Isolation, Crystal Structure, and Anti-inflammatory Activity of Sakuranetin from Populus tomentosa

The title compound of sakuranetin, a main active flavanone component, was first isolated from Populus tomentosa Carr. and characterized by X-ray single-crystal diffraction analysis. It crystallizes in the monoclinic lattice, space group P21/c with a = 12.8531（12）, b = 5.7141（3）, c = 18.0355（12） , β = 97.333（8）°, V = 1313.77（16） ;, Z = 4, M;= 286.27, C;H;O;, μ（MoKα） = 0.108 mm;, D;= 1.447 g/cm;, F（000） = 600, the final R = 0.0350 and wR = 0.0859 for 2571 independent reflections (R;= 0.0246) which were used in all calculations. The molecular crystal structure of sakuranetin shows relative stereochemistry of 5,4?-dihydroxy-7-methoxyflavanone. Intermolecular hydrogen bonds together with the continuous π-π interactions construct the three-dimensional architecture of the title compound. The preliminary bioassay reveals that the title compound exhibits moderate anti-inflammatory activity in vitro against the nitric oxide release.