Cytotoxic Metabolites from Willd.: Isolation and Detection through Feature-Based Molecular Networking.

Isocaloteysmannic acid (), a new chromanone, was isolated from the leaf extract of the medicinal species Willd. along with 13 known metabolites belonging to the families of biflavonoids (), xanthones (-, ), coumarins (-) and triterpenes (, -). The structure of the new compound was characterized based on nuclear magnetic resonance (NMR), high-resolution electrospray mass spectrometry (HRESIMS), ultraviolet (UV) and infrared (IR) data. Its absolute configuration was assigned through electronic circular dichroism (ECD) measurements. Compound () showed a moderate cytotoxicity against HepG2 and HT29 cell lines, with IC values of 19.65 and 25.68 µg/mL, respectively, according to the Red Dye method. Compounds , and - exhibited a potent cytotoxic activity, with IC values ranging from 2.44 to 15.38 µg/mL, against one or both cell lines. A feature-based molecular networking (FBMN) approach led to the detection of a large amount of xanthones in the leaves extract, and particularly analogues of the cytotoxic isolated xanthone pyranojacareubin ().