Gentisein is a xanthone that has been found in H. annulatum and has diverse biological activities.1,2,3 It scavenges DPPH radicals and inhibits the activity of α-glucosidase in cell-free assays (IC50s = 23.3 and 14.7 µM, respectively).1,2 Gentisein is cytotoxic against K562 chronic multiple leukemia cells, drug-sensitive HL-60 acute promyelocyte leukemia cells, and multidrug-resistant HL-60/DOX cells (IC50s = 102, 90.9, and 88.3 µM, respectively).3
1.Zhong, F.-F., Chen, Y., and Yang, G.-Z.Prenylated xanthones from the bark of Garcinia xanthochymus and their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activitiesMolecules15(10)7438-7449(2008) 2.Liu, Y., Zou, L., Ma, L., et al.Synthesis and pharmacological activities of xanthone derivatives as α-glucosidase inhibitorsBioorg. Med. Chem.14(16)5683-5690(2006) 3.Biljali, S., Nedialkov, P., Zheleva-Dimitrova, D., et al.Cytotoxic effects and multidrug resistance modulation by five benzophenones and a xanthone Isolated from Hypericum annulatum Moris SUBSP. AnnulatumBiotechnol. Biotechnol. Equip.27(1)3561-3568(2014)