Undescribed prenylated anthraquinones from Asperula sintenisii Asch. Ex Bornm. with cytotoxic activities

Two previously unreported anthraquinones, named sintenisiquinones A (1) and B (2), were isolated from the MeOH extract of Asperula sintenisii together with five iridoid glycosides, five flavonoids, as well as three phenolic acid derivatives. Their chemical structures were elucidated on the basis of extensive 1D (¹H and ¹³C) and 2D (COSY, HSQC, and HMBC) NMR spectroscopy and HRESIMS. Compounds 1 and 2 represent rare type of anthraquinone derivatives bearing a prenyl group cyclized to dihydrofuran ring. The in vitro cytotoxic activities of selected compounds (1-3, 5, 7, 11, 12 and 15) were evaluated against SW480, DU145, MCF7, and A549 cancer cell lines as well as a healthy cell line, L929 by MTS assay. Compounds 1 and 2 displayed weak cytotoxicity compared to positive control, doxorubicin. This is the first phytochemical and bioactivity studies on A. sintenisii, an endemic species to Türkiye.