Tithonia diversifolia is a medicinal plant from the Municipality of Suchiapa, Chiapas, Mexico, that according to local folk medicine is considered useful in the treatment of gastric ulcers. The aim of the present study was to investigate the gastroprotective activity of T. diversifolia by using an ethanol-induced gastric ulcer experimental model in male Wistar rats. The results showed that T. diversifolia had gastroprotective activity, and that the dichloromethane extract had the highest protective activity (close to 90% when using doses between 10 to 100 mg/kg), and that further the compound tagitinin C isolated from this extract was the main active gastroprotective agent. Rats treated with tagitinin C suspended in Tween 80 at 1, 3, 10 and 30 mg/kg showed 37.7, 70.1, 100, and 100% gastroprotection, respectively. The effect elicited by tagitinin C (30 mg/kg) was not attenuated by pretreatment with either NG-nitro-L-arginine methyl ester (70 mg/kg, i.p.), a nitric oxide (NO) synthase inhibitor, N-ethylmaleimide (10 mg/kg, s.c.), a blocker of sulfhydryl groups, or indomethacin (10 mg/kg, s.c.), a blocker of prostaglandin synthesis, which suggests that the gastroprotective mechanism of action of this sesquiterpene lactone does not involve NO, sulfhydryl groups or prostaglandins.

No abstract

Peperomia pellucida is a plant used in traditional medicine to treat gastric ulcers. Although this gastroprotective activity was reported, the active compounds have not been identified. Therefore, the aim herein was to identify the most active compound in the gastroprotective activity of P. pellucida using an ethanol-induced gastric ulcer experimental rat model. A gastroprotective effect was observed when the hexane and dichloromethane extracts were tested, with the higher effect being obtained with the dichloromethane extract (82.3 ± 5.6%) at 100 mg/kg. Dillapiole was identified as the most active compound in this extract. Although there have been previous reports on dillapiole, this is the first on its gastroprotective activity. Rats treated with this compound at 3, 10, 30 and 100 mg/kg showed 23.1, 56.1, 73.2 and 85.5% gastroprotection, respectively. The effect elicited by dillapiole at 100 mg/kg was not attenuated by pretreatment with indomethacin (10 mg/kg, s.c.), a prostaglandin synthesis blocker, N G -nitro-L-arginine OPEN ACCESSMolecules 2013, 18 11328 methyl ester (70 mg/kg, i.p.), a nitric oxide (NO) synthase inhibitor, or N-ethylmaleimide (10 mg/kg, s.c.), a blocker of sulfhydryl groups. This suggests that the gastroprotective mechanism of action of dillapiole does not involve prostaglandins, NO or sulfhydryl groups.

In this study we investigated the relaxant effect of the aerial parts of Argemone ochroleuca (Papaveraceae), which is used in Mexican traditional medicine for the treatment of various respiratory diseases such as cough, bronchitis and asthma. The alkaloid berberine was identified as one of the active relaxant principles (EC50 = 118.50 +/-3.91 microM) in the dichloromethane extract of A. ochroleuca (EC50 = 78.03 +/- 2.15 microg mL(-1) with 95.12 +/- 3.56% of relaxation). Berberine concentration-dependently relaxed the carbachol-induced precontractions but not histamine- or KCl-induced precontraction. The relaxant effect of berberine was unaffected by the presence of propranolol (3 microM), glibenclamide (10 microM) or ODQ (10microM). However, 2', 5'-dideoxyadenosine (10 microM) blocked the log concentration-response curves of berberine. On the other hand, berberine produced a leftward shift of the log concentration-response curves of isoproterenol, forskolin and nitroprusside. Additionally, berberine produced a parallel rightward shift of the concentration-response curve of carbachol in a competitive manner with a pA2 of 3.87 +/- 0.045. The above results suggest that the relaxant effect of berberine on tracheal muscle is due to its antagonistic effect on muscarinic acetylcholine receptors.