Novel compounds from Gentiana purpurea L. and their anti-plasmodial evaluation.

Gentiana pupurea L. (Gentianaceae) is an important medicinal plant in Norway and the bitter roots were used against a number of diseases, often related to gastrointestinal ailments and respiratory diseases. Gentian species are reported to be used against malaria in several geographic regions, and in vitro and computational experiments indicate that secoiridoids have an anti-plasmodial effect. Three previously undescribed compounds; the biphenyl secoiridoid glycoside 5''-deoxyamaroswerin, the benzophenone 6''-O-sinapoyl-2,4,3'-trihydroxy-benzophenone-6-O-β-glucopyranoside, and the benzyl benzoate (3-hydroxy-2-methoxybenzyl)-2,3-dihydroxybenzoate, together with eleven other low-molecular compounds were isolated from the 70 % ethanol extract of G. purpurea roots. The structures were elucidated by 1D and 2D NMR methods and high-resolution mass spectrometry. No in vitro anti-plasmodial activity was observed for the 70 % ethanol extract, swertiamarin, sweroside, gentiopicrin, amaroswerin, amarogentin, 5''-deoxyamaroswerin, and amaropanin obtained from G. purpurea.