Paratrimerins J-Y, Dimeric Coumarins Isolated from the Stems of .

Paratrimerins J-Y (- and -, new dimeric coumarins, were obtained from the EtOH(aq) extract of the stems of (Rutaceae) utilizing LC/MS guided isolation. The structures of the dimeric coumarins were elucidated based on 1D/2D NMR spectroscopic and HR-ESIMS data analyses. The absolute configurations of paratrimerins J-Y along with those of two known dimers paratrimerins A () and B () were established on the basis of the experimental and simulated ECD data. In addition, the absolute configurations of the sugar units of paratrimerins A, B, and J-V (-) were confirmed by LC/MS analysis on l-cysteine methyl ester and phenyl isothiocyanate derivatives. The variety of the absolute configurations of the dimeric diastereomers - highlighted a diversity in stereochemical outcomes following a Diels-Alder biosynthesis in . With regard to being a recently emerging medicinal resource for liver cancer, the dimers - were evaluated for cytotoxicity against a wide panel of human cancer cell lines. Paratrimerin W () was cytotoxic toward Huh7 hepatocellular carcinoma, HT1080 fibrosarcoma, and HT29 colorectal cancer cells with IC values of 14.9, 18.4, and 22.5 μM, respectively.