Antibacterial constituents of spreng and its emodin derivatives.

The CHCl-MeOH (1:1) extract of roots of (Polygonaceae) displayed significant antibacterial activity against five bacterial strains with MICs (62.5-31.2 μg.mL). The EtOAc soluble fraction displayed a significant activity against the same strains with MICs (31.2-3.9 μg.mL). The purification of the EtOAc fraction yielded one new phenylisobenzofuranone derivative, berquaertiide (), along with 19 known compounds (-). Their structures were elucidated based on the analysis of their NMR and MS data. All the isolated compounds were assessed for their antibacterial activity. Compound was the most active against all the tested strains (15.7 to 1.9 μg.mL), while compounds - displayed good activities on at least one of the tested strains. In addition, seven analogues (-) of compound were prepared and further assessed for their antibacterial activity. Compounds and were most active than against with MIC (125 and 15.6 μg.mL, respectively).