Ozonolysis of dipterocarpol and its derivatives

Oxidation of dipterocarpol and its derivatives with ozone gave compounds containing lactone, lactol, alkoxytetrahydrofuran, aldehyde, and methyl ketone fragments in the side chain, as well as 1,2,4-trioxolane fragment in the A ring. The molecular and crystalline structures of dipterocarpol were determined by X-ray analysis.     

Polymeric coumarin derivatives

Summary Copolymers of vinylpyrrolidone with coumarin, umbelliferone, esculetin, osthole, ostholic acid, meranzin hydrate, isoimperatorin, oxypeucedanin hydrate, isooxypeucedanin, gosferol, pranchimgin, and marmesin have been synthesized and their structures have been studied.On the basis of a study of UV, IR, and NMR spectra, and also of chemical properties, it has been established that copolymerization takes place at the 3,4 double bond of the lactone ring and side chains do not participate in polymerization.In a pharmacological study of monomeric coumarins and their copolymers it was found that they all possess well-defined spasmolytic and hypotensive properties.Leningrad Sanitary-Hygienic Medical Institute. Institute of Macromolecular Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 714–720, November–December, 1974.     

A new diarylheptanoid and a rare dammarane triterpenoid from <Emphasis Type="Italic">Alnus nepalensis</Emphasis>

A new diarylheptanoid, a rare dammarane triterpenoid, and centrolobol were isolated from the leaves of Alnus nepalensis D. Don (Betulaceae). Their structures were determined by using spectroscopic analysis.     

Polymeric dressing formulations containing water-soluble fullerene derivatives

The effect of small additions of water-soluble fullerene C₆₀ derivatives on the strength properties of polyvinyl alcohol films was examined. Solutions of polyvinyl alcohol and fullerenol were tested as polymeric dressing formulations for glass-reinforced plastics based on a thermoplastic polyethylene or polyamide matrix.     

Synthesis of triterpenoid derivatives and their anti-tumor and anti-hepatic fibrosis activities

Abstract

Oleanolic acid (1), ursolic acid (2), hederagenin (3), betulinol (4), betulinic acid (5), and glycyrrhetinic acid (6) are obtained from acorn/licorice industrial wastes with common triterpenoid structure as a model set for esterification. Eight 3,4,5-methoxybenzoyl triterpenoid derivatives (1a–6a), including four new derivatives (1a, 3a–1, 3a–2, and 3a–3), are synthesized by classical procedures. Their antitumor and anti-hepatic fibrosis activities are evaluated on four human tumor cell lines and t-HSC/Cl-6 cells. Derivative 1a shows maximum antiproliferative effects against all cell lines, especially against tumor cells with IC₅₀ values in the range of 5.32–15.23?μM, but does not affect the viability of normal cells. The anti-tumor mechanisms of 1a are also investigated by western blot and docking studies. The 3,4,5-methoxybenzoyl triterpenoids offers an intriguing solution for naturally derived antitumor drugs and may be invaluable for further development of cancer therapy.     

Glycosylation of triterpenoids of the dammarane series. IV. β-D-glucopyranosides of betulafolienetriol and its derivatives

The glycosylation of betulafolienetriol (dammar-24-ene-3,12,20(S)-triol) under the conditions of the Koenigs-Knorr, the Helferich, and the orthoester methods has been studied. It has been shown that the condensation of -folienetriol and its 3-epimer with -acetobromoglucose in the presence of silver oxide leads to a mixture of the corresponding 3-, 12-, and 20-mono- and 3,12- and 3,20-di-O--pD-glucopyranosides. It has been established that the glycosylation of dammar-24-ene-3,12,20(S)-triol under Helferich's conditions and those of the orthoester method is accompanied by a side reaction of dehydration in the side chain and leads to 20-dehydroxy derivatives. The structures of all the newly obtained compounds have been established on the basis of the results of IR and of¹H and¹³C NMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Science Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 301–312, May–June, 1986.     

Podocarpaside, a triterpenoid possessing a new backbone from Actaea podocarpa

Podocarpaside (1), a novel arabinoside possessing a unique triterpene skeleton was isolated from Actaea podocarpa, a closely related species to black cohosh (dietary supplement used for menopausal disorders). Podocarpaside belongs to a new class of triterpenoids, for which the name "ranunculane" is proposed. Compound 1 possesses anticomplement activity. [structure: see text].     

Renchanglactone A, a new triterpenoid lactone from Kadsura renchangiana

From the stems of Kadsura rechangiana, a new triterpenoid lactone named renchanglactone A (1), was isolated together with four known triterpenoids, kadsulactone A, mawuweizic acid, ganwuweizic acid and kadsuric acid. Their structures were determined by spectroscopic methods including 2D-NMR techniques.     

Polymeric micelle systems of hydroxycamptothecin based on amphiphilic N-alkyl-N-trimethyl chitosan derivatives

This research investigated the possible utilization of amphiphilic N-octyl-N-trimethyl chitosan (OTMCS) derivatives in solublization and controlled release of 10-hydroxycamptothecin (10-HCPT), a hydrophobic anticancer drug. The release behavior of the 10-HCPT-OTMCS micelles was measured and compared to that of a commercial 10-HCPT lyophilized powder in vitro and in vivo. This research also examined the effects of chemical structure of the chitosan derivatives and the micellar preparation conditions on the encapsulation efficiency, drug loading content, and particle size of the polymeric micelles. The results showed that these chitosan derivatives were able to self-assemble and form spherical shape polymeric micelles with an average particle size range of 24–280 nm and a drug loading content of 4.1–32.5%, depending on the modified structures and loading procedures. The solubility of 10-HCPT in aqueous fluid was increased about 80,000-fold from 2 ng/ml in water to 1.9 mg/ml in OTMCS micellar (degree of octyl and trimethyl substitution is 8% and 54%, respectively) solution. In addition, OTMCS was able to modulate the in vitro release of 10-HCPT and improve its pharmacokinetic properties and lactone ring stability in vivo. These data suggested the possible utilization of the amphiphilic micellar chitosan derivatives as carriers for hydrophobic drugs for improving their delivery and release properties.     

Fibrarecisin, a novel triterpenoid from Fibraurea recisa with antitumor activity

Fibrarecisin (1), a novel triterpenoid, was isolated from chloroform extract of the stem bark of Fibraurea recisa Pierre. Its structure was elucidated by spectroscopic methods. Compound 1 exhibited significant antitumor activity in vitro against A-549 cancer cell at 10 microM by SRB and MTT methods.     

Cecropiacic acid, a new pentacyclic A-ring seco triterpenoid from .

From the methylated polar extract of stem bark of (Cecropiaceae) a novel triterpenic A-ring seco derivative has been obtained and the structure elucidated by spectroscopic methods.     

Schisanlactone G,a new 3,4-seco-lanostane triterpenoid from Schisandra sphenanthera

A new 3,4-seco-lanostane triterpenoid,schisanlactone G (1),was isolated from the fruits of Schisandra sphenanthera.Its structure was established on the basis of extensive spectroscopic analysis.2009 Rong Tao Li.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All fights reserved.     

Polymeric arylsulfonylmethyl isocyanide,a novel polymer reagent

p-Vinylphenylsulfonylmethyl isocyanide (1M) was synthesized starting with sodium p-styrenesulfinate via p-vinylphenylsulfonylmethylformamide (4M). Free-radical polymerization of 1M provided cross-linked insoluble polymers (1), whereas 4M provided soluble polymers, which could be converted to soluble polymer 1. Conversions of carbonyl compounds to nitriles and Schiff bases to 1,5-disubstituted imidazoles with both soluble and cross-linked polymers 1 as reagents proceeded almost as efficiently as with their low molecular weight analog. Reusability of polymer 1 was fairly good.     

Pristimerin, a triterpenoid, inhibits tumor angiogenesis by targeting VEGFR2 activation

Pristimerin is a triterpenoid isolated from Celastrus and Maytenus spp. that has been shown to possess a variety of biological activities, including anti-cancer activity. However, little is known about pristimerin's effects on tumor angiogenesis. In this study, we examined the function and the mechanism of this compound in tumor angiogenesis using multiple angiogenesis assays. We found that pristimerin significantly reduced both the volume and weight of solid tumors and decreased angiogenesis in a xenograft mouse tumor model in vivo. Pristimerin significantly inhibited the neovascularization of chicken chorioallantoic membrane (CAM) in vivo and abrogated vascular endothelial growth factor (VEGF)-induced microvessel sprouting in an ex vivo rat aortic ring assay. Furthermore, pristimerin inhibited the VEGF-induced proliferation, migration and capillary-like structure formation of human umbilical vascular endothelial cells (HUVECs) in a concentration-dependent manner. Mechanistic studies revealed that pristimerin suppressed the VEGF-induced phosphorylation of VEGF receptor 2 kinase (KDR/Flk-1) and the activity of AKT, ERK1/2, mTOR, and ribosomal protein S6 kinase. Taken together, our results provide evidence for the first time that pristimerin potently suppresses angiogenesis by targeting VEGFR2 activation. These results provide a novel mechanism of action for pristimerin which may be important in the treatment of cancer.