Potential usefulness of methyl gallate in the treatment of experimental colitis

Methyl gallate is a gallotannin widely distributed in nature. Previous studies have demonstrated its antioxidant, anti-inflammatory, antimicrobial and anti-tumor activities. In the present study, the activity of methyl gallate on experimental models of inflammatory bowel disease has been investigated. Experimental colitis was induced in Sprague-Dawley rats through the intracolonic instillation of an acetic acid solution (2 mL, 4% v/v). Methyl gallate (100 and 300 mg/kg, p.o.) and the reference drug mesalazine (100 mg/kg, p.o.) were tested. Methyl gallate induced a significant reduction in the colon weight/length ratio and macroscopic lesion score. Besides, the malondialdehyde content and the GSSG/GSH ratio were remarkably decreased. Furthermore, the administration of methyl gallate reduced the expression of COX₂, IL-6, TNFα and the severity of microscopic tissue damage induced by acetic acid, while the mean goblet cell density was significantly higher in both the group treated with methyl gallate and the one treated with mesalazine, in comparison with untreated animals. The Na⁺K⁺ATPase pump activity was recovered in treated groups (control: 827.2 ± 59.6, colitis: 311.6 ± 54.8, methyl gallate 100 mg/kg: 642.2 ± 175.0, methyl gallate 300 mg/kg: 809.7 ± 100.6, mesalazine: 525.3 ± 81.7). Methyl gallate was also found to induce a significant reduction in the castor oil-induced intestinal motility in Swiss mice, decreasing the peristalsis by 74.5 and 58.82% at 100 and 300 mg/kg p.o., respectively. This compound also antagonized the jejunum contractions induced by Ach and CaCl₂. This study demonstrates that methyl gallate exerts beneficial effects in a preclinical model of intestinal disorders.

Beneficial properties of Passiflora caerulea on experimental colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Passiflora caerulea L. (Passifloraceae) is a medicinal plant commonly used in traditional medicine in South America for different pathologies associated with the gastrointestinal tract.

AIM OF THE STUDY

In the present study, the activity of the ethanolic extract of P. caerulea on an experimental colitis model related to inflammatory bowel disease has been investigated.

MATERIALS AND METHODS

Colitis was induced by intracolonic instillation of a 2mL of 4% (v/v) acetic acid solution. Macroscopic scoring, myeloperoxidase activity and thiobarbituric acid reactive substances levels were evaluated on isolated colon mucosae. The histopathological studies of colon mucosae were performed by hematoxylin and eosin and Alcian blue staining. Diarrhoea was induced by the administration of castor oil (0.3mL/mouse). The first watery defecation time, the total amount of solid, semi-solid and watery stools and the amount of watery stools were determined. The effect of the extract on a cumulative concentration-response curve of acetylcholine and CaCl₂ on isolated rat jejunum was also evaluated. The phytochemical analysis was performed.

RESULTS

The extract (250mg/kg, p.o.) induced a significant reduction in the weight/length ratio, the macroscopic lesion score, TBARS levels and the microscopic tissue damage when compared with the acetic acid-treated group of animals. P. caerulea (125mg/kg, p.o.) decreased significantly the amount of watery stools in the castor oil-induced-diarrhoea model. Moreover, the P. caerulea extract antagonized the jejunum contractions induced by Ach (E_max for 0.3mg/mL: 76.25%; E_max for 1mg/mL: 63.47%; E_max for 3mg/mL: 42.01%) and CaCl₂ (E_max for 0.3mg/mL: 75.69%; E_max for1 mg/mL: 56.1%; E_max for 3mg/mL: 53.4%). Isoorientin, vitexin, isovitexin, and vicenin-2 were identified in the extract.

CONCLUSION

P. caerulea showed anti-inflammatory, anti-diarrhoeal and spasmolityc activities on preclinical models.

Hydroalcoholic extract of Urtica circularis: a neuropharmacological profile

CONTEXT

The genus Urtica has been known since ancient times. It has known to be useful for the treatment of different human ailments.

OBJECTIVE

The present work evaluated the neuropharmacological effects of a hydroalcoholic extract of Urtica circularis (Hicken) Sorarú (Urticaceae). materials and method: The effect on central nervous system of U. circularis hydroalcoholic extract (from leaves and stems) administered by the intraperitoneal route in mice was evaluated by several tests: Pentobarbital- and midazolam-induced hypnosis, open field, hole board, elevated plus-maze and forced swimming. Phytochemical analysis was performed by high-performance liquid chromatography.

RESULTS

A total of 300 mg/kg i.p. of the extract produced a significant prolongation of pentobarbital- (40 mg/kg i.p.; 60.1 min versus 25.4 min) and midazolam- (50 mg/kg i.v.; 53.4 min versus 25.1 min) induced sleeping time. The extract's administration caused a marked reduction of the head-dipping response (DE50: 373 mg/kg i.p.) in the hole-board test. Urtica circularis extract (DE50: 46 mg/kg i.p.) reduced the spontaneous locomotor activity in the open field test. Flumazenil and atropine significantly antagonized the extract's effect on the locomotor activity. No motor coordination disturbance was observed in the rota rod test at any doses. In the forced swimming test, the extract did not produce any change in the immobility time and it had no significant effects in elevated plus maze test. The phytochemical analysis revealed the presence of chlorogenic acid, vanillic acid, caffeic acid, vicenin-2, p-cumaric acid, ferulic acid, vitexin and isovitexin.

CONCLUSION

This study revealed that U. circularis hydroalcoholic extract possesses sedative activity, facilitating GABAergic and cholinergic transmission.