Sophalines E–I, Five Quinolizidine-Based Alkaloids with Antiviral Activities against the Hepatitis B Virus from the Seeds of <i>Sophora alopecuroides</i>

Five novel quinolizidine-based alkaloids (<b>1</b>–<b>5</b>) were obtained from the seeds of <i>Sophora alopecuroides</i> L. Compounds <b>1</b> and <b>2</b> are the first examples of sparteine-indolizine and matrine-indolizine alkaloids, respectively, whereas <b>3</b> and <b>4</b> are epimeric normatrine-julolidine alkaloids with unusual skeletons. The structures of these compounds were determined by spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism analyses. Hypothetical biosynthetic pathways of <b>1</b>–<b>5</b> were proposed. Compound <b>2</b> exhibited significant antiviral activity against the hepatitis B virus.