Analgesic and anti-inflammatory activities of ethanol root extract of Mahonia oiwakensis in mice

Aims of the study

This study investigated the anti-inflammatory and analgesic activities, and protoberberine alkaloid contents of ethanol extract of MO roots (MOR_EtOH).

Materials and methods

The analgesic activity of MOR_EtOH was determined using acetic acid-induced writhing response and formalin test. The anti-inflammatory activity of MOR_EtOH was determined using the λ-carrageenan-induced paw oedema model. The protoberberine alkaloid contents of MOR_EtOH were identified by high-performance liquid chromatography (HPLC).

Results

MOR_EtOH (100 and 500 mg/kg) decreased the acetic acid-induced writhing responses and licking times of the second phase in the formalin test. Moreover, carrageenan-induced paw oedema was significantly reduced in a dose-dependent manner by administering MOR_EtOH (100 and 500 mg/kg) at 3, 4, and 5 h after the carrageenan injection. The serum levels of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) of MOR_EtOH-treated mice were significantly reduced compared with those in the serum of animals administered carrageenan. Notably, MOR_EtOH attenuated the expression of cyclo-oxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) and neutrophil infiltration in paw tissues injected with carrageenan. The anti-inflammatory mechanisms of MOR_EtOH appear to be related to the inhibition of neutrophil infiltration, iNOS and COX-2 protein expression, NO release, and the decreasing TNF-α level in serum. The analytical results showed that the contents of berberine, palmatine and jatrorrhizine were 191.45 mg/g extract, 100.15 mg/g extract and 66.45 mg/g extract, respectively.

Conclusion

These experimental results suggest that MOR_EtOH produced both analgesic and anti-inflammatory effects in mice and may be a candidate for the development of pharmacological agents used in the treatment of inflammatory disorders.