Evaluation of pharmacological activity of a crude hydroalcoholic extract from Jatropha elliptica

The pharmacological effect of the hydroalcoholic extract of Jatropha elliptica was analysed in in vivo and in vitro models. When given orally in mice, the extract showed a low acute toxicity (LD₅₀ 5 g/kg). In a dose of 0.5 or 1 g/kg p.o. the extract did not interfere with diuresis in the rat, but was found to be effective in blocking rat paw oedema induced by carrageenan and partially, serotonin-induced oedema. In the same dose, the extract failed to inhibit rat paw oedema induced by dextran and the increase of rat cutaneous vascular permeability caused by Bothrops Jararaca venom, dextran, histamine, PAF-acether and serotonin. Pre-incubation of the isolated rat uterus and guinea-pig ileum with the extract (0.2–0.8 mg/mL), produced a concentration-related and non-competitive inhibition of contractions induced by acetylcholine and bradykinin. However, the extract was about 2-fold more potent in inhibiting the contraction of both agonists in guinea-pig ileum than in rat uterine muscle. In rat aorta, the extract (50–100 μg/mL) caused a concentration-dependent inhibition of noradrenaline-evoked contractions, being about 5-fold more potent when compared to the IC₅₀ values obtained in rat uterus.     

Vasoconstrictor and cardiotonic actions of Haloxylon recurvum extract

Intravenous administration of an ethanolic extract of Haloxylon recurvum (30–300 μg/kg) caused a rise in arterial blood pressure in normotensive anaesthetized rats. Pretreatment of animals with phentolamine (1 mg/kg) abolished the vasoconstrictor response of the plant extract in a way similar to that of norepinephrine (NE). In an isolated rabbit aorta preparation, both plant extract and NE produced contractile responses which were blocked by phentolamine (0.3 μg/mL). In isolated guinea-pig atria, the plant extract caused positive inotropic and chronotropic responses similar to that of NE and was blocked by propranolol (0.3 μg/mL). These results suggest that vasoconstrictor and cardiac stimulatory effects of the plant extract are mediated through mechanisms similar to those of NE (stimulation of α-adrenergic receptors in the blood vessels and cardiac β-receptors respectively) and hence this plant contains sympathomimetic constituent(s).     

Pharmacological studies on hypotensive and spasmolytic activities of pure compounds from Moringa oleifera

Bioassay directed fractionation of an ethanolic extract of Moringa oleifera (MO) leaves resulted in the isolation of four pure compounds, niazinin A (1), niazinin B (2), niazimicin (3) and niaziminin A + B (4 + 5). Intravenous administration of either one of the compounds (1–10 mg/kg) produced hypotensive and bradycardiac effects in anaesthetized rats. Pretreatment of the animals with atropine (1 mg/kg) completely abolished the hypotensive and bradycardiac effects of acetylcholine (ACh), whereas cardiovascular responses to the test compounds remained unaltered, ruling out the possible involvement of muscarinic receptor activation. In isolated guinea-pig atria all the compounds (50–150 μg/mL) produced negative inotropic and chronotropic effects. Each compound inhibited K⁺ -induced contractions in rabbit aorta as well as ileal contractions induced by ACh or histamine at similar concentrations. Spontaneous contractions of rat uterus were also inhibited equally by all compounds. These data indicate that the direct depressant action of these compounds exhibited on all the isolated preparations tested is probably responsible for its hypotensive and bradycardiac effects observed in vivo. Moreover, spasmolytic activity exhibited by the constituents of the plant provides a scientific basis for the traditional uses of the plant in gastrointestinal motility disorders.     

Antispasmodic,bronchodilator and blood pressure lowering properties of Hypericum oblongifolium – possible mechanism of action

The crude extract of Hypericum oblongifolium (Ho.Cr), which tested positive for flavonoids, saponins and tannins caused concentration‐dependent (0.1–1.0 mg/mL) relaxation of spontaneous and high K⁺ (80 mM)‐induced contractions in isolated rabbit jejunum preparations, suggesting a Ca⁺⁺ antagonistic effect, which was confirmed when pretreatment of the tissue with Ho.Cr produced a rightward shift in the Ca⁺⁺ concentration‐response curves, like that caused by verapamil. Ho.Cr relaxed carbachol (1 μM) and high K⁺‐induced contractions in guinea pig tracheal preparations. It caused a dose‐dependent (3–100 mg/kg) fall in arterial blood pressure of rats under anesthesia. In isolated guinea pig atria, Ho.Cr caused inhibition of both atrial force and rate of spontaneous contractions. When tested in rabbit aortic rings, Ho.Cr exhibited a vasodilator effect against phenylephrine (1 μM) and high K⁺‐induced contractions. These results indicate that Ho.Cr possesses gastrointestinal, respiratory and cardiovascular inhibitory effects, mediated via a Ca⁺⁺ antagonist mechanism. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

Effects of crinum glaucum aqueous extract on intestinal smooth muscle activity

Crinum glaucum aqueous extract (1–8 mg/mL) produced a concentration dependent, non-competitive inhibition of contractions induced by acetylcholine (1.1 × 10⁻⁸–3.3 × 10⁻⁷M ) and calcium chloride (CaCl₂, 0.05–2 mM ) on the rat duodenum. Contractions of the guinea-pig ileum induced by acetylcholine (1.1 × 10⁻⁸–3.3 × 10⁻⁷M ) and histamine (1.1 × 10⁻⁸–3.3 × 10⁻⁷M ) were inhibited by the extract (1–4 mg/mL). The extract (0.125–2.0 mg/mL) also, produced a concentration dependent relaxation of the guinea-pig taenia coli, precontracted with potassium chloride (40 mM ). It is concluded that the extract is a non-specific relaxant of the gastrointestinal smooth muscles used. © 1998 John Wiley & Sons, Ltd.     

Blood pressure lowering,cardiovascular inhibitory and bronchodilatory actions of Achillea millefolium

Achillea millefolium Linn. (Asteraceae) is used in folk medicine for the treatment of overactive cardiovascular and respiratory ailments. This study describes its hypotensive, cardio‐depressant, vasodilatory and bronchodilatory activities. The crude extract of Achillea millefolium (Am.Cr) caused a dose‐dependent (1–100 mg/kg) fall in arterial blood pressure of rats under anaesthesia. In spontaneously beating guinea‐pig atrial tissues, Am.Cr exhibited negative inotropic and chronotropic effects. In isolated rabbit aortic rings, Am.Cr at 0.3–10 mg/mL relaxed phenylephrine (PE, 1 µm ) and high K⁺ (80 mm )‐induced contractions, as well as suppressed the PE (1 µm ) control peaks obtained in Ca⁺⁺‐free medium, like that caused by verapamil. The vasodilator effect of Am.Cr was partially blocked by N_ω‐nitro‐l ‐arginine methyl ester in endothelium intact preparations. In guinea‐pig tracheal strips, Am.Cr inhibited carbachol (CCh, 1 µm ) and K⁺‐induced contractions. These results indicate that Achillea millefolium exhibits hypotensive, cardiovascular inhibitory and bronchodilatory effects, thus explaining its medicinal use in hyperactive cardiovascular and airway disorders, such as hypertension and asthma. Copyright © 2010 John Wiley & Sons, Ltd.     

Antidiarrhoeal activity of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm (‘African potato’) aqueous extract in rodents

This study investigated the antidiarrhoeal activity of Hypoxis hemerocallidea corm aqueous extract (APE) on experimentally‐induced diarrhoea, gastrointestinal motility, intestinal transit and enteropooling in rodents. H. hemerocallidea corm aqueous extract (APE, 50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) protection of rats and mice against castor oil‐induced diarrhoea, inhibited intestinal transit and delayed gastric emptying. Like atropine (1 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) antimotility effect, and caused dose‐related inhibition of castor oil‐induced enteropooling in the animals. Like loperamide (10 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p < 0.05–0.01) delayed the onset of castor oil‐induced diarrhoea, decreased the frequency of defaecation and reduced the severity of diarrhoea in the rodents. Compared with control animals, APE (50–400 mg/kg, p.o.) 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 faecal droppings. APE (50–400 mg/mL) also produced concentration‐related and significant (p < 0.05–0.01) inhibitions of the spontaneous, pendular contractions of the rabbit isolated duodenum, and attenuated acetylcholine (ACh, 0.1–5.0 µg/mL)‐induced contractions of the guinea‐pig isolated ileum. Although the precise mechanism of the antidiarrhoeal activity of APE could not be established, the results of this study indicate that APE possesses antidiarrhoeal activity. This finding supports the use of ‘African potato’ as a natural supplementary remedy for the treatment, management and/or control of diarrhoea in some rural communities of southern Africa. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of the essential oil of Croton zehntneri,and its constituent estragole on intestinal smooth muscle

The effects on isolated guinea-pig ileum of the essential oil of Croton zehntneri (CZEO) and of its main constituent estragole (57% of CZEO by weight) were studied. CZEO and estragole (0.1–100 μg/mL) decreased the tonus in 56% and 61.5%, respectively, of the muscles. At concentrations above 10 μg/mL, they induced spontaneous rhythmic movements of small amplitude (less than 11% of the potassium contraction peak to peak). At concentrations from 1 to 100 μg/mL and with similar potencies, these agents blocked the contractions induced by acetylcholine, histamine and 50 mM K⁺ and caused relaxation of already established potassium contractures. Tested separately, CZEO, estragole and anethole (28% of CZEO by weight) blocked the contraction induced by Ca⁺⁺ in the presence of 50 mM K⁺, but CZEO was more potent than estragole or anethole in blocking the Ca⁺⁺-induced contractions than those induced by K⁺. With large increases in the agonist concentration, the action of the oils on the contractions induced by Ca⁺⁺ was reversible; however, their effect on contractions induced by histamine or ACh was not. The data show that the essential oil of Croton zehntneri has an effect on intestinal smooth muscle that is predominantly antispasmodic, and attributable in part to the effect of estragole, a major constituent. © 1997 John Wiley & Sons, Ltd.     

Calcium channel blocking activity of Mentha longifolia L. explains its medicinal use in diarrhoea and gut spasm

Mentha longifolia has a reputation in traditional medicine in the indications of diarrhoea and gut spasm. This study was carried out to provide a possible pharmacological basis for its medicinal use in hyperactive gut disorders. In a castor oil induced diarrhoeal model, the crude extract of Mentha longifolia (Ml.Cr), at doses of 100–1000 mg/kg, provided 31–80% protection, similar to loperamide. In isolated rabbit jejunum preparations, Ml.Cr caused inhibition of spontaneous and high K⁺‐induced contractions, with respective EC₅₀ values of 1.80 (1.34–2.24; n = 6–8) and 0.60 mg/mL (0.37–0.85; n = 6–8), which suggests spasmolytic activity, mediated possibly through calcium channel blockade (CCB). The CCB activity was further confirmed when pretreatment of the tissue with Ml.Cr (0.3–1 mg/mL) caused a rightward shift in the Ca⁺⁺ concentration–response curves (CRCs), similar to verapamil. Loperamide also inhibited spontaneous and high K⁺‐induced contractions and shifted the Ca⁺⁺ CRCs to the right. Activity‐directed fractionation revealed that the petroleum spirit fraction was more potent than the parent crude extract and aqueous fraction. These data indicate that the antidiarrhoeal and spasmolytic effects of the crude extract of Mentha longifolia are mediated through the presence of CCB‐like constituent(s), concentrated in the petroleum spirit fraction and this study provides indirect evidence for its medicinal use in diarrhoea and spasm. Copyright © 2010 John Wiley & Sons, Ltd.     

Selective modulatory effects of the essential oil of Croton zehntneri on isolated smooth muscle preparations of the guinea-pig

The effects of the essential oil of the plant Croton zehntneri (EOCz) in the concentration range 1–200 μg/mL were studied on the mechanical activity of various in vitro smooth muscle preparations of the guinea-pig. In isolated ileum EOCz induced a variable response such that in 57% of tissues basal tone was reduced (EC₅₀ 5 μg/mL) whereas the rest remained unaffected by the oil. In concentrations above 10 μg/mL EOCz induced spontaneous oscillatory contractions in all preparations. In contrast the basal tone of the aorta, portal vein and bladder remained unaltered by the oil. In the portal vein EOCz concentration-dependently inhibited the amplitude of spontaneous contractions (IC₅₀ 109 μg/mL) without reducing frequency, whereas in the bladder such activity was increased by the oil (EC₅₀ 44 μg/mL). In ileum precontracted with 60 mM KCl, EOCz induced a complete and concentration-dependent relaxation with an IC₅₀ value of approximately 26 μg/mL. In contrast EOCz did not relax KCl-induced tone in the aorta or bladder, whilst eliciting less than 20% relaxation of the precontracted portal vein. Thus our data show that EOCz exerts differential modulatory effects on the contractility of various smooth muscles of the guinea-pig. That EOCz appears to selectively relax intestinal smooth muscle may support its use in folk medicine as a gastrointestinal antispasmodic. © 1998 John Wiley & Sons, Ltd.     

Differential antagonistic effect of hydroalcoholic extract from Hymenaea martiana hayne arzeik on kinin and other agonist-induced contractions of the isolated rat uterus and Guinea-pig ileum

This study was undertaken to evaluate the action of the hydroalcoholic extract (HE) from the bark of Hymenaea martiana on bradykinin (BK), lysyl-bradykinin (L-BK), acetylcholine (ACh), angiotensin II (AII), prostaglandin F_2a (PGF_2a), serotonin (5-HT), oxytocin (Ot) and histamine (His)-induced contractions of the isolated rat uterine muscle and guinea-pig ileum. The HE (50–200 μg/mL) added to the bath for 20 min caused a concentration-dependent rightward displacement of BK, L-BK and ACh-induced contractions in the rat uterus, allied to a discrete but significant reduction of maximal responses to the latter two agonists. By contrast, at the same range of concentrations the HE antagonized in a concentration-dependent but noncompetitive manner the contractions induced by AII, but only at high concentrations (200 μg/mL) it significantly inhibited contractions evoked by both PGF_2a and Ot, while contractile responses induced by 5-HT were not affected. In the guinea-pig ileum, the HE of H. martiana (50 and 100 μg/ml) caused a discrete rightward displacement of the BK and ACh concentration—response curves. Higher concentrations of the HE of H. martiana (200 μg/mL) caused a marked depression of BK and ACh-induced maximal responses. These findings show that the active principle(s) presents in the HE from the bark of H. martiana exhibits an interesting pharmacological profile against several neurotransmitter-induced contractions in nonvascular smooth muscles. Such actions may be relevant for supporting, at least in part, the use of this plant in folk medicine.     

Studies on antihypertensive and antispasmodic activities of methanol extract of Acacia nilotica pods

A methanol extract of Acacia nilotica pods (AN) caused a dose-dependent (3-30 mg/kg) fall in arterial blood pressure. Treatment of animals with atropine abolished the vasodilator response of acetylcholine (ACh), whereas the antihypertensive effect of the plant extract remained unaltered. Phentolamine (an alpha-adrenergic blocker) abolished the vasoconstrictor effect of norepinephrine (NE), whereas pretreatment of the animal with AN, did not modify the NE response. These results indicate that the antihypertensive effect of plant extract is independent of muscarinic receptor stimulation or adrenoceptor blockade. In the in vitro studies, AN produced a dose-dependent (0.3-3.0 mg/mL) inhibitory effect on force and rate of spontaneous contractions in guinea-pig paired atria. Similarly, it inhibited the spontaneous contraction of rabbit jejunum in a concentration-dependent (0.1-3.0 mg/mL) manner. AN also inhibited K(+)-induced contractions in rabbit jejunum at a similar concentration range, which suggests that the antispasmodic action of AN is mediated through calcium channel blockade, and this may also be responsible for the blood pressure lowering effect of AN, observed in the in vivo studies.     

The Prokinetic,Laxative, and Antidiarrheal Effects of Morus nigra: Possible Muscarinic,Ca2+ Channel Blocking,and Antimuscarinic Mechanisms

Morus nigra Linn. (black mulberry) is used in gastrointestinal ailments. This study demonstrates gut modulatory properties of M. nigra. The prokinetic, laxative, and antidiarrheal activities of M. nigra were assessed in mice, while isolated rabbit jejunum and guinea‐pig ileum were used to explore insight into mechanism(s). At 30 and 70 mg/kg, the crude extract of M. nigra (Mn.Cr) exhibited atropine‐sensitive prokinetic and laxative effects, similar to carbachol (CCh). While at higher doses (100, 300, and 500 mg/kg), Mn.Cr offered protection against castor oil‐induced diarrhea. In rabbit jejunum, Mn.Cr and its chloroform fraction inhibited CCh‐induced contractions more potently compared with high K⁺ (80 mm ). Conversely, petroleum fraction was more potent against high‐K⁺‐induced contractions. At 0.01 mg/mL, Mn.Cr caused a parallel shift in acetylcholine concentration–response curves (CRCs) followed by a non‐parallel shift at 0.03 mg/mL, similar to dicyclomine. At further tested concentrations, Mn.Cr (0.1 and 0.3 mg/mL) and petroleum fraction suppressed Ca²⁺ CRCs, similar to verapamil. In guinea‐pig ileum, Mn.Cr, its aqueous and ethyl acetate fractions exhibited atropine‐sensitive gut stimulant activity along with additional uncharacterized excitatory response in the aqueous fraction only. These results suggest that black mulberry possesses prokinetic, laxative, and antidiarrheal effects, putatively mediated through cholinomimetic, antimuscarinic, and Ca²⁺ antagonist mechanisms, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Cardiovascular effects of oblongine chloride,an alkaloid from Leontice leontopetalum,in the anaesthetized guinea-pig

The effects of (?)oblongine chloride, a quaternary alkaloid from Leontice leontopetalum on blood pressure, heart rate and blood flow of the anaesthetized guinea-pig were studied. At doses ranging from 0.5 mg/kg to 30 mg/kg, i.v., oblongine chloride caused a dose-dependent reduction of systolic and diastolic blood pressure. These doses were associated with an increase in heart rate. Propranolol (5 mg/kg) failed to block the effects of oblongine chloride on systolic and diastolic blood pressure but significantly reduced the increase in heart rate observed with low doses (0.5–6 mg/kg) of oblongine chloride. In doses ranging from 0.05 mg/kg to 0.5 mg/kg, oblongine chloride caused a small increase in blood flow. Larger doses (1.5, 4.5, 15 and 30 mg/kg) caused an initial decrease followed by an increase of blood flow. The net effect of cumulative doses was an increase in blood flow over the control value. These observations suggest that oblongine chloride may have potential haemodynamic effects and that these effects are not mediated by β-adrenergic receptor stimulation.     

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.     

Presence of blood‐pressure lowering and spasmolytic constituents in Buddleja crispa

This aim of this study was to investigate the crude extract of Buddleja crispa (Bc.Cr) and its active constituent(s) for their antihypertensive and antispasmodic activities. The Bc.Cr caused a dose‐dependent (3–10 mg/kg) fall in mean arterial pressure in rats under anesthesia. In rabbit aorta preparations, Bc.Cr (0.03–1 mg/mL) caused inhibition of high K⁺ (80 mM) precontractions. The Bc.Cr (0.03–1 mg/mL) also inhibited spontaneous and high K⁺ precontractions in rabbit jejunum preparations, suggestive of calcium channel blocking (CCB) activity. CCB activity was further confirmed when pretreatment of the tissues with Bc.Cr (0.03–0.10 mg/mL) caused a rightward shift in Ca⁺⁺ concentration response curves, similar to verapamil. Among the pure compounds, BdI‐H3 was more potent against the high K⁺ than spontaneous contractions and was around eight times more potent than Bc.Cr against the spontaneous contractions while the other two compounds, BdI‐2 and BH‐3 were inactive. Activity‐directed fractionation revealed that the hexane fraction was more potent against K⁺ precontractions. These data indicate that Bc.Cr possesses a blood‐pressure lowering effect, mediated possibly through CCB, though additional mechanism(s) cannot be ruled out. Among the pure compounds, Bdl‐H3 is likely to be the active compound involved in the spasmolytic and possibly BP lowering effect of the parent crude extract. Copyright © 2008 John Wiley & Sons, Ltd.     

Calcium Channel Blocking Activity in Desmostachya bipinnata (L.) Explains its use in Gut and Airways Disorders

Desmostachya bipinnata, despite of its popular medicinal uses, has not been widely studied for its effect in diarrhea, indigestion, and asthma. The aim of the present investigation was to provide scientific rationale for these applications. The crude aqueous‐methanolic extract of D. bipinnata (Db.Cr) was evaluated through in vivo and in vitro experiments. Db.Cr (100–500 mg/kg) protected mice against castor oil–induced diarrhea, similar to loperamide. When tested on gut preparations, Db.Cr produced an atropine‐sensitive spasmogenic effect in rabbit jejunum up to 5 mg/mL, followed by a partial relaxation at 10 mg/mL. With atropine preincubation, a verapamil‐like inhibitory effect was evident against spontaneous and high K⁺ (80 mM)–induced contractions. The maximum stimulant effect was comparable with the acetylcholine‐induced maximum contraction and was similarly reproducible in guinea pig ileum. Db.Cr inhibited carbachol (1 μM)‐induced contraction in rabbit trachea but caused an atropine‐sensitive accentuation of high K⁺–induced contraction at 0.003–0.3 mg/mL followed by inhibition at 1–5 mg/mL. On activity‐directed fractionation, inhibitory effect was concentrated on organic and stimulant effect in aqueous fraction. This study, suggesting the presence of calcium antagonist activity, possibly underlying its medicinal effect in hyperactive gut and respiratory disorders, and cholinergic activity, possibly underlying its digestive effect, provides rationale for these therapeutic uses of D. bipinnata. Copyright © 2012 John Wiley & Sons, Ltd.     

Different Effects of Some Isoquinoline Alkaloids from Argemone mexicana on Electrically Induced Contractions of Isolated Guinea-pig Ileum

The present study examines the effects of the extracts [petroleum ether, CHCl₃, CHCl₃/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Argemone mexicana on the electrically induced contractions of the isolated guinea-pig ileum (E.C.I.). The results of the experiments indicate that CHCl₃/MeOH (9:1) and MeOH extracts, tested at a concentration of 400, 200 and 100 μg/mL, dose-dependently reduced the guinea-pig ileum contractions, whereas the petroleum ether and CHCl₃ extracts did not affect it. Furthermore, the partially purified fractions II–V from the MeOH extract, each tested at concentrations of 200, 100 and 50 μg/mL also inhibited E.C.I. Finally the pure compounds 1–2 (5×10⁻⁶–1×10⁻⁵–5×10⁻⁵ M ) isolated and purified from the above fractions significantly reduced, in a dose dependent manner, the electrical contractions of the ileum, whereas compound 3 (5×10⁻⁶–1×10⁻⁵×10⁻⁵ M ) increased them. Since the active compounds 1–3 were respectively identified as protopine, allocryptopine and berberine by NMR, the observed effects could be related mainly to these compounds. © 1997 by John Wiley & Sons, Ltd.     

The pharmacological properties of the ethanolic root extract of Combretum dolichopetalum

The pharmacological actions of the crude ethanolic extract and the active fractions of the roots of Combretum dolichopetalum were tested on guinea-pig isolated ileum and in intact rats. The extract relaxed guinea-pig ileum in a concentration-dependent manner. Two active fractions (R_f 0.96 and 0.84) which also relaxed the guinea-pig ileum were isolated using column chromatography and TLC respectively. Both the crude extract and the active fractions inhibited the contractions induced by acetylcholine and histamine concentration-dependently in the guinea-pig ileum. The crude extract inhibited ulcers and gastric secretions induced in rats by pyloric ligation together with histamine 100 mg/kg, i.p. (p<0.05). The extract also delayed gastric emptying in rats in a dose-dependent manner. The effects of the extract were compared with cimetidine at each stage of the study.