Zebiriosides A-L, oleanane saponins from the roots of Dendrobangia boliviana

Abstract

Twelve oleanane saponins, zebiriosides A-L, were isolated from the roots of Dendrobangia boliviana Rusby, together with two known saponins, talunùmoside I and 3-O-β-d-glucuronopyranosyl serjanic acid. These saponins are glycosides of serjanic or phytolaccinic acid. Their structures were established on two basis: first, their spectral data, mainly HR-TOFESIMS, 1D-NMR ((1)H, (13)C, DEPT) and 2D-NMR ((1)H(1)H COSY, TOCSY, HSQC, HMBC, and ROESY), and second by comparison with literature data. These compounds were evaluated for their cytotoxic, antileishmanial and hemolytic activities. No antileishmanial or hemolytic activities were revealed, however zebirioside C and zebirioside I showed cytotoxicity against fibroblasts with IC50 of 6.4 and 5.6 μM, respectively.

New oleanane saponins from the roots of Dendrobangia boliviana identified by LC‐SPE‐NMR

“…Eighteen compounds were isolated and identified as five new compounds ( 1 – 5 ) (Figure ). 12 known compounds that were previously isolated by chromatography (on silica gel or RP‐18) from this plant (Figure S1) and the 3‐ O ‐β‐D‐glucuronopyranosylphytolaccagenic acid known from Diploclisia glaucescens . The known compounds were identified by comparison of their NMR spectral data and high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS) data to zebiriosides A‐G and J‐L, talunùmoside I, and 3‐ O ‐β‐D‐glucuronopyranosylserjanic acid .…”

“…12 known compounds that were previously isolated by chromatography (on silica gel or RP‐18) from this plant (Figure S1) and the 3‐ O ‐β‐D‐glucuronopyranosylphytolaccagenic acid known from Diploclisia glaucescens . The known compounds were identified by comparison of their NMR spectral data and high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS) data to zebiriosides A‐G and J‐L, talunùmoside I, and 3‐ O ‐β‐D‐glucuronopyranosylserjanic acid . Comparing to the previous study, in which 14 saponins were isolated after fractionation by vacuum liquid chromatography (on RP‐18) and separation by successive HPFC and preparative HPLC, in this study, the extract was fractionated in two steps (HPFC and LC‐SPE‐NMR) affording 18 saponins.…”

“…We also detected the presence of four sugars by the resonance of their H‐1 (Figure S2). The four sugars were identified by studying their chemical shifts after analysis of ROESY (Figure S3) and HSQC (Figure S4) spectra and by comparison with the spectra of zebiriosides A‐C to a β‐D‐glucopyranose (δ H 4.62, J = 7.7 Hz), a α‐L‐rhamnopyranose (δ H 4.97, J = 1.8 Hz), a β‐D‐glucuronopyranose (δ H 4.56, J = 8.1 Hz) and a second β‐D‐glucopyranose (δ H 5.39, J = 8.1 Hz) (Table ) . The chemical shifts of C‐1 and H‐1 of the second β‐D‐glucopyranose (δ C 95.3, δ H 5.39) suggest an ester linkage on the aglycon via the carboxyl group at position 28, as in zebirioside B .…”

“…The wood of this tree is very hard and therefore used in construction, for furniture, sporting goods, tool handles, and interior coverings . In order to discover new secondary metabolites of biological importance from Peru's Amazon rainforest, we investigated in a previous phytochemical study the roots of D. boliviana and isolated 14 oleanane saponins that are glycosides of serjanic or phytolaccinic acid . In order to push our investigation further, the saponin‐enriched fractions were analyzed using a hyphenated LC‐SPE‐NMR system in order to identify as many compounds as possible.…”

“…It appeared as a timesaving method with a broad application range. As a result, the LC‐SPE‐NMR study allowed us to identify five new saponins, together with 12 known saponins already identified in these roots and another known saponin from another plant species. Their structural characterization has been carried out through NMR spectroscopy and mass spectrometry studies.…”