New xanthone from Cratoxylum glaucum Korth. leaves exhibited in vitro antiplasmodial activity against Plasmodium falciparum.

Cratoxylum glaucum has been utilised in traditional medicine to manage fever associated with malaria. It contains various bioactive compounds, mainly xanthones. This study intends to purify and identify bioactive xanthone from C. glaucum leaves through antiplasmodial bioassay-guided isolation. Several chromatography steps and a lactate dehydrogenase (LDH) assay were conducted to obtain active compounds. The structure identification of compounds was performed based on 1D, 2D NMR, and MS data. This study resulted in one new compound, cratoxyarborenone G (1,3,5,7-tetrahydroxy-8-(2-(2-hydroxypropan-2-yl)-5-methylhex-4-en-1-yl)-2-(3-methylbut-2-en-1-yl)-9H-xanthen-9-one) (1) and one known compound, cratoxyarborenone A (2), belonging to the xanthone group. Compounds (1) and (2) revealed antiplasmodial activity with the IC50 values of 3.61 ± 0.02 µM and 4.07 ± 0.03 µM, respectively. Meanwhile, the cytotoxicity test of compound (1) and compound (2) showed the CC50 values of 51.34 ± 0.04 µM and 17.51 ± 0.02 µM, respectively, which suggested non-toxic substances. Cratoxylum glaucum leaves showed potential as a source of antiplasmodial compounds, and further investigation was warranted.