Firmosides A and B: two new sucrose ferulates from the aerial parts of Silene firma and evaluation of radical scavenging activities

Two new tri-ferulates of sucrose, firmosides A and B (1 and 2, respectively), together with 18 known compounds (3-20), were isolated from the aerial parts of Silene firma. The structures of the isolated compounds were elucidated by various spectroscopic methods, including 1D, 2D NMR, and high-resolution electro-spray ionization-mass spectrometry (HR-ESI-MS). All the isolated compounds were evaluated for their free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. As a result, two new compounds (1, 2) and 11 demonstrated significant radical scavenging activity, implying the usefulness as antioxidant agents.