Triangesinenolides A–C: Trimeric Phthalides with Anti-Renal Fibrosis Potential from Angelica sinensis

Trimeric phthalides in nature are rarely reported. This research successfully isolated three novel trimeric phthalides, triangesinenolides A-C (1-3), from Angelica sinensis. These compounds, derived from Z-ligustilide via diverse linkage patterns, display intricate polycyclic skeletons. Their structures were confirmed by spectroscopic and crystallographic analyses. Unlike previously identified trimeric phthalides, triangesinenolide C (3) is the first trimeric phthalide synthesized via [2 + 2]/[4 + 2] cycloaddition. In vitro assays evaluated the anti-renal fibrosis activity of trimeric phthalides for the first time.