Muscarinic-dependent inhibition of gastric emptying and intestinal motility by fractions of Maytenus ilicifolia Mart ex. Reissek

Ethnopharmacological relevance

Maytenus ilicifolia Mart. ex. Reissek (Celastraceae) is widely used in Brazilian folk medicine to treat gastric disturbances.

Aim of the study

This work intended to characterize the effects of Maytenus ilicifolia on gastrointestinal motility.

Materials and methods

Gastric emptying and intestinal transit were measured in the same animal. Mice received a semisolid marked with phenol red, half an hour after treatment with extracts. The amount of marker in the stomach and the distance reached in the intestine after 15 min were measured as index of gastrointestinal emptying and intestinal transit, respectively.

Results

Intraperitoneal administration of a flavonoid-rich extract potently reduced the gastric emptying (ED₅₀ = 89 mg/kg) and the intestinal transit (ED₅₀ = 31 mg/kg) of mice. Bio-guided purification of the flavonoid-rich extract by chemical partition with solvents of decreasing polarity yielded fraction insF with about 12–14 times higher activity than the initial flavonoid extract in both the gastric emptying and the intestinal transit. The inhibitory effects of the insF (9.7 mg/kg, i.p.) on gastric emptying and intestinal transit were reversed by co-administration of bethanechol (10 mg/kg, s.c.) but not by co-administration of metoclopramide (30 mg/kg, p.o.) indicating muscarinic but not dopaminergic interaction of the compounds of Maytenus.Chemical investigation of the insF fraction by HPLC–MS allowed the identification of 4 free flavonoids (catechin, epicatechin, quercetin and kaempferol), 29 flavonol glycosides and 8 tannins. The flavonol glycosides ranged from 1 to 4 monosaccharide units, having mainly quercetin and kaempferol as aglycone moieties, and the tannins were composed by catechin/epicatechin and/or afzelechin/epiafzelechin.

Conclusions

Overall, the results indicate that the components of Maytenus ilicifolia have a potential use in the treatment of gastrointestinal motility disturbances such as diarrhea.     

Antinociceptive effect of Lecythis pisonis Camb. (Lecythidaceae) in models of acute pain in mice

Ethnopharmacological relevance

Lecythis pisonis Camb., also known in Brazil as sapucaia, is used in folk medicine against pruritus, muscle pain and gastric ulcer.

Aim of the study

To investigate the antinociceptive effect of ethanol extract from Lecythis pisonis leaves (LPEE), fractions (hexane-LPHF, ether-LPEF and ethyl acetate-LPEAF) and mixture of triterpenes [ursolic and oleanolic acids (MT)] in mice.

Materials and methods

LPEE and LPEF were evaluated on the acetic acid induced writhings and formalin, capsaicin and glutamate tests. In addition, MT was investigated on the writhings induced by acetic acid, capsaicin and glutamate tests. In the study of some possible mechanisms involved on the antinociceptive effect of LPEF, it was investigated the participation of opioid system, K⁺_ATP channels and l-arginine-nitric oxide pathway.

Results

LPEE (12.5 and 25 mg/kg, p.o.), LPEF and MT (6.25, 12.5 and 25 mg/kg, p.o.) reduced the writhings in comparison to saline. LPEE (100 mg/kg, p.o.) and LPEF (50 mg/kg, p.o.) were effective in inhibiting both phases of formalin test. In capsaicin test, LPEE (100 and 200 mg/kg, p.o.), LPEF (12.5–50 mg/kg, p.o) and MT (6.25–25 mg/kg, p.o.) showed a significant antinociceptive effect compared to the control. LPEE (25 and 50 mg/kg, p.o.), LPEF (50 and 100 mg/kg, p.o.) and MT (12.5 and 25 mg/kg, p.o.) reduced the glutamate-evoked nociceptive response. Treatment with naloxone, l-arginine and glibenclamide reversed the effect of LPEF in glutamate test.

Conclusions

These results indicate the antinociceptive effect of Lecythis pisonis leaves and suggest that this effect may be related to opioid pathway, K⁺_ATP channels, and l-arginine-nitric oxide modulation. Furthermore, these data support the ethnomedical use of this plant.     

Involvement of glutamate and cytokine pathways on antinociceptive effect of Pfaffia glomerata in mice

Ethnopharmacological relevance

Pfaffia glomerata (Spreng) Pedersen (Amaranthaceae) is a medicinal plant known in Brazil as “Paratudo” and “Brazilian ginseng” and is commonly used as tonic, antidiabetic and to treat gastric disorders.

Aim of the study

This study evaluates the possible mechanism by which hydroalcoholic extract (HE) of Pfaffia glomerata exerts its antinociceptive effect.

Materials and methods

The HE was evaluated in acetic acid and glutamate models of pain or by biting behavior following intrathecal (i.t.) administration of agonists of excitatory aminoacids (EAA) receptors glutamate and pro-inflammatory cytokines, IL-1β and TNF-α in mice.

Results

Oral administration of HE produced dose-dependent inhibition of acetic acid-induced visceral pain and glutamate-induced pain, with ID₅₀ of 64.6 (47.7–87.5) mg/kg and ID₅₀ of 370.8 (253.4–542.7) mg/kg, respectively. The HE (300 mg/kg, p.o.) antinociception, in the acetic acid test, was not affected by i.p. treatment of animals with naloxone. In addition, HE (300 mg/kg, p.o.) inhibited the pain-related behaviors induced by i.t. injection of trans-ACPD and TNF-α, but not by NMDA, AMPA, kainate or IL-1β.

Conclusions

Our results suggest that inhibition of glutamatergic metabotropic receptors and TNF-α may account for the antinociceptive action reported for the HE in models of chemical pain used in this study.     

Evidence for a role of 5-HT1A receptor on antinociceptive action from Geissospermum vellosii

Ethnopharmacological relevance

Geissospermum vellosii is a tree widely found throughout the Amazonic forest and frequently used by the native population for painful disorders.

Aim of the study

The present study examined the antinociceptive effects of Geissospermum vellosii in behavioral models of nociception.

Materials, methods and results

Oral administration of crude extract of Geissospermum vellosii or its dichloromethane fraction (1–100 mg/kg) inhibited formalin-induced inflammatory nociception and acetic acid-induced visceral nociception. The antinociceptive effect of Geissospermum vellosii was unrelated with motor dysfunctions. Furthermore, the alkaloid 12-metoxy-1-methyl-aspidospermidine (0.001–1 mg/kg), isolated from the dichloromethane fraction, also produced antinociception. The antinociception caused by the dichloromethane fraction was significantly attenuated by pre-treatment of mice with p-chlorophenylalanine methyl ester (PCPA, an inhibitor of serotonin synthesis, 100 mg/kg once a day for 4 consecutive days) and WAY-100635 (a 5-HT_1A receptor antagonist, 0.3 mg/kg). In contrast, dichloromethane fraction antinociception was not affected by pre-treatment of animals with ketanserin (a 5-HT₂ receptor antagonist, 0.3 mg/kg) or ondansetron (a 5-HT₃ receptor antagonist, 0.5 mg/kg).

Conclusions

Together, these results indicate that Geissospermum vellosii produces antinociception through an interaction with 5-HT_1A receptors. Furthermore, the alkaloid 12-metoxy-1-methyl-aspidospermidine contributes to the antinociceptive properties reported for Geissospermum vellosii.     

Characterization of the antinociceptive and anti-inflammatory activities from Cocos nucifera L. (Palmae)

Aim of the study

Cocos nucifera cultivated in Brazil is known as “coco-da-Bahia” or “coqueiro-da-Índia”. The tea from the husk fiber is widely used to several inflammatory disorders. Crude extract and fractions obtained from Cocos nucifera “common variety” were evaluated to test the anti-inflammatory and antinociceptive activities.

Materials and methods

Crude extract (CE, 50, 100, and 150 mg/kg), fraction 1 (F1, molecular weight lesser than 1 kDa, 1, 10, and 50 mg/kg), fraction 2 (F2, molecular weight higher than 1 kDa, 1, 10, and 50 mg/kg), and the references drugs morphine (5 mg/kg), acetilsalicilic acid (200 mg/kg), prometazine (30 mg/kg), and metisergide (5 mg/kg) were evaluated on models of analgesia and inflammation.

Results

CE, F1, and F2 significantly develop peripheral and central antinociceptive activity but with less effect on supra-spinal regions of the brain. Administration of the opioid antagonist, naloxone (5 mg/kg) inhibited the antinociceptive effect indicating that Cocos nucifera crude extract and fractions may be acting in opioid receptors. CE and F1 also inhibited rat paw edema induced by histamine, and serotonin.

Conclusions

results demonstrated that Cocos nucifera and its fractions have antinociceptive and anti-inflammatory activities which confirm the popular use of this plant in several inflammatory disorders.     

Dose-dependent antihypertensive determination and toxicological studies of tilianin isolated from Agastache mexicana

Ethnopharmacological relevance

Agastache mexicana is used in Mexican traditional medicine for the treatment of hypertension, anxiety and related diseases.

Aim of the study

Current work was developed to establish pharmacological/toxicological parameters of tilianin, a flavone extracted from Agastache mexicana in order to propose it for clinical trials.

Materials and methods

Acute and sub-acute toxicology studies in Imprinting Control Region (ICR) mice and median effective dose (ED₅₀) determination in conscious spontaneously hypertensive rats (SHR) were done.

Results

A median lethal dose (LD₅₀) of 6624 mg/kg (6201, 7076) in mice and significant antihypertensive effect (ED₅₀=53.51 mg/kg) in SHR were determined. Moreover, sub-acute oral administration of tilianin did not alter body weight, clinical chemistry parameters (alanine amino-transferase, aspartate amino-transferase, total cholesterol, high density lipoprotein, low density lipoprotein, triglycerides, glucose and insulin), and also did not induce any toxic or adverse effects on kidney, heart, liver, and lung functions.

Conclusions

We have shown that tilianin, isolated from Agastache mexicana, was not toxic for rodents. Also, its antihypertensive effect was dose-dependent and ED₅₀ (53.51 mg/kg) calculated was lesser than LD₅₀ determined (6624 mg/kg), which suggest a wide range of pharmacology–toxicology patterns. Results support the hypothesis that tilianin must be investigated and developed for clinical trials as antihypertensive drug.     

Antinociceptive effectiveness of triterpenes from rosemary in visceral nociception

Ethnopharmacological relevance

Rosemary is a species used worldwide as a common spice, but also in folk medicine for their therapeutic properties against abdominal pain. The rationale of this study was to examine the involvement of triterpenes and to compare their effectiveness in the antinociceptive effect of an ethanol extract of Rosmarinus officinalis L. (Lamiaceae).

Material and methods

Fractionation and HPLC analyses allowed the identification of a mixture of micromeric (121 mg/g), oleanolic (64 mg/g) and ursolic (83 mg/g) acids as partial antinociceptive responsible in an ethyl acetate fraction of R. officinalis by using the acetic acid-induced abdominal constrictions model in mice.

Results

These triterpenes individually evaluated produced a significant and dose-dependent antinociceptive response with similar potency as follows: ED₅₀=1.1 mg/kg (0.9–1.3 mg/kg), 2.1 mg/kg (1.6–2.6 mg/kg) and 1.6 mg/kg (1.1–2.1 mg/kg), respectively, by using the intraperitoneal (i.p.) route of administration in mice. Their maximal antinociceptive efficacy resembled that produced by ketorolac (10 mg/kg, i.p.), a common clinic analgesic.

Conclusion

Our results provide evidence that these triterpenes participate in the antinociceptive activity of R. officinalis. In addition, each individual triterpene showed a similar potency to that observed with ketorolac, a non-steroidal anti-inflammatory drug, in this experimental model.     

Antinociceptive effect of Zanthoxylum rhoifolium Lam. (Rutaceae) in models of acute pain in rodents

Aim of the study

Zanthoxylum rhoifolium Lam. (Rutaceae) is locally known as “mamica de cadela”, and its bark is popularly used for toothache and earache. The objective of this study was to investigate the antinociceptive effect of the ethanolic extract from this species’ stem bark (EtOH), its fractions of partition (hexane—HEX, ethyl acetate—AcOEt, aqueous—AQ) and lupeol (a triterpene obtained from HEX) in models of acute pain.

Materials and methods

Male and female Swiss mice (25–35 g, n = 6–12 animals/group) were used to assess acute toxicity and nociception (Animal Ethics Committee/UFPI, No. 09/2008). Acute toxicity was studied up to 2 g/kg p.o. of EtOH. In the formalin test (2%, 20 μL/paw), the licking time of the stimulated paw was quantified during the first 5 min (first phase) and at 15–30 min (second phase), 1 h after oral treatment with EtOH, HEX, AcOEt or saline, and 30 min after use of morphine—MOR (5 mg/kg i.p.). The same response evoked by capsaicin (2 μg/20 μL/paw) was quantified during 5 min, after administration of EtOH, HEX, AcOEt, AQ, saline and MOR. The licking time of the paw that was stimulated with glutamate (10 μmol/20 μL) was measured (15 min) after treatment with EtOH, HEX, AcOEt, AQ, lupeol, saline or MK801 (0.03 mg/kg, i.p.). Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of EtOH (250 mg/kg p.o.) and HEX (500 mg/kg p.o.).

Results

The animals did not exhibit any acute toxicity to EtOH (up to 2 g/kg p.o.), so it was not possible to calculate the LD50. EtOH, HEX and AcOEt (62.5–250 mg/kg) produced a significant antinociceptive effect in the formalin and capsaicin tests. However, AQ was ineffective. EtOH, HEX, AcOEt and lupeol reduced the glutamate-evoked nociceptive response, but AQ had no effect. EtOH and HEX did not alter the locomotion of animals in the open-field or rota-rod tests, which suggest a lack of a central depressant effect.

Conclusion

The results confirm the popular use of Zanthoxylum rhoifolium as an analgesic, and contribute to the pharmacological knowledge of this species because it was shown that EtOH and its less polar partition fractions (HEX, AcOEt) have an antinociceptive effect in models of chemical nociception, and that lupeol appears to be one of the constituents responsible for this effect.     

Anti-inflammatory and antinociceptive activities of Campomanesia adamantium

Ethnopharmacological relevance

Campomanesia species are used in folk medicine as anti-inflammatory, anti-rheumatic, anti-diarrheal and hypocholesterolemic.

Aim of the study

The present study investigated the in vivo anti-inflammatory and antinociceptive properties of ethyl acetate (AE) and aqueous (Aq) extracts from leaves of Campomanesia adamantium and in vitro anti-inflammatory activity of AE and its isolated flavonols, myricitrin and myricetin.

Materials and methods

The antinociceptive activity of AE and Aq was evaluated using acetic acid-induced writhing and formalin methods. The in vivo anti-inflammatory effect of AE and Aq was evaluated using carrageenan-induced paw oedema in mice. AE, myricitrin and myricetin were evaluated for their abilities to modulate the production of NO, TNF-α and IL-10 in LPS/IFN-γ stimulated J774.A1 macrophages.

Results

It was found that orally administrated AE and Aq (125 and 250 mg/kg) inhibited carrageenan-induced paw oedema in mice. AE (125 and 250 mg/kg) and Aq (125 mg/kg) reduced the time to licking at the second phase of the formalin method in vivo in mice. AE (250 mg/kg) and Aq (125 mg/kg) also reduced the number of writhes. AE, myricitrin and myricetin inhibited NO (320 μg/mL and 6.25–100 μM, respectively) and TNF-α production by macrophages (320 μg/mL for AE, 100 μM for myricitrin and 25–100 μM for myricetin). AE (160 and 320 μg/mL), myricitrin (50 and 100 μM) and myricetin (25–100 μM) increased IL-10 production by macrophages.

Conclusions

The ethyl acetate and aqueous extracts from Campomanesia adamantium showed antinociceptive and anti-inflammatory effects supporting the use of the plant in folk medicine. The results suggest that anti-oedematogenic effect promoted by aqueous extract involves several anti-inflammatory mechanisms of action. The antinociceptive effect shown by aqueous extract can be due to the modulation of release of inflammatory mediators involved in nociception. The anti-inflammatory effects of AE and of its isolated flavonols may be attributed to inhibition of pro-inflammatory cytokines production, TNF-α and NO and to the increased of IL-10 production.     

Antinociceptive activity of methanol extract of fruits of Capparis ovata in mice

Ethnopharmacological relevance

Capparis ovata Desf. and Capparis spinosa L. have wide natural distribution in Turkey and they are consumed in pickled form. Flower buds, root bark, and fruits of the plant are used in folk medicine due to their analgesic, wound healing, cell regeneration, tonic, and diuretic effects.

Aim of the study

In this study, we attempted to identify the possible antinociceptive action of methanol extract prepared from fruits of Capparis ovata.

Materials and methods

Using tail immersion, hot plate and writhing tests, the antinociceptive effect of the methanol extract of Capparis ovata (MEC) fruits was assessed after intraperitoneal administration into mice. Morphine sulfate (5 mg/kg; i.p.) and diclofenac (10 mg/kg; i.p.) were used as reference analgesic agents. Naloxone (5 mg/kg; i.p.) was also tested.

Results

MEC was studied at the doses of 50, 100, and 200 mg/kg (i.p.) and exhibited significant antinociceptive activities in all tests used. The above-mentioned doses of the extract reduced the writhing responses by 32.21, 55.70, and 68.36%, respectively. MPE% were increased by 7.27, 12.07, 14.60% in the tail immersion, and 7.88, 11.71, 16.73% in the hot plate test at the tested doses, respectively. Naloxone antagonized antinociceptive effect at the doses of 100 and 200 mg/kg whereas partially antagonized the effect of MEC at the dose of 50 mg/kg.

Conclusions

Based on the results obtained, it can be concluded that MEC has antinociceptive effects both at the peripheral and central levels.     

Orofacial antinociceptive effect and antioxidant properties of the hydroethanol extract of Hyptis fruticosa salmz ex Benth

Ethnopharmacological relevance

Hyptis fruticosa is a plant native to Brazil with antinociceptive and antiinflamatory properties. This study evaluated the antinociceptive activity of the hydroethanol extract of the plant leaves (CHEE) against orofacial pain as well as its in vitro effect against lipid peroxidation.

Materials and methods

The antinociceptive activity was investigated in mice orally treated with different doses of the CHEE (50, 100, and 200 mg/kg) and morphine (5 mg/kg) using formalin, glutamate, and capsaicin orofacial pain models using. Lipoperoxidation was induced in egg yolk by AAPH and FeSO₄ in the absence and presence of the CHEE (5, 50, 100, and 150 μg/mL).

Results

CHEE (200 mg/kg) significantly reduced (ρ<0.001) the pain response in the first (69.6%) and second (81.8%) phases of the formalin test, while the nociception caused by capsaicin was significantly (ρ<0.001) reduced by up to 62% at 200 mg/kg of extract. When glutamate was used as algogen, a significant (ρ<0.001) nociception reduction of up to 85% at 200 mg/kg extract was observed. CHEE showed a higher protection against lipoperoxidation caused by FeSO₄ (82.3% TBARS inhibition) than AAPH (35.7% TBARS inhibition) at 150 μg/mL.

Conclusion

Hyptis fruticosa leaf CHEE is of pharmacological interest because it was able to inhibit the peripheral and central transmission of orofacial pain, while reducing the spreading of the inflammatory processes by neutralizing reactive oxygen species, which are by-products in the biosynthesis of pain mediators.     

Anticonvulsant activity of Benkara malabarica (Linn.) root extract: In vitro and in vivo investigation

Aim of the study

To systematically investigate the anticonvulsant activity of methanol extract of Benkara malabarica roots and to provide a biochemical basis elucidating its mode of action.

Methods

The median lethal dose (LD₅₀) of Benkara malabarica extract was determined. The anticonvulsant activity of the extract was assessed in strychnine-induced and isoniazide-induced convulsion models; phenytoin (20 mg/kg) and diazepam (1 mg/kg) were used as standards, respectively. Percentage protection provided by the drug was accounted as decrease in the number of convulsions within 8 h of observation. Mechanism of action was studied by performing GABA transaminase (GABA-T) assay, isolated from rat brain. Active constituent was isolated and characterized from the plant extract.

Results

The median lethal dose (LD50) of Benkara malabarica was found to be more than 500 mg/kg. It demonstrated 30% and 35% protection against strychnine-induced convulsions and 60% and 80% protection against isoniazide-induced convulsions, at doses of 25 mg/kg and 50 mg/kg, respectively. Enzyme assay results revealed that Benkara malabarica extract possesses GABA-T inhibitory activity (IC50 = 0.721 mg/ml). Scopoletin which was identified as the major constituent of the extract was found to be an inhibitor of GABA-T (IC50 = 10.57 μM).

Conclusions

The anticonvulsant activity of the plant extract is predominantly GABA mediated and may be due to the action of scopoletin alone or is a result of synergy of different compounds in the extract in which scopoletin is the major constituent.     

Anti-ulcer activity of Cyrtocarpa procera analogous to that of Amphipterygium adstringens, both assayed on the experimental gastric injury in rats

Ethnopharmacological relevance

The bark of Amphipterygium adstringens (Aa) is commonly mixed or adulterated with the bark of Cyrtocarpa procera (Cp) and sold in Mexican markets. Aa is a well known species in Mexico used as decoction to relieve ulcers. Scientific reports reinforcing the anti-ulcer activity of Aa have been previously described, but those describing the anti-ulcer properties of Cp as a substitute for Aa in folk medicine are scarce.

Aim of the study

To investigate anatomical and phytochemical differences between these species, as well as to assess the anti-ulcer effect of Cp extracts in comparison to the Aa extracts.

Material and methods

Anatomical micro-technique and physical and spectroscopic data were used to analyze differences between Cp and Aa. Regard to the pharmacological activity, it was assessed by using the ethanol-induced gastric damage model in rats.

Results

Whereas the bark anatomy of Aa was characterized by vertical canals in the periderm and the rare occurrence of fibers in its phloem, a periderm without vertical canals and abundant fibers in the phloem were distinctive features of Cp. Phytochemical analysis allowed the identification of tirucallane, masticadienonic and 3α-hydroxymasticadienonic acids as major components in Aa, while β-amyrin and β-sitosterol were obtained from Cp. Gastric lesions observed in the control group decreased in the presence of 100 mg/kg of hexane, ethyl acetate and methanol extracts from the normal or regenerated bark of Cp, thus resembling the anti-ulcer effect of Aa. Nevertheless, major anti-ulcer potency was observed with the most active methanol extract from Cp obtained from normal [the effective dose fifty ED₅₀ = 45.54 mg/kg] or regenerated (ED₅₀ = 36.68 mg/kg) bark in comparison to Aa (ED₅₀ = 115.64 mg/kg).

Conclusion

Chemical and anatomical differences were found between these species, but since the anti-ulcer activity of Cp is similar to that shown by Aa our results reinforce the use of both species for the relief of gastric ulcer in folk medicine.     

Anticonvulsant,anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata Fresen.

Aim of the study

The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata.

Materials and methods

The anticonvulsant effect of the aqueous root extract (100, 200 and 400 mg/kg) was evaluated in mice using the strychnine- and picrotoxin-induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze (EPM) and the Y maze (YM) methods (14 and 32) while the hexobarbitone induced sleep and the hole board models were used to evaluate the sedative and exploratory activities in mice respectively. The acute toxicity studies and phytochemical analysis of the extract were also carried out.

Results

The extract (100–400 mg/kg) produced a significant (P < 0.01) dose dependent increase in onset of convulsion compared to the control for strychnine- and picrotoxin-induced seizures. It also produced a significant (P < 0.01) dose dependent prolongation of the cumulative time spent in the open arms of the elevated plus maze and Y maze compared with the control. The extract (100–400 mg/kg) produced significant (P < 0.01) reduction in the time of onset of sleep induced by hexobarbitone. The prolongation of hexobarbitone sleeping time by the extract (200 mg/kg) was comparable to that produced by diazepam (3 mg/kg). At doses of 100–400 mg/kg, the extract produced a dose dependent decrease in exploratory activity of the mice. The reduction in exploratory activity produced by the extract (400 mg/kg) was greater than that of chlorpromazine (1 mg/kg). The results obtained from the experiments indicate that the extract has central nervous system depressant and anxiolytic activities. The LD₅₀ obtained for the acute toxicity studies using both oral and intraperitoneal routes of administration were 1.74 g/kg and 19.95 mg/kg respectively.

Conclusion

These findings justify the use of Securidaca longepedunculata in traditional medicine for the management of convulsion and psychosis.     

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.     

Gastroprotective effect of Hintonia latiflora and Hintonia standleyana aqueous extracts and compounds

Ethnopharmacological relevance

The stem-barks of Hintonia latiflora and Hintonia standleyana, locally known as “copalchi”, are used for treating several maladies such as diabetes and gastrointestinal complaints, including gastric ulcers. Although the antidiabetic properties have been demonstrated, the gastroprotective action remains unexplored.

Aim of the study

The main goals of this study were to establish the potential acute toxicity and the gastroprotective activity of aqueous extracts and compounds from Hintonia latiflora and Hintonia standleyana in order to demonstrate their preclinical efficacy for the treatment of gastric ulcers in Mexican folk medicine.

Materials and methods

The aqueous extracts from the stem-barks (HLSB and HSSB) and leaves (HLL and HSL) from Hintonia latiflora and Hintonia standleyana were prepared by infusion. Investigation of the acute toxicity was accomplished by the Lorke method. The gastroprotective effect was assessed by means of a conventional ethanol-induced gastric injury model in rats using carbenoxolone as positive control. 5-O-[β-d-apiofuranosyl-(1→6)-β-d-glucopyranosyl]-7-methoxy-3′,4′-dihydroxy-4-phenylcoumarin (1) and chlorogenic acid (2) were also assayed. Preliminary mechanism of action of the tested compounds was analyzed using the same pharmacological models but pretreating the animals with N^G-nitro-l-arginine methyl ester (l-NAME), N-ethylmaleimide (NEM) and indomethacin.

Results

Investigation of the acute toxicity revealed that infusions of the leaves and stem-barks of both Hintonia species were not toxic to mice (LD₅₀>5000 mg/kg in all cases). HLSB, HSSB, HLL and HSL provoked a significant gastroprotective effect [80.5±3.35% (ED₅₀=184.7 mg/kg), 80.26±3.96%, 75.1±7.26% (ED₅₀=109.1 mg/kg), 76.85±3.17% (ED₅₀=149.7 mg/kg) of gastroprotection respectively]. Compounds 1 and 2, present in all the extracts, were also active [68.85±8.4% (ED₅₀=15 mg/kg), 74.04±4.4% (ED₅₀=26 mg/kg) of gastroprotection respectively] and their mode of action involved non-protein sulfhydryl endogenous (NP-SH) compounds, since only pretreatment with NEM inhibited their gastroprotective action.

Conclusions

The present investigation tends to support the ethnomedical use of HLSB, HSSB for treating gastric ulceration. Since HLL and HSL were also active, the leaves could be use alternatively, which in terms of natural resources conservation is an outstanding finding, considering that the plant populations of both Hintonia are scarce and in danger of extinction. Mainly two compounds (1 and 2) are important active principles of the plants.     

Anti-inflammatory effects of ethanolic extract and alkamides-derived from Heliopsis longipes roots

Ethnopharmacological relevance

Heliopsis longipes (A. Gray) Blake (Asteraceae) is a broadly used species in the Mexican, Central and South American Traditional Medicine for its anaesthetic, analgesic, anti-inflammatory and anti-ulcerative properties. The ethanolic extract contains alkamides, mainly affinin (spilanthol). This family of compounds exerts an in vitro inhibitory action on the cyclooxygenase and lipoxygenase enzymes.

Aim of the study

The present study approaches the anti-inflammatory effect of the extract and its main bioactive component affinin and derived isobutyl-decanamide.

Materials and methods

The anti-inflammatory effect was evaluated through the mouse ear oedema test by means of two irritating agents, arachidonic acid (AA) and phorbol myristate acetate (PMA).

Results

Heliopsis longipes, affinin and isobutyl-decanamide displayed a marked anti-inflammatory effect on the AA model with ED₅₀ = 0.8, 1.2 and 0.9 mg/ear, respectively. Nimesulide (1 mg/ear) was used as a reference drug. In PMA model, the extract and two alkamides also showed a dose-dependent anti-inflammatory effect with ED₅₀ = 2.0, 1.3 and 1.1 mg/ear, respectively. Indomethacin (3 mg/ear) was used as reference drug.

Conclusions

These results could represent an important contribution to explain the anti-inflammatory ethnobotanical effects reported for Heliopsis longipes and other species containing affinin (spilanthol). For the first time the topical anti-inflammatory effects of Heliopsis longipes, affinin and isobutyl-decanamide were studied.     

Antinociceptive,neurobehavioral and antioxidant effects of Eupatorium triplinerve Vahl on rats

Ethnopharmacological relevance

Eupatorium triplinerve Vahl belongs to the Asteraceae family, popularly known as Japana. It is a perennial shrub native to Amazon rainforests of South America. Its leaves are used through infusions, decoctions, baths, and tea. It is largely used in Brazilian folk medicine as sedative, febrifuge, stimulant, tonic and anti-inflammatory.

Aim of the study

The present study evaluated the putative effects of Eupatorium triplinerve on the central nervous system (CNS), including locomotor and anxiety activity, depression-like behavior, and antinociception and oxidative stress.

Materials and methods

Two-month-old male Wistar rats (n=7–10 rats/group) and Swiss male and female mice of the species Mus musculus (n=7–10 per group) were administered with 100 mg/kg, 200 mg/kg, 400 mg/kg, 600 mg/kg, and 800 mg/kg of hydroalcoholic extracts of Eupatorium triplinerve (HEET). The behavioral assays included open-field (OF), elevated Plus-maze (EPM), and forced swimming tests (FS). The antinociceptive activity was verified using chemical (acetic acid and formalin) and thermal (hot plate) models of nociception. The oxidative stress levels were measured in rat blood samples after behavioral assays and Trolox equivalent antioxidant capacity (TEAC), nitric oxide and malondialdehyde (MDA) levels were measured in vivo.

Results

Oral pretreatment with HEET reduced the locomotion in OF test (200–800 mg/kg), increased central locomotion and open arms entries in the OF and EPM tests, respectively (600–800 mg/kg), and decreased the immobility time in the FS (200–800 mg/kg). It also reduced the writhing number evoked by acetic acid injection (200–800 mg/kg) and licking time in the first phase of the formalin test (400–800 mg/kg). In the oxidative stress assays, the extract decreased TEAC, Nitric Oxide and MDA levels in response to swimming stress induced in rats.

Conclusions

These results were indicative for the first time that Eupatorium triplinerve exerted mild sedative, anxiolytic and antidepressive effects on the CNS. Antinociceptive effects not related to opioid system and antioxidant activity were also observed. These results support the ethnopharmacological use of Eupatorium triplinerve in popular medicine.     

Evaluation of the antidiarrhoeal activity of the hydroethanolic leaf extract of Pupalia lappacea Linn. Juss. (Amaranthaceae)

Ethnopharmacological Relevance

Pupalia lappacea is a medicinal plant found in savannah and woodland localities and forest path sides from Senegal to Southern Nigeria. It has been used in the management of diarrhoea in Nigerian traditional medicine. This study was designed to evaluate the antidiarrhoeal activity of the hydroethanolic leaf extract of Pupalia lappacea (PL).

Materials and methods

The antidiarrhoeal activity of PL was evaluated using the normal and castor oil-induced intestinal transit, castor oil-induced diarrhoea, gastric emptying and intestinal fluid accumulation tests in rodents.

Results

PL (100–400 mg/kg, p.o.) produced a significant dose-dependent decrease in normal and castor oil-induced intestinal transit compared with the control group (distilled water 10 ml/kg, p.o.). This effect was significantly (P<0.05) inhibited by pilocarpine (1 mg/kg, s.c.) but not by yohimbine (10 mg/kg, s.c.), prazosin (1 mg/kg, s.c.), or propranolol (1 mg/kg, i.p.). The extract produced a dose-dependent and significant increase in the onset of diarrhoea. PL (100–400 mg/kg) also reduced the diarrhoea score, number and weight of wet stools. The in-vivo antidiarrhoeal index (ADI_{in vivo}) of 56.95% produced by the extract at the dose of 400 mg/kg was lower compared to that produced by loperamide 5 mg/kg (77.75%). However, PL (400 mg/kg) significantly increased gastric emptying in rats but significantly reduced the volume of intestinal content in the intestinal fluid accumulation test. Phytochemical analysis of the extract revealed the presence of alkaloids, saponins, and fixed oils and fats. The acute toxicity studies revealed that the extract is relatively safe when given orally; no death was recorded at a dose of 10 g/kg.

Conclusion

Results showed that the hydroethanolic leaf extract of Pupalia lappacea possesses antidiarrhoeal activity possibly mediated by antimuscarinic receptor activity.     

Anti-inflammatory action of hydroalcoholic extract,dichloromethane fraction and steroid α-spinasterol from Polygala sabulosa in LPS-induced peritonitis in mice

Ethnopharmacological relevance

Polygala sabulosa A. W. Bennett is a small herb popularly known as “timutu-pinheirinho” that is widely distributed in southern Brazil and that is used to treat disorders of the bowel and kidney and as a topical anesthetic and expectorant in folk medicine. This study was designed to investigate the anti-inflammatory properties of the hydroalcoholic extract (HEPs), CH₂Cl₂ fraction and the steroid α-spinasterol obtained from the aerial parts of Polygala sabulosa in a model of acute inflammation induced by intraperitoneal injection of bacterial lipopolysaccharide in mice.

Materials and methods

The anti-inflammatory effect of HEPs (3–300 mg/kg, i.g.), CH₂Cl₂ fraction (0.003–30 mg/kg, i.g.) and steroid α-spinasterol (0.001–1 mg/kg, i.p. or 1–10 mg/kg, i.g.), were evaluated in mice subjected to the acute inflammation caused by intraperitoneal (i.p.) injection of lipopolysaccharide (LPS, 0.02 µg/kg). The anti-inflammatory activity of the HEPs, CH₂Cl₂ fraction and steroid were assessed by determining the total numbers of leukocytes and differential cell counts (neutrophils and mononuclear cells) and levels of pro-inflammatory (IL-1β, TNF-α, IL-6) or anti-inflammatory (IL-10) cytokines in peritoneal fluid.

Results

The administration of HEPs (3–300 mg/kg, i.g.) completely inhibited inflammatory cell infiltration (300 mg/kg, i.g.) and it reduced TNF-α (100–300 mg/kg) and IL-1β (100 mg/kg) levels in LPS-injected mice. Furthermore, the administration of CH₂Cl₂ fraction (0.003–30 mg/kg, i.g.) or α-spinasterol (0.001–10 mg/kg, by i.p. or i.g.) significantly reduces inflammatory cell infiltration in LPS-injected mice. Moreover, dexamethasone (0.5 mg/kg, i.p., used as a positive control) inhibited inflammatory cell infiltration and reduced the levels of TNF-α, IL-1β and IL-6 in LPS-injected mice.

Conclusions

Taken together, these results provide the first experimental evidence demonstrating that HEPs have significant anti-inflammatory effects on LPS-induced inflammation. These effects appear to be, at least in part, due to the presence of α-spinasterol. These findings support the widespread use of Polygala sabulosa in popular medicine and demonstrate that this plant has therapeutic potential for the development of phytomedicines with anti-inflammatory properties.