O-Galloyl Flavonoids from Geranium pyrenaicum and Their in vitro Antileishmanial Activity

Authors: DİLEK ERCİL, MAEKI KALOGA, OLIVER A. RADTKE, M. KORAY SAKAR, ALBRECHT F. KIDERLEN, HERBERT KOLODZIEJ

Abstract: From the aerial parts of Geranium pyrenaicum Burm., a new flavonol glycoside, kaempferol 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (7), along with 6 known related glycosides [kaempferol 3-O-\beta-D-glucopyranoside (1), quercetin 3-O-\beta-D-glucopyranoside (2), quercetin 3-O-\beta-D-galactopyranoside (3), kaempferol 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (4), quercetin 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (5) and quercetin 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (6)] and the ellagitannins corilagin (8) and tellimagrandin I (9) were isolated. Their structures were established from spectroscopic studies (UV, FAB-MS, ^1H and ^{13}C-NMR, ^1H-^1H COSY, HETCOR, HMBC). Compounds 1-7 were evaluated for antileishmanial activity against a panel of Leishmania species (L. major, L. donovani and L. amazonensis), indicating appreciable in vitro activities (IC_{50} 4-27 nM) when compared with Pentostam (IC_{50} 10-11 nM).

Keywords: Geranium pyrenaicum, Geraniaceae, Flavonoids, Ellagitannins, Antileishmanial activity

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