Antiviral C-geranylated flavonoids from Artocarpus communis.

Ten C -geranylated flavonoids, along with three known analogues, were isolated from the leaves of Artocarpus communis. The chemical structures of these compounds were unambiguously determined via comprehensive spectroscopic analysis, single-crystal X-ray diffraction experiments, and quantum chemical electronic circular dichroism calculations. Structurally, artocarones A–I (1 – 9) represent a group of unusual, highly modified C -geranylated flavonoids, in which the geranyl chain is cyclised with the ortho -hydroxy group of flavonoids to form various heterocyclic scaffolds. Notably, artocarones E and G–I (5 and 7 – 9) feature a 6 H -benzo[ c ]chromene core that is hitherto undescribed in C -geranylated flavonoids. Artocarone J (10) is the first example of C-9–C-16 connected C -geranylated aurone. Meanwhile, the plausible biosynthetic pathways for these rare C -geranylated flavonoids were also proposed. Notably, compounds 1 , 2 , 4 , 8 , 11 , and 12 exhibited promising in vitro inhibitory activities against respiratory syncytial virus and herpes simplex virus type 1. Ten C -geranylated flavonoids, and three biosynthetically related ones, were isolated from the leaves of Artocarpus communis. Some of them exhibited promising antiviral activities against RSV and HSV-1. [Display omitted] • Thirteen C -geranylated flavonoids were isolated from Artocarpus communis. • First examples of C -geranylated flavonoids with a 6 H -benzo[ c ]chromene core. • Structures were elucidated via spectral analysis and X-ray crystallography. • Compounds 1 , 2 , 4 , 8 , 11 , and 12 exhibited promising antiviral activities. [ABSTRACT FROM AUTHOR]