Analysis of eleven iridoid glycosides by micellar electrokinetic capillary chromatography (MECC) and screening of plant samples by partial filling (MECC)-electrospray ionisation mass spectrometry

Of ammonium, lithium and sodium salts of dodecyl sulfate studied as surfactants in the separation of iridoid glycosides by micellar electrokinetic capillary chromatography (MECC), the last one gave the best results. Eleven neutral iridoid glycosides were separated by MECC with sodium dodecyl sulfate as surfactant, and the water–micelle partition coefficients of the compounds were calculated. The separation system was coupled via a coaxial sheath flow electrospray interface to a mass spectrometer, and the partial filling technique was used in the on-line analysis. Seven plant species belonging to five genera (Plantago, Veronica, Melampyrum, Succisa and Valeriana) were screened for the iridoid glycosides by the new method that was developed. The findings confirmed those of an earlier study on five of the iridoid glycosides. Some new iridoid glycosides were found in Plantago lanceolata, Veronica spicata and V. chamaedrys.     

New analytical method for the study of the metabolism of gentiopicroside in rats after oral administration by LC–TOF‐MS following picolinoyl derivatization

The metabolism of gentiopicroside (GPS) in vivo was studied for the first time by LC–MS following picolinoyl derivatization. Incubation of erythrocentaurin, one of the main in vitro metabolites of GPS by intestinal bacteria, with liver microsome indicated that GPS might be metabolized to a final metabolite 3,4‐dihydro‐5‐(hydroxymethyl)isochroman‐1‐one (HMIO) in vivo. After hydrolysis with sulfatase, HMIO was successfully detected in rat plasma after oral administration of GPS by LC–MS following picolinoyl derivatization. 4‐Methoxyphenyl methanol was used as an internal standard to quantify HMIO in rat plasma. A metabolic pathway of GPS in rats is proposed. The monoterpene compound GPS was found to be metabolized to dihydroisocoumarin, which may be responsible for the pharmacological effect of GPS.     

Iridoid,phenylethanoid and flavonoid glycosides from Forsythia suspensa

Abstract

As part of our continuing efforts to explore bioactive compounds from natural resources, a new iridoid glycoside, adoxosidic acid-6′-oleuroperic ester (1), together with one known phenylethanoid glycoside (2) and two known flavonoid glycosides (3–4) were isolated from the fruit of Forsythia suspensa. The structure of the new compound (1) was elucidated through 1D and 2D NMR spectroscopic data and HR-ESIMS. Interestingly, compound 1 was a monoterpene ester of one iridoid glycoside. Compounds 2–4 were identified as calceolarioside A (2), kaempferol-3-O-rutinoside (3), kampferol-3-O-robinobioside (4) on the basis of NMR spectroscopic data analyses and comparison with the data reported in the literature. The antiviral activity aganisist influenza A (H5N1) virus of compound 1 was studied as well.     

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification sys...     

Formal Synthesis of (±)-Mitsugashiwalactone and (±)-Isodihydronepetalactone from Norborn-5-en-2-one Involving Shapiro Reaction

A formal synthesis of (±)-mitsugashiwalactone ( 1 ) and (±)-isodihydro nepetalactone ( 2 ) was accomplished. Baeyer-Villiger lactonization of ketone 9 followed by acidic treatment led to the rearranged lactone 8 , which underwent a series of functional group transformations to give cyclopentanone derivatives 19 and 20 . Shapiro reaction on 21 and 22 in the presence of excess dry ice gave lactones 5 and 6 . Lactones 5 and 6 previously have been converted to mitsugashiwalactone ( 1 ) and isodihydronepetalactone ( 2 ), respectively.     

Two new epimeric pairs of iridoid from mangrove plant Scyphiphora hydrophyllacea

Two new epimeric pairs of iridoid scyphiphin A_1(1a),A_2(1b) and scyphiphin B_1(2a),B_2(2b) were isolated from Scyphiphora hydrophyllacea Gaertn.F.Their structures were elucidated by spectroscopic methods.The mixture of scyphiphin B_1 and scyphiphin B_2 showed moderate cytotoxicity against human hepatoma SMMC-7721 cell line in vitro by MTT method.     

First total synthesis of (±)-floribundane B: An approach based on Johnson-Claisen rearrangement of a Morita-Baylis-Hillman adduct

The first total synthesis of (±)-floribundane B is reported. Johnson-Claisen rearrangement of a Morita-Baylis-Hillman adduct assembled all of the stereochemical features of this secoiridoid. The formal synthesis of (±)-oleocanthal and the synthesis of a chemical constituent of olive press juice is also reported.     

Two novel iridoid derivatives isolated from Phlomis likiangensis

The extract of the aerial and underground parts of Phlomis likiangensis afforded two new iridoid derivatives, namely as phloloside H (1) and phloline (2), along with four known compounds (3–6), and compound 2 was a novel normonoterpene. Their structures were elucidated on the basis of spectroscopic studies and chemical methods. Six compounds were assayed for cytotoxic, antibacterial and antioxidative activities, but were either inactive or very weakly active.     

Synthesis of deuterium-labelled substrates for the study of oleuropein biosynthesis in Olea europaea callus cultures

We propose the cell culture approach to investigate oleuropein (1) biogenesis in Olea europaea L. We suggest employing olive callus cultures to identify the iridoidic precursor of oleuropein. In fact, we confirmed that callus cells from olive shoot explants are able to produce key secoiridoid as 1. To enable this approach, we synthesised and characterised deuterium-labelled iridoidic precursors belonging both to the loganin and the 8-epiloganin series. These iridoids are [7,8-²H₂]-7-deoxy-8-epi-loganin (2^D), [8,10-²H₂]-8-epi-loganin (4^D) and [7,8-²H₂]-7-deoxy-loganin (3^D).     

阿拉善马先蒿植物中单萜环烯醚甙的研究

阿拉善马先蒿(Pedicularis alaschania maxim)系玄参科马先蒿属植物,民间可代替夏枯草入药,主治淋巴结核、淋巴腺炎、高血压和甲状腺肿大等疾病。其化学成分研究尚未见报道。我们从马先蒿中分离得到2个单萜环烯醚甙P1和P2。P2经质谱(FAB MS)、核磁共振谱(~1H和~(13)C NMR)和红外光谱等数据与文献对照确定为桃叶珊瑚甙(aucubin)。P1为一新化合物。本文报道它们的分离与鉴定。