The antidiarrheal and spasmolytic activities of Phyllanthus emblica are mediated through dual blockade of muscarinic receptors and Ca2+ channels

Aim of the study

This study was aimed at providing the possible mechanisms for the medicinal use of Phyllanthus emblica in diarrhea.

Materials and methods

The in vivo studies were conducted in mice, while isolated rabbit jejunum and guinea-pig ileum were used for the in vitro experiments.

Results

The crude extract of Phyllanthus emblica (Pe.Cr), which tested positive for alkaloids, tannins, terpenes, flavonoids, sterols and coumarins, caused inhibition of castor oil-induced diarrhea and intestinal fluid accumulation in mice at 500-700 mg/kg. In isolated rabbit jejunum, Pe.Cr relaxed carbachol (CCh) and K⁺ (80 mM)-induced contractions, in a pattern similar to that of dicyclomine. The preincubation of guinea pig-ileum with Pe.Cr (0.3 mg/mL), caused a rightward parallel shift in the concentration-response curves (CRCs) of acetylcholine without suppression of the maximum response. While at the next higher concentration (1 mg/mL), it produced a non-parallel rightward shift with suppression of the maximum response, similar to that of dicyclomine, suggesting anticholinergic and Ca²⁺ channel blocking (CCB)-like antispasmodic effect. The CCB-like activity was further confirmed when pretreatment of the tissue with Pe.Cr, shifted the CRCs of Ca²⁺ to the right with suppression of the maximum response, similar to nifedipine or dicyclomine. The activity-directed fractions of Pe.Cr showed a combination of Ca²⁺ antagonist and anticholinergic like components in all fractions but with varying potency.

Conclusion

These results indicate that the Phyllanthus emblica fruit extract possesses antidiarrheal and spasmolytic activities, mediated possibly through dual blockade of muscarinic receptors and Ca²⁺ channels, thus explaining its medicinal use in diarrhea.     

Gut and airways relaxant effects of Carum roxburghianum

Ethnopharmacological relevance

Carum roxburghianum is traditionally used in hyperactive gastrointestinal and respiratory disorders. The present study was carried out to investigate the possible gut and airways relaxant potential of Carum roxburghianum to rationalize its folk uses.

Materials and methods

Crude extract of Carum roxburghianum (Cr.Cr) was studied in in vivo and in vitro techniques.

Results

Cr.Cr exhibited protective effect against castor oil-induced diarrhea in mice at 100–1000 mg/kg. In rabbit jejunum preparations, Cr.Cr (0.03–3.0 mg/mL) caused relaxation of spontaneous and K⁺ (80 mM)-induced contractions at similar concentrations, like papaverine. Pretreatment of tissues with Cr.Cr (0.1–1.0 mg/mL) shifted Ca⁺⁺ concentration–response curves (CRCs) to right, like verapamil. Cr.Cr (0.03 and 0.1 mg/mL) caused leftward shift of isoprenaline-induced inhibitory CRCs, similar to papaverine. In isolated guinea-pig ileum, Cr.Cr (0.01 and 0.03 mg/mL) produced rightward parallel shift of acetylcholine-curves, like atropine. Cr.Cr (1.0–30 mg/kg) caused suppression of carbachol (CCh, 100 μg/kg)-induced increase in inspiratory pressure of anaesthetized rats. In guinea-pig trachea, Cr.Cr (0.03–1.0 mg/mL) relaxed CCh and high K⁺-induced contractions, shifted isoprenaline-induced inhibitory CRCs to left at 0.1 and 0.3 mg/mL and CCh-curves parallel to right (0.01 and 0.03 mg/mL). Cr.Cr did not cause any mortality of mice up to 10 g/kg dose.

Conclusion

These results indicate that Carum roxburghianum possess combination of antidiarrheal, antispasmodic and bronchodilatory effects, which provides pharmacological basis to its traditional use in the disorders of gut and airways hyperactivity, like diarrhea, colic and asthma.     

Mechanisms underlying the antispasmodic and bronchodilatory properties of Terminalia bellerica fruit

AIM OF THE STUDY: The present investigation was carried out to provide the pharmacological basis for the medicinal use of Terminalia bellerica in hyperactive gastrointestinal and respiratory disorders. MATERIALS AND METHODS: Crude extract of Terminalia bellerica fruit (Tb.Cr) was studied in in vitro and in vivo. RESULTS: Tb.Cr caused relaxation of spontaneous contractions in isolated rabbit jejunum at 0.1-3.0mg/mL. Tb.Cr inhibited the carbachol (CCh, 1microM) and K(+) (80mM)-induced contractions in a pattern similar to that of dicyclomine, but different from nifedipine and atropine. Tb.Cr shifted the Ca(++) concentration-response curves to right, like nifedipine and dicyclomine. In guinea-pig ileum, Tb.Cr produced rightward parallel shift of acetylcholine-curves, followed by non-parallel shift at higher concentration with the suppression of maximum response, similar to dicyclomine, but different from nifedipine and atropine. Tb.Cr exhibited protective effect against castor oil-induced diarrhea and carbachol-mediated bronchoconstriction in rodents. In guinea-pig trachea, Tb.Cr relaxed the CCh-induced contractions, shifted CCh-curves to right and inhibited the contractions of K(+). Anticholinergic effect was distributed both in organic and aqueous fractions, while CCB was present in the aqueous fraction. CONCLUSIONS: These results indicate that Terminalia bellerica fruit possess a combination of anticholinergic and Ca(++) antagonist effects, which explain its folkloric use in the colic, diarrhea and asthma.     

Pharmacological basis for the medicinal use of Carissa carandas in constipation and diarrhea

Ethnopharmacological relevance

Carissa carandas Linn. commonly known as “Karaunda” (Apocynaceae) is a popular medicinal herb widely distributed in different parts of Pakistan. In addition to other medicinal uses, Carissa carandas is popular in indigenous system of medicine for its medicinal use in gut motility disorders like, constipation and diarrhea.

Objective

This study was planned to provide pharmacological basis to the medicinal use of Carissa carandas in constipation and diarrhea.

Materials and methods

The crude extract of the leaves of Carissa carandas (Cc.Cr) was prepared in methanol and its fractionation was carried out with ethylacetate, petroleum ether and n-butanol. In-vivo studies were conducted on mice, while isolated rabbit jejunum and guinea-pig ileum preparations were used for the in-vitro experiments. The spasmogenic and spasmolytic responses of gut tissues were recorded using isotonic transducers coupled with PowerLab data acquisition system.

Results

The HPLC fingerprints of Cc.Cr, its petroleum (Cc.Pef), ethylacetate (Cc.Eaf) and n-butanol (Cc.Baf) fractions showed the presence of oleanolic acid, ursolic acid, stigmasterol and β-sitosterol. Oral administration of Cc.Cr to mice increased fecal output at lower doses (30 and 50 mg/kg), while it showed protection against castor oil-induced diarrhea at higher doses (300 and 600 mg/kg). In isolated guinea-pig ileum and rabbit jejunum, Cc.Cr and Cc.Baf exhibited stimulatory effect at 0.003–3 mg/ml, which was partially sensitive to atropine or pyrillamine or partially/fully sensitive to atropine+pyrillamine, followed by relaxation at higher tested concentrations, being more potent in rabbit tissues. The ethylacetate fraction (0.1–5 mg/ml) exhibited fully atropine-sensitive contractions in both guinea-pig and rabbit tissues, being more potent in guinea-pig while more efficacious in rabbit tissues. However, the petroleum fraction (0.003–1.0 mg/ml) showed only spasmolytic activity in spontaneously contracting rabbit tissues, similar to nifedipine. In guinea-tissue, Cc.Pef did not cause any stimulant effect. When studied against high K⁺ (80 mM)-induced contraction, the crude extract and its fractions caused a dose-dependent inhibition, with the following order of potency: Cc.Pef>Cc.Eaf>Cc.Cr≥Cc.Baf, similar to nifedipine indicating Ca⁺⁺ channel antagonist like activity, which was further confirmed when the plant extract displaced Ca⁺⁺ curves to the right with suppression of maximum effect similar to that of nifedipine.

Conclusion

This study demonstrates that the crude extract of Carissa carandas possesses a gut-stimulatory effect mediated primarily through the activation of muscarinic and histaminergic receptors while its spasmolytic effect was mediated possibly through Ca⁺⁺ antagonist pathway. Thus, this study provides a clear evidence for the dual effectiveness of Carissa carandas in constipation and diarrhea, thus validating its medicinal use.     

Coriander fruit exhibits gut modulatory,blood pressure lowering and diuretic activities

Aim of the study

Coriander (Coriandrum sativum) is traditionally used for various gastrointestinal and cardiovascular disorders and this study was designed to rationalize its use in dyspepsia, abdominal colic, diarrhea, hypertension and as diuretic.

Materials and methods

Coriander crude extract (Cs.Cr) was evaluated through in vitro and in vivo techniques.

Results

Cs.Cr caused atropine sensitive stimulatory effect in isolated guinea-pig ileum (0.1–10 mg/ml). In rabbit jejunum preparations, Cs.Cr evoked a similar contractile response but in the presence of atropine, it exhibited relaxation against both spontaneous and high K⁺ (80 mM)-induced contractions as well as shifted the Ca²⁺ concentration–response curves to right, similar to that caused by verapamil. Cs.Cr (1–30 mg/ml) caused fall in arterial blood pressure of anesthetized animals, partially blocked by atropine. Cs.Cr produced vasodilatation against phenylephrine and K⁺ (80 mM)-induced contractions in rabbit aorta and cardio-depressant effect in guinea-pig atria. Cs.Cr produced diuresis in rats at 1–10 mg/kg. Bio-assay-directed fractionation revealed the separation of spasmogenic and spasmolytic components in the aqueous and organic fractions respectively.

Conclusions

These results indicate that coriander fruit exhibits gut stimulatory, inhibitory and hypotensive effects mediating possibly through cholinergic, Ca²⁺ antagonist and the combination of these mechanisms respectively. Diuretic activity adds value to its use in hypertension.     

Screening of the topical anti-inflammatory activity of the bark of Acacia cornigera Willdenow, Byrsonima crassifolia Kunth, Sweetia panamensis Yakovlev and the leaves of Sphagneticola trilobata Hitchcock

Ethnopharmacological relevance

An investigation of topical anti-inflammatory activity was undertaken on plants used in Central America traditional medicine.

Aim of study

Four herbal drugs used in the folk medicine of Central America to treat inflammatory skin affections (Acacia cornigera bark, Byrsonima crassifolia bark, Sphagneticola trilobata leaves and Sweetia panamensis bark) were evaluated for their topical anti-inflammatory activity.

Materials and methods

Petroleum ether, chloroform and methanol extracts were obtained for herbal medicines and then extracts were tested on Croton oil-induced ear dermatitis model in mice.

Results

Almost all the extracts reduced the Croton oil-induced ear dermatitis in mice and the chloroform ones showed the highest activity, with ID₅₀ (dose giving 50% oedema inhibition) values ranging from 112 μg/cm² (Byrsonima crassifolia) to 183 μg/cm² (Sphagneticola trilobata). As reference, ID₅₀ of the non-steroidal anti-inflammatory drug indomethacin was 93 μg/cm².

Conclusions

Lipophilic extracts from these species can be regarded as potential sources of anti-inflammatory principles.     

Neuroprotective effect of Artemisia absinthium L. on focal ischemia and reperfusion-induced cerebral injury

Ethnopharmacological relevance

Artemisia absinthium L. has long been used as traditional herbal medicine in China, Europe and Pakistan for the treatment of gastric pain, cardiac stimulation, to improve memory and for the restoration of declining mental function.

Aim of the study

The present study was designed to investigate the potential protective effects of Artemisia absinthium on cerebral oxidative stress and damage as well as behavioral disturbances induced by cerebral ischemia and reperfusion injury in rats.

Materials and methods

Focal ischemia and reperfusion were induced by middle cerebral artery occlusion (MCAO) for 90 min, followed by 24 h reperfusion. MCAO led to significant rise in infarct size and lipid peroxidation, and depletion in glutathione content, superoxide dismutase and catalase activity in brain. Further, behavioral deficits like motor incoordination and impairment of short-term memory were also significantly impaired by MCAO as compared with sham group.

Results

The brain oxidative stress and damage, and behavioral deficits were significantly attenuated by pre-treatment with the methanol extract of Artemisia absinthium (100 mg/kg and 200 mg/kg, p.o.).

Conclusion

These findings suggested that Artemisia absinthium is neuroprotective and may prove to be useful adjunct in the treatment of stroke.     

Antidiarrheal activity of Pyrenacantha staudtii Engl. (Icacinaceae) aqueous leaf extract in rodents

Ethnopharmacological relervance

Pyrenacantha staudtii Engl. (Icacinaceae) is a plant which is traditionally used for the treatment of blemnorrhea, hernia, insomnia, intestinal pain and diarrhea in Nigeria. Therefore the core aim of the present study is to evaluate antidiarrheal activity of Pyrenacantha staudtii aqueous extract (PSE).

Materials and methods

The antidiarrheal activity was evaluated using castor oil-induced diarrhea method. The effects of Pyrenacantha staudtii aqueous extract on gastrointestinal motility, intestinal transit and enteropooling were also examined in rodents. The acute toxicity effect of the aqueous extract of Pyrenacantha staudtii was also investigated.

Results

Pyrenacantha staudtii aqueous extract (PSE, 100-400 mg/kg, p.o.) produced dose-dependent and significant (P < 0.05-0.01) protection of rats and mice against castor oil-induced diarrhea, inhibited intestinal transit, and delayed gastric emptying. PSE, produced dose-dependent and significant (P < 0.05-0.01) antimotility effect, caused dose-related inhibition of castor-oil-induced enteropooling in animals, comparable to atropine (1 mg/kg, p.o.). Like loperamide (10 mg/kg, p.o.), PSE, dose-dependently and significantly (P < 0.05-0.01) delayed the onset of castor-oil induced diarrhea, decreased the frequency of defecation, and reduced the severity of diarrhea in the rodents. Compared with control animals, PSE, dose-dependently and significantly (P < 0.05-0.01) decreased the volume of castor oil-induced intestinal fluid secretion, and reduced the number, weight and wetness of fecal droppings.

Conclusion

The findings of this study indicate that PSE possesses antidiarrheal property in rats and mice. These findings confirm the ethnomedicinal use of Pyrenacantha staudtii leaf as a valuable natural remedy for the treatment, management and/or control of diarrhea.     

The anti-ulcer activities of bisabolangelone from Angelica polymorpha

Aim of the study

Evaluate the anti-ulcer effects of bisabolangelone from Angelica polymorpha Maxim and provide the basic data to further study for the Angelica polymorpha and bisabolangelone.

Materials and methods

Bisabolangelone was isolated from Angelica polymorpha Maxim collected from Shennongjia Forest District of China. The structure of bisabolangelone was elucidated by NMR and MS spectrums. The anti-ulcer effects were evaluated with length of lesion (mm) and activity of H⁺/K⁺-ATPase in two models induced by ethanol and Pylorus ligation. Experimental groups were administered with different doses of bisabolangelone (3.8, 7.6 and 15.3 mg/kg). The positive control group was administered omeprazole with a dose of 3.3 mg/kg.

Results

Bisabolangelone significantly reduced the length of lesion (3.8, 7.6 and 15.3 mg/kg, P < 0.01), inhibited the activity of H⁺/K⁺-ATPase (3.8, 7.6 and 15.3 mg/kg, P < 0.01), decreased the volume of gastric juice (7.6 and 15.3 mg/kg, P < 0.05), and increased the pH value of gastric juice (7.6 and 15.3 mg/kg, P < 0.01, 3.8 mg/kg, P < 0.05).

Conclusions

Bisabolangelone is the main anti-ulcer active compound of Angelica polymorpha, and remarkably preventive and therapeutic action on gastric ulcer. It is possible that bisabolangelone inhibited the activity of the H⁺/K⁺-ATPase, then reducing the secretion of H⁺, and the anti-ulcer mechanism of bisabolangelone was deserved to be further studied.     

Artemisia copa aqueous extract as vasorelaxant and hypotensive agent

Ethnopharmacological relevance

Artemisia copa Phil. (Asteraceae) is a medicinal plant commonly used in traditional medicine in Argentina.

Aim of the study

The vasorelaxant and hypotensive activities of the aqueous extract of Artemisia copa have been investigated.

Materials and methods

The in vitro effect of the extract and isolated compounds from Artemisia copa was investigated using isolated rat aortic rings. The acute effect caused by the intravenous (i.v.) infusion (0.1–300 mg/kg) on blood pressure and heart rate was evaluated in spontaneous hypertensive rats. In addition, a phytochemical analysis of the extract was performed by HPLC.

Results

Artemisia copa had a relaxant effect in endothelium-intact aortic rings that had been pre-contracted with 10⁻⁷ M phenylephrine (E_max=96.7±1.3%, EC₅₀=1.1 mg/ml), 10⁻⁵ M 5-hydroxytriptamine (E_max=96.7±3.5%, EC₅₀=1.5 mg/ml) and 80 mM KCl (E_max=97.9± 4.4%, EC₅₀=1.6 mg/ml). In denuded aortic rings contracted by phenylephrine, a similar pattern was observed (E_max=92.7±6.5%, EC₅₀=1.8 mg/ml). l-NAME, indomethacin, tetraethylammonium and glibenclamide were not able to block the relaxation induced by the extract. Nevertheless, the pre-treatment with Artemisia copa attenuated the CaCl₂-induced contraction in a concentration-dependent manner (E_max: 86% of inhibition for 3 mg/ml and 52% de-inhibition for 1 mg/ml). This pre-treatment also induced a significant attenuation of the norepinephrine-induced contraction in a concentration-dependent manner (E_max: 72.7% of inhibition for 3 mg/ml and 27% de inhibition for 1 mg/ml) in a Ca²⁺ free medium. Upon analyzing the composition of the extract, the presence of p-coumaric acid, isovitexin, luteolin and chrysoeriol were found. Luteolin (CE₅₀: 1.5 μg/ml), chrysoeriol (CE₅₀: 13.2 μg/ml) and p-coumaric acid (CE₅₀: 95.2 μg/ml), isolated from the aqueous extract, caused dilatation of thoracic aortic rings pre-contracted with phenylephrine. Artemisia copa administered i.v. also induced a decrease in the mean arterial pressure but did not affect the heart rate in hypertensive rats.

Conclusions

The aqueous extract of Artemisia copa proved to have vasorelaxing and hypotensive effects through the inhibition of Ca²⁺ influx via membranous calcium channels and intracellular stores. The presence of luteolin, chrysoeriol and p-coumaric acid found in this plant could be involved in this effect.     

Effect of plants used in Mexico to treat gastrointestinal disorders on charcoal–gum acacia-induced hyperperistalsis in rats

Ethnopharmacological relevance

A total of 28 plant extracts, belonging to 26 different plant species are commonly used in Traditional Mexican Medicine for the treatment of gastrointestinal disorders such as diarrhea.

Aim of the study

To evaluate the effect of medicinal plant extracts on induced hyperperistalsis in rats.

Materials and methods

Charcoal meal test was used in this study. Extracts were tested at a dose of 300 mg/kg.

Results

From all the plant extracts tested, only Geranium mexicanum (roots) showed 100% of inhibition. The extracts of Artemisia absinthium, Matricaria recutita, Caesalpinia pulcherrima, Lygodium venustum, Chenopodium ambrosoides (green variety), Aloysia triphylla, Artemisia ludoviciana, Chiranthodendron pentadactylon, and Cocos nucifera showed moderate inhibitory activity with values ranging from 30 to 57%. Their activities were greater than that of or equal to loperamide (34% of inhibition at doses of 10 mg/kg) drug used as control. The remaining plants exhibited marginal or null inhibitory effect on hyperpropulsive movement of the small intestine.

Conclusions

The results obtained in this study give some scientific support to the popular use of 23 of the plants tested for the treatment of gastrointestinal disorders such as diarrhea in Mexican traditional medicine. However, roots of Geranium mexicanum should be used in herbal medicine with care to avoid toxicity.     

Anti-secretory,anti-inflammatory and anti-Helicobacter pylori activities of several fractions isolated from Piper carpunya Ruiz & Pav.

Ethnopharmacological relevance

The leaves of Piper carpunya Ruiz & Pav. (syn Piper lenticellosum C.D.C.) (Piperaceae), are widely used in folk medicine in tropical and subtropical countries of South America as an anti-inflammatory, anti-ulcer, anti-diarrheal and anti-parasitical remedy as well as an ailment for skin irritations.

Aims of the study

To study the anti-inflammatory, anti-secretory and anti-Helicobacter pylori activities of different fractions isolated from an ethanolic extract of the leaves of Piper carpunya, in order to provide evidence for the use of this plant as an anti-ulcer remedy. Moreover, to isolate the main compounds of the extract and relate their biological activity to the experimental results obtained with the fractions.

Materials and methods

Sixteen fractions were obtained from the ethanolic extract (F I–XVI) and 16 pure compounds were isolated and identified from these fractions. We studied the effects of the fractions (0.1–400 μg/mL) on the release of myeloperoxidase (MPO) enzyme from rat peritoneal leukocytes, on rabbit gastric microsomal H⁺, K⁺-ATPase activity and anti-Helicobacter pylori anti-microbial activity using the microdilution method (MM). The main compounds contained in the fractions were isolated and identified by ¹H- and ¹³C NMR spectra analysis and comparison with the literature data.

Results

Eight fractions showed inhibition of MPO enzyme (F I–IV, X, XII, XIV and XV). The highest inhibition was observed with F XIV (50 μg/mL, 60.9%, p < 0.001). F X and XII were the most active ones, inhibiting the gastric H⁺, K⁺-ATPase activity with IC₅₀ values equal to 22.3 μg/mL and 28.1 μg/mL, respectively. All fractions, except F XV, presented detectable anti-Helicobacter pylori activity, with a diameter of inhibition zones ranging from 11 mm up to 50 mm. The best anti-Helicobacter pylori activity was obtained with F III and V. Both fractions killed Helicobacter pylori with lowest concentration values, about 6.25 μg/mL. Sixteen pure compounds were isolated, five of them are flavonoids that possess strong anti-oxidant and free radical scavenging activity, e.g. vitexin, isovitexin, and rhamnopyranosylvitexin. Terpenoids like sitosterol, stigmasterol and phytol, which have shown gastroprotective activity, and dihydrochalcones, like asebogenin, with anti-bacterial activity, were also isolated. Furthermore, the rare neolignan 1, that is a DNA polymerase β lyase inhibitor, and (6S, 9S)-roseoside, that shows strong anti-bacterial activity, were isolated, for the first time, from the genus Piper.

Conclusions

We suggest that the flavonoids isolated from F I and II (vitexin, isovitexin, rhamnopyranosylvitexin and isoembigenin) contribute to the anti-MPO activity, as well as to their anti-Helicobacter pylori activity. These flavonoids may also be responsible for the important inhibition of H⁺, K⁺-ATPase activity. Also the phytosterols and phytol obtained from F XIV and XV could be involved in these gastroprotective activities. These results encourage us to continue phytochemical studies on these fractions in order to obtain full scientific validation for this species.     

α-Glucosidase inhibitory activity of selected Philippine plants

Ethnopharmacological relevance

Antidesma bunius Spreng. (Phyllantaceae), Averrhoa bilimbi L. (Oxalidaceae), Biophytum sensitivum (L.) DC. (Oxalidaceae), Ceriops tagal (Perr.) C.B. Rob. (Rhizophoraceae), Kyllinga monocephala Rottb. (Cyperaceae), and Rhizophora mucronata Lam. (Rhizophoraceae) are used as remedies to control diabetes. In the present study, these plants were screened for their potential α-glucosidase inhibitory activity.

Materials and methods

The 80% aqueous ethanolic extracts were screened for their α-glucosidase enzyme inhibitory activity using yeast alpha glucosidase enzyme.

Results

Except for A. bilimbi with IC₅₀ at 519.86±3.07, all manifested a significant enzyme inhibitory activity. R. mucronata manifested the highest activity with IC₅₀ at 0.08±1.82 μg mL⁻¹, followed by C. tagal with IC₅₀ at 0.85±1.46 μg mL⁻¹ and B. sensitivum with IC₅₀ at 2.24±1.58 μg mL⁻¹.

Conclusion

This is the first report on the α-glucosidase inhibitory effect of the six Philippine plants; thus, partly defining the mechanism on why these medicinal plants possess antidiabetic properties.     

Vasorelaxant effects of extracts of the stem bark of Terminalia superba Engler & Diels (Combretaceae)

Aim of the study

The stem bark of Terminalia superba (Combretaceae) (TS) is used in traditional Cameroonian medicine as antihypertensive remedy. In the present study, we investigated the vasorelaxant properties of different extracts of TS and their underlying mechanisms.

Materials and methods

Activities of aqueous (AQU), methanolic (MET), methylene chloride (MC), and methylene chloride–methanol (MCM) extracts of TS were evaluated on isolated rat aortic rings precontracted with phenylephrine (PE) or high KCl.

Results

All extracts induced a vasodilating effect both on KCl- and PE-induced contractions. The effects of MC and MCM extracts were greater than those of AQU or MET extracts (P < 0.05). MC had an endothelium-independent effect and reduced Ca⁺⁺-induced contraction following PE or KCl challenge (P < 0.05). After incubation with verapamil, MC induced a relaxation in rings precontracted by PE (P < 0.001). By contrast, the effect of MCM was endothelium-dependent and decreased by the nitric oxide synthase inhibitor N_W-nitro-l-arginine methyl ester (P < 0.05).

Conclusions

These data demonstrate that the MC extract exhibits vasorelaxant effects that are partly due to inhibition of extracellular Ca⁺⁺ influx and/or inhibition of intracellular Ca⁺⁺ release in vascular smooth muscle cells. By contrast, the effect of the MCM extract was found to be endothelium- and nitric oxide dependent.     

Permeability of rosmarinic acid in Prunella vulgaris and ursolic acid in Salvia officinalis extracts across Caco-2 cell monolayers

Ethnopharmacological relevance

Rosmarinic acid (RA), a caffeic acid-related compound found in high concentrations in Prunella vulgaris (self-heal), and ursolic acid (UA), a pentacyclic triterpene acid concentrated in Salvia officinalis (sage), have been traditionally used to treat inflammation in the mouth, and may also be beneficial for gastrointestinal health in general.

Aim of the study

To investigate the permeabilities of RA and UA as pure compounds and in Prunella vulgaris and Salvia officinalis ethanol extracts across human intestinal epithelial Caco-2 cell monolayers.

Materials and methods

The permeabilities and phase II biotransformation of RA and UA as pure compounds and in herbal extracts were compared using Caco-2 cells with HPLC detection.

Results

The apparent permeability coefficient (P_app) for RA and RA in Prunella vulgaris extracts was 0.2 ± 0.05 × 10⁻⁶ cm/s, significantly increased to 0.9 ± 0.2 × 10⁻⁶ cm/s after β-glucuronidase/sulfatase treatment. P_app for UA and UA in Salvia officinalis extract was 2.7 ± 0.3 × 10⁻⁶ cm/s and 2.3 ± 0.5 × 10⁻⁶ cm/s before and after β-glucuronidase/sulfatase treatment, respectively. Neither compound was affected in permeability by the herbal extract matrix.

Conclusion

RA and UA in herbal extracts had similar uptake as that found using the pure compounds, which may simplify the prediction of compound efficacy, but the apparent lack of intestinal glucuronidation/sulfation of UA is likely to further enhance the bioavailability of that compound compared with RA.     

Pharmacological Basis for Medicinal Use of Lens culinaris in Gastrointestinal and Respiratory Disorders

Crude extract of Lens culinaris (Lc.Cr), which tested positive for presence of anthraquinones, flavonoids, saponins, sterol, tannins, and terpenes exhibited protective effect against castor oil‐induced diarrhea in mice at 100–1000 mg/kg. In rabbit jejunum preparations, Lc.Cr caused relaxation of spontaneous contractions at 0.03–5.0 mg/mL. Lc.Cr inhibited carbachol (CCh, 1 μM) and K⁺ (80 mM)‐induced contractions in a pattern similar to dicyclomine, but different from verapamil and atropine. Lc.Cr shifted the Ca⁺⁺ concentration‐response curves to the right, like dicyclomine and verapamil. Pretreatment of tissues with Lc.Cr (0.03–0.1 mg/mL) caused leftward shift of isoprenaline‐induced inhibitory CRCs, similar to papaverine. In guinea‐pig ileum, Lc.Cr produced rightward parallel shift of CCh curves, followed by non‐parallel shift at higher concentration with suppression of maximum response, similar to dicyclomine, but different from verapamil and atropine. Lc.Cr (3.0–30 mg/kg) caused suppression of carbachol (CCh, 100 µg/kg)‐induced increase in inspiratory pressure of anesthetized rats. In guinea‐pig trachea, Lc.Cr relaxed CCh and high K⁺‐induced contractions, shifted CCh curves to right and potentiated isoprenaline response. These results suggest that L. culinaris possesses antidiarrheal, antispasmodic, and bronchodilator activities mediated possibly through a combination of Ca⁺⁺ antagonist, anticholinergic, and phosphodiesterase inhibitory effects, and this study provides sound mechanistic background to its medicinal use in disorders of gut and airways hyperactivity, like diarrhea and asthma. Copyright © 2014 John Wiley & Sons, Ltd.     

Vasorelaxant and anti-platelet aggregation effects of aqueous Ocimum basilicum extract

Aim of the study

In this work the endothelium-dependant vasorelaxant and anti-platelet aggregation activities of an aqueous extract from Ocimum basilicum were studied.

Materials and methods

The vasorelaxant effect was undertaken in thoracic aorta from three experimental groups of rats: one of them (NCG) fed with standard diet, the second (HCG) with hypercholesterolemic diet (HCD) and the third (BTG) with hypercholesterolemic diet together with an intragastric administration of Ocimum basilicum extract at a dose of 0.5 g/kg body weight for a period of 10 weeks. The in vitro anti-platelet aggregation of Ocimum basilicum extract was studied using thrombin (0.5 U/ml) and ADP (5 μM) as agonists.

Results

The results show that the HCD statistically decreases vascular relaxation in HCG compared to NCG (p < 0.001) and increases the vascular responses to phenylephrine (p < 0.02). Ocimum basilicum extract exerts a significant vasorelaxant effect at 10⁻⁵ M (p < 0.01) and 10⁻⁴ M carbachol (p = 0.001). The plant extract also tends to suppress the elevated contractions induced by HCD (p = 0.05). The extract inhibits ADP-induced platelet aggregation by 13%, 28.2%, 30.5%, 44.7% and 53% at a dose of 1, 2, 3, 4 and 5 g/l, respectively. Thrombin-induced platelet activation was also reduced by 15%, 23%, 40%, 38.4%, and 42% at the same doses of extract described above.

Conclusion

The use of Ocimum basilicum as medicinal plant could be beneficial for cardiovascular system.     

Hypotensive and endothelium-independent vasorelaxant effects of methanolic extract from Curcuma longa L. in rats

Ethnopharmacological relevance

Curcuma longa L. (CL) is a yellow rhizome that is used in African traditional medicine to treat palpitation, hypertension or other related blood circulation disorders.

Aim of the study

To justify the use of CL in ethnomedicine, we investigated the vasorelaxant effect of methanolic extract of CL (CLME) and its underlying mechanisms in isolated rat mesenteric artery.

Materials and methods

The effect of CLME on the mean arterial pressure (MAP) and heart rate (HR) (pulse interval) were determined in vivo in non-anaesthetized rats. Superior mesenteric rings were isolated, suspended in organ baths containing Tyrode solution at 37 °C and gassed with 95% O₂ + 5% CO₂, under a resting tension of 0.75 g. The vasorelaxant effects of CLME were studied by means of isometric tension recording experiments.

Results

In normotensive rats, CLME (10, 20 and 30 mg/kg, i.v.) induced dose-dependent hypotension (2.0 ± 0.5%; 27.1 ± 5.0% and 26.7 ± 4.6%, respectively), and pronounced bradycardia (5.8 ± 1.2%, 19.3 ± 3.2% and 22.9 ± 4.6%, respectively). CLME (1–1000 μg/mL) induced concentration-dependent relaxation of tonic contractions evoked by phenylephrine (Phe) (10 μM) and KCl (80 mM) in rings with intact-endothelium (E_max = 82.3 ± 3.2% and 97.7 ± 0.7%) or denuded-endothelium (E_max = 91.4 ± 1.0% and 97.8 ± 1.1%). Also, in a depolarized, Ca²⁺ free medium, CLME inhibited CaCl₂ (1 μM–30 mM)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that CLME inhibited the contractile mechanisms involving extracellular Ca²⁺ influx. In addition, in Ca²⁺ free media containing EGTA (1 mM), CLME inhibited the transient contraction of denuded rings constricted with Phe, but not those evoked by caffeine (20 mM). In contrast, neither glibenclamide, BaCl₂, tetraethylammonium nor 4-aminopyridine affected CLME-induced relaxation.

Conclusions

These results demonstrate the hypotensive and bradycardic effects of CLME, as well as its potent vasodilation of rat mesenteric arteries. These effects, may in part, be due to the inhibition of extracellular Ca²⁺ influx and/or inhibition of intracellular Ca²⁺ mobilization from Phe-sensitive stores.     

Anti-diarrhoeal and anti-microbial activity of Flos populi (male inflorescence of Populus tomentosa Carrière) aqueous extracts

Ethnopharmacological relevance

Flos populi (male inflorescence of Populus tomentosa Carrière) has been traditionally used in East Asian countries for the treatment of various inflammatory diseases, strengthening the spleen and stomach, anti-rheumatic, anti-tumor and anti-diarrhoeal.

Aim of the study

To evaluate the in vivo or in vitro anti-diarrhoeal and anti-microbial activity of Flos populi aqueous extract.

Materials and methods

Acute toxicity of Flos populi aqueous extract (FPAE) was investigated. Castor oil-induced diarrhoea method was used to evaluate the anti-diarrhoeal activity, inhibition of defecation and diarrhoea were determined in mice, effects on castor oil-induced enteropooling, intestinal transit and intestinal fluid secretion in rats or mice. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of FPAE against strains of three clinical bacterial isolates and one reference strain were used to test the anti-microbial activity.

Results

The FPAE reduced the frequency of diarrhoea episodes and decreased the propulsion of charcoal meal through the gastrointestinal tract in a dose dependent manner. FPAE (100–500 mg/kg, p.o.) produced dose-dependent and significant (P<0.01) protection of mice against castor oil-induced diarrhoea. FPAE, dose-dependently and significantly (P< 0.01) delayed the onset of castor-oil induced diarrhoea, decreased the frequency of defecation, and reduced the severity of diarrhoea. Compared with control animals, FPAE, dose-dependently and significantly (P< 0.01) decreased the volume of castor oil-induced intestinal fluid secretion, and reduced the number, weight and wetness of faecal droppings. There was no deaths or abnormalities in behaviour seen in the acute toxicity test. The aqueous extract displayed anti-microbial effects to three species of bacteria in anti-microbial test.

Conclusion

The findings of this study indicate that FPAE possesses anti-diarrhoeal property in rats and mice and confirm the ethnomedicinal use of Flos Populi as a valuable natural remedy for the treatment, management and/or control of diarrhoea. These results may support the fact that this plant is traditionally used to cure diarrhoea.     

Antidiarrheal and antioxidant activities of chamomile (Matricaria recutita L.) decoction extract in rats

Ethnopharmacological relevance

Matricaria recutita L. (Chamomile) has been widely used in the Tunisian traditional medicine for the treatment of digestive system disorders. The present work aims to investigate the protective effects of chamomile decoction extract (CDE) against castor oil-induced diarrhea and oxidative stress in rats.

Methods

The antidiarrheal activity was evaluated using castor oil-induced diarrhea method. In this respect, rats were divided into six groups: Control, Castor oil, Castor oil+Loperamide (LOP) and Castor oil+various doses of CDE. Animals were per orally (p.o.) pre-treated with CDE during 1 h and intoxicated for 2 or 4 h by acute oral administration of castor oil.

Results

Our results showed that CDE produced a significant dose-dependent protection against castor oil-induced diarrhea and intestinal fluid accumulation. On the other hand, we showed that diarrhea was accompagned by an oxidative stress status assessed by an increase of malondialdehyde (MDA) level and depletion of antioxidant enzyme activities as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Castor oil also increased gastric and intestinal mucosa hydrogen peroxide (H₂O₂) and free iron levels. Importantly, we showed that chamomile pre-treatment abrogated all these biochemical alterations.

Conclusion

These findings suggested that chamomile extract had a potent antidiarrheal and antioxidant properties in rats confirming their use in traditional medicine.