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.

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.

Study on action mechanism of 1-(4-methoxy-2-methylphenyl)piperazine (MMPP) in acquisition, formation, and consolidation of memory in mice.

In the present study, the mechanism of action of MMPP (1-(4-methoxy-2-methylphenyl) piperazine) in the acquisition (pretraining administration), formation (posttraining administration), and consolidation (pretest administration) of memory was assessed in the passive avoidance test using a short- and long-term memory protocol in mice. MMPP modified avoidance in the acquisition and formation of memory protocols but not in the consolidation protocol. Scopolamine (0.1 mg/kg i.p.), dizocilpine (0.003 mg/kg i.p.), and buspirone (0.1 mg/kg i.p.) completely inhibited MMPP-induced effects on memory acquisition and partially inhibited memory formation in the short-term but not long-term paradigm. This suggested that cholinergic, N-methyl-D-aspartate (NMDA) and 5-hydroxytryptamine-1A (5-HT1A ) receptors were implicated in the MMPP-induced improvements in memory. The sedative, anxiolytic, motor impairment, myorelaxant, and anticonvulsive (pentylenetetrazole-induced seizures) properties of MMPP were also assessed with the compound only showing a nondose-dependent myorelaxation. These results suggest that MMPP can enhance acquisition and formation, but not consolidation, of memory in short-term and long-term protocol via cholinergic, NMDA-glutamatergic, and 5-HT1A receptors.

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.

Development and validation of a column high-performance liquid chromatography method for quantification of ganaphaliin A and B in inflorescences of Gnaphalium liebmannii Sch. Bp ex Klatt.

An HPLC method was developed for the simultaneous determination of gnaphaliin A and B, active compounds of Gnaphalium liebmannii Sch. Bp ex Klatt. The HPLC separation was performed on an Inertsil ODS-3 (150 x 4.6 mm id, 5 microm) RP C18 column operated at 40 degrees C; the isocratic mobile phase was 0.02% aqueous orthophosphoric acid-methanol-acetonitrile (50 + 30 + 20, v/v/v), with a run time of 20 min and flow rate of 1.5 mL/min. Detection with a photodiode array detector (PDAD) was at 270 nm. The method was validated for linearity, repeatability, LOD, and LOQ. The LOD and LOQ for gnaphaliin A and B were found to be in the range of 0.4-0.5 and 1.0-1.4 microg/mL, respectively. This is the first report of an analytical method developed for the quantitative analysis of flavones from Gnaphalium species by HPLC-PDAD with applications for raw material and commercial products.