New Sphingolipids and Other Constituents of Pancovia laurentii

Phytochemical investigation of the bark and leaves of Pancovia laurentii (Sapindaceae) resulted in the isolation of a new ceramide and a new cerebroside, named pancoviamide ( 1 ), and pancovioside ( 2 ) respectively, together with six known compounds: uracil, (R)‐N‐[(1S,2S,3R)‐2,3‐dihydroxy‐1‐(hydroxymethyl)heptadec‐5‐en‐1‐yl]‐2‐hydroxytetracosanamide, stigmasta‐7,22‐dien‐3‐ol, β‐stitosterol, β‐sitosterol 3‐O‐β‐D ‐glucopyranoside, and 2,3‐dihydroxypropyl pentadecanoate. The structures of 1 and 2 were determined by means of spectroscopic methods. Compounds 1 and 2 were tested in vitro for their antiprotozoal properties against several protozoa and for their cytotoxicity.     

Structure elucidation of new acacic acid‐type saponins from Albizia coriaria

Three new acacic acid derivatives, named coriariosides C, D, and E ( 1–3 ) were isolated from the roots of Albizia coriaria. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR studies and mass spectrometry as 3‐O‐[β‐D ‐xylopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl‐(1 → 6)‐2‐(acetamido)‐2‐deoxy‐β‐D ‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐ 6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D ‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐glucopyranosyl ester ( 1 ), 3‐O‐{β‐D ‐fucopyranosyl‐(1 → 6)‐[β‐D ‐glucopyranosyl‐(1 → 2)]‐β‐D ‐glucopyranosyl}‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D ‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐α‐L ‐rhamno pyranosyl‐(1 → 2)‐β‐D ‐glucopyranosyl ester ( 2 ), and 3‐O‐[β‐D ‐fucopyranosyl‐(1 → 6)‐β‐D ‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl)‐β‐D ‐quinovopyranosyl]octa‐2,7‐dienoyl}acacic acid 28‐O‐β‐D ‐glucopyranosyl ester ( 3 ). Copyright © 2010 John Wiley & Sons, Ltd.     

Lebbeckoside C,a new triterpenoid saponin from the stem barks of Albizia lebbeck inhibits the growth of human glioblastoma cells

One new acacic acid-type saponin, named lebbeckoside C (1), was isolated from the stem barks of Albizia lebbeck. Its structure was established on the basis of extensive analysis of 1D and 2D NMR (¹H, ¹³C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence as 3-O-[β-d-xylopyranosyl-(l→2)-β-d-fucopyranosyl-(1→6)-[β-d-glucopyranosyl(1→2)]-β-d-glucopyranosyl]-21-O-{(2E,6S)-6-O-{4-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl)octa-2,7-dienoyl]-4-O-[(2E,6S)-2,6-dimethyl-6-O-(β-d-quinovopyranosyl)octa-2,7-dienoyl]-β-d-quinovopyranosyl}-2,6-dimethylocta-2,7-dienoyl}acacic acid 28 O-[β-d-quinovopyranosyl-(l→3)-[α-l-arabinofuranosyl-(l→4)]-α-l-rhamnopyranosyl-(l→2)-β-d-glucopyranosyl] ester. The isolated saponin (1) displayed significant cytotoxic activity against the human glioblastoma cell line U-87 MG and TG1 stem-like glioma cells isolated from a patient tumor with IC₅₀ values of 1.69 and 1.44 μM, respectively.     

A new flavonoid and other constituents from Centaurea nicaeensis All. var. walliana M

A new flavone glucoside, apigenin 4'-(6″-methylglucuronide) (1), together with six known compounds, cirsilineol, jaceosidin, melitensin, apigenin, apigenin 7-(6″-methylglucuronide) and prunasin, were isolated from the ethanolic extract of the aerial parts of Centaurea nicaeensis All. var. walliana M. (Asteraceae) collected from Souk-Ahras, eastern Algeria. The structures were established by spectral analysis, mainly HRESI-MS, UV and 2D-NMR experiments (COSY, HSQC and HMBC).     

Purification of vandaterosides from Vanda teres (Orchidaceae) by stepwise gradient centrifugal partition chromatography

Vandaterosides are polar glucosyloxybenzyl eucomate derivatives found in Vanda teres (Orchidaceae), which display biological activities that slow the skin ageing process. In order to obtain larger quantities to allow us to go further in the bioassays, the hydroalcoholic extract of aerial parts (leaves and stems) of V. teres were fractionated by centrifugal partition chromatography, combining isocratic, gradient, and dual elution modes. The first fractionation was performed on the extract maintained in the stationary phase as water saturated in butanol, while increasing the polarity of the mobile phase by changing the proportions of ethyl acetate/1‐butanol/water, in order to obtain two enriched fractions. Vandateroside I was then purified by isocratic mode with ethyl acetate/ethanol/water (46:14:40), while vandateroside II was obtained by combining isocratic elution with ethyl acetate/isopropanol/water (30:20:50) followed by a multiple dual mode with ethyl acetate/ethanol/water (46:14:40). In this manner, hundreds of milligrams of vandateroside I and II were recovered from 10 g of V. teres extract.