New Oleanane-type glycosides and secoiridoid glucoside from Aptandra zenkeri

Abstract

Four new saponins, camelliagenin A and B derivatives, and one new secoiridoid glucoside were isolated from the stem bark of Aptandra zenkeri Engl. (Aptandraceae) together with two known secoiridoid glucosides. Their structures were determined based on a combination of 1D- and 2D-NMR experiments techniques and HR-ESI-MS analysis. This is the first report on saponins in genus Aptandra.     

1H and 13C NMR signal assignments of carboxyl‐linked glucosides of bile acids

Complete ¹H and ¹³C resonance assignments were carried out for a new type of carboxyl‐linked glucosides of chenodeoxycholic (3α,7α‐dihydroxy‐5β‐cholan‐24‐oic) and hyodeoxycholic (3α,6α‐dihydroxy‐5β‐cholan‐24‐oic) acids by using several homonuclear (¹H–¹H) and heteronuclear (¹H–¹³C) 2D NMR techniques. Differences in the ¹H and ¹³C resonances between the α‐ and β‐anomers of the ester glucosides of bile acids were clarified for the first time. A comparison of the ¹H and ¹³C signal shifts induced by β‐D ‐glucosidation at the 24‐carboxyl and 3α‐hydroxyl groups in the parent 5β‐cholanoic acid was also made. Copyright © 2003 John Wiley & Sons, Ltd.     

Secoiridoids and other chemotaxonomically relevant compounds in Pedicularis: phytochemical analysis and comparison of Pedicularis rostratocapitata Crantz and Pedicularis verticillata L. from Dolomites

We compared the respective metabolite patterns of two Pedicularis species from Dolomites. Seven phenylethanoid glycosides, i.e., verbascoside (1), echinacoside (2), angoroside A (3), cistantubuloside B1 (4), wiedemannioside C (5), campneoside II (11) and cistantubuloside C1 (12), together with several iridoid glucosides as aucubin (6), euphroside (7), monomelittoside (8), mussaenosidic acid (9) and 8-epiloganic acid (13) were identified. Pedicularis verticillata showed also the presence of greatly unexpected secoiridoids, ligustroside (14) and excelside B (15), very rare compounds in Lamiales. Both PhGs and iridoids are considered of taxonomical relevance in the Asteridae and their occurrence in Pedicularis was discussed. In particular, the exclusive presence of several compounds such as 8-epiloganic acid (13), campneoside II (11), cistantubuloside C1 (12), ligustroside (14) and excelside B (15) in Pedicularis rostratocapitata, and angoroside A (3), cistantubuloside B1 (4) and wiedemannioside C (5) in P. verticillata could be considered specific markers for the two botanical entities.     

Two new lignan-iridoid glucoside diesters from the leaves of Vaccinium bracteatum and their relative and absolute configuration determination by DFT NMR and TDDFT-ECD calculation

Two new lignan-iridoid glucoside diesters (2 and 3), together with their putative biosynthetic precursor 10-O-trans-caffeoyl-6α-hydroxyl-dihydromonotropein (1), were characterized from the leaves of Vaccinium bracteatum. Their planar structures and relative configuration were elucidated by spectroscopic measurements and DFT C NMR calculations, and their absolute configurations were determined by time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The plausible biosynthetic pathways of new compounds were also proposed.     

Chemical composition and antioxidant activity of a polar extract of Thymelaea microphylla Coss. et Dur.

Thymelaea microphylla Coss. et Dur. (Thymelaeaceae) is a rare medicinal plant endemic to Algeria. In order to continue our studies on this species, herein we report the isolation and characterisation of 20 compounds from a hydroalcoholic extract (EtOH–H₂O 7:3) of the aerial parts. They include monoterpene glucosides (1–3), phenolic acid derivatives (4, 8 and 9), phenylpropanoid glucosides (5 and 6), flavonoids (7, 10 and 11), a benzyl alcohol glucoside (12), ionol glucosides (13–16), lignans (17–19) and a bis-coumarin (20). All the structures were elucidated by spectroscopic methods including 1D and 2D NMR experiments, as well as ESI-MS analysis. Moreover, the extract of T. microphylla showed a significant and concentration-dependent free radical-scavenging activity in vitro, correlated to the presence of phenolic and chlorogenic acid derivatives (8, 9 and 4).     

Three New Benzophenone Glucosides from the Leaves of Planchonella obovata

Chemical investigation of the EtOH extract of the leaves of Planchonella obovata resulted in the isolation of four benzophenone glucosides, 1 – 4 , of which three, 2 – 4 , are new chemical entities together with five known flavonol glycosides. Their structures were elucidated by spectroscopic analysis. Among the isolated compounds, iriflophenone 2‐O‐(2,6‐di‐O‐galloyl)‐β‐D ‐glucopyranoside ( 4 ) showed some activity (91.4 and 15.0% inhibition at 100 and 10 μg/ml, resp.) against the α‐glucosidase of Bacillus stearothermophilus.     

Secoiridoid Constituents from the Fruits of Ligustrum lucidum

Four new secoiridiod glucosides, p‐hydroxyphenethyl 7‐β‐D ‐glucosideelenolic acid ester ( 1 ), 6′‐elenolylnicotiflorine ( 2 ), 6′′′‐acetylnicotiflorine ( 3 ), and oleoside 7‐ethyl 11‐methyl ester ( 4 ), as well as six known glucosides, nuezhenide ( 5 ), Gl‐3 ( 6 ), nicotiflorine ( 7 ), isonuezhenide ( 8 ), neonuezhenide ( 9 ), and oleoside 11‐methyl ester ( 10 ) were isolated from the fruits of Ligustrum lucidum. Their structures were elucidated by spectroscopic methods. Compound 4 was an artifact produced during extraction.     

Structure determination of chamaedryosides A—C,three novel nor‐neo‐clerodane glucosides from Teucrium chamaedrys,by NMR spectroscopy

Three new nor‐neo‐clerodane diterpenes, named chamaedryoside A (1), B (2) and C (3), have been isolated from the organic extracts of Teucrium chamaedrys (L.) and their structural characterization has been accomplished by ¹H and ¹³C‐NMR spectra, and DEPT, by COSY, TOCSY, HSQC, HSQC‐TOSCY and HMBC experiments, as well as by ESI‐MS/MS techniques. The stereostructures have been elucidated by NOESY and computational calculations. Copyright © 2009 John Wiley & Sons, Ltd.     

液相色谱/电喷雾质谱测定柑桔中的柠檬苦素类似物配糖体

 利用液相色谱 /电喷雾质谱联用技术对柚皮中的柠檬苦素类似物配糖体进行了定向分析 ,在柚皮的乙醇提取物中检测出奥巴叩酮配糖体和诺米林配糖体。利用制备液相色谱对这两种柠檬苦素类似物配糖体进行纯化 ,并用核磁共振对其结构进行鉴定。测定结果表明 ,液质联用法不需标样即可对柑桔中的柠檬苦素类似物配糖体进行定性分析。方法准确、快速、简便。     

New cucurbitane-type triterpenoid glucosides from the tubers of Hemsleya amabilis with anti-tumor activity

Abstract

Two new cucurbitane-type triterpenoid glucosides, 3β,11α-dihydroxycucurbita-5,24(E)-diene-3,26-glucosides (1) and 3β,11α-dihydroxycucurbita-5,24(Z)-diene-3,27-glucosides were isolated from the tubers of Hemsleya amabilis. Their structures were elucidated by various spectroscopic techniques including IR, HRESIMS, 1D and 2D NMR. The two compounds were evaluated for their anti-tumor activity against HeLa and HepG-2 cell lines, and both displayed moderate anti-tumor activity towards HeLa cell lines with IC₅₀ values of 9.8 and 15.7?μM, respectively.