Nine New Gingerols from the Rhizoma of Zingiber officinale and Their Cytotoxic Activities

Nine new gingerols, including three 6-oxo-shogaol derivatives [(Z)-6-oxo-[6]-shogaol (1), (Z)-6-oxo-[8]-shogaol (2), (Z)-6-oxo-[10]-shogaol (3)], one 6-oxoparadol derivative [6-oxo-[6]-paradol (4)], one isoshogaol derivative [(E)-[4]-isoshogaol (5)], and four paradoldiene derivatives [(4E,6Z)-[4]-paradoldiene (8), (4E,6E)-[6]-paradoldiene (9), (4E,6E)-[8]-paradoldiene (10), (4E,6Z)-[8]-paradoldiene (11)], together with eight known analogues, were isolated from the rhizoma of Zingiber officinale. Their structures were elucidated on the basis of spectroscopic data. It was noted that the isolation of 6-oxo-shogaol derivatives represents the first report of gingerols containing one 1,4-enedione motif. Their structures were elucidated on the basis of spectroscopic and HRESIMS data. All the new compounds were evaluated for their cytotoxic activities against human cancer cells (MCF-7, HepG-2, KYSE-150).