the relaxant effect observed on the isolated rat diaphragm.     

Bioactivity-directed isolation, identification of diuretic compounds from Polyporus umbellatus

Aim of the study

Polyporus umbellatus is a fungus used as a diuretic medicine. The objective of this study was to isolate and elucidate the diuretic constituents of n-hexane, ethyl acetate, n-butanol and water extracts of Polyporus umbellatus and to evaluate their diuretic activity.

Materials and methods

The n-hexane, ethyl acetate, n-butanol and water extracts of Polyporus umbellatus were tested by diuretic experiment of normal rats in metabolic cage. The n-hexane extract and n-butanol extract were prepared separately by the bioassay-guided approach. Three isolated compounds doses (5, 10 and 20 mg/kg BW) were orally administered to normal rats. Water excretion rate, pH and content of Na⁺, K⁺ and Cl⁻ were measured in the urine of saline-loaded rats.

Results

n-Hexane extract (P < 0.05), n-butanol extract (P < 0.05) and three isolated compounds (ergosta-4,6,8(14),22-tetraen-3-one, ergosterol and d-mannitol) displayed diuretic activity.

Conclusions

The ergosta-4,6,8(14),22-tetraen-3-one was the strongest diuretic constituent in the three compounds. Ergosterol and d-mannitol were found to be also responsible for duiretic effects in Polyporus umbellatus for the first time. Data show that 20 mg/kg dose of the ergosterol for urine out put became significantly higher than in the control rats, but the ratio of Na⁺/K⁺ almost unaltered in the three doses. The highest dose of the d-mannitol was significant and increased the cumulative urine output. Regarding the electrolyte excretion, data show that the doses 10 and 20 mg/kg produce significant increase for excretion of Na⁺ and Cl⁻. The present results provide a quantitative basis explaining application of Polyporus umbellatus as a diuretic medicine. The result proved that its diuretic effects were also due to the contribution of multi-components in clinical application.     

Diuretic activity of the ethanol and aqueous extracts of the surface layer of Poria cocos in rat

Ethnopharmacological relevance

Poria cocos Wolf (Polyporaceae) is a well-known traditional East-Asian medicinal fungus. the epidermis (“Fu-Ling-Pi” in Chinese) of the sclerotia is used as a diuretic. This study was conducted to evaluate of ethanol extract (EE) and aqueous extract (AE) of the diuretic activity of Fu-Ling-Pi in saline-loaded rats.

Material and methods

The EE and AE were orally administered to rats. Urinary excretion rate, pH and electrolyte excretion were measured in the urine of saline-loaded rats.

Results

Urinary excretion rates were significantly increased by the EE. The three doses of AE only produced a slight increase urinary output. The EE had little or no effect on K⁺ excretion, but did indeed induce a notable excretion of Na⁺, that was in agreement with the urinary excretion. The three doses of AE produced an increase Na⁺ and K⁺ excretion, but did not arrive at statistical significance.

Conclusions

The present study confirmed that the not aqueous but ethanol extracts of the epidermis of Poria cocos presents a remarkable diuretic effect.     

Influence of Prostanoids in the Diuretic and Natriuretic Effects of Extracts and Kaempferitrin from Bauhinia forficata Link Leaves in Rats

Although Bauhinia forficata Link is popularly used in Brazil to induce diuresis, no scientific investigation has focused on demonstrating its efficacy in preclinical trials. For that, normotensive male Wistar and spontaneously hypertensive rats were used to test the effect of extracts and kaempferitrin obtained from Bauhinia forficata leaves in the experimental model of diuresis. Cumulative urine volume, Na⁺ and K⁺ excretion, calcium, creatinine, prostaglandin E₂, pH, density, and conductivity were measured at the end of the experiment (after 8 or 24 h). The treatment with aqueous infusion, methanolic extract, trichloromethane, or ethyl acetate–butanolic fractions significantly increase urinary volume and electrolytes levels when orally given to rats, without altering the pH or density parameters. Kaempferitrin induced diuretic, natriuretic, but not kaliuretic effects in both normotensive and hypertensive rats. In addition, kaempferitrin enhanced urinary creatinine and prostaglandin E₂ excretion, without modifying calcium levels. Kaempferitrin‐induced diuresis was unaffected by previous treatment with a nonselective inhibitor of nitric oxide synthase and neither with a nonselective muscarinic receptor antagonist. On the other hand, a cyclooxygenase inhibitor was able to decrease its effect when compared with vehicle‐treated rats, suggesting that the diuretic and natriuretic properties from kaempferitrin are associated with endogenous prostanoids generation. Copyright © 2017 John Wiley & Sons, Ltd.     

白术利尿作用研究

目的:研究白术及其拆分组分对大鼠的利尿作用。方法:采用多模式联用的方法对白术化学组分进行拆分;通过预先胃水负荷模型,以6 h尿量为指标考察白术及其拆分组分对水负荷大鼠利尿作用;进一步测定红细胞和肾髓中Na~+-K~+-ATP酶活力、血尿素氮浓度、肾髓中碳酸酐酶水平和Na~+、K~+、Cl-排出量,研究其相关机理。结果:高剂量白术水煎液和白术挥发油组分对大鼠有一定的抗利尿作用;与空白组相比,白术水煎液及其拆分组分组红细胞中Na~+-K~+-ATP酶活力、肾髓中Na~+-K~+-ATP酶和碳酸酐酶水平无显著变化。结论:白术对正常动物无利尿作用,相反表现出一定的抗利尿作用,且首次研究发现白术挥发油有一定的抗利尿作用。     

Antihypertensive effect of Lepidium sativum L. in spontaneously hypertensive rats

The antihypertensive and diuretic effects of the aqueous extract of Lepidium sativum L. (LS) were studied both in normotensive (WKY) and spontaneously hypertensive rats (SHR). Daily oral administration of the aqueous LS extract (20mg/kg for 3 weeks) exhibited a significant decrease in blood pressure (p<0.01) in SHR rats while in WKY rats, no significant change was noted during the period of treatment. The systolic blood pressure was decreased significantly from the 7th day (p<0.05) to the end of treatment (p<0.01) in SHR rats. The aqueous LS extract enhanced significantly the water excretion in WKY rats (p<0.001) but no statistically significant change was observed in SHR rats. Furthermore, oral administration of aqueous LS extract at a dose of 20mg/kg produced a significant increase of urinary excretion of sodium (p<0.05), potassium (p<0.01) and chlorides (p<0.01) in WKY rats. In spontaneously hypertensive rats, the aqueous LS extract administration induced a significant increase of urinary elimination of sodium (p<0.01), potassium (p<0.001) and chlorides (p<0.001). Glomerular filtration rate showed a significant increase after oral administration of LS in normal rats (p<0.001) while in SHR rats, no significant change was noted during the period of treatment. Furthermore, no significant changes were noted on heart rate after LS treatment in SHR as well as in WKY rats. Our results suggest that daily oral administration of aqueous LS extract for 3 weeks exhibited antihypertensive and diuretic activities.     

Involvement of bradykinin and prostaglandins in the diuretic effects of Achillea millefolium L. (Asteraceae)

Ethnopharmacological relevance

Achillea millefolium L. (Asteraceae), popularly known as “mil-folhas”, is well recognized and widely used in Brazilian folk medicine to treat heart and kidney disorders. Among its popularly described effects are diuretic and hypotensive actions.

Aim of the study

The diuretic activity of Achillea millefolium L. extracts and its semi-purified fractions, as well as the mechanisms involved, were evaluated in male Wistar rats.

Material and methods

An aqueous extract (AEAM, 125–500 mg/kg), hydroethanolic extract (HEAM, 30–300 mg/kg), dichloromethane subfractions (DCM-2, 10 and 30 mg/kg), or hydrochlorothiazide (10 mg/kg), were orally administered and the animals were kept in metabolic cages for 8 h for urine collection. To evaluate the involvement of bradykinin and prostaglandins in the diuretic action of Achillea millefolium, selected groups of rats received HOE-140 (1.5 mg/kg, i.p.) or indomethacin (5 mg/kg, p.o.), before treatment with a DCM-2 subfraction (30 mg/kg). The urinary volume, conductivity, pH, density and electrolyte excretion were measured.

Results

Similar to hydrochlorothiazide, both HEAM and DCM-2, but not AEAM, increased urinary volume and the excretion of Na⁺ and K⁺ when compared with the control group (vehicle). The diuretic effect of DCM-2 was abolished by HOE-140 (a bradykinin B2 receptor antagonist), as well as by indomethacin (a cyclooxygenase inhibitor).

Conclusion

The present study reveals that extracts obtained from Achillea millefolium are able to effectively increase diuresis when orally administered in rats. This effect depends on both the activation of bradykinin B2 receptors and the activity of cyclooxygenases.