Four undescribed sulfoxide-containing derivatives, sinkiangenoxides A and B, (2Z, 4E)-sinkiangenoxide C, and (2E, 4E)-sinkiangenoxide C (1 – 4), and one known compound, 1-(methylthio)propyl (E)-1-propenyl disulfide (5), were isolated from the resin of Ferula sinkiangensis. Their structures were determined based on spectroscopic methods, including IR, UV, HRESIMS, NMR, and CD analysis. Compounds 2 – 4 showed moderate cytotoxic activities against four human cancer cell lines with IC50 values ranging from 15.0 to 40.3 µM. Sinkiangenoxide B (2) was shown to induce apoptosis in HepG2 cells. In addition, compound 5 effectively attenuated lipopolysaccharide-induced nitric oxide release and TNF-α, IL-1β, IL-6, and IL-10 expression.