Three new alkaloids and a new iridoid glycoside from the roots of Rehmannia glutinosa.

Three new alkaloids, rehmanalkaloid A-C ( 1 - 3 ), and a new iridoid glycoside, rehmaglutoside L ( 4 ), together with nine known compounds, including (8 S )-7,8-dihydrogeniposid ( 5 ), diglycoside ( 6 ), monomelittoside ( 7 ), mussaenoside ( 8 ), darendoside A ( 9 ), syringing ( 10 ), phenyl-6- O - β - d -xylopyranosyl- O - β - d -glucopyranoside ( 11 ), (7 R , 8 S )-4,9-dihydroxy-3,3′-dimethoxy-7,8-dihydrobenzofuran-1′-propanalneolignan ( 12 ), and trans -liovil ( 13 ), were isolated from a 95% EtOH extract of dried roots from Rehmannia glutinosa . Their structures were determined by extensive spectroscopic (UV, IR, HR-ESI–MS, and 1D and 2D NMR) analyses. Additionally, compounds 4 - 8 (iridoid glycosides) were evaluated for their protective effects on H714444444444444444444466666666669c2 cardiocytes impaired by doxorubicin. Among them, compounds 4-8 exhibited protective effects against DOX-induced cardiotoxicity. [ABSTRACT FROM AUTHOR]