Seven diterpenoids from the resin of Pinus yunnanensis Franch and their anti-inflammatory activity

Phytochemical investigation of the 95% ethanol extract from Pinus yunnanensis Franch resin induced the isolation of six previously unreported diterpenoids pinuyunnanacids K - N, P - Q, a nor-diterpenoid with a novel skeleton pinuyunnanacid O and six known analogues. Their structures were elucidated by spectroscopic analysis and computational methods, including nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, calculated NMR chemical shifts method and electronic circular dichroic (ECD) spectra. All the compounds were analyzed for anti-inflammatory activity through western blotting and cell viability, compounds 2, 10 and 12 significantly downregulated the protein expression of iNOS at the concentration of 40 μM. At the same time, compounds 10 and 12 decreased the expression of COX-2 in LPS-treated RAW264.7 (leukemia cells in mouse macrophage) cells at the concentration of 40 μM.