Three new diterpenoids from <i>Croton laui</i> Merr. et Metc

<p>Three new diterpenoids, including one labdane diterpenoid (<b>1</b>) and two cembrane diterpenoids (<b>2</b>–<b>3</b>), were isolated from the aerial parts of <i>Croton laui</i>, along with four known analogues (<b>4</b>–<b>7</b>). Their structures were elucidated by spectroscopic analysis and comparison with literature data. All compounds were evaluated for their cytotoxicity against two tumour cell lines.</p

Four Matrine-Based Alkaloids with Antiviral Activities against HBV from the Seeds of Sophora alopecuroides

Four novel matrine-based alkaloids (<b>1</b>–<b>4</b>) were isolated from the seeds of Sophora alopecuroides. Compounds <b>1</b> and <b>2</b> possess unprecedented 6/6/6/4 and 6/5/6/6 ring systems, respectively, while <b>3</b> and <b>4</b> are a pair of stereoisomeric matrine–acetophenone alkaloids with an unusual skeleton. Their structures were elucidated by means of spectroscopic methods and single-crystal X-ray diffraction. Hypothetical biogenetic pathways for <b>1</b>–<b>4</b> are proposed, and their antiviral activities are also discussed

Drychampones A–C: Three Meroterpenoids from <i>Dryopteris championii</i>

Three novel sesquiterpenoid-based meroterpenoids, drychampones A–C (<b>1</b>–<b>3</b>, respectively), were isolated from <i>Dryopteris championii</i>. Compounds <b>1</b> and <b>3</b> possessed a novel carbon skeleton which was constructed by an 11/6/6 ring system coupled with a pyronone moiety, and <b>1</b>–<b>3</b> were three racemates. Their structures and absolute configurations were elucidated by NMR, MS, and computational methods. The hypothetical biosynthetic pathways of these meroterpenoids and their antibacterial activities were also discussed