Daphnogirins A and B, two biflavones from Daphne giraldii.

Two new biflavonoids, daphnogirins A (1) and B (2), were obtained from the roots of Daphne giraldii. Their structures were established on the basis of the spectral data and X-ray diffraction data of the co-crystal of 1 and 2. Daphnogrins A and B have the same configuration at C-1 and opposite configurations at C-16 and C-17. Oxygen radical scavenging assay has indicated that they are of significant antioxidative activity.