Isoprenylated Flavones from the Twigs of Artocarpus chama and Their Anti-Viral Activities

A new isoprenylated flavone, 8,4′-dimethoxy-6-(4′′-methylfuran-2-yl)-flavone ( 1 ), together with five known isoprenylated flavones ( 2–6 ) were isolated from the twigs of Artocarpus chama . Interestingly, compound 1 is a rare flavone bearing an unusual 4-methylfuran-2-yl moiety. The anti-tobacco mosaic virus (anti-TMV) activities assay revealed that compound 1 showed obvious anti-TMV activity with an inhibition rate of 40.2% ± 2.8, and this rate is obviously higher than that of the positive control (with an inhibition rate of 35.1 ± 2.6). Compounds 2–6 also showed potential anti-TMV activities with inhibition rates in the range of 23.5–30.2%, respectively. In addition, to evaluate whether the isoprenylated flavones have more broad antiviral activity, compounds 1–6 were also tested for their anti-rotavirus activities. The results revealed that compounds 1–6 exhibited potential anti-rotavirus activities with therapeutic index (TI) values in the range of 13.0–19.9. These values are lower than that of positive control (with TI valve of 22.7).