Macroporous resin chromatography, silica gel column chromatography, preparative thin layer chromatography, and semi-preparative high performance liquid chromatography were performed to isolate two compounds from the acid extract of the lateral roots of Aconitum carmichaelii: a new 9-phenylisoquinoline alkaloid(1) and a known pavine alkaloid(2). Their structures were elucidated by spectroscopy. The absolute configuration of compound 1 was identified by electronic circular dichroism(ECD) and it was determined to be(aS)-7,8-dimethoxy-9-(2-carboxy-4,5-dimethoxyphenyl)-3,4-dihydroisoquinoline-1(2H)-one(1). The cardioprotective effects of 1 and 2 against doxorubicin-induced toxicity in H9 c2 cells were evaluated. Both of the isoquinoline alkaloids showed cardioprotective activity.
Keywords: Aconiti Lateralis Radix Praeparata; alkaloid; isoquinoline-type; myocardial protection; phenylisoquinoline.