Three new diarylheptanoids and their antioxidant property

Three new diarylheptanoids, i.e., sodium(5S,2E)-1,7-bis(4-hydroxyphenyl)-1-hydroxy-2-hepten-5-sulfonate (1), sodium(5R,2E)-1,7-bis(4-hydroxyphenyl)-1-hydroxy-2-hepten-5-sulfonate (2) and 3,5-diacetoxy-1-(3-methoxy-4,5-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)heptane (3) were isolated from the rhizomes of Zingiber officinale. The structures of the new compounds were elucidated on the basis of spectroscopic methods. The antioxidant activities of 3 were assayed by in vitro models involving DPPH free radicals and superoxide anion radicals.