Flavones isolated from Pseudognaphalium liebmannii with tracheal smooth muscle relaxant properties.

The inflorescences of Pseudognaphalium liebmannii are used as folk medicine to treat various respiratory diseases. In this work, we report the isolation of seven known flavones: 5-hydroxy-3,7-dimethoxyflavone 1, 5,8-dihydroxy-3,7-dimethoxyflavone 2, 5,7-dihydroxy-3,8-dimethoxyflavone 3 (gnaphaliin A), 3,5-dihydroxy-7,8-dimethoxyflavone 4 (gnaphaliin B), 3,5-dihydroxy-6,7,8-trimethoxyflavone 5, 3,5,7-trimethoxyflavone 6 and 3-O-methylquercetin 7. All these flavones except 1 and 6 showed a relaxant effect on guinea pig tracheal preparation with EC50 between 69.91 ± 15.32 and 118.72 ± 7.06 µM. Aminophylline (EC50 = 122.03 ± 7.05 µM) was used as a relaxant reference drug. The active flavones shifted the concentration-response curves of forskolin and nitroprusside leftward, and significantly reduced the EC50 values of these drugs. Furthermore, these flavones dose-dependently inhibited phosphodiesterase (PDE) in an in vitro assay. This reveals that the inflorescences of P. liebmannii contain several flavones with relaxant effect on airway smooth muscle and with PDEs inhibition that contribute to supporting the anti-asthmatic traditional use.

Gastroprotective effect methanol extract of Caesalpinia coriaria pods against indomethacin- and ethanol-induced gastric lesions in Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Caesalpinia coriaria (Jacq.) Willd is widely used as a traditional medinal plant in Mexico for protective and healing purposes and the treatment of gastrointestinal diseases. AIM OF THE STUDY: To investigate the gastroprotective effect of extract of Caesalpinia coriaria pods against ethanol-induced and indomethacin-induced gastric lesion models, its anti-inflammatory and antioxidative activities, and its main compounds through LC-MS analysis. MATERIALS AND METHODS: Male Wistar rats were orally administered a methanol extract obtained from the pods of C. coriaria at doses of 10, 30, 100, and 300 mg/kg prior to inducing gastric lesions with ethanol or indomethacin. Gastric mucosal lesions were evaluated by macroscopic and histopathological alterations. Determination of prostaglandin E2 (PGE2), alpha tumor necrosis factor (TNF-α), leukotriene B4 (LTB4), nitrites/nitrates, superoxide dismutase (SOD), and H2S gastric levels were investigated. Its main compounds of the active extract through LC-MS analysis. RESULTS: Phenolic compounds were identified as major components of methanol extract. LC-MS analysis identified 15 constituents, and the significant compounds were gallic acid, 3-O-galloylquinic acid, digalloylglucose, tetragalloylglucose, valoneic acid dilactone, pentagalloylglucose, digalloylshikimic acid, and ellagic acid. Pretreatment with the extract at doses of 100 and 300 mg/kg significantly reduced gastric ulcer lesions in both models. Compared with the reference drugs (omeprazole or ranitidine, respectively), no significant difference was found (p < 0.05). The extract's gastroprotective effect was accompanied by significant decreases in leukocyte recruitment, and gastric levels of TNF-α and LTB4 by two to fourfold (p < 0.05). Also, gastric levels of PGE2 gastric levels were maintained and the antioxidant enzyme activities of SOD and nitrate/nitrite in the gastric tissue were improved (p < 0.05). The LC-MS analysis indicated the presence of hydrolyzable tannins (mainly gallic acid derivatives). CONCLUSION: The results suggest that the gastroprotective effect of the methanol extract of C. coriaria pods occurs through anti-inflammatory, antioxidant, and NO modulation properties, and gallic acid derivatives may be the main possible compounds responsible for its actions.

Wound healing activity of the hydroalcoholic extract and the main metabolites of Amphipterygium adstringens (cuachalalate) in a rat excision model.

ETHNOPHARMACOLOGICAL RELEVANCE: The bark of Amphipterygium adstringens Schiede ex Schltdl (Anacardiaceae), commonly known as 'cuachalalate' has been used in Mexican traditional medicine for the treatment of skin and oral lesions, gastric ulcers, and other conditions. The use as wound healing of the bark of this plant has been known since before the Spanish conquest of Mexico. Its uses are mentioned in the first writings of the Spanish in the 16th century. It is important to highlight that its use for wound healing treatment has no scientific previous reports. AIM OF THE STUDY: The objectives of this study were to determine the wound healing effect of the hydroalcoholic extract of the stem bark of Amphipterygium adstringens and its main metabolites, using a model of excision in the back of Wistar rats. To evaluate its antimicrobial effect against common bacteria that living on the skin of wounds and to evaluate its effect on angiogenesis. MATERIALS AND METHODS: The hydroalcoholic extract of cuachalalate (HAE, 10 mg/wound/day), the 3α-hydroxymasticadienoic acid (3 MA, 300 µg/wound/day), the masticadienoic acid (MA, 300 µg/wound/day), and a mixture of anacardic acids (ANA, 300 µg per wound) were tested in a murine excision model topically for 15 days, to evaluate their wound-healing effect. The results were reported in a wound closure percentage (n = 30 animals per treatment curve), using pirfenidone (PIR, 8% in vehicle) as a reference drug. In addition, histologic analysis was performed to evaluate the structure and quality of the scar. The effect on angiogenesis was assessed using the chick embryo chorioallantoic membrane (CAM) model (n = 6 eggs per treatment). The concentration evaluated for each treatment was 300 µg, using as proangiogenic reference drug the histamine (HIS, 5.6 µg) and as antiangiogenic drugs pirfenidone (9 µg) and acetylsalicylic acid (ASA, 9 µg). The antimicrobial test was performed against S. mutans, S. aureus, P. aeruginosa y E. coli using a minimum inhibitory concentration (MIC) assay. RESULTS: The 3α-hydroxymasticadienoic (3 MA) acid and the anacardic acids (ANA) improve the wound closure by approximates 30% (similar to pirfenidone) in comparison with the control-treated with the vehicle in the proliferative phase. On the other hand, the hydroalcoholic extract of cuachalalate (HAE) did not show an effect on the wound healing process. The histologic analysis demonstrated that the three main metabolites showed an improvement in the scar structure. According to the CAM results, it is probable that the main action mechanism of the 3α-hydroxymasticadienoic acid and the anacardic acids is related to their proangiogenic effect. In addition, ANA showed a modest antimicrobial effect. CONCLUSIONS: The 3α-hydroxymasticadienoic acid and anacardic acids showed a better tissue structure and reduced the time closure of the wound. In addition, the anacardic acids showed antimicrobial effects and both metabolites promote angiogenesis, suggesting that these effects may be related to their action mechanism. These metabolites of cuachalalate could be a good alternative for wound healing treatment.

Mexican Plants and Derivates Compounds as Alternative for Inflammatory and Neuropathic Pain Treatment-A Review.

Despite the availability of many anti-pain drugs, in the form of NSAIDs, steroids, gabapentinoids, opioids, and antidepressants, in this study we address the natural compounds belonging to the group of Mexican medicinal plants or "Mexican folk medicine", used for pain management in Mexico. Our interest in this subject is due to the growing idea that "natural is harmless" and to the large number of side effects exhibited in pharmacotherapy. The objective of this review was to document the scientific evidence about Mexican medicinal plants and their derivatives used for inflammatory and neuropathic pain treatment, as well as the mechanisms of action implicated in their antinociceptive effects, their possible adverse effects, and the main pharmacological aspects of each plant or compound. Our data review suggested that most studies on Mexican medicinal plants have used inflammatory experimental models for testing. The anti-pain properties exerted by medicinal plants lack adverse effects, and their toxicological assays report that they are safe to consume; therefore, more studies should be performed on preclinical neuropathic pain models. Moreover, there is no convincing evidence about the possible mechanisms of action involved in the anti-pain properties exerted by Mexican plants. Therefore, the isolation and pharmacological characterization of these plant derivatives' compounds will be important in the design of future preclinical studies.

Effect of the proportion of curcuminoids on the gastroprotective action of Curcuma longa L. in rats.

The gastroprotective effect of a turmeric acetone extract (TAE) (Curcuma longa L. [Zingiberaceae]) was evaluated and compared against its major curcuminoids; curcumin (CUR), demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC). Additionally, to demonstrate the importance of the metabolites' ratio in the extract on the synergistic effect, different mixtures were evaluated. An ethanol-induced gastric injury model was used to evaluate the gastroprotection activity in Wistar rats. The pharmacologic interaction analysis was performed using the Combination Index (CI)-Isobologram Equation method. The CI calculated at 0.5 of affected fraction (fa) for the TAE indicated a synergistic interaction between its components. However, when the proportion of curcuminoids changed from 3.7:1:10 in TAE to a 1:1:1 ratio, the CI implied an antagonistic effect. The binary combinations of curcuminoids (1:1) also showed an antagonistic interaction. The results of this work suggest that the proportion of curcuminoids in the TAE is crucial for the gastroprotective effect against ethanol-induced damage.

Endopleura uchi (Huber) Cuatrec.: A medicinal plant for gynecological treatments - A reproductive toxicity assessment in zebrafish (Danio rerio).

ETHNOPHARMACOLOGICAL RELEVANCE: Endopleura uchi (Huber) Cuatrec is a plant species from the Brazilian Amazon. The barks of this tree are used in folk medicine - mainly as a decoction - for dyslipidemia, uterine infection, fibroids, polycystic ovary, menstrual disorders, as a contraceptive and abortive agent, among others. However, the data available about its developmental toxicity are still insufficient. AIM OF THE STUDY: This study aimed to evaluate the reproductive toxicity and teratogenic effects in embryos from zebrafish treated with the hydroethanolic extract from the barks of Endopleura uchi (EEu). MATERIALS AND METHODS: Both sexes of zebrafish (Danio rerio) were treated with EEu either through immersion (1.2, 2.5, and 5 mg/L) or orally (75, 200, and 500 mg/kg) over 21 consecutive days. Next, we assessed their fertility and gonads' histopathology; in their embryos were assessed teratogenesis, lethalities, and heart rate during daily observations (24, 48, 72, and 96 hpf). RESULTS: The phytochemical analysis of EEu through HPLC/MS shows bergenin as the major compounds. After 21 days of treatment were detected minor histopathological changes in parental fishes, such as atretic oocytes, interstitial fibrosis, and decreased the percentage of early vitellogenic oocytes, but without impairing the reproduction of treated animals. However, in the embryos was observed significantly increased frequency of malformation in all the groups treated through immersion, and in the group treated orally with the highest concentration (500 mg/kg). CONCLUSION: Based on the results, EEu caused no adverse effects in the progenitors on both treatments (immersion and oral). However, it was observed that the concentrations 1.2, 2.5, and 5 mg/L (immersion), and the dose 500 mg/kg (oral) caused malformations in the offspring (F1 generation). These results emphasize the need for attention when using preparations from E. uchi, mainly for pregnant women. Further studies are needed to compare its effects with the extract's primary compound (bergenin).

Mucoadhesive effect of Curcuma longa extract and curcumin decreases the ranitidine effect, but not bismuth subsalicylate on ethanol-induced ulcer model.

The study of pharmacological interactions between herbal remedies and conventional drugs is important because consuming traditional herbal remedies as supplements or alternative medicine is fairly common and their concomitant administration with prescribed drugs could either have a favorable or unfavorable effect. Therefore, this work aims to determine the pharmacological interactions of a turmeric acetone extract (TAE) and its main metabolite (curcumin) with common anti-ulcer drugs (ranitidine and bismuth subsalicylate), using an ethanol-induced ulcer model in Wistar rats. The analysis of the interactions was carried out via the Combination Index-Isobologram Equation method. The combination index (CI) calculated at 0.5 of the affected fraction (fa) indicated that the TAE or curcumin in combination with ranitidine had a subadditive interaction. The results suggest that this antagonistic mechanism is associated to the mucoadhesion of curcumin and the TAE, determined by rheological measurements. Contrastingly, both the TAE and curcumin combined with bismuth subsalicylate had an additive relationship, which means that there is no pharmacological interaction. This agrees with the normalized isobolograms obtained for each combination. The results of this study suggest that mucoadhesion of curcumin and the TAE could interfere in the effectiveness of ranitidine, and even other drugs.

Multi-target antidiabetic mechanisms of mexicanolides from Swietenia humilis.

BACKGROUND: Swietenia humilis seeds are consumed in Mexico to treat type 2 diabetes; the antihyperglycemic effect of this species was previously demonstrated and related to the presence of tetranortriterpenoids of the mexicanolide class. PURPOSE AND STUDY DESIGN: The present investigation was conducted to determine the mechanism of action of selected mexicanolides, including 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), methyl-2-hydroxy-3-ß-tigloyloxy-1-oxomeliac-8(30)-enate (2) and humilinolide H (3), using in vivo experiments with hyperglycemic mice, and cell-based models. METHODS: Nicotinamide-streptozotocin hyperglycemic mice (50-130 mg/kg, i.p.) were used to build antihyperglycemic drug-response curves using an oral glucose tolerance test model. In vitro studies were carried out on INSE1, H4IIE and C2C12 cells to assess insulin secretion, glucose-6-phosphatase inhibition, glucose uptake and mitochondrial bioenergetics, respectively. RESULTS: The combination of the decoction of S. humilis or 2-hydroxy-destigloyl-6-deoxyswietenine acetate (mexicanolide 1) with glibenclamide resulted in a reduction of the antihyperglycemic effect while a significant increase was observed when they were dosed with metformin. These effects were related to KATP SUR blockade, insulin secretion in INSE1 cells, and modulation of 5-HT2 receptors. Furthermore, mexicanolides 1-3 inhibited glucose-phosphatase in H4IIE cells, and enhanced glucose uptake and spare respiratory capacity in C2C12 myotubes. CONCLUSION: S. humilis mexicanolides interact with pharmacological targets at pancreas (KATP channels), liver (glucose-6-phosphatase), and skeletal muscle (mitochondria and possibly glucose transporters) to modulate glucose homeostasis, and could be a promising resource to treat type 2 diabetes.

Chemistry and Biology of Selected Mexican Medicinal Plants.

Herbal medicines are an integral element of alternative medical care in Mexico, and the best testimony to their efficacy and cultural value is their persistence in contemporary Mexican marketplaces where the highest percentages of medicinal and aromatic plants are sold. This chapter summarizes current trends in research on medicinal plants in Mexico, with emphasis on work carried out at the authors' laboratories. The most relevant phytochemical and pharmacological profiles of a selected group of plants used widely for treating major national health problems are described.From this contribution, it is evident that in the last five decades a significant amount of research on medicinal plants has been performed by Mexican scientists. Such efforts have led to the publication of many research papers in noted peer-reviewed journals and technical books. The isolation and structural characterization of hundreds of bioactive secondary metabolites have been accomplished, and most importantly, these studies have tended to support the ethnomedical uses of many different species. A multidisciplinary approach for investigating these plants has led to an increased emphasis on areas such as phytopharmacology, phytotoxicology, quality control, regulation, and conservation issues for these valuable resources. The medicinal plants analyzed so far have shown a very broad chemical diversity of their constituents, which have a high potential for exhibiting novel mechanistic effects biologically. The chapter shows also that there is need to conduct additional clinical studies on herbal drugs, in particular because the longstanding traditional evidence for their safety is not always sufficient to assure their rational use. There is also need to move to "omics" approaches for investigating the holistic effect and the influence of groups of phytochemicals on the whole organism. Mexican scientists may be expected to have bright prospects in this regard, which will imbue medicinal plant research with a new dynamism in the future.

Leaves of Spondias mombin L. a traditional anxiolytic and antidepressant: Pharmacological evaluation on zebrafish (Danio rerio).

ETHNOBOTANICAL RELEVANCE: Spondias mombin L. is a plant dispersed throughout the tropical regions of South America, Africa, and Asia, being found mainly in the North and Northeast of Brazil, where the leaves are used in preparations for neuropsychiatric disorders. Therefore, it is of great importance to carry out studies in different pharmacological models that can prove the traditional use of this plant species. MATERIALS AND METHODS: the hydroethanolic extract from S. mombin leaves (HELSm) was evaluated by oral administration (25 mg/kg) and by immersion (25 mg/l) in scototaxis test in zebrafish (Danio rerio). For this study, caffeine (100 mg/kg) and buspirone (25 mg/kg) were used as standard drugs. The antidepressant action of the HELSm was evaluated assessed in the novel tank diving test (NTDT). In this study, a group with 1% ethanol, one with unpredictable chronic mild stress (UCMS), and another with developmental, social isolation (DSI) were used as induction groups for depression-like behavior and fluoxetine (20 mg/kg) as a drug pattern. RESULTS: by the HPLC-UV fingerprint analysis, the HELSm presented several derivatives of polyphenolic compounds and flavonoids and identified ellagic acid and isoquercitrin, and by the gas-chromatographic, the majority of the identified compounds were fatty acids, esters, and alcohols. By immersion, the LC50 was 49.86 mg/l and by oral via the LD50 in 48 h, was 4.515 g/kg in zebrafish. For all spatiotemporal and behavioral variables (time spent, white compartment, latency, toggle, erratic swimming, freezing duration, thigmotaxis, and risk assessment), the treatment with HELSm produced a similar effect to buspirone and was significant when compared to the caffeine and control group (p < 0.01, Tukey-Kramer test). For all spatiotemporal and behavioral variables evaluated (time spent at the top of the apparatus, crossed quadrants, erratic swimming, and duration of freezing), treatment with HELSm produced a change in the depression-like behavior in the groups tested, with a similar effect to fluoxetine, both with a significant difference when compared to the control groups (p < 0.01). CONCLUSIONS: Our results suggest that the acute administration of the HELSm in the scototaxis and NTDT tests in a zebrafish model (Danio rerio) produced anxiolytic and antidepressant effects, devoid of hypnotic and sedative actions by immersion, and this action was improved when administered by oral via. Possibly, the presence of isoquercitrin in the leaves of Spondias mombin participates in the anxiolytic and antidepressant effects.

Oil from the fruits of Pterodon emarginatus Vog.: A traditional anti-inflammatory. Study combining in vivo and in silico.

ETHNOBOTANICAL RELEVANCE: The oil obtained from the fruits of Pterodon emarginatus Vog. (OPe) is used orally and topically, in traditional medicine for some purposes, such as acute and chronic inflammatory states as rheumatoid arthritis. MATERIALS AND METHODS: In this work, the anti-inflammatory activity of the OPe was demonstrated based on several animal models and presented an in silico study based on the 6α,7ß-dihydroxy-vouacapan-17ß-oic acid (DHVA) majority compound of the OPe to evaluate the interaction this compound, with cyclooxygenase-2 (COX-2) in 4COX (Mus musculus) and 5KIR (Homo sapiens) and molecular dynamics simulation. RESULTS: The OPe (498 mg/kg, p.o) significantly inhibited (p < 0.05, Student t-test) the primary and secondary reactions of arthritis by Freund's Complete Adjuvant (FCA) and in dermatitis induced by croton oil in mice, OPe inhibited peak of edema. In vascular permeability test in rats, the treatment with OPe was able to block the response to PGE2, serotonin, and bradykinin (p < 0.05, Student t-test). In the writhing test in mice, the OPe at doses of 498 and 980 mg/kg (p.o) produced inhibition of 73% and 92%, respectively, and was not significantly effective in the hot plate test. In the evaluation of the potency in relation to gastric injury (gastric ulcer induced by stress) and combined assay in the assessment of anti-inflammatory potency and gastric damage, it was observed that indomethacin (10 mg/kg, p.o.) inhibited carrageenan edema by 51% and produced a higher number of gastric lesions when compared to the group treated with OPe, where only areas of hyperemia were observed, without the occurrence of ulcerative lesion, and which inhibited the edema by 47%. In the in silico study, it was found that the DHVA is capable of binding to two organisms (4COX - Mus musculus and 5KIR - Homo sapiens), however, with higher binding affinity to the organism Homo sapiens. CONCLUSIONS: As expected, all tested ligands were capable of forming hydrogen interactions with residues at their respective binding sites, but the DHVA ligand was capable of creating slightly more hydrogen bonds when docked to either 4COX or 5KIR than the other tested ligands, thus demonstrating the participation of this compound in the anti-inflammatory and antialgic responses observed in the in vivo assays as a COX-2 inhibitor. Therefore, the results obtained support the traditional use of OPe for inflammatory and gastric problems.

Effect of Euterpe oleracea Mart. (Açaí) Oil on Dyslipidemia Caused by Cocos nucifera L. Saturated Fat in Wistar Rats.

Dyslipidemia is caused by disturbances in lipid metabolism that lead to chronic elevations of serum lipids, especially low-density lipoprotein (LDL)-cholesterol and triglycerides, increasing the risk of metabolic syndrome, obesity, diabetes, atherogenic processes, and cardiovascular diseases. The oil from the fruits of Euterpe oleracea (OFEO) is rich in unsaturated fatty acids with potential for treating alterations in lipid metabolism. In this study, we aimed to investigate the effect of OFEO on hyperlipidemia induced by Cocos nucifera L. saturated fat (GSC) in Wistar rats. Chromatographic profile showed that unsaturated fatty acids account for 66.08% in OFEO, predominately oleic acid (54.30%), and saturated fatty acids (palmitic acid 31.6%) account for 33.92%. GSC-induced dyslipidemia resulted in an increase in total cholesterol, LDL-cholesterol, triglycerides, glucose, and liver and abdominal fat, as well as atherogenic processes in the thoracic aorta. OFEO treatment did not reduce hypertriglyceridemia, but did reduce total cholesterol and LDL-cholesterol, thus contributing to the antiatherogenic action of OFEO. OFEO treatment inhibited the formation of atheromatous plaques in the vascular endothelium of the treated rats, as well as those who were treated with simvastatin. The results obtained suggest that OFEO has an antiatherogenic effect in a rat model of dyslipidemia.

Anti-Hyperglycemic Activity of Major Compounds from Calea ternifolia.

Demethylisoencecalin (1) and caleins A (4) and C (5) (3.16-31.6 mg/kg, p.o.), the major components from an infusion of Calea ternifolia controlled postprandial glucose levels during an oral sucrose tolerance test (OSTT, 3 g/kg) in normal and nicotinamide/streptozotocin (NA/STZ, 40/100 mg/kg) hyperglicemic mice. The effects were comparable to those of acarbose (5 mg/kg). During the isolation of 1, 4, and 5, four additional metabolites not previously reported for the plant, were obtained, namely 6-acetyl-5-hydroxy-2-methyl-2-hydroxymethyl-2H-chromene (3), herniarin (6), scoparone (7), and 4',7-dimethylapigenin (8). In addition, the structure of calein C (5) was confirmed by X-ray analysis. Pharmacological evaluation of the essential oil of the species (31.6-316.2 mg/kg, p.o.) provoked also an important decrement of blood glucose levels during an OSTT. Gas chromatography coupled with mass spectrometry (GC-MS) analysis of the headspace solid phase microextraction (HS-SPME)-adsorbed compounds and active essential oil obtained by hydrodistillation revealed that chromene 1 was the major component (19.92%); sesquiterpenes represented the highest percentage of the essential oil content (55.67%) and included curcumene (7.10%), spathulenol (12.95%) and caryophyllene oxide (13.0%). A suitable High Performance Liquid Chromatography (HPLC) method for quantifying chromenes 1 and 6-hydroxyacetyl-5-hydroxy-2,2-dimethyl-2H-chromene (2) was developed and validated according to standard protocols.

Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle.

CONTEXT: Agastache mexicana ssp. mexicana (Kunth) Lint & Epling (Lamiaceae), popularly known as 'toronjil morado', is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders. OBJECTIVE: This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model. MATERIALS AND METHOD: AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5-50 µg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3 × 10 - 6 M) or histamine (3 × 10 - 5 M) in the presence or absence of glibenclamide (10 - 5 M), propranolol (3 × 10 - 6 M) or 2',5'-dideoxyadenosine (10 - 5 M). The antagonist effect of AMEO (10-300 µg/mL) against contractions elicited by carbachol (10 - 15-10 - 3 M), histamine (10 - 15-10 - 3 M) or calcium (10-300 µg/mL) was evaluated. RESULTS: Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC50 = 18.25 ± 1.03 µg/mL) and histamine (EC50 = 13.3 ± 1.02 µg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2',5'-dideoxyadenosine, suggesting that effect of AMEO is not related to ß2-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA2' = -1.507 ± 0.122) than carbachol (pA2' = -2.180 ± 0.357). Also, AMEO antagonized the calcium chloride-induced contractions. CONCLUSION: The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.

Gnaphaliin A and gnaphaliin B synergize the relaxant effect of salbutamol but not of ipratropium in guinea pig trachea.

OBJECTIVE: This work was aimed to investigate the pharmacodynamic interactions between gnaphaliins A and B with ipratropium bromide (IBR) and salbutamol (SAL) using the guinea pig trachea model through application of the combination index (CI)-isobologram equation. METHODS: The guinea pig trachea rings in isolated chamber with Krebs-Henseleit solution (37°C) were contracted with carbachol (3 µm), and then, concentration-relaxant effect curves were constructed for individual drugs and in combination at fixed constant ratios (1 : 1, 3 : 1 and 1 : 3). Median effect and combination index (CI)-isobologram equations were used for determining interactions. KEY FINDINGS: Gnaphaliin A and gnaphaliin B showed clear synergistic interaction with salbutamol, reducing the dose of salbutamol more than sevenfolds to produce the same relaxant effect. However, the combination of either flavonoids with ipratropium bromide showed no interaction. CONCLUSIONS: Applying the combination index-isobologram method, we determined that gnaphaliin A and gnaphaliin B have synergistic effect with salbutamol due probably to their inhibitory effect on phosphodiesterases to maintain high levels of cAMP in the tracheal smooth muscle. However, these compounds did not show any effect with ipratropium.

Gastroprotective effect of diligustilide isolated from roots of Ligusticum porteri coulter & rose (Apiaceae) on ethanol-induced lesions in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The rhizome of Ligusticum porteri Coulter& Rose (LP) has been traditionally used by the ethnic group Raramuri in the North of México for treatment of diabetes, tuberculosis, stomachaches, diarrhea and ritual healing ceremonies. It is use as antiulcer remedy has been extended to all Mexico. AIM OF THE STUDY: To evaluate the gastroprotective activity of LP organic extracts and the major natural product diligustilide (DLG),using as experimental model the inhibition of the ethanol-induced lesions in rats. MATERIALS AND METHODS: Gastric ulcers were induced by intragastric instillation of absolute ethanol (1 mL). We tested the gastroprotective activity of the organic extracts of LP and the pure compound DLG. The ulcer index (UI) was determined to measure the activity. In order to elucidate the action mechanism of DLG the animals were treated with L-NAME, N-ethylmalemide, Forskolin, 2',5'-dideoxyadenosine, Indomethacin, Glibenclameide, Diazoxide, NaHS and DL-Propargylglycine. The pylorus-ligated rat model was used to measure gastric secretion. RESULTS: The oral administration of organic extracts of Ligusticum porteri showed gastroprotective effect at 30 mg/Kg on ethanol induced gastric lesions; hexane and dichloromethane extracts were the most active. DLG was the major compound in the hexane extract. This compound at 10 mg/kg prevented significantly the gastric injuries induced by ethanol. The alkylation of endogenous non-protein-SH groups with N-ethylmaleimide abolished the gastroprotective effect of DLG and blocking the formation of endogenous prostaglandins by the pretreatment with indomethacin attenuated the gastroprotective effect of DLG. CONCLUSION: The gastroprotective activity demonstrated in this study tends to support the ethnomedical use of Ligusticum porteri roots. DLG, isolated as major compound of this medicinal plant has a clear gastroprotective effect on the ethanol-induced gastric lesions. The results suggest that the antiulcer activity of DLG depends on the participation of the endogenous non-protein -SH groups and prostaglandins.

Antineuropathic effect of 7-hydroxy-3,4-dihydrocadalin in streptozotocin-induced diabetic rodents.

BACKGROUND: Painful neuropathy is the most common and debilitating complication of diabetes and results in hyperalgesia and allodynia. Hyperglycemia clearly plays a key role in the development and progression of diabetic neuropathy. Current therapeutic approaches are only partially successful and they are only thought to reduce the pain associated with peripheral neuropathy. Some natural products offer combined antioxidant, anti-inflammatory and antinociceptive properties that may help to treat in a more integrative manner this condition. In this regard, the purpose of this study was to investigate the antineuropathic effect of 7-hydroxy-3,4-dihydrocadalin in streptozotocin-induced diabetic rats and mice without glucose control as well as the possible mechanism of action involved in this effect. METHODS: Rats and mice were injected with 50 or 200 mg/kg streptozotocin, respectively, to produce hyperglycemia. The formalin test and von Frey filaments were used to assess the nociceptive activity. Rota-rod was utilized to measure motor activity and malondialdehyde assay to determine anti-oxidative properties. RESULTS: After 3 weeks of diabetes induction, chemical hyperalgesia was observed in streptozotocin-injected rats. Oral acute administration of 7-hydroxy-3,4-dihydrocadalin (0.3-30 mg/kg) decreased in a dose-dependent manner formalin-evoked hyperalgesia in diabetic rats. In addition, methiothepin (non-selective 5-HT receptor antagonist, 1 mg/kg, i.p.) and ODQ (guanylyl cyclase inhibitor, 2 mg/kg, i.p.), but not naltrexone (opioid receptor antagonist, 1 mg/kg, s.c.), prevented 7-hydroxy-3,4-dihydrocadalin-induced antihyperalgesic effect. The anti-hyperalgesic effect of 7-hydroxy-3,4-dihydrocadalin was similar to that produced by pregabalin (10 mg/kg, p.o.). Furthermore, oral acute administration of 7-hydroxy-3,4-dihydrocadalin (30 mg/kg) reduced streptozotocin-induced changes in malondialdehyde concentration from plasma samples. Unlike pregabalin, 7-hydroxy-3,4-dihydrocadalin did not affect motor activity. Six weeks after diabetes induction, tactile allodynia was observed in the streptozotocin-injected rats. At this time, oral administration of 7-hydroxy-3,4-dihydrocadalin (30 mg/kg) or pregabalin (10 mg/kg) reduced in a similar way tactile allodynia in diabetic rats. Finally, chronic oral administration of 7-hydroxy-3,4-dihydrocadalin (30-300 mg/kg, 3 times/week, during 6 weeks), significantly prevented the development of mechanical hyperalgesia and allodynia in streptozotocin-induced diabetic mice. CONCLUSIONS: Data suggests that 7-hydroxy-3,4-dihydrocadalin has acute and chronic effects in painful diabetic neuropathy. This effect seems to involve antioxidant properties as well as activation of 5-HT receptors and inhibition of guanylyl cyclase enzyme.

Toxic rather than neuropharmacological effect of Ternstroemia sylvatica fruits and identification of 28-O-[ß-l-6-rhamnopyranosyl]-R1-barrigenol as a new compound with toxic effects in mice.

CONTEXT: Fruits of Ternstroemia sylvatica Schltdl. and Cham. (Theaceae) are used in Mexican traditional medicine to alleviate anxiety, sleep disorders and seizures; however, the active principles have not been identified. OBJECTIVE: To identify the neuroactive principles of T. sylvatica fruits using neuropharmacological tests on mice. MATERIALS AND METHODS: The methanol and aqueous extracts of pericarp or seeds of T. sylvatica fruits were intraperitoneally administered (1-562 mg/kg, single doses) to mice. The exploratory cylinder, hole board, open field, Rota-rod and sodium pentobarbital-induced hypnosis tests were used to evaluate the CNS depressant effect after 30 min single administration of extracts. From aqueous seeds extract, triterpene glycoside 28-O-[ß-l-6-rhamnopyranosyl]-R1-barrigenol was isolated an active compound. RESULTS: Crude extracts of T. sylvatica fruits, separated from seed and pericarp, showed sedative effect in mice. The aqueous (ED50 = 4.9 ± 0.8 mg/kg) seed extracts is the most active among them. This extract also decrease locomotor activity and disrupt motor coordination of mice. This extract was also the most toxic extract (LD50 = 5.0 ± 1.4 mg/kg; i.p.). The triterpene glycoside 28-O-[ß-l-6-rhamnopyranosyl]-R1-barrigenol was identified in this extract as one of the active sedative compounds (ED50 = 0.12 ± 0.01 mg/kg) also with toxic effect (LD50 = 1.11 ± 0.23 mg/kg). CONCLUSION: The results suggest that T. sylvatica fruits has toxic activity rather than CNS depressant activity in mice and that this effect might be related to the presence of 28-O-[ß-l-6-rhamnopyranosyl]-R1-barrigenol, one of the active principles of T. sylvatica fruits with sedative and toxic effect.

Hypericum silenoides†Juss. and Hypericum philonotis†Cham. & Schlecht. extracts: in-vivo hypolipidaemic and weight-reducing effects in obese rats.

OBJECTIVES: This study was carried out to assess the anti-obesity effect of Hypericum silenoides Juss. and Hypericum philonotis Cham. & Schlecht. in male Wistar rats fed with a cafeteria diet. METHODS: Adult male Wistar rats with an initial body weight of 290-320 g were used in this trial. The rats were fed with a cafeteria diet for 77 days. Hypericum species were administered orally at a dose of 10, 30 or 100 mg/kg of body weight daily for 35 days. Body weight, food intake, anorexic effect and various biochemical parameters, such as serum glucose, lipid profile, alanine transaminase (ALT), aspartate transaminase (AST) and atherogenic index (AI), were assessed. Additionally, inhibitory lipase activity assay and forced swimming test were also carried out. KEY FINDINGS: Oral administration of H. silenoides and H. philonotis extracts resulted in a significant decrease in body weight and serum glucose levels in obese male Wistar rats. Treatment with aqueous extract of H. silenoides showed anorexic and antidepressant effects and also significantly (P < 0.05) decreased total cholesterol, triglycerides and high-density lipoprotein-cholesterol, while low-density lipoprotein-cholesterol, AI, AST and ALT were not changed. The dichloromethane extract of H. silenoides (half maximal inhibitory concentration (IC50 ) = 262.79 ± 0.09 µg/ml) and hexane extract of H. philonotis (IC50 = 162.60 ± 0.02 µg/ml) showed the most potent lipase inhibitory activity. CONCLUSION: Some H. silenoides and H. philonotis extracts showed a significant anti-obesity activity in cafeteria-diet-fed rats. This research provides the first scientific support for the use of the Hypericum genus for weight reduction in Mexican folk medicine.