Iridoids from <Emphasis Type="Italic">Symphoricarpos albus</Emphasis>

Twelve compounds including secologanin, loganin, the aglycon of loganin, and a new iridoid called glucologanin were isolated from fruit of common snowberry Symphoricarpos albus (L.) Blake. The structure of glucologanin was confirmed using PMR and mass spectroscopy and chemical transformations. 2′,3′,4′,6′,7-Penta-O-acetylloganin and 2′,3′,4′,6′-tetra-O-acetylloganin were synthesized. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 37–40, January–February, 2009.     

A short synthesis of some monoterpenoids from the adduct of myrcene with benzenesulfinyl chloride

The title adduct was converted into 1,2-epoxymyrcene; its cationic 5-exo-cyclization gave a (±)-hop ether having the iridane-type skeleton. Effective syntheses of a furanoterpene perillene and some functionalized cyclopentanoid monoterpenes regioisomeric to iridoids were elaborated using sulfur-containing geraniol derivatives easily accessible from the same adduct in a synthetic sequence including the Pummerer reaction and anionic cyclization.Deceased Nov., 1, 1992.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 113–117, January, 1993.     

The Chemical Constituents from Fruits of Catalpa bignonioides Walt. and Their α-Glucosidase Inhibitory Activity and Insulin Secretion Effect

Catalpa pod has been used in traditional medicine for the treatment of diabetes mellitus in South America. Studies on the constituents of Catalpa species have shown that it is rich in iridoids. In the present study, three previously undescribed compounds (2–4), including two secoiridoid derivatives along with twelve known compounds, were isolated from the fruits of Catalpa bignonioides Walt. In addition, fully assigned ¹³C-NMR of 5,6-dihydroxy-7,4’-dimethoxyflavone-6-O-sophoroside (1) is reported for the first time in the present study. The structures of compounds were determined on the basis of extensive spectroscopic methods, including UV, IR, 1D, and 2D NMR, mass spectroscopy, and CD spectroscopic data. All the isolated compounds were evaluated for α-glucosidase inhibitory activity. Among the tested compounds, compounds 2, 3, and 9 exhibited significant inhibitory activity against α-glucosidase enzyme assay. Meanwhile, the effect of compounds 2, 3, and 9 on glucose-stimulated insulin secretion (GSIS) was measured using pancreatic β-cells. Compounds 2, 3, and 9 exhibited non-cytotoxicity-stimulated insulin secretion in INS-1 cells. The expression levels of proteins associated with β-cell function and insulin secretion such as phosphorylation of total insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, activated pancreatic duodenal homeobox-1 (PDX-1), and peroxisome proliferator-activated receptor-γ (PPAR-γ) were increased in INS-1 cells after treatment with compounds 2, 3, and 9. The findings of the present study could provide a scientific warrant for their application as a potential antidiabetic agent.     

Sesquiterpene and iridoids from <Emphasis Type="Italic">Valeriana pseudofficinalis</Emphasis> roots

A new sesquiterpene, named valeriene (1), along with three iridoids, namely valepotriate (2), dihydrovaltrate (3) and acevaltrate (4) were isolated from the ethyl acetate extract of Valeriana pseudofficinalis roots. The structures of these compounds were determined by 1D and 2D NMR, MS techniques, and X-ray single crystal diffractometry. This is the first report of the chemical components isolated from this plant. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 308–310, May–June, 2009.     

Iridoid glycosides and polyphenolic compounds from Teucrium chamaedrys L.

In this work, the phytochemical analysis of Teucrium chamaedrys L. collected in Italy was reported. Eight compounds were isolated and identified by means of classical column chromatography and spectroscopic techniques, such as NMR and MS. In detail, these compounds were: verbascoside (1), forsythoside b (2), samioside (3), alyssonoside (4), harpagide (5), 8-O-acetyl-harpagide (6), cirsiliol (7) and β-arbutin (8). The presence of these compounds, in particular iridoids and phenyl-ethanoid glycosides, has a chemotaxonomic relevance and results to be in perfect accordance with the current botanical classification of the species. In addition, it provides a phytochemical rationale for the use of this particular plant in the ethno-pharmacological field. Conversely, it is worth of mention the absence of potentially toxic components, unlike to what observed in other species of the genus which can no longer be used for ethno-medicinal purposes.     

Determination of Iridoids in Gentiana rigescens by Infrared Spectroscopy and Multivariate Analysis

Gentiana rigescens is a famous herbal medicine in China for treatment of convulsion, rheumatism, and jaundice. Here, the infrared determination of gentiopicroside, swertiamarin, sweroside, and loganic acid in G. rigescens from different areas and varieties was presented for the first time. Reference information for the iridoids were obtained by high-performance liquid chromatography. Partial least squares was used to characterize the relationship between spectra matrix and concentration vector for the determination of the analytes. For determination of gentiopicroside, the appropriate performance of partial least squares model was acquired with coefficient of determination of calibration and coefficient of determination of prediction values of 0.965 and 0.868. The root mean square error of estimation (RMSEE), root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP), and residual predictive deviation (RPD) values were 2.612, 5.292, 5.239?mg g^?1, and 2.701, respectively, based on the first derivative and multiplicative scatter correction. For determination of the total iridoids, the best results were obtained using the coefficient of determination of calibration and coefficient of determination of prediction of 0.943 and 0.834, RMSEE, RMSECV, RMSEP and RPD of 3.896, 7.536, 6.543?mg g^?1 and 2.438, respectively, based on the first derivative. Both models were reliable and robust. The results demonstrated that infrared spectroscopy provided a rapid, low-cost tool to monitor the quality of G. rigescens by the determination of the iridoids.     

New approaches to stereo- and regiocontrolled transformation of linear isoprenoids

New approaches suggested by the authors to the selective transformation of isoprene, 3-methylbut-3-en-1-ol, 6-methylhept-5-en-2-one and the series of monoisoprenoids into functionalized derivatives, which were used as the synthetic building blocks for the formation of naturally occurring terpenes, are reviewed.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1423–1448, August, 1995.     

Polar compounds from Parentucellia viscosa (L.) Caruel from Sardinia

In this work, we examined a sample of Parentucellia viscosa from Sardinia island, showing similarities and differences of the secondary metabolite content with respect to previous study conducted on an accession of continental origin, and also with Bellardia trixago, a species very close to Parentucellia. In this aspect, the proximity between these species, previously stated by a phylogenetic study, was confirmed by a phytochemical approach. Within the non-iridoidic fraction a chiral polyol (mannitol) and two aromatic acids (benzoic acid and gallic acid) were evidenced. These two acids are not common in Scropulariaceae since they have been reported only from a few species, and it is worth to note that gallic acid was never reported from the Orobanchaceae family.