Extract of Pinus densiflora needles suppresses acute inflammation by regulating inflammatory mediators in RAW264.7 macrophages and mice.

Context: Pinus densiflora Siebold & Zucc. (Pinaceae) needle extracts ameliorate oxidative stress, but research into their anti-inflammatory effects is limited. Objective: To investigate antioxidant and anti-inflammatory effects of a Pinus densiflora needles (PINE) ethanol extract in vitro and in vivo. Materials and methods: We measured levels of reactive oxygen species (ROS), superoxide dismutase (SOD) and inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells at various PINE concentrations (25, 50 and 100 lg/mL; but 6.25, 12.5 and 25 lg/mL for interleukin-1b and prostaglandin E2 (PGE2)). Thirty ICR mice were randomized to six groups: vehicle, control, PINE pre-treatment (0.1, 0.3 and 1 mg/left ear for 10 min followed by arachidonic acid treatment for 30 min) and dexamethasone. The posttreatment ear thickness and myeloperoxidase (MPO) activity were measured. Results: PINE 100 lg/mL significantly decreased ROS (IC50, 70.93 lg/mL, p<0.01), SOD (IC50, 30.99 lg/mL, p<0.05), malondialdehyde (p<0.01), nitric oxide (NO) (IC50, 27.44 lg/mL, p<0.01) and tumour necrosis factor-alpha (p<0.05) levels. Interleukin-1b (p<0.05) and PGE2 (p<0.01) release decreased significantly with 25 lg/mL PINE. PINE 1mg/ear inhibited LPS-stimulated expression of cyclooxygenase-2 and inducible NO synthase in RAW264.7 macrophages and significantly inhibited ear oedema (36.73-15.04% compared to the control, p<0.01) and MPO activity (167.94-105.59%, p<0.05). Discussion and conclusions: PINE exerts antioxidant and anti-inflammatory effects by inhibiting the production of inflammatory mediators. Identified flavonoids such as taxifolin and quercetin glucoside can be attributed to effect of PINE. [ABSTRACT FROM AUTHOR]