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

Isocaloteysmannic acid ( 1 ), a new chromanone, was isolated from the leaf extract of the medicinal species Calophyllum tacamahaca Willd. along with 13 known metabolites belonging to the families of biflavonoids ( 2 ), xanthones ( 3 - 5 , 10 ), coumarins ( 6 - 8 ) and triterpenes ( 9 , 11 - 14 ). 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 ( 1 ) showed a moderate cytotoxicity against HepG2 and HT29 cell lines, with IC 50 values of 19.65 and 25.68 µg/mL, respectively, according to the Red Dye method. Compounds 7 , 8 and 10 - 13 exhibited a potent cytotoxic activity, with IC 50 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 ( 10 ).