Two New Isoflavones from the Flowers of Rosa damascena and Their Biological Activities

Two new isoflavones, 6-hydroxy-7-(3-hydroxypropyl)-4′-methoxyisoflavone (1) and 6,4′-dihydroxy-7-(3-hydroxypropyl)-isoflavone (2), were isolated from the flowers of Rosa damascena. 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 revealed that compounds 1 and 2 showed weak inhibition with IZD of 11.6 ± 1.2 and 11.2 ± 1.0 mm, respectively. Compounds 1 and 2 were also tested for their antioxidant activity and showed good activity with an IC50 value of 4.2 and 4.0 μg/mL, respectively.