Analgesic and Anti-Inflammatory Activities of Methanol Extract of Cissus repens in Mice

Abstract

The aim of this study was to investigate possible analgesic and anti-inflammatory mechanisms of the CR(MeOH). Analgesic effect was evaluated in two models including acetic acid-induced writhing response and formalin-induced paw licking. The anti-inflammatory effect was evaluated by λ-carrageenan-induced mouse paw edema and histopathologic analyses. The results showed that CR(MeOH) (500 mg/kg) decreased writhing response in the acetic acid assay and licking time in the formalin test. CR(MeOH) (100 and 500 mg/kg) significantly decreased edema paw volume at 4th to 5th hours after λ-carrageenan had been injected. Histopathologically, CR(MeOH) abated the level of tissue destruction and swelling of the edema paws. These results were indicated that anti-inflammatory mechanism of CR(MeOH) may be due to declined levels of NO and MDA in the edema paw through increasing the activities of SOD, GPx, and GRd in the liver. Additionally, CR(MeOH) also decreased IL-1β, IL-6, NFκB, TNF-α, COX-2, and iNOS levels. The contents of two active ingredients, ursolic acid and lupeol, were quantitatively determined. This paper demonstrated possible mechanisms for the analgesic and anti-inflammatory effects of CR(MeOH) and provided evidence for the classical treatment of Cissus repens in inflammatory diseases.

Figure 1

Analgesic effect of CR_MeOH and indomethacin (Indo) on acetic-acid-induced writhing response in mice. Each value represents mean ± SEM (n = 8). *P < 0.05 and ***P < 0.001 as compared to the solvent control (CON) group (one-way ANOVA followed by Scheffe's multiple range test).

Figure 2

Effect of CR_MeOH and indomethacin (Indo) on (a) early phase and (b) late phase of formalin test in mice. Each value represents mean ± SEM (n = 8). *P < 0.05 and ***P < 0.001 as compared to the solvent control (CON) group (one-way ANOVA followed by Scheffe's multiple range test).

Figure 3

Effect of CR_MeOH and indomethacin (Indo) on λ-carrageenan induced mouse paw edema. Each value represents mean ± SEM (n = 8). *P < 0.05, **P < 0.01, and ***P < 0.001 as compared to the λ-carrageenan control group (one-way ANOVA followed by Scheffe's multiple range test).

Figure 4

Histopathological examinations on λ-carrageenan-induced paw tissue swelling, edema and neutrophil infiltration (a: epidermis, b: connective tissue, c: muscle fibers): (a) normal, (b) λ-carrageenan, (c) indomethacin, (d) CR_MeOH (20 mg/kg), (e) CR_MeOH (100 mg/kg), (f) CR_MeOH (500 mg/kg). More swelling of the connective tissue, the distance is greater of the gap.

Figure 5

Inhibition of iNOS protein expression by CR_MeOH induced by λ-carrageenan (Carr) in mice paw edema for 4 h. Tissue suspended were then prepared and subjected to western blotting using an antibody specific for iNOS. β-actin was used as an internal control. (a) Representative western blot from two separate experiments is shown. (b) Relative iNOS protein levels were calculated with reference to Carr-injected mouse. The data were presented as mean ± S.D. for three different experiments performed in triplicate. **P < 0.01 and ***P < 0.001 were compared with Carr-alone group.