Objective To study the chemical constituents fromdried whole plant of alpine herb Gentiana nanobella, and to conduct preliminary screening for antimalarial activity of the isolated constituents. Methods Ethyl acetate and n-butanol fractions of 75% ethanol extract of the whole plant of G. nanobella were isolated and purified by repeated column chromatography padded with silica gel, RP-18 and Sephadex LH-20, respectively. The structures of the isolated compounds were identified based on their physicochemical properties and spectral data. The in vitro inhibitory activity of the testing compound against human Plasmodium falciparum 3D7 strain was achieved with the SYBR Green I method. Results A total of 11 phenol compounds were obtained and identified as 2,3-dihydroxy benzoic acid methyl ester-3-O-β-L-rhamnosyl-(1''→2')-b-D-glucopyranoside (1), 2,3-dihydroxy benzoic acid-3-O-β-L-rhamnosyl-(1''→2')-b-D-glucopyranoside (2), 2,3-dihydroxy benzoic acid methyl ester-3-O-β-D-glucopyranosyl-(1''→6')-β-D-glucopyranoside (3), benzyl β-D-xylopyranosyl-(1''→6')-β-D-glucopyranoside (4), apigenin 5-O-β-D-glucopyranoside (5), salcolin B (6), apigenin-7-O-β-D-glucopyranoside (7), benzoic acid (8), p-hydroxybenzoic acid (9), 3-hydroxy-2-methoxybenzoic acid (10), and isovanillic acid (11). Compound 6 exhibited an in vitro antimalarial activity against Plasmodium falciparum 3D7 strain with IC₅₀ 18.50 μmol/L and inhibition rate of 98.48% at a concentration of 50 μmol/L. Conclusion Compounds 1 and 2 are new compounds, named gentinanoside A and gentinanoside B. Compounds 1—11 were isolated from G. nanobella for the first time. G. nanobella is abundant in phenolic compounds, and some compounds had certain antimalarial activity.

Gentiana nanobella C. Marquand  /  new phenolic glycosides  /  antimalarial activity  /  gentinanoside A  /  gentinanoside B  /  apigenin 5-O-β-D-glucopyranoside