A new alkaloid and a new benzaldehyde derivative from the twig of Zanthoxylum rhetsa (Roxb.) DC.

A new alkaloid, 2-acetyl-4-methoxyfuro[2,3-b]quinoline (1), and a new benzaldehyde derivative, (2'S)-4-(2'-hydroxy-3'-methyl-3'-butenoxy)benzaldehyde (2), were isolated from the twig of Zanthoxylum rhetsa (Roxb.) DC. along with twenty-six known compounds (3-28). Their structures were determined by spectroscopic analysis (1D and 2D NMR spectroscopy and HRMS analysis) and comparison with data reported in the literature. Thirteen of the known compounds were evaluated for their cytotoxic activities against human cancer cell lines that included MDA-MB-231, SW1353, A549, and HCT116. (±)-8-Acetonyldihydronitidine (15) showed moderate cytotoxicity toward the SW1353 cancer cell line with an IC₅₀ value of 18.90±0.39 µg/mL, and exhibited weak cytotoxic activity against MDA-MB-231, A549 and HCT116 cell lines with IC₅₀ values of 49.86-71.32 µg/mL.