Two New Flavones from the Barks of Cassia alata and their Bioactivity

Two new flavones (1 and 2), together with two known flavones (3 and 4), were isolated from the barks of Cassia alata. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1–4 were evaluated for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. The results revealed that compound 1 showed good inhibition with IZD of 13.8 ± 1.0 mm. Compounds 2–4 also showed weak inhibition with IZD of 11.2 ± 0.8, 9.6 ± 0.6, and 7.8 ± 0.7 mm, respectively. Compounds 1 and 2 were also tested for their antioxidant activity, and show good antioxidant activity with an IC50 values of 4.8 and 4.5 μg/mL, respectively.