The antiulcer effect of Croton cajucara Benth in normoproteic and malnourished rats

Phytochemical analysis and anti-inflammatory evaluation of compounds from an aqueous extract of Croton cajucara Benth

Croton cajucara Benth. is a medicinal plant popularly used in the Brazilian Amazonia, where it is known as sacaca, being consumed as tea, decoction or infusion of the leaves and stem bark. From a decoction of the leaves, a comprehensive phytochemical analysis was developed by liquid chromatography-mass spectrometry. Many compounds were identified for the first time in C. cajucara, such as O-glycosides of kaempferol and quercetin, flavonoid-C-glycosides, tannins and cinnamic acid derivatives. These compounds were fractionated by polarity and assayed for their anti-inflammatory activity, using a model of mice edema, induced by an intraplantar injection of carrageenan. All fractions exhibited anti-inflammatory properties.

Anti-nociceptive and anti-inflammatory effects of Croton crassifolius ethanol extract

ETHNOPHARMACOLOGICAL RELEVANCE

Croton crassifolius has been used to treat snake bites, stomach ache, sternalgia, joint pain, as well as pharyngitis, jaundice, and rheumatoid arthritis in traditional Chinese medicine. However, there is no scientific evidence which supports the use in the literature.

AIM OF THE STUDY

To investigate the anti-nociceptive and anti-inflammatory effects of ethanol extract of C. crassifolius.

MATERIALS AND METHODS

Anti-nociceptive actions of C. crassifolius were assessed in mice using the hot-plate test, acetic acid-induced writhing test, and formalin test. Anti-inflammatory effects of C. crassifolius were determined in three animal models: acetic acid-induced capillary permeability accentuation in mice, carrageenan-induced edema of the hind paw in rats, and cotton pellet-induced granuloma formation in rats.

RESULTS

Ethanol extract of C. crassifolius showed no significant anti-nociceptive activity in the hot-plate test. However, extract at dosages of 45, 90 and 180 mg/kg significantly reduced acetic acid-induced writhing by 28.89% (P<0.05), 38.37% (P<0.05), and 56.53% (P<0.001), respectively. The extract also caused marked dose-related inhibition of formalin-induced pain in the second phase (P<0.05 for 45 mg/kg, P<0.001 for 90 and 180 mg/kg extract). C. crassifolius extract at dosages of 45, 90 and 180 mg/kg significantly reduced acetic acid-induced capillary permeability accentuation in mice by 26.18% (P<0.05), 65.70% (P<0.001), and 79.19% (P<0.001), and suppressed carrageenan-induced paw edema by 21.28% (P<0.05), 30.69% (P<0.01), and 49.17% (P<0.001) at 6 h after carrageenan injection, respectively. 180 mg/kg of the extract also showed significant activity against carrageenan-induced paw edema at 4 h. At 90 and 180 mg/kg, the extract inhibited cotton pellet-induced granuloma formation in rats.

CONCLUSIONS

These results collectively demonstrate that the ethanol extract of C. crassifolius possesses peripheral anti-nociceptive and anti-inflammatory effects, providing evidence to rationalize the traditional use of C. crassifolius for the treatment of pain and inflammation.

Involvement of glutathione, sulfhydryl compounds, nitric oxide, vasoactive intestinal peptide, and heat-shock protein-70 in the gastroprotective mechanism of Croton cajucara Benth. (Euphorbiaceae) essential oil

This study aimed to evaluate the gastroprotective mechanism of action of the essential oil of Croton cajucara Benth. (Euphorbiaceae) stem bark in ethanol-induced gastric ulcers and its in vitro anti-Helicobacter pylori activity. The involvement of heat-shock protein-70, vasoactive intestinal peptide, glutathione, nitric oxide, and nonprotein sulfhydryl compounds in the gastroprotective effect was determined in male Wistar rats. The minimum inhibitory concentration against H. pylori was determined in vitro. The results were analyzed by analysis of variance followed by the Dunnett test, and a P value less than 0.05 was considered to represent a statistically significant difference. C. cajucara decreased ethanol-induced ulcer area in 100% of ulcers and decreased the histologic lesions. In the C. cajucara group, the area marked by heat-shock protein-70 was significantly higher than the area in the control group; this finding was not seen for vasoactive intestinal peptide. C. cajucara could not maintain glutathione levels close to those in the sham group. The gastric ulcer area of rats treated with the sulfhydryl compound blocker was decreased, but the ulcer area of rats treated with nitric oxide synthase inhibitor showed no alteration. The minimum inhibitory concentration obtained for C. cajucara was 125 μg/mL. These findings suggest that sulfhydryl compounds and heat-shock protein-70, but not nitric oxide, glutathione, or vasoactive intestinal peptide, are involved in the C. cajucara gastroprotective effect against ethanol-induced gastric ulcers.