Xanthone Derivatives from the Twigs of Garcinia hombroniana L. and Their Antioxidant Activity

Garcinia is a largely underexplored genus that produces chemically diverse and biologically active secondary metabolites, including xanthones that have previously been demonstrated to exhibit antioxidant and cytotoxic activities. Xanthones are the major secondary metabolites that are likely to be commonly found in plants. This work aims to evaluate the potential of xanthones in G. hombroniana L. twigs as DPPH radical scavengers. Three known xanthone derivatives, xanthone I (1), α-mangostin (2), and dulcisxanthone B (3), were isolated from G. hombroniana twigs cultivated in Ecopark, Bogor, West Java, Indonesia. Their structures were elucidated using high-resolution electrospray ionization mass spectrometry and extensive nuclear magnetic resonance (1D, 2D) spectroscopy. Antioxidants evaluation against (2,2-diphenyl-1-picrylhydrazyl) radicals revealed that xanthones 1–3 exhibited high activity, with IC₅₀ values of 22.60, 8.76, and 11.25 μg/mL, respectively. These results demonstrate that G. hombroniana is a source of diverse xanthone derivatives with potential antioxidant activity.