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.     

Saponin rich fractions from Polygonatum odoratum (Mill.) Druce with more potential hypoglycemic effects

Ethnopharmacological relevance

Peppers from Capsicum species (Solanaceae) are native to Central and South America, and are commonly used as food and also for a broad variety of medicinal applications.

Aim of the study

The red pepper Capsicum baccatum var. pendulum is widely consumed in Brazil, but there are few reports in the literature of studies on its chemical composition and biological properties. In this study the antioxidant and anti-inflammatory activities of Capsicum baccatum were evaluated and the total phenolic compounds and flavonoid contents were determined.

Materials and methods

The antioxidant property was assayed by scavenging abilities using DPPH and the anti-inflammatory activity was tested through the carrageenan-induced pleurisy model in mice. The total phenolic compounds and flavonoid contents were determined spectrophotometrically.

Results

The ethanolic and butanol extracts (200 mg/kg, p.o.) presented a significant anti-inflammatory activity toward carrageenan-induced pleurisy model in mice in comparison to dexamethasone (0.5 mg/kg, s.c.). Among the parameters evaluated, the treatment with these samples inhibited leukocyte migration and reduced the formation of exudate. The contents of flavonoids and total phenolic compounds could be correlated with the antioxidant and anti-inflammatory activities observed for Capsicum baccatum.

Conclusions

Our findings suggest that Capsicum baccatum contains potential antioxidant and anti-inflammatory compounds which could be tested as drug candidates against oxidative and inflammation-related pathological processes in medicinal chemistry studies.     

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.     

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.     

Bronchodilatory effect of Acorus calamus (Linn.) is mediated through multiple pathways

Aim of the study

This study was undertaken to provide a pharmacological basis for traditional use of Acorus calamus in airways disorders.

Materials and methods

Isolated guinea-pig trachea and atria were suspended in organ baths bubbled with carbogen and mechanisms were found using different parameters.

Results

In isolated guinea-pig tracheal segments, crude extract of Acorus calamus was more effective than carbachol in causing relaxation of high K⁺ (80 mM) precontractions, similar to verapamil, suggesting blockade of calcium channels. The n-hexane fraction was equipotent against both precontractions, similar to papaverine, while ethylacetate fraction was more potent against carbachol precontractions but had a negligible dilator effect against K⁺, similar to atropine and or rolipram. Pretreatment of tracheal preparations with n-hexane or ethylacetate fractions potentiated isoprenaline-induced inhibitory concentration-response curves, similar to papaverine or rolipram. Pretreatment of tracheal preparations with ethylacetate fraction caused a rightward parallel shift in carbachol response curve at lower concentration (0.003 mg/mL) similar to atropine and a non-parallel shift at higher concentrations (0.01 mg/mL), with reduction of maximum response, similar to rolipram. In isolated guinea-pig atrial preparations, crude extracts, its fractions and papaverine inhibited force and rate of contractions at higher concentrations than the smooth muscle while verapamil was equipotent.

Conclusion

These data indicate the presence of unique combination of airways relaxant constituents in crude extract of Acorus calamus, a papaverine-like dual inhibitor of calcium channels and phosphodiesterase in n-hexane fraction and a novel combination of anticholinergic, rolipram-like phosphodiesterase4 inhibitor in ethylacetate fraction and associated cardiac depressant effect, provide a pharmacological basis for traditional use of Acorus calamus in disorders of airways.     

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.     

Species Differences in the Antidiarrheal and Antispasmodic Activities of Lepidium sativum and Insight into Underlying Mechanisms

The aim of this study was to see if the crude extract of Lepidium sativum (Ls.Cr) exhibits species specificity in its antidiarrheal and antispasmodic activities along with insight into the underlying mechanisms using the in‐vivo and in‐vitro experiments. Ls.Cr inhibited castor oil‐induced diarrhea in mice at doses (300 and 1000 mg/kg) three times higher dose than for rats. In isolated rat ileum and jejunum, Ls.Cr completely inhibited carbachol (CCh), low K⁺ (25 mM) and high K⁺ (80 mM)‐induced contractions, while in guinea‐pig tissues, Ls.Cr caused complete inhibition of only CCh‐induced contraction. In rabbit tissues, Ls.Cr completely inhibited CCh and low K⁺‐induced contractions sensitive to K⁺ channel antagonists. Pretreatment of guinea‐pig and rat tissues with Ls.Cr caused a rightward shift in CCh‐induced contractions in a pattern similar to dicyclomine, while in rabbit and rat tissues, Ls.Cr shifted isoprenaline curves to the left similar to papaverine. These data indicate that the antidiarrheal and antispasmodic activities of L. sativum are species dependent, mediating its antispasmodic effect through combinations of multiple pathways including activation of K⁺ channels, and inhibition of muscarinic receptors, Ca⁺⁺ channels and PDE enzyme. Rat tissues showed the highest potency. Based on the results, we recommend using multiple species to know the real pharmacological profile of medicinal products. Copyright © 2012 John Wiley & Sons, Ltd.     

Antidepressant effect of Valeriana wallichii patchouli alcohol chemotype in mice: Behavioural and biochemical evidence

Ethnopharmacological relevance

Valeriana wallichii DC, an ayurvedic traditional medicine has now been shown to exist chemically as three distinct chemotypes. The study aimed to investigate the antidepressant effect of dichloromethane extract of Valeriana wallichii patchouli alcohol chemotype.

Materials and methods

Antidepressant effect of dichloromethane extract of Valeriana wallichii (10, 20 and 40 mg/kg, p.o.) using forced swim test, was determined in both acute and chronic study. The neurotransmitter levels were estimated in mouse forebrain after two weeks of dosing.

Results

Single administration of extract (40 mg/kg) significantly inhibited the immobility period in mice (p < 0.05). Similarly, chronic administration of extract (20 and 40 mg/kg) significantly reduced the immobility period and significantly increased the levels of norepinephrine and dopamine in mouse forebrain (p < 0.05).

Conclusions

The extract demonstrated antidepressant effect and significantly increased the norepinephrine and dopamine levels in forebrain.     

Gastrointestial and respiratory activities of Acacia leucophloea

Ethnopharmacological relevance

The barks of Acacia leucophloea (Fabaceae) are used in Pakistan traditional medicine as an astringent, a bitter, a thermogenic, a styptic, a preventive of infections, an anthelmintic, a vulnery, a demulcent, an expectorant, an antipyretic, an antidote for snake bites and in the treatment of bronchitis, cough, vomiting, wounds, ulcers, diarrhea, dysentery, internal and external hemorrhages, dental caries, stomatitis, and intermittent fevers and skin diseases.

Materials and methods

A study was carried out for the possible elucidation of mechanisms justifying the traditional medicinal uses of A. leucophloea (Fabaceae) in gastrointestinal and respiratory diseases. In vitro experiments were carried out over isolated rabbit jejunum and guinea-pig ileum in order to determine spasmolytic and bronchorelaxant activities, while in vivo studies were conducted in mice for antidiarrheal properties.

Results

A methanol crude extract of barks of the plant caused a concentration-dependent relaxation (0.1-3 mg/ml) of isolated rabbit jejunum preparations in a pattern similar to that of nifedipine and dicyclomine, suggesting a Ca²⁺ channel-blocking mechanism in addition to an anticholinergic effect. In guinea-pig ileum the extract caused a parallel shift in the Ach-curves without suppression of maximum contractile response, followed by a non-parallel shift with the suppression of maximum contractile response at higher concentration similar to that caused by dicyclomine. Moreover, in rabbit trachea, it also caused the relaxation of carbachol (1 μM) and high K⁺-induced contractions at a dose ranging between 0.1578 and 0.734 mg/ml and 0.46-0.94 mg/ml, respectively. These findings indicate that the extract possesses spasmolytic and bronchodilator activities, mediated possibly through blockade of Ca²⁺ channels, thus justifying its medicinal use in diarrhea and asthma. Acacia leucophloea methanol extract exhibited dose-dependent (100-500 mg/ml) protective effect against castor oil induced diarrhea.

Conclusions

The data obtained contribute to the validation of the traditional use of Acacia leucophloea bark in treating gastrointestinal and respiratory disorders, providing an hypothesis on the possible mechanisms of action.     

Identification of a new antinociceptive alkaloid isopropyl N-methylanthranilate from the essential oil of Choisya ternata Kunth

Ethnopharmacological relevance

Mexican people employed infusion of leaves of Choisya ternata Kunth for their antispasmodic and “simulative properties”.

Aim of the study

In the present study the detailed GC and GC-MS analyses of the essential oil of Choisya ternata Kunth (Rutaceae) were performed. The presence of a minor constituent isopropyl N-methylanthranilate (1) was revealed among other identified volatiles. A synthesis of 1 was undertaken in order to corroborate this find and obtain gram quantities that would allow the testing of its biological activity (peripheral and central antinociceptive activity).

Materials and methods

The oils were investigated by GC and GC-MS. Synthesized compounds were spectrally characterized (UV-Vis, IR, 1D and 2D NMR, MS). The obtained synthetic samples of compounds were assayed for peripheral and central antinociceptive activity in two models (effects on acetic acid induced writhing in mice and the hot plate test for nociception).

Results

Detailed GC and GC-MS analyses of the essential oil of Choisya ternata Kunth (Rutaceae) among 157 other identified volatiles revealed the presence of a minor constituent isopropyl N-methylanthranilate (1). Compound 1, named ternanthranin, is therefore detected as a natural product for the first time with a very restricted occurrence (samples of several citrus oils were screened for the presence of 1). The antinociceptive activities were assayed for ternanthranin, the two other synthetic analogs, methyl and propyl N-methylanthranilate, as well as the essential oil and the crude ethanol extract of the leaves. The results clearly demonstrate a very high (even significant at 0.3 mg/kg) dose dependent activity for the anthranilates (and the extracts). Isopropyl N-methylanthranilate showed the highest, while methyl N-methylanthranilate showed the lowest activity (with the methyl ester at 3 mg/kg still better than acetylsalicylic acid, at 200 mg/kg, in the first, or comparable with morphine, at 5 mg/kg, in the second test).

Conclusion

This study once again revealed that detailed investigations of plant species with ethnopharmacologically documented activity may yield new natural compounds—a new alkaloid (ternanthranin), a volatile simple anthranilate that can be considered responsible for the antinociceptive activity of the crude plant extracts.     

Hepatoprotection of Graptopetalum paraguayense E. Walther on CCl₄-induced liver damage and inflammation

Aim of this study

Graptopetalum paraguayense E. Walther, a vegetable consumed in Taiwan, has been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain. Therefore, we investigated the protective effects of Graptopetalum paraguayense E. Walther against carbon tetrachloride (CCl₄)-induced liver damage in rats.

Materials and methods

Water extracts of Graptopetalum paraguayense E. Walther (WGP) were administered for 8 consecutive weeks to male Sprague-Dawley rats. And a dose-dependent manner in preventing liver damage was confirmed. Moreover, the major ingredient of WGP, gallic acid, was also orally administrated in the CCl₄-induced rats. The hepatoprotective activity was assessed using various biochemical parameters such as antioxidant enzymes and histopathological studies.

Results

WGP ranging from 50 to 300 mg/kg bw administrations significantly lowered serum aspartate transaminase (AST) and alanine transaminase (ALT) levels, and inhibited malondialdehyde (MDA) generation in CCl₄-treated rats. WGP increased cellular GSH level and antioxidant enzymes, including superoxide dismutase, glutathione reductase, and catalase. Serum tumor necrosis factor-alpha (TNF-α) was decreased in the group treated with CCl₄ plus WGP (150 and 300 mg/kg bw). Histopathological examination of livers showed that WGP reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl₄-treated rats. In contrary, 10 mg/kg bw of gallic acid was administrated, this dose was related with WGP (300 mg/kg bw), and had significantly decreased the AST and ALT compared to the CCl₄-treated group. Aforesaid results suggested that gallic acid from WGP offered antioxidative activity against CCl₄-induced oxidative liver damage.

Conclusions

Taken together, this study is the first time to suggest that Graptopetalum paraguayense E. Walther exerts hepatoprotection via promoting antioxidative and anti-inflammatory properties against CCl₄-induced oxidative liver damage.     

Studies on antidiarrheal and antispasmodic activities of Lepidium sativum crude extract in rats

This study was aimed to provide the pharmacological basis for the medicinal use of Lepidium sativum in diarrhea using in vivo and in vitro assays. The seed extract of Lepidium sativum (Ls.Cr) at 100 and 300 mg/kg inhibited castor oil‐induced diarrhea in rats. In isolated rat ileum, Ls.Cr (0.01–5 mg/mL) reversed carbachol (CCh, 1 µ m ) and K⁺ (80 m m )‐induced contractions with higher potency against CCh, similar to dicyclomine. Preincubation of rat ileum with a lower concentration of Ls.Cr (0.03 mg/mL) caused a rightward parallel shift in the concentration–response curves (CRCs) of CCh without suppression of the maximum response, while at the next higher concentration (0.1 mg/mL), it produced a non‐parallel rightward shift with suppression of the maximum response, similar to that of dicyclomine. Ls.Cr shifted the CRCs of Ca⁺⁺ to the right with suppression of the maximum response, similar to verapamil. These data suggest that Lepidium sativum seed extract possesses antidiarrheal and spasmolytic activities mediated possibly through dual blockade of muscarinic receptors and Ca⁺⁺ channels, though additional mechanism(s) cannot be ruled out and this study explains its medicinal use in diarrhea and abdominal cramps. Copyright © 2011 John Wiley & Sons, Ltd.     

Investigation of the in vitro and ex vivo acetylcholinesterase and antioxidant activities of traditionally used Lycopodium species from South America on alkaloid extracts

Ethnopharmacological relevance

The study was aimed at evaluating medicinal and therapeutic potentials of two Lycopodiaceae species, Lycopodium clavatum (L.) and Lycopodium thyoides (Humb. & Bonpl. ex Willd), both used in South American folk medicine for central nervous system conditions. Alkaloid extracts were evaluated for chemical characterization, acetylcholinesterase and antioxidant activities.

Materials and methods

The alkaloid extracts obtained by alkaline extraction were determined for each species by GC/MS examination. The evaluation of the anticholinesterase and the antioxidant activities of the extracts were tested by determining in vitro and ex vivo models. Effects on acetylcholinesterase (AChE) were tested in vitro using rat brain homogenates and ex vivo after a single administration (25, 10 and 1 mg/kg i.p.) of the alkaloid extracts in mice. The in vitro antioxidant effects were tested for the 2-deoxyribose degradation, nitric oxide (NO) interaction, 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and total reactive antioxidant potential (TRAP). After an acute administration (25 and 10 mg/kg i.p.) of the extracts in middle-aged (12 months) mice, the antioxidant effects were estimated through the thiobarbituric acid reactive substances test (TBARS), and the antioxidant enzymes activities for catalase (CAT) and superoxide dismutase (SOD) were measured.

Results

AChE activity was inhibited in vitro by the alkaloid-enriched extracts of both Lycopodium species in a dose and time-dependent manner in rat cortex, striatum and hippocampus. A significant inhibition was also observed in areas of the brain after acute administration of extracts, as well as decreased lipid peroxidation and increased CAT activity in the cortex, hippocampus and cerebellum. A moderate antioxidant activity was observed in vitro for the extracts. Chemically, the main alkaloids found for the two species were lycopodine and acetyldihidrolycopodine.

Conclusion

This study showed that the biological properties of the folk medicinal plants Lycopodium clavatum and Lycopodium thyoides include AChE inhibitory activity and antioxidant effects, two possible mechanisms of action in Alzheimer's related processes.     

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).     

Chemical composition, antinociceptive and anti-inflammatory effects in rodents of the essential oil of Peperomia serpens (Sw.) Loud

Ethnopharmacological relevance

Peperomia serpens (Piperaceae), popularly known as “carrapatinho”, is an epiphyte herbaceous liana grown wild on different host trees in the Amazon rainforest. Its leaves are largely used in Brazilian folk medicine to treat inflammation, pain and asthma.

Aim of the study

This study investigated the effects of essential oil of Peperomia serpens (EOPs) in standard rodent models of pain and inflammation.

Materials and methods

The antinociceptive activity was evaluated using chemical (acetic acid and formalin) and thermal (hot plate) models of nociception in mice whereas the anti-inflammatory activity was evaluated by carrageenan- and dextran-induced paw edema tests in rats croton oil-induced ear edema, as well as cell migration, rolling and adhesion induced by carrageenan in mice. Additionally, phytochemical analysis of the EOPs has been also performed.

Results

Chemical composition of the EOPs was analyzed by gas chromatography and mass spectrometry (GC/MS). Twenty-four compounds, representing 89.6% of total oil, were identified. (E)-Nerolidol (38.0%), ledol (27.1%), α-humulene (11.5%), (E)-caryophyllene (4.0%) and α-eudesmol (2.7%) were found to be the major constituents of the oil. Oral pretreatment with EOPs (62.5-500 mg/kg) significantly reduced the writhing number evoked by acetic acid injection, with an ED₅₀ value of 188.8 mg/kg that was used thereafter in all tests. EOPs had no significant effect on hot plate test but reduced the licking time in both phases of the formalin test, an effect that was not significantly altered by naloxone (0.4 mg/kg, s.c.). EOPs inhibited the edema formation induced by carrageenan and dextran in rats. In mice, EOPs inhibited the edema formation by croton oil as well as the leukocyte and neutrophil migration, the rolling and the adhesion of leukocytes.

Conclusions

These data show for the first time that EOPs has a significant and peripheral antinociceptive effect that seems unrelated to interaction with the opioid system. EOPs also displays a significant anti-inflammatory effect in acute inflammation models. This effect seems to be related to components which inhibit the production of several inflammatory mediators. These results support the widespread use of Peperomia serpens in popular medicine to treat inflammation and pain.     

Antinociceptive effect of extracts and compounds from Hofmeisteria schaffneri

Ethnopharmacological relevance

Hofmeisteria schaffneri (Asteraceae) is a medicinal plant widely commercialized in the most important Markets of Mexico City for the treatment of gastro-intestinal complaints and skin afflictions.

Aim of the study

The main goals of this study were to establish the potential acute toxicity and the antinociceptive activity in animal models of several preparations and compounds from Hofmeisteria schaffneri.

Materials and methods

The aqueous and organic extracts as well as the essential oil of Hofmeisteria schaffneri were prepared by infusion, maceration and hydrodistillation, respectively. Investigation of the acute toxicity was accomplished by the Lorke method. The antinociceptive effect was assessed using the writhing and the hot plate tests. Natural compounds were isolated by standard phytochemical procedures. In addition, a few thymol esters were prepared by chemical synthesis. The stability of natural and synthetic esters was qualitatively analyzed by measuring their susceptibility to hydrolysis by pig liver estearase and mouse plasma at 37 °C.

Results

The LD₅₀ for each preparation tested was higher than 5000 mg/kg revealing that they were not toxic to mice after exposure for short space of time. On the other hand, the extracts showed significant antinociceptive effect when tested in the hot plate model. The most active natural product as antinociceptive agent was hofmeisterin III (1) which also was the most stable in the stability study. Its pharmacological effect seems to be partially mediated by an opioid mechanism since naloxone inhibits its action. Using compound 1 as a lead molecule, several synthetic thymol esters were prepared and only compounds 13, 15 and 17 were antinoceptive at the dose of 1 mg/kg.

Conclusions

The present investigation provided evidence of the efficacy of several preparations of Hofmeisteria schaffneri as antinociceptive agents. The most active preparation was the essential oil which contained large amount of hofmeisterin III (1) and other thymol derivatives. Some novel synthetic analogs of hofmeisterin III with antinociceptive properties were discovered. The nature of the ester chain of these analogs did not have a clear impact on the antinociceptive activity. The phyto-preparations analyzed in this study were not toxic to mice according to the Lorke's test; therefore considering their long term use of the plant they might be secure for human consumption.     

Anti-hypoxic activity at simulated high altitude was isolated in petroleum ether extract of Saussurea involucrata

Ethnopharmacological relevance

Rhodiola algida, Saussurea involucrata, and other herbs grown in Qinghai-Tibetan plateau have long been used to prevent and treat acute mountain sickness.

Aim of the study

To screen and identify the anti-hypoxic constituents in the herbs grown in Qinghai-Tibetan plateau of Northwestern China.

Materials and methods

The anti-hypoxic activities of 20 selected plateau herbs were examined against two positive controls, Rhodiola algida and acetazolamide, using the normobaric hypoxia model of mice. The herb with the highest activity was successively extracted with 70% ethanol, petroleum ether, chloroform, ethyl acetate and n-butanol. The extract with the highest activity was identified by comparing the survival time of mice under normobaric hypoxia condition after being subjected to different extracts. The identified extract was further tested by simulating high altitudes through an acute decompression model and a chronic decompression model for mice.

Results

The herb found to have the highest anti-hypoxic activity was Saussurea involucrate (Kar. et Kir.) Sch.-Bip, and the most effective fraction was in the petroleum ether extract. Administration of petroleum ether extract of Saussurea involucrata (PESI) to mice at 50 mg/kg significantly decreased the mortality of animals under acute decompression conditions. Changes in biochemical indicators for glycometabolism and energy metabolism, including adenosine triphosphate (ATP) content and adenosine triphosphatase (ATPase) activity in brain and cardiac muscle, lactic acid (LAC) and lactate dehydrogenase (LDH) in blood and cardiac muscles, blood sugar, and glycogen content in liver and skeletal muscle were reversed under chronic decompression conditions.

Conclusions

Saussurea involucrata (Kar. et Kir.) Sch.-Bip exhibits high anti-hypoxic activity that may be effective in preventing acute mountain sickness, and the active constituents are mainly in the petroleum ether extract.     

Neuroprotective effect of Momordica charantia in global cerebral ischemia and reperfusion induced neuronal damage in diabetic mice

Ethnopharmacological relevance

Momordica charantia L. (Cucurbitaceae) fruits have been used traditionally for centuries, especially for treating diabetes and associated complications.

Aim of the study

The present study was performed to evaluate neuroprotective effect of lyophilized M. charantia fruit juice against global cerebral ischemia and reperfusion induced neuronal injury in diabetic mice.

Materials and methods

Global cerebral ischemia induced by occluding both common carotid arteries for 10 min followed by 24 h reperfusion was used to induce neuronal injury. Ischemia-reperfusion induced neuronal injury was evaluated in terms of cerebral infarct size, generation of free radicals measured as thiobarbaturic acid reactive substances (TBARS), and neurological functions measured as short term memory and motor activity.

Results

The cerebral oxidative stress and damage, and neurological deficits were dose dependently attenuated by pre-treatment with the lyophilized M. charantia juice (200-800 mg/kg, p.o., o.d.). Moreover, M. charantia also exhibited dose dependent antihyperglycemic activity in diabetic mice.

Conclusions

These results suggest that M. charantia has potent neuroprotective activity against global cerebral ischemia-reperfusion induced neuronal injury and consequent neurological deficits in diabetic mice.     

Analgesic effect of Coptis chinensis rhizomes (Coptidis Rhizoma) extract on rat model of irritable bowel syndrome

Ethnopharmacological relevance

Coptis chinensis rhizomes (Coptidis Rhizoma, CR), also known as “Huang Lian”, is a common component of traditional Chinese herbal formulae used for the relief of abdominal pain and diarrhea. Yet, the action mechanism of CR extract in the treatment of irritable bowel syndrome is unknown. Thus, the aim of our present study is to investigate the effect of CR extract on neonatal maternal separation (NMS)-induced visceral hyperalgesia in rats and its underlying action mechanisms.

Materials and methods

Male Sprague-Dawley rats were subjected to 3-h daily maternal separation from postnatal day 2 to day 21 to form the NMS group. The control group consists of unseparated normal (N) rats. From day 60, rats were administrated CR (0.3, 0.8 and 1.3 g/kg) or vehicle (Veh; 0.5% carboxymethylcellulose solution) orally for 7 days for the test and control groups, respectively.

Results

Electromyogram (EMG) signals in response to colonic distension were measured with the NMS rats showing lower pain threshold and increased EMG activity than those of the unseparated (N) rats. CR dose-dependently increased pain threshold response and attenuated EMG activity in the NMS rats. An enzymatic immunoassay study showed that CR treatment significantly reduced the serotonin (5HT) concentration from the distal colon of NMS rats compared to the Veh (control) group. Real-time quantitative PCR and Western-blotting studies showed that CR treatment substantially reduced NMS induced cholecystokinin (CCK) expression compared with the Veh group.

Conclusions

These results suggest that CR extract robustly reduces visceral pain that may be mediated via the mechanism of decreasing 5HT release and CCK expression in the distal colon of rats.     

Src/NF-κB-targeted inhibition of LPS-induced macrophage activation and dextran sodium sulphate-induced colitis by Archidendron clypearia methanol extract

Ethnopharmacological relevance

Raw and processed Polygoni Multiflori Radix (PMR) are used in the prevention and treatment of non-alcoholic fatty liver disease (NAFLD), hyperlipidemia or related diseases. However, few researches compared the activities of raw and processed PMR on lipid metabolism regulation. Moreover, the active substances of Polygonum multiflorum are still not clearly elucidated.

Materials and methods

In this research, a sensitive, accurate and rapid in vitro model, steatosis hepatic L02 cell, was applied to compare the relative activities of raw and processed PMR on lipid metabolism regulation. Furthermore, the lipid regulation activities of emodin, physcion and 2,3,5,4′-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG) were evaluated. The steatosis L02 cells were obtained after cultured with 1% fat emulsion-10% fetal bovine serum (FBS)-RPMI 1640 medium for 48 h. Contents of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) in L02 cells are evaluated after exposure.

Results

The intracellular TG contents were increased from 16.50 ± 1.29 mmol/L to 34.40 ± 1.36 mmol/L in steatosis L02 cells, while the intracellular contents of TC were increased from 5.07 ± 1.80 mmol/L to 11.79 ± 0.54 mmol/L. Water extract of raw PMR showed much remarkable TG-regulation and TC-regulation effects than its processed products. Emodin displayed the best TG regulation activity while TSG showed the best TC regulation activity. At the same time, the exposure of emodin and physcion could reduce the LDL-C contents in steatosis L02 cells.

Conclusions

On account of these in vitro results, raw PMR might have more satisfactory effects in clinic treatment of NAFLD or hyperlipidemia characterized by the elevation of cholesterol than processed PMR.