Five new homoisoflavonoid derivatives, including three meta-homoisoflavanes (1-3), one homoisoflavanone (4), and one homoisoflavan (5), along with five known analogues (6-10), were isolated from the red resin of Dracaena cochinchinensis (Chinese dragon's blood). Their structures were elucidated by analysis of spectroscopic data (1D and 2D NMR, IR, and HRESIMS). The absolute configuration of compound 1 was determined by single-crystal X-ray crystallographic analysis, and those of 2-5 were established on the basis of experimental and computed ECD data. Compounds 4, 6, and 9 exhibited moderate inhibition of nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells with IC50 values of 60.4-75.6 μM.
Keywords: Anti-neuroinflammation; Chinese dragon's blood; Dracaena cochinchinensis; Homoisoflavanone; Meta-homoisoflavane.
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