IntroductionKalanchoe Adans. (Crassulaceae) is a genus of widespread succulent plants extensively studied for their biological activities. Plants of the genus are considered a potential source of antitumor agents.ObjectiveThis study aimed to investigate the effect of an aqueous extract and fractions of leaves of Kalanchoe fedtschenkoi R. Hamet & H. Perrier on the proliferation of melanoma cell lines employing an NMR‐based biochemometric approach complemented with HPLC‐DAD and UHPLC–MS/MS analyses.Material and MethodsThe n‐butanol fraction (KFBuOH) from K. fedtschenkoi aqueous leaf extract, which decreased B16F10 murine melanoma cells viability by 65% at 100 μg/mL, was fractionated with RP‐18 SPE and Sephadex LH‐20 column chromatography. The fractions were analyzed by 1H‐NMR spectroscopy and submitted to MTT cytotoxicity assays against cultured melanoma cells. Orthogonal projection to latent structures discriminant analysis (OPLS‐DA) was used to correlate their 1H‐NMR profile and cytotoxic activity.ResultsThis strategy enabled the identification of gallic acid (1) and two gallic acid glucosides—gallic acid 4‐O‐(6′‐O‐galloyl)‐glucopyranoside) (2) and gallic acid 3‐O‐(6′‐O‐galloyl)‐glucopyranoside) (3)—as putative bioactive substances, which was further corroborated by subsequent assays with enriched fractions and a gallic acid standard. The fractions enriched in gallic acid (KFA) and gallic acid galloylglucosides (KFB) evidenced selective cytotoxicity towards B16F10 cells (IC50 43.0 and 56.6 μg/mL, respectively) and MV3 human melanoma cells (IC50 93.6 and 66.1 μg/mL, respectively).ConclusionThese results suggest a potential therapeutic use for K. fedtschenkoi in melanoma treatment. This is the first study to evidence a potential antitumor activity for gallic acid galloylglucosides.