Chemical constituents from the <i>Knema globularia</i> fruits and their <i>in vitro</i> cytotoxicity

Abstract

Two new compounds, designated as knecorticosanones A-B (<b>1</b>-<b>2</b>), along with three known compounds (<b>3</b>-<b>5</b>) were isolated from the fruits of <i>Knema globularia</i>. Their structures were elucidated by extensive spectroscopy analysis, including 1D- and 2D-NMR, UV, IR, and HRESIMS and by comparison with the reported data in the literature. Compounds <b>1</b>-<b>5</b> were evaluated for their cytotoxicity. Knecorticosanone B (<b>2</b>) and malabaricone D (<b>5</b>) exhibited moderate cytotoxic effect against Hep-G2, MCF-7 and SK-LU-1 cell lines with IC₅₀ values ranging from 8.76 ± 1.02 to 18.74 ± 1.75 μM while knecorticosanone A (<b>1</b>), virolane (<b>3</b>) and 7-hydroxy-3',4'-methylenedioxyflavan (<b>4</b>) exhibited weak inhibitory effect against these cell lines with IC₅₀ values ranging from 25.85 ± 2.75 to 66.75 ± 2.08 μM.