Two symmetrical unsaturated acids isolated from Viscum album

In the present study, two new acetylene conjugate compounds, dibutyl (2Z, 6Z)-octa-2, 6-dien-4-yne dioate ( 1 ), and dibutyl (2E, 6E)- octa-2, 6-dien-4-yne dioate ( 2 ), were isolated from the dry stem leaves of Viscum album, along with nine known compounds ( 3 - 11 ). Their structures were confirmed on the basis of spectroscopic data. Compounds 1 and 8 showed antioxidant activity against xanthine oxidase (XOD) and 1, 1-diphenyl-2-picrylhydrazyl radical 2, 2-diphenyl-1-(2, 4, 6-trinitrophenyl) hydroxyl (DPPH), with the IC₅₀ of 1.22 and 1.33 μmol·L^-1, and the SC₅₀ of 4.34 and 8.22 μmol·L^-1, respectively.