Antiviral prenylated C-C derivatives containing a methylenedioxyl group from the roots of Illicium brevistylum.

Five previously undescribed prenylated C-C compounds (1-3 and 5-6) and four known prenylated C-C compounds (4 and 7-9) were isolated from the roots of Illicium brevistylum A. C. Smith. Their structures were elucidated using extensive spectroscopic analyses, including HRESIMS, NMR (H and C NMR, H-H COSY, HSQC, HMBC and NOESY), and CD spectra, ECD calculations, and NOE difference experiments. The absolute configurations of 1-3 were further determined using the modified Mosher's method. All the isolates were evaluated for their antiviral activity against Coxsackievirus B3 and influenza virus A/Hanfang/359/95, their anti-inflammatory potential for nitric oxide generation in lipopolysaccharide-stimulated RAW264.7 and BV2 cells, and their cytotoxicity against the HGC27, T98G, HepG2, A549 and MCF-7 cell lines. Compounds 1-2, 5, and 7-8 exhibited moderate activity against CVB3, whereas all the isolates displayed weak anti-inflammatory effects and no significant cytotoxicity.