Phenolic compounds from sappan lignum and their anti-neuroinflammatory activities.

Caesappanols A-F (1-6), six undescribed phenolic compounds, including two dibenzofurans (1, 2), three biphenols (3-5), and one homoisoflavan (6), along with ten known compounds (7-16), were isolated from Sappan Lignum, the heartwood of Caesalpinia sappan L. Compounds 1 and 2 represent the initial discovery of dibenzofuran skeletons within this herb. Structural elucidation of these compounds was achieved through comprehensive analysis of 1D NMR, 2D NMR, and mass spectrometry data. Moreover, their anti-neuroinflammatory activities were evaluated by determining the NO production. All isolated compounds demonstrated inhibitory effects on LPS-induced NO production in BV-2 cells, of which compounds 1, 2, 6, 7, and 15 were more effective with IC50 values of 37.89, 19.99, 30.15, 15.21, and 16.74 μM, respectively.