Hypotensive and cardio-chronotropic constituents of Tinospora crispa and mechanisms of action on the cardiovascular system in anesthetized rats

Ethnopharmacological relevance

Tinospora crispa has been used in folkloric medicine for the control of blood pressure. We previously found that an extract of Tinospora crispa stems decreased the mean arterial blood pressure (MAP) with a transient decrease, followed by an increase in the heart rate (HR) in rats.

Aim of the study

To identify the active components of the Tinospora crispa extract and investigate the mechanisms of action on blood pressure and heart rate in anesthetized rats.

Materials and methods

The active components of Tinospora crispa extract were separated by column chromatography and a preparative HPLC. The effects and mechanisms of the active compounds on blood pressure and heart rate were studied in anesthetized, normal and reserpinized rats in vivo.

Results

5 active compounds: adenosine, uridine, salsolinol, higenamine and tyramine were isolated. Adenosine decreased MAP and HR and this effect was inhibited by DMPX (A_2A adenosine receptor antagonist). Uridine increased MAP and decreased HR and this was inhibited by suramin but not by DMPX. Salsolinol decreased the MAP and HR and this was inhibited by phentolamine but not by ICI-118,551 (β₂-adrenoceptor antagonist) or atropine. In reserpinized rats, salsolinol had a hypertensive effect that was inhibited by prazosin and phentolamine, but not by atenolol, and caused an increase in HR that was inhibited by atenolol, but not by prazosin or phentolamine. Higenamine decreased the MAP with an increase in HR. The hypotensive effect was inhibited by ICI-118,551 or atenolol, whereas the increase in HR was not inhibited by ICI-118,551. Atenolol inhibited the increase in HR at a small dosage of higenamine but potentiated it at a higher dosage. In reserpinized rats, a small dosage of higenamine tended to potentiate the effect but at a higher dosage it caused inhibition. ICI-118,551 significantly inhibited this hypotensive effect. Tyramine caused an increase in MAP and HR and these effects almost disappeared in reserpinized rats.

Conclusions

The results demonstrate that these 5 compounds from Tinospora crispa acted in concert on the cardiovascular system of anesthetized rats. Salsolinol, tyramine and higenamine acted via the adrenoreceptors, whereas uridine and adenosine acted via the purinergic adenosine A₂ and P₂ receptors to decrease blood pressure with a transient decrease of HR followed by an increase.     

Crude extract and purified components isolated from the stems of Tinospora crispa exhibit positive inotropic effects on the isolated left atrium of rats

Ethnopharmacological relevance

Tinospora crispa has been used in folkloric medicine for the control of blood pressure. We previously found that an extract of Tinospora crispa and its constituents effect the heart rate and blood pressure in anesthetized rats.

Aim of the study

The aim was to investigate the effects and mechanisms of the Tinospora crispa extract and bioactive components on the rat isolated left atria.

Materials and methods

Air-dried stems of Tinospora crispa were extracted with water, followed by partitioning with chloroform, ethyl acetate, and finally by n-butanol. The n-butanol soluble material was concentrated and dried under reduced pressure and lyophilized to obtain a crude powder (Tinospora crispa extract). The active components of Tinospora crispa extract were separated by column chromatography and preparative HPLC. The effects and mechanisms of the n-butanol extract and the bioactive purified components (adenine, uridine, adenosine, salsolinol, tyramine, higenamine, syringin, (−)-litcubinine, borapetoside A, borapetoside B, borapetoside D and borapetoside E) were studied in isolated left atria from normal and reserpinized rats.

Results

Tinospora crispa extract caused an increase in the force of contraction of the electrical field stimulated left atrium. This effect was inhibited by propranolol, atenolol, ICI-118,551, phentolamine and atropine. The positive inotropic effect on the reserpenized isolated left atrium of the Tinospora crispa extract was significantly inhibited by propranolol, atenolol and ICI-118,551. Phentolamine, on the other hand, caused potentiation and the effect was inhibited when propranolol was also added. Higenamine caused an increase in the force of contraction of the electrical field stimulated left atrium and this effect was significantly inhibited by ICI-118,551 and atenolol but not by phentolamine. Reserpine did not significantly shift the concentration–response curve (C–R curve) of the inotropic effect of the higenamine. ICI-118,551 and atenolol caused a parallel shift of the C–R curve to the right of about 8 and 33 fold, respectively. At low concentrations salsolinol caused a slight increase in the force of contraction of the left atrium, but at higher concentrations a decrease was observed. The negative inotropic effect of salsolinol was significantly inhibited by propranolol and atropine. In the reserpinized isolated left atrium, the negative inotropic effect of salsolinol was potentiated and again this effect was significantly inhibited by propranolol and atropine. Tyramine caused a positive inotropic effect, and this effect was inhibited by propranolol or by pretreatment of the rat with reserpine. Adenosine caused a negative inotropic effect, while uridine caused a slight positive inotropic effect on the left atrium. This effect was significantly inhibited by DPCPX.

Conclusions

Crude extracs of Tinospora crispa exert a positive inotropic effect on the electrical field stimulated isolated left atria that results from the concerted action of 5 bioactive compounds: higenamine, salsolinol, tyramine, adenosine and uridine. Higenamine, salsolinol (at low concentration) and tyramine acted via the adrenergic receptors to increase the force of the atrial contraction, whereas a high concentration of salsolinol acted indirectly by stimulating the release of acetylcholine. Adenosine and uridine acted via the purinergic pathways to cause negative inotropic effects on the isolated left atria.     

Tracheal relaxation of five Ivorian anti-asthmatic plants: role of epithelium and K⁺ channels in the effect of the aqueous-alcoholic extract of Dichrostachys cinerea root bark

Ethnopharmacological relevance

Leaves of Boerhavia diffusa (Nyctaginaceae), Baphia nitida, Cassia occidentalis, Desmodium adscendens (Fabaceae), and root bark of Dichrostachys cinerea (Fabaceae) are used in Ivory Coast for the treatment of asthma. The aim of this study was to evaluate the potential airway relaxant activity of different extracts of these plants.

Materials and methods

Extracts of different polarities (H₂O, EtOH/H₂O, MeOH and CH₂Cl₂) were obtained from these five plants. Their ex vivo relaxant activity was tested in mice isolated trachea precontracted with carbachol (1 μM).

Results

Cumulative concentrations of most extracts induced moderate to strong relaxation, the methanolic extracts being the most potent and the polar extracts the most active at the concentrations used, supporting the traditional use of these five plants as anti-asthmatic remedies. We further investigated the molecular and cellular mechanisms of the mouse trachea relaxant effect of the aqueous-alcoholic extract of Dichrostachys cinerea root bark, the most potent extract. Its effect was not modified in the presence of β-adrenoceptor antagonists (propranolol or ICI 118,551) or a PKA inhibitor (H89). By contrast, it was decreased after depolarization-induced precontraction (with 80 mM KCl), in the presence of some K⁺ channels blockers [4-aminopyridine as voltage-dependent K⁺ (K_v) channel blocker and tetraethylammonium chloride as large conductance Ca²⁺-activated K⁺ (BK_Ca) channel blocker, but not with glibenclamide, an ATP-sensitive K⁺ (K_ATP) channel blocker] or after epithelium removal.

Conclusions

The mouse tracheal relaxant effect of Dichrostachys cinerea EtOH/H₂O extract was independent of β₂-adrenoceptors activation and cAMP/PKA pathway, but dependent on epithelium and K⁺ channels, namely K_v and BK_Ca channels. Further investigation will be required to identify the component(s) responsible for this airways relaxant activity.     

Acute and subacute toxicity of ethanol extracts from Salvia przewalskii Maxim in rodents

Aim

The present investigation was carried out to evaluate the safety of the lipid-soluble ethanol extracts from rhizome of Salvia przewalskii Maxim (SPM) by determining its potential toxicity after acute and subacute administration in rodents.

Materials and methods

For the acute study, SPM extract was administered to mice in single doses given by gavage, intramuscular and intraperitoneal route. General behavior adverse effects and mortality were determined for up to 14 days. In the subacute study, the extract was administered orally at doses of 0, 50 and 250 mg/kg daily for 30 days to rats. Body weight, heart rate, blood pressure, biochemical and hematological parameters were determined at the end of 0, 15 and 30 days of daily administration.

Results

In acute study, SPM extract caused dose-dependent general behavior adverse effects and mortality. The no-observed adverse effect levels (NOAEL) of the extract were 1723, 288 and 500 mg/kg, when given by gavage, intramuscular and intraperitoneal routes, respectively, and the lowest-observed adverse effect levels (LOAEL) were 1981, 840 and 781 mg/kg. Mortality increased with increasing doses, with LD₅₀ of 2547.8, 901.3 and 780.8 mg/kg for the oral, intramuscular and intraperitonal administration. In subacute study, daily oral administration of SPM extract for up to 30 days did not result in death or significant changes in the body weight, heart rate and blood pressure, hematological and mainly biological parameters. In biological analysis, some significant changes occurred, including total protein and albumin, glucose and triglycerides, indicating that SPM extract has lipid-modulating activity.

Conclusions

SPM extract was found to be low or non-toxic when acute toxicities and subacute toxicities in rodents. In view of the doses of the components consumed in traditional medicine, there is a wide margin of safety for the therapeutic use.     

Aqueous extract of Zanthoxylum schinifolium elicits contractile and secretory responses via β1-adrenoceptor activation in beating rabbit atria

Aim of study

Although Zanthoxylum schinifolium has long been used in the traditional oriental medicine, cardiac effects have not well been documented. The aim of the present study was to investigate the effects of aqueous extract of leaves and stems from Zanthoxylum schinifolium (AZS) on inotropic effect and atrial natriuretic peptide (ANP) secretion.

Materials and methods

The AZS-induced changes in atrial dynamics, cAMP efflux and atrial ANP secretion were determined in isolated perfused beating rabbit atria.

Results

AZS increased atrial pulse pressure, stroke volume, and cAMP efflux concomitantly with inhibition of ANP secretion in a concentration-dependent manner. The AZS-induced increases in atrial dynamics and cAMP efflux, and decrease in ANP secretion were attenuated by pretreatment with propranolol and CGP 20712 but not ICI 118,551. Also, the AZS-induced changes in atrial dynamics and ANP secretion were attenuated by diltiazem and KT 5720. Diltiazem and KT 5720 had not significant effect on the AZS-induced increase in cAMP efflux.

Conclusion

These results suggest that AZS elicits a positive inotropic effect and decrease in ANP secretion via β₁-adrenoceptor-cAMP-Ca²⁺ signaling in beating rabbit atria.     

Investigation of plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts

Aim of the study

To investigate the activities of the 217 plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts.

Materials and methods

Plant extracts were prepared by the method of maceration using solvents of different polarities. The growth inhibition of chloroquine-resistant Plasmodium falciparum strain (FcB1) was determined by measuring the radioactivity of the tritiated hypoxanthine incorporated. Activity against Leishmania (Leishmania) chagasi and Trypanosoma cruzi was measured by the MTT colorimetric assay. The antifungal tests were carried out by using the CLSI method. The active extracts were tested also by cytotoxicity assay using NIH-3T3 cells of mammalian fibroblasts.

Results

Two hundred and seventeen extracts of plants were tested against Plasmodium falciparum. The eleven active extracts, belonging to eight plant species were evaluated against L. (L.) chagasi, Trypanosoma cruzi, yeasts and in NIH-3T3 cells. The results found in these biological models are consistent with the ethnopharmacological data of these plants. The ethyl acetate extract of Diospyros hispida root showed IC₅₀ values of 1 μg/mL against Plasmodium falciparum. This extract demonstrated no toxicity against mammalian cells, resulting in a significant selectivity index (SI) of 435.8. The dichloromethane extract of Calophyllum brasiliense root wood was active against Cryptococcus gattii LMGO 01 with MIC of 1.95 μg/mL; and Candida albicans ATCC 10231 and Candida krusei LMGO 174, both with MIC of 7.81 μg/mL. The same extract was also active against Plasmodium falciparum and L. (L.) chagasi with IC₅₀ of 6.7 and 27.6 μg/mL respectively. The ethyl acetate extract of Spiranthera odoratissima leaves was active against Cryptococcus gattii LMGO 01 with MIC of 31.25 μg/mL, and against Plasmodium falciparum with IC₅₀ of 9.2 μg/mL and Trypanosoma cruzi with IC₅₀ of 56.3 μg/mL.

Conclusion

The active extracts for protozoans and human pathogenic yeasts are considered promising to continue the search for the identification and development of leading compounds.     

The effects of hydroxysafflor yellow A on blood pressure and cardiac function

Aim of the study

This work aims to investigate the effects of HSYA on cardiac function and blood pressure.

Materials and methods

To evaluate changes in mean arterial pressure (MAP) and heart rate (HR), different groups of pentobarbitone-anesthetized normotensive and spontaneously hypertensive rats (SHR) were treated with intravenous HSYA (0.1-3 mg/kg). Isolated WKY rat hearts in Langendorff system were employed for examining the effect of HSYA on hemodynamic. After 30 min equilibration time the isolated hearts were perfused with HSYA (30 μmol/L) in a stepwise fashion. Potassium channel inhibitors were used to determine the role of potassium channel activation in HSYA effect.

Results

Intravenous injection of the HSYA significantly reduced MAP and HR in both normotensive rats and SHR in a dose-dependent manner. HSYA reduced left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), the maximum rate of increase of left ventricular pressure (+dp/dt_max) and heart rate (HR) in a dose-dependent manner. HSYA had no remarkable effect on the maximum rate of decrease of left ventricular pressure (−dp/dt_max); BK_Ca and K_ATP blocker can weakened the inhibitory effect of HSYA on heart function and HR, but K_V and K_ACh blocker did not significantly weaken the HSYA effects.

Conclusion

Our results show that HSYA could significantly reduce blood pressure and heart rate, which may be related to activation of BK_Ca and K_ATP channels.     

The aqueous extract of Terminalia superba (Combretaceae) prevents glucose-induced hypertension in rats

Aim of the study

The stem bark of Terminalia superba (Combretaceae) (TS) is used in traditional Cameroonian medicine as antihypertensive remedy. The aim of this study was to investigate the hypotensive and the antihypertensive effects of the aqueous extract of the stem bark of Terminalia superba.

Materials and methods

Hypertension was obtained in rats by oral administration of 10% d-glucose for 3 weeks. The acute effects of Terminalia superba were studied on blood pressure (BP) and heart rate (HR) after intravenous administration in normotensive rats (NTR) and glucose hypertensive rats (GHR). The antihypertensive effects were studied after oral administration of the extract (50 and 100 mg/kg/day) or nifedipine (10 mg/kg/day) for 3 weeks. At the end of the experiment, BP and HR were measured and reduced glutathione (GSH), malondialdehyde (MDA) and superoxide dismutase (SOD) activity levels were measured in heart, aorta, liver and kidney.

Results

Intravenous administration of the aqueous extract of Terminalia superba induced a significant hypotensive response without any change in HR. The hypotensive effect of the extract was unaffected by atropine or propranolol but decreased by reserpine (5 mg/kg) and yohimbine (0.1 mg/kg). In addition, the oral administration of the extract significantly prevented the rise in BP in glucose-hypertensive rats. Finally, the treatment with plant extract significantly blunted the decrease in GSH and the increase in MDA levels associated with hypertension, and significantly prevents the increase in aortic SOD activity.

Conclusions

The present study demonstrates that the aqueous extract of the stem bark of Terminalia superba exhibits hypotensive and anti-hypertensive properties that are, at least in part, related to a withdrawal of sympathetic tone and to an improvement of the antioxidant status, respectively. Overall data validate the use of Terminalia superba as antihypertensive therapy in traditional medicine.     

Inhibitory effect of hydro-methanolic extract of seed of Holarrhena antidysenterica on alpha-glucosidase activity and postprandial blood glucose level in normoglycemic rat

Ethnopharmacological relevance

The present experiment was conducted to search out the effect of hydro-methanolic extract of seed of Holarrhena antidysenterica on intestinal α-glucosidase activity in dose dependent manner and on the management of postprandial hyperglycemia in starch loaded rats.

Materials and methods

Activity of intestinal α-glucosidase was measured by in vitro method. Fasting blood glucose level was determined by single touch glucometer. Total phenol and flavonoids of seed extract of Holarrhena antidysenterica were estimated using gallic acid and quercetin standard curves, respectively.

Results

The degree of elevation in blood glucose level after starch administration was significantly (p < 0.05) less by the extract in respect to the control. The said extract also inhibited α-glucosidase activity having an IC₅₀ of 0.52 mg/ml. Phytochemical study revealed that the extract is rich in phenolic compounds (60.23 mg of gallic acid equivalent/g of extract) and flavonoids (360.23 mg of quercetin equivalent/g of the extract).

Conclusion

The extract exerts its antihyperglycemic effect by retarding the carbohydrate absorption from intestine through the inhibition in α-glucosidase activity and therefore resists postprandial hyperglycemia.     

Gypsum fibrosum and its major component CaSO4 increase cutaneous aquaporin-3 expression levels

Ethnopharmacological relevance

We have previously reported that Byakkokaninjinto improves cutaneous pruritus by increasing the expression level of aquaporin-3 (AQP3). In this study, we examined the effect of Gypsum fibrosum (main component: CaSO₄), which is the main component of Byakkokaninjinto, on the cutaneous AQP3 expression level.

Materials and methods

KKAy mice were given a diet containing 0.3% Gypsum fibrosum extract, or a diet containing 0.3% CaSO₄ for 4 weeks. The urine volume, plasma glucose levels, cutaneous AQP3 protein expression, and the Ca²⁺ content were measured.

Results

The 24-h urine volumes and the plasma glucose levels in the Gypsum fibrosum extract group were not significantly different from those in the control group. In the Gypsum fibrosum extract group, the cutaneous AQP3 protein levels increased significantly, by approximately 3.2-fold, compared to the control group. The cutaneous Ca²⁺ content in the control group was approximately 35 μg/g. In the Gypsum fibrosum extract group, the Ca²⁺ content increased to approximately 51 μg/g, which was significant compared to the control group. In the CaSO₄ group, an increase in the AQP3 protein expression levels and Ca²⁺ content were observed; the extent of these increases were similar to those in the Gypsum fibrosum extract group.

Conclusions

The results of this study suggest that Gypsum fibrosum plays an important role in the increased levels of cutaneous AQP3 expression enhanced by Byakkokaninjinto. The results also indicate that the increase in AQP3 caused by Gypsum fibrosum is attributable to an increase in the cutaneous Ca²⁺ content from its main component, CaSO₄.     

Hypotensive effect of aqueous extract of Averrhoa carambola L. (Oxalidaceae) in rats: an in vivo and in vitro approach

Aim of the study

Averrhoa carambola L. (Oxalidaceae) leaves are used in Brazilian traditional medicine to treat hypertension. This study was conducted to evaluate the hypotensive effect of the aqueous extract of Averrhoa carambola (AEAc) and its underlying mechanisms in the isolated rat aorta.

Materials and methods

The effect of AEAc on the mean arterial pressure (MAP) was determined in vivo in anesthetized rats. In vitro, thoracic aortic rings were isolated and suspended in organ baths, and the effects of AEAc were studied by means of isometric tension recording experiments. In HPLC analysis, the fingerprint chromatogram of AEAc was established.

Results

In normotensive rats, AEAc (12.5-50.0 mg/kg, i.v.) induced dose-dependent hypotension. In vitro, AEAc caused a depression in the E_max response to phenylephrine without a change in sensibility. Also, in a depolarized Ca²⁺-free medium, AEAc inhibited CaCl₂-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that AEAc inhibited the contractile mechanisms involving extracellular Ca²⁺ influx.

Conclusions

These results demonstrate the hypotensive effects of AEAc, and these effects may, in part, be due to the inhibition of Ca²⁺, which supports previous claims of its traditional use.     

In vitro modulatory effects of Andrographis paniculata, Centella asiatica and Orthosiphon stamineus on cytochrome P450 2C19 (CYP2C19)

Ethno pharmacological relevance

Andrographis paniculata (AP), Centella asiatica (CA) and Orthosiphon stamineus (OS) are three popular herbs traditionally used worldwide. AP is known for the treatment of infections and diabetes and CA is good for wound healing and healthy skin while OS is usually consumed as tea to treat kidney and urinary disorders. Interaction of these herbs with human cytochrome P450 2C19 (CYP2C19), a major hepatic CYP isoform involved in metabolism of many clinical drugs has not been investigated to date.

Aim of the study

In this study, the modulatory effects of various extracts and major active constituents of AP, CA and OS on CYP2C19 activities were evaluated.

Materials and methods

S-Mephenytoin, the CYP2C19 substrate probe, was incubated in the presence or absence of AP, CA and OS components. The changes in the rate of metabolite (hydroxymephenytoin) formation were subsequently determined by a high-performance liquid chromatography (HPLC)-based enzyme assay to characterize the modulatory effects.

Results

Among the herbal extracts studied, AP ethanol extract and CA dichloromethane extract exhibited mixed type inhibition towards CYP2C19 with K_i values of 67.1 and 16.4 μg/ml respectively; CA ethanol extract and OS petroleum ether extract competitively inhibited CYP2C19 activity (K_i = 39.6 and 41.5 μg/ml respectively). Eupatorin (a major active constituent of OS) was found to significantly inhibit CYP2C19 by mixed type inhibition (K_i = 7.1 μg/ml or 20.6 μM).

Conclusions

It was observed that AP, CA and OS inhibited CYP2C19 activity with varying potency. While weak inhibitory effect was observed with AP, moderate to strong inhibition was observed with CA dichloromethane extract and eupatorin, the major OS constituent. Therefore care should be taken when these CA and OS components are co-administered with CYP2C19 substrates (such as omeprazole, proguanil, barbiturates, citalopram, and diazepam).     

Actions of Artemisia vulgaris extracts and isolated sesquiterpene lactones against receptors mediating contraction of guinea pig ileum and trachea

Aim of the study

The present study evaluates the Philippine medicinal plant Artemisia vulgaris for antagonistic activity at selected biogenic amine receptors on smooth muscle of the airways and gastrointestinal tract in order to explain its traditional use in asthma and hyperactive gut.

Materials and methods

The antagonistic activity of chloroform crude extract (AV-CHCl₃) and methanol crude extract (AV-MeOH) of Artemisia vulgaris was studied against concentration-response curves for contractions of the guinea pig ileum and trachea to 5-hydroxytrptamine (5-HT₂ receptors), methacholine (M₃ muscarinic receptors), histamine (H₁ receptors) and β-phenylethylamine (trace amine-associated receptors, TAAR1).

Results and discussion

The Artemisia vulgaris chloroform (AV-CHCl₃) and methanol (AV-MeOH) extract showed histamine H1 antagonism in the ileum and trachea. Further analysis of AV-CHCl₃ isolated two major components, yomogin and 1,2,3,4-diepoxy-11(13)-eudesmen-12,8-olide. Yomogin, a sesquiterpene lactone, exhibited a novel histamine H1 receptor antagonism in the ileum.

Conclusion

The presence of a specific, competitive histamine receptor antagonist and smooth muscle relaxant activity in Artemisia vulgaris extracts on the smooth muscle in ileum and trachea explains its traditional use in the treatment of asthma and hyperactive gut.     

Inhibition effect of Gynura procumbens extract on UV-B-induced matrix-metalloproteinase expression in human dermal fibroblasts

Ethnopharmacological relevance

Gynura procumbens Merr. (Asteraceae) has been used as a traditional remedy for various skin diseases in certain areas of Southeast Asia.

Aim of the study

In order to evaluate the protective activity of Gynura procumbens extract on skin photoaging and elucidate its mode of action.

Materials and methods

Matrix-metalloproteinase (MMP)-1 and -9 expressions were induced by UV-B irradiation in human primary dermal fibroblasts. MMP-1 expression level was measured by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Zymography was employed for evaluating the enzymatic activity of MMP-9. Anti-inflammatory activity and anti-oxidative capacity of the extract were evaluated by ELISA and dichlorodihydrofluorescein diacetate (DCF-DA) assay.

Results

The ethanolic extract of Gynura procumbens inhibited MMP-1 expression up to 70% compare to negative control group. The enzymatic activity of MMP-9 was inhibited around 73% by the treatment of 20 μg/mL of the extract. The extract markedly reduced the production of reactive oxygen species (ROS). Gynura procumbens extract showed an inhibitory effect on releasing pro-inflammatory cytokines (IL-6 and IL-8) in human HaCat keratinocyte.

Conclusion

The ethanolic extract of Gynura procumbens inhibited MMP-1 and MMP-9 expressions induced by UV-B irradiation via inhibition of pro-inflammatory cytokine mediator release and ROS production.     

Dandelion (Taraxacum officinale) decreases male rat fertility in vivo

Ethnopharmacological relevance

Taraxacum officinale (L.) Weber ex F.H. Wigg. is commonly used in Jordan folk medicine for the treatment of panophthalmitis, chronic constipation, and diabetes. In addition, herbalists prescribe the aqueous extract of Taraxacum officinale to enhance male's fertility.The current work was undertaken to investigate the validity and/or invalidity of the aqueous extract of Taraxacum officinale on enhancing the reproductive activity in male rat.

Materials and methods

Thirty three adult male rats were divided into three groups. Experimental groups received the aqueous extract of Taraxacum officinale orally for 60 days in two different sublethal doses; 1/10 LD₅₀ as high dose and 1/20 LD₅₀ as low dose, whereas the control group received distilled water.

Results

The administration of the aqueous extract of Taraxacum officinale resulted in a significant decrease in testis weight in the two experimental groups in comparison to the control group but had no effect on body or organ weight. The extract of this plant caused a decrease of the following in the two experimental groups, compared to the control group: sperm count, motility and normal morphology, pregnancy rate and diameter and wall thickness of seminiferous tubules. Also, distortion of morphology of the seminiferous tubules and arrest in spermatogenesis was observed in the experimental groups. In addition, the percentage of sperm with damaged chromatin integrity was significantly higher in the two experimental groups.

Conclusions

From the present study, we can conclude that the aqueous extract of Taraxacum officinale acts as an anti-fertility agent rather than a fertility booster as prescribed by Jordanian herbalists.     

Bioactivity-guided fractionation for anti-fatigue property of Acanthopanax senticosus

Ethnopharmacological relevance

The root of Acanthopanax senticosus (also called Eleutherococcus senticosus or Siberian ginseng) has been used extensively in China, Russia and Japan as an adaptogen to fight against stress and fatigue.

Aim of the study

The present study was designed to ascertain the anti-fatigue property of Acanthopanax senticosus by load-weighted swimming test, sleep deprivation test, also to isolate and characterize the active constituents.

Materials and methods

Animals were orally administered with the extract of Acanthopanax senticosus. The anti-fatigue effects of the four fractions with different polarities from the 80% ethanol extract, and the different eluates collected from D101 macroporous resin chromatography and eleutheroside E, were examined based on the weight-loaded swimming capacity (physical fatigue) and the change of biochemical parameters in ICR mice. Moreover, the active fraction was later submitted to sleep-deprived mice (mental fatigue).

Results

The results shown that the n-butanol fraction significant extends the swimming time of mice to exhaustion. Furthermore, the 60% ethanol-water eluate, more purified eleutherosides (including eleutheroside E, E₂ and derivatives), were the exactly active constituents. Two compounds were isolated, which were identified as eleutheroside E, E₂.

Conclusions

The eleutherosides possess the potent abilities to alleviate fatigue both in physical and mental fatigue. Eleutheroside E may be responsible for the pharmacological effect of anti-fatigue. Furthermore, the possible mechanisms were reduced the level of TG by increasing fat utilization, delayed the accumulation of blood urea nitrogen (BUN), and increased the LDH to reduce the accumulation of lactic acid in muscle and then protect the muscle tissue.     

The anti-hypertensive effect of Danshen (Salvia miltiorrhiza) and Gegen (Pueraria lobata) formula in rats and its underlying mechanisms of vasorelaxation

Ethnopharmacological relevance

Radix Salviae miltiorrhizae (Danshen) and Radix Puerariae lobatae (Gegen) have long been used in traditional Chinese Medicine and serve as the principal herbs in treating cardiovascular disease.

Aims of the study

In the present study, an aqueous extract comprising Danshen and Gegen in the ratio of 7:3 (DG) was investigated for its anti-hypertension in vivo and vasodilative activities ex vivo.

Materials and methods

The anti-hypertensive effect of DG extract was investigated in spontaneously hypertensive rat (SHR) by measuring systolic blood pressure (SBP). Oral administration of DG extract was started at age of 6 weeks and 14 weeks for the preventive and therapeutic studies, respectively. Blood pressure was measured by tail-cuff method biweekly for 12 weeks. The ex vivo vasodilative activities of DG extract, its dependency on endothelium and the involvement of nitric oxide, prostacyclin and potassium channels were investigated using isolated rat aorta ring in organ bath.

Results

For in vivo study, systolic blood pressure was significantly reduced in DG extract-treated groups (90.2 and 300 mg/kg) as compared with the SHR control in both preventive and therapeutic studies. However, DG extract was unable to suppress or delay the onset of hypertension in the preventive study. For ex vivo study, the results showed that DG extract induced a concentration-dependent relaxation in aorta and persisted response was observed with the removal of endothelium. Besides, pretreatment with a non-selective potassium channel inhibitor tetraethylammonium (TEA) also significantly inhibited DG extract-induced vasodilation. Further investigations on specific potassium channel blockers revealed that ATP-sensitive potassium (K_ATP) channel inhibitor glibenclamide, inward rectifier potassium (Kir) inhibitor barium chloride and voltage-dependent potassium (K_v) channel inhibitor 4-aminopyridine, but not BK_Ca channel inhibitor iberiotoxin, exerted significant inhibition on DG extract-induced vasodilation.

Conclusions

The results of in vivo SHR animal model suggested that DG aqueous extract possessed blood pressure lowering effect on both pre- and post-hypertensive rats, which could be explained by its endothelium-independent vasodilation via the opening of K_ATP, Kir and K_v channels.     

Anticonvulsant activity of the methanolic extract of Justicia extensa T. Anders

Ethnopharmacological relevance

To investigate the anticonvulsant activity of the leaf extract of Justicia extensa T. Anders used traditionally in the treatment of convulsion.

Materials and methods

The anticonvulsant activity of the methanolic extract of Justicia extensa (50, 100 and 200 mg/kg, p.o.) was assessed in strychnine-induced (STR) and picrotoxin-induced (PCT) convulsion models in mice. Diazepam (1 mg/kg) and phenobarbitone (2 mg/kg) were used as reference drugs respectively.

Results

The extract showed no toxicity and significantly prolonged (p < 0.01-0.05) the onset and reduced the duration of the seizures induced by picrotoxin (5 mg/kg, i.p.) in a dose dependent manner. Phenobarbitone completely inhibited the seizures in this model. Similarly, in the seizures induced by strychnine (1 mg/kg, i.p.), the extract also prolonged the onset and reduced the duration of the seizures though not in a dose dependent manner. Diazepam failed to inhibit the strychnine-induced seizures. The plant extract however showed a significantly higher anticonvulsant activity at 100 and 200 mg/kg in comparison with diazepam.

Conclusions

The results obtained from this work suggest that Justicia extensa has anticonvulsant activity and this supports the use of the plant traditionally in the treatment of convulsion.     

Aqueous extracts from Menyanthes trifoliate and Achillea millefolium affect maturation of human dendritic cells and their activation of allogeneic CD4+ T cells in vitro

Ethnopharmacological relevance: Menyanthes trifoliate and Achillea millefolium have been used in traditional medicine to ameliorate chronic inflammatory conditions. The aim of this study was to identify the effects of ethanol and aqueous extracts of Menyanthes trifoliate and Achillea millefolium on maturation of dendritic cells (DCs) and their ability to activate allogeneic CD4⁺ T cells.

Materials and methods

Human monocyte-derived DCs were matured in the absence or presence of lyophilised aqoueous or ethanol extracts from Menyanthes trifoliate or Achillea millefolium and their expression of surface molecules analysed with flow cytometry and cytokine secretion measured by ELISA. DCs matured in the presence of aqueous extracts from Menyanthes trifoliate and Achillea millefolium were co-cultured with allogeneic CD4⁺ T cells and the expression of surface molecules by T cells and their cytokine secretion and cell proliferation determined.

Results

Maturation of DCs in the presence of aqueous extracts from Menyanthes trifoliate or Achillea millefolium did not affect expression of the surface molecules examined but reduced the ratio of secreted IL-12p40/IL-10, compared with that by DCs matured in the absence of extracts. Allogeneic CD4⁺ T cells co-cultured with DCs matured in the presence of aqueous extract from Menyanthes trifoliate secreted less IFN-γ, IL-10 and IL-17 than CD4⁺ T cells co-cultured with DCs matured without an extract. Maturation of DCs in the presence of aqueous extract from Achillea millefolium decreased IL-17 secretion but did not affect IFN-γ and IL-10 secretion by allogeneic CD4⁺ T cells.

Conclusions

Aqueous extract from Menyanthes trifoliate induces a suppressive phenotype of DCs that has reduced capacity to induce Th1 and Th17 stimulation of allogeneic CD4⁺ T cells, whereas aqueous extract from Achillea millefolium reduces the capacity of DCs to induce a Th17 response.     

Inhibitory effect of Aralia continentalis on the cariogenic properties of Streptococcus mutans

Ethnopharmacological relevance

Aralia continentalis has been used in traditional Korean medicine for dental diseases such as toothache, dental caries, periodontal disease and gingivitis, and also has been used for neuralgia, analgesia, sweating, and as an antirheumatic.

Aim of the study

The present study was designed to investigate the inhibitory effect of Aralia continentalis extract on cariogenic properties of Streptococcus mutans, which is one of the most important bacteria in the formation of dental caries and dental plaque.

Materials and methods

The inhibitory effects of Aralia continentalis extract on the growth, acid production, water-insoluble glucan synthesis, and adhesion were investigated in Streptococcus mutans. The biofilm formation of Streptococcus mutans was determined by scanning electron microscopy (SEM) and safranin staining.

Results

The ethanol extract of Aralia continentalis showed concentration dependent inhibitory activity on the growth of Streptococcus mutans and significant inhibition of acid production at the concentrations of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The synthesis of water-insoluble glucan by glucosyltransferase (GTFase) was decreased in the presence of 0.5-4 mg/ml of the extract of Aralia continentalis. The extract markedly inhibited Streptococcus mutans adherence to saliva-coated hydroxyapatite beads (S-HAs). The extract of Aralia continentalis has an inhibitory effect on the formation of Streptococcus mutans biofilms at the concentrations higher than 2 mg/ml.

Conclusions

These results suggest that Aralia continentalis may inhibit cariogenic properties of Streptococcus mutans, and also may support the scientific rationale that native inhabitants used the extract for the treatment of dental diseases.