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A new alkaloid and flavonoids isolated from Solanum cernuum leaves by high-performance countercurrent chromatography

Ramos, Amaro Chaves, de Oliveira, Rodrigo Rodrigues
Natural product research 2017 v.31 no.20 pp. 2405-2412
Solanum cernuum, alkaloids, chemical composition, countercurrent chromatography, ethyl acetate, glycosylation, guanidines, kaempferol, leaves, medicinal plants, medicine, methanol, solvents, Brazil
Solanum cernuum is a medicinal plant widely distributed in south-east regions of Brazil and popularly used to treat several disorders. Despite their utilisation as a medicine, few studies on its chemical composition are reported. An efficient separation method for the ethyl acetate fraction was developed by high-performance countercurrent chromatography using n -butanol/chloroform/methanol/water (3:7:3:4, v/v/v/v) as the solvent system, affording five compounds (1 – 5) in one-step separation. A new cyclic guanidine alkaloid named cernidine (5) was obtained, besides four glycosylated flavonoids: afzelin (1), astragalin (2), kaempferol 3-O-α[apiofuranosyl-(1 → 2)]-α-rhamnopyranoside (3) and kaempferol 3-O-α[apiofuranosyl-(1→2)]-β-galactopyranoside (4). A further purification step afforded a mixture of trans - and cis -tiliroside (6 – 7). Countercurrent chromatography proved itself as a powerful tool for the isolation of similar compounds since compounds 1 – 2 and 3 – 4 possess little structural differences.