Chemopreventive effects of Peucedanum praeruptorum DUNN and its major constituents on SGC7901 gastric cancer cells

In this study, the effects of Peucedanum praeruptorum DUNN methanolic extract (PPME) and its major constituents on SGC7901 human gastric cancer cells were evaluated. Two pyranocoumarins, namely, (±) praeruptorin A (PA) and (±) praeruptorin B (PB), were isolated from PPME. A high performance liquid chromatographic (HPLC) method was developed to determine the contents of PA and PB in PPME. The anti-proliferative and cytotoxic actions of PPME were observed using the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and release of lactate dehydrogenase (LDH) assays. At 300 μg/mL, PPME inhibited cell growth by 51.2% (P < 0.01), probably linked to the high concentration of PA and PB. Both PA and PB exhibited antiproliferative and cytotoxic activities on the SGC7901 cells. Furthermore, the active principle compound, PA, also enhanced the actions of doxorubincin (DOX) on SGC7901 cells. Cell growth decreased higher with the combined treatment of PA and DOX than that with the chemotherapy agent applied alone, suggesting that PA could reduce the dose of DOX for the desired effects.     

Potential of radioiodinated anti cancer compounds of natural origin for cancer therapy

Plumbagin and Quercetin are naturally occurring compounds which exhibit anti-cancerous activity. To evaluate the effect of radioiodination on cytotoxicity, both Plumbagin and Quercetin were radioiodinated with ¹²⁵I ¹²⁵I-Plumbagin and ¹²⁵I-Quercetin could be prepared in moderate yields and good radiochemical purity and were charactenzed using reverse phase HPLC. In Swiss mice bearing fibrosarcoma, ¹²⁵I-Plumbagin showed a tumor uptake of ∼2.5%ID/g at 3 h p.i. and ∼0.5% ID/g at 24 h p.i. on i.v. injection. When injected intratum orally, greater tumor uptake and retention was observed (∼20%ID/g at 3 h p.i. and ∼14%ID/g at 24 h p.i. respectively).     

Transformation of natural compounds

-Piperazinylmethylenedeoxyvasicinones have been synthesized by the interaction of -hydroxymethylenedeoxyvasicinones with various N-substituted piperazines.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 62 70 71. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 331–333, May–June, 1998.     

Adhesive compounds based on natural rubber,modified by nitrogen-containing compounds

The possibility of modifying adhesive compounds based on natural rubber by nitrogen-containing adhesion promoters has been studied. It was shown that the properties of modified adhesive compounds based on natural rubber are comparable to those of adhesive compounds based on polychloroprene, as well as that the implementation of the elaborated technology will enable one to obtain high-strength constructions based on different rubbers.     

PMR spectra of natural stilbene compounds

1. The PMR spectra of 13 natural stilbenes have been studied. 2. The dominating role of π-electron interaction of the fragments of the stilbene molecule in the screening of the aromatic and olefinic protons has been shown. A series of increments presenting interest for determining the structure of stilbene compounds is proposed.     

CEC and EKC of natural compounds

In this review, an overview of CEC and EKC methods with their developments are summarized for different natural compounds. It is divided into three main parts. The first part elaborates the separation of lipophilic compounds without any charged groups. The second part constitutes CEC and EKC of lipophilic compounds containing ionizable functional groups whereas the third part contains hydrophilic compounds. Packed, monolithic, coated, or raw fused-silica (FS) capillaries are among the choice for stationary phases. Applications of these phases on the above-mentioned three classes of compounds, coupled with different detection methods, e.g. MS or LIF, are explored and their advantages and disadvantages are discussed.     

PMR spectra of natural stilbene compounds

Summary 1. The PMR spectra of 13 natural stilbenes have been studied.2. The dominating role of -electron interaction of the fragments of the stilbene molecule in the screening of the aromatic and olefinic protons has been shown. A series of increments presenting interest for determining the structure of stilbene compounds is proposed.3. It has been established that the nature and nature and number of the substituents in the aglycone part of the molecule have no influence on the screening of the anomeric proton of glycosidated stilbenes, but it does depend on the position of attachment of the carbohydrate fragment.A. A. Zhdanov Irkutsk State University. Irkutsk Institute of Organic Chemistry, Siberian Branch of the Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–10, January–February, 1976.     

DTA of natural and synthetic uranium compounds

A brief outline of structural considerations is given, concerning compounds one can meet as secondary uranium minerals. The authors report the thermal analysis of minerals deposited at the National Museum Collection in Prague. Three different types of instruments were used: a MOM derivatograph, a Netzsch DTA equipment, and an instrument constructed according to Rosický for microspecimens. The thermal analysis results were correlated with X-ray structure analysis and infrared spectra analysis data. The examples applied were: synthetic rutherfordine and related compounds, synthetic andersonite and the minerals liebigite and schoeckingerite, and synthetic schoepite.

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Zusammenfassung Ein kurzer Bericht über strukturelle Erwägungen bezüglich sekundärer Uraniumerz-Verbindungen wird gegeben. Es werden an die durch thermoanalytische Überprüfung der in der Sammlung des Nationalmuseums zu Prag befindlichen Erze gewonnenen Erfahrungen mitgeteilt. Drei verschiedene Typen von Geräten wurden eingesetzt: der Derivatograph MOM, die DTA-Vorrichtung Netzsch und ein nach Rosický gebautes Gerät für Mikroproben. Die Ergebnisse der Thermoanalyse wurden mit den Daten der Röntgen-Strukturanalyse und denen der Analyse des Infrarotspektrums in Zusammenhang gebracht. Als Beispiele wurden synthetisches Rutherfordin und verwandte Verbindungen, synthetisches Andersonit, sowie die Erze Liebigit und Schoekingerit und synthetisches Schopit verwendet.

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Résumé Un bref rappel sur les considérations structurales concernant les composés que l'on peut rencontrer comme minéraux secondaires d'uranium est donné. Les auteurs ont eu l'intention de faire partager leur expérience acquise lors de la révision des minéraux déposés dans la Collection du Musée National de Prague, à l'aide de l'analyse thermique. Trois types d'instruments ont été utilisés le Derivatograph MOM, l'appareil ATD Netsch et un instrument construit d'après Rosický, pour l'étude de microéchantillons. On a établi une corrélation entre les résultats de l'analyse thermique et ceux obtenus lors des analyses de structures par rayons X et par spectroscopie infrarouge. Les exemples cités concernent la rutherfordine synthétique et les composés analogues, l'andersonite synthétique, ainsi que les minéraux liebigite et schoeckingérite et la schopite synthétique.

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NMR-13C specteoscopy of natural compounds

Russian Chemical Bulletin -     

Chemistry of natural compounds and bioorganic chemistry

The racemic form of the metabolite of theDysidea sea sponge, furanoterpenoid pallescensin A, was synthesized by cationic cyclization of the sulfonyl-substituted linear sesquiterpene precursors. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2060–2064, November, 1997.     

紫草萘醌类物质与巯基亲核试剂的反应研究

从中药紫草中提取了其主要有效成分β,β-二甲基丙烯酰阿卡宁,研究了其与含巯基亲核试剂的反应,探讨了这类反应的作用机制。     

天然化合物的分子工程研究新进展

分子天然化合物的研究主要指的是在分子水平上得到天然化合物的新方法,即天然产物的遗传工程合成和仿生合成。本文总结和评述了这方面近年来研究所取得的进展。     

Chemopreventive action of xanthone derivatives on photosensitized DNA damage

Photosensitized DNA damage participates in solar-UV carcinogenesis, photogenotoxicity and phototoxicity. A chemoprevention of photosensitized DNA damage is one of the most important methods for the above phototoxic effects. In this study, the chemopreventive action of xanthone (XAN) derivatives (bellidifolin [BEL], gentiacaulein [GEN], norswertianin [NOR] and swerchirin [SWE]) on DNA damage photosensitized by riboflavin was demonstrated using [32P]-5'-end-labeled DNA fragments obtained from genes relevant to human cancer. GEN and NOR effectively inhibited the formation of piperidine-labile products at consecutive G residues by photoexcited riboflavin, whereas BEL and SWE did not show significant inhibition of DNA damage. The four XAN derivatives decrease the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), an oxidative product of G, by photoexcited riboflavin. The preventive action for the 8-oxodGuo formation of these XAN derivatives increased in the following order: GEN>NOR>BEL>SWE. A fluorescence spectroscopic study and ab initio molecular orbital calculations suggested that the prevention of DNA photodamage is because of the quenching of the triplet excited state of riboflavin by XAN derivatives through electron transfer. This chemoprevention is based on neither antioxidation nor a physical sunscreen effect; rather, it is based on the quenching of a photosensitizer. In conclusion, XAN derivatives, especially GEN, may act as novel chemopreventive agents by the quenching mechanism of an excited photosensitizer.     

Stereochemical aspects of organic sulphur compounds of natural derivation

Selected groups of chiral, tri- and tetra-co-ordinate sulphur compounds are briefly discussed in a historical context. Special attention is given to naturally derived sulphonium salts, sulphoxides, and sulphoximides, and to certain stereochemical problems associated with their structures. The fruitful alliance between biochemistry and stereochemistry, also in studies of sulphur compounds, is emphasized and illustrated. Possible subjects for future studies are adumbrated.     

Investigation of the effects of natural compounds isolated from Arum rupicola var. rupicola on glutathione reductase enzyme purified from bovine liver

Glutathione reductase (GR, E.C. 1.8.1.7), a flavoenzyme, is responsible for recycling of oxidized glutathione disulfide. This study was performed in two main sections. In the first GR was purified from bovine liver by affinity column chromatography and the purification rate and specific activity of the enzyme were calculated as 1832‐fold and 141 EU/mg protein, respectively. The subunit molecular weight of the enzyme was determined as 55 kDa by means of SDS–PAGE. The second section isolated natural components of Arum rupicola Boiss. var. rupicola using column chromatography. The isolation protocol for this plant was performed with a series of different‐sized columns with hexane–ethyl acetate. According to the thin‐layer chromatography plate, seven substances (R1–R7) were isolated. Our study's aim was to find new activators or inhibitors for GR activity. With this aim, all isolated substances were tested for GR activity. R6 showed competitive inhibition, while R4 had noncompetitive inhibition of GR activity. R1 played a role as an activator of GR activity. The inhibitory activity percentage vs. concentration graph was plotted. Values of IC₅₀ for R4 and R6 were calculated as 0.193 mg/mL and 3.98 μg/mL, respectively, from the equation of this graph.