Antioxidant, analgesic, and anti-inflammatory activities of the ethanolic extracts of Taxillus liquidambaricola

Abstract

Ethnopharmacological relevance: [corrected] The Taxillus liquidambaricola has been used to treat rheumatic arthralgia, threatened abortion and hypertension in the Chinese traditional medicine. However, there is no scientific evidence which supports the use in the literature. This study aimed to determine the antioxidant, and analgesic activities and the mechanism of anti-inflammatory activities of the ethanolic extracts of Taxillus liquidambaricola (ETL) in cell and animal models.

Materials and methods: The following activities were investigated: free radical scavenging and antioxidant activities [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and DPPH (1, 1-diphenyl-2-picrylhydrazyl)], analgesic (writhing and formalin test), and anti-inflammatory [lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 macrophages and paw-edema induced by λ-carrageenan (Carr)]. We also investigate the anti-inflammatory mechanism of ETL via studies of the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) and the levels of malondialdehyde (MDA) in the edema paw. Serum NO and tumor necrosis factor α (TNF-α) were also measured in vivo.

Results: ETL showed the highest TEAC and DPPH radical scavenging activities, respectively. ETL also had highest contents of polyphenol and flavonoid contents. We evaluated that ETL and the reference compound of quercetin decreased the LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells. Treatment of male ICR mice with ETL significantly inhibited the numbers of acetic acid-induced writhing response and the formalin-induced pain in the late phase. Administration of ETL showed a concentration dependent inhibition on paw edema development after Carr treatment in mice. The anti-inflammatory effects of ETL could be via NO and TNF-α suppression and associated with the increase in the activities of antioxidant enzymes. Western blotting revealed that ETL decreased Carr-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions.

Conclusions: Anti-inflammatory mechanisms of ETL might be correlated to the decrease in the level of MDA, iNOS, and COX-2 via increasing the activities of CAT, SOD, and GPx in the edema paw. Overall, the results showed that ETL demonstrated antioxidant, antinociceptive, and anti-inflammatory activity, which supports previous claims of the traditional use for inflammation and pain.