Antioxidant, anti-inflammatory and anti-influenza properties of components from Chaenomeles speciosa

The fruit of Chaenomeles speciosa is a traditional Chinese medicine used for the treatment of dyspepsia and various inflammatory diseases. In the present study, we evaluated the potential radical scavenging capacity, and activity against nitrous oxide, inflammatory cytokines production and neuramindase (NA) of its isolates. The results showed that 3,4-dihydroxybenzoic acid (1) displayed higher inhibitory activities on DPPH and NA with IC(50) values of 1.02 mg/mL and 1.27 mg/mL respectively, and quercetin (2) also showed significant inhibitory action on DPPH and NA, with IC(50 )values of 3.82 mg/mL and 1.90 mg/mL. Compounds 1, 2 and methyl 3-hydroxybutanedioic ester (3) could inhibit the production of TNF-a by 22.73%, 33.14% and 37.19% at 5 mg/mL (P < 0.05) compared with the control. In addition, compound 2 was found to be active on the release of IL-6 in RAW264.7 macrophage cells, with an inhibitory rate of 39.79% (P < 0.05). The anti-inflammatory effect of compound 3 is disclosed for the first time in this study. Avian influenza is usually accompanied by virus invasion followed by the occurrence of oxidative stress and serious inflammation, so the multiple effects of the isolates may play a cocktail-like role in the treatment of avian influenza, and C. speciosa components, especially quercetin, might be a potent source for anti-viral and anti-inflammatory agents.