Two New Flavones from the Seeds of Arctium lappa and Their Bioactivity

Two new flavones, 8,4′-dimethoxy-6-(2-oxopropyl)-flavone (1) and 8,4′-dimethoxy-6-(3-hydroxypropyl)- flavone (2), were isolated from the seeds of Arctium lappa. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results showed that compounds 1 and 2 exhibited weak active with diameter of inhibition zone (IZD) 10.8 ± 1.0 and 9.3 ± 0.8 mm, respectively. Compounds 1 and 2 were also tested for antioxidant activity, and they show good antioxidant activity with IC50 values of 3.85 and 3.47 μg/mL, respectively.