Synthesis of analogs of natural isoflavones from 2,4-dihydroxydeoxybenzoins

A number of analogs of natural isoflavones have been synthesized. The starting materials were 2,4-dihydroxydeoxybenzoins obtained under modified conditions of the Houben-Hoesch reaction. The yields of the isoflavones synthesized were 63–69%. All the analogs of natural flavones possess a pronounced hypolipidemic action.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 781–784, November–December, 1985.     

Synthetic and modified isoflavonoids XVIII. Synthesis of 7-isopropoxy-substituted analogs of pseudobaptigenin

7-Isopropoxy derivatives of isoflavones have been synthesized from 1,3-benzodioxole, 1,4-benzodioxane, and 1,4-benzodioxepane analogs of pseudobaptigenin. Their structures have been confirmed by PMR.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 365–369, May–June, 1997.     

Synthetic and modified isoflavonoids

Water-soluble diethanolamine and morpholine salts of derivatives of 1,3-benzodioxole, 1,4-benzodioxane, and 1,5-benzodioxepane analogs of isoflavones have been synthesized.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 306–312, May–June, 1998.     

Synthetic and modified isoflavonoids. I. Synthetic analogues of pseudo-baptigenin

New isoflavones derived from pseudobaptigenin containing alkyl substituents in position 6 have been synthesized. The structures of the compounds have been confirmed by PMR and IR spectroscopies.Taras Shevchenko Kiev University KIEN. and Karakalpak Division. Academy of Sciences of the Republic of Uzbekistan, Nukus. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 669–674, September–October, 1993.     

Synthetic and modified isoflavonoids XVI. The interaction of synthetic isoflavone analogs with hydroxylamine

Under the action of hydroxylamine, 1,3-benzodioxolane, 1,4-benzodioxane, and 1,5-benzodioxepane analogs of isoflavones recyclize into 5-(2-hydroxyphenyl)isoxazole derivatives. Their structures have been shown by their PMR spectra.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 633–636, September–October, 1994.     

Basicity constants of natural isoflavonoids

The basicities (pK_BH+) of 13 natural isoflavones have been determined spectrophotometrically in sulfuric acid solutions. It has been shown that the change of basicity in this series of compounds depends on the geometry of the molecules and on intramolecular effects.All-Union Scientific-Research Institute of Drug Chemistry and Technology, Khar'kov. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 773–775, November–December, 1985.     

Spectrophotometric determination of flavones and isoflavones inThermopsis alterniflora

A spectrophotometric method has been developed for the quantitative separate determination of the total flavonones and isoflavones when they are present together in an extract ofThermopsis alterniflora.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 667–669, September–October, 1993.     

Interrelationships of the structures and antioxidant activities of some flavonoids from the plants of Central Asia

A study has been made of the influence 27 flavonoids on the processes involved in the peroxide oxidation of lipids. The interrelationship between the chemical structures of isoflavones, flavones, flavanones, and flavonols and their antioxidant activities is discussed.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 350–356, May–June, 1996. Original article submitted November 21, 1994.     

Chromatographic separation of isoflavones

The optimum ratios of the components of the solvent systems have been determined with the aid of the simplex-grid method of experimental planning and the separation of a number of isoflavones has been carried out with the aid of these systems in thin layers of silica gel (Silufol plates); in addition, the chromatographic constants of the functional groups have been determined, which makes it possible to obtain the R_f values of compounds under investigation in an analysis of plant material by a mathematical method.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 712–716, November–December, 1983.     

Chemistry of heteroanalogues of isoflavones. 15. Synthesis and study of the reaction of lanthanide

2-Ethyl substituted isoflavones have been synthesized. 7-Isopropyloxyisoflavones carrying 1,3-benzodioxole and 1,4-benzodioxan nuclei have been obtained from them. The spectral characteristics of the compounds obtained are discussed. The reaction of several of the products with various lanthanide shift reagents (LSR) has been studied. The preferred conformation of compounds in solution has been determined. It was shown that optically active LSR must not be used for obtaining quantitative data on the molecular conformation of a substrate due to the lack of effective axial symmetry in the adduct.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1631–1637, December, 1993.     

Atropo-isomerism and abnormal temperature dependence of paramagnetic shifts in 1H NMR spectra of heterocyclic analogs of isoflavones in the presence of lanthanide chelates

It has been found that spatially hindered analogs of isoflavones can occur as a mixture of atropo-isomers, which is conveniently detected by using optically active lanthanide shift reagents. It is shown that on lowering the temperature the individual shifts of the signals of the isoflavone protons can either increase or decrease. The observed anomalies are attributed to changes in the predominant conformations of the molecules as the temperature is varied.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 5, pp. 629–633, September–October, 1989.     

Simple Extraction and Rapid Quantitative Analysis of Isoflavones in Soybean Seeds

A simple extraction and rapid HPLC method, suitable to separate and quantify the isoflavonoids in soybean seeds, are proposed and discussed. The method has been applied to the separation and quantification of seed isoflavonoids in five naturally grown soy cultivars; the total amount of isoflavones ranged from 1.83 g kg^–1 to 11.88 g kg^–1 of fresh weight. The detection limits (200 g/kg^–1), evaluated for genistein and daidzein, are presented together with a list of the soy polyphenols analysed by HPLC-DAD and HPLC-MS.     

Quantitative determination of flavonoids in some representatives of the family Fabaceae

The quantitative composition of the combined flavonoids in the epigeal parts of eight representatives of the family Fabaceae (four species ofOnobrychis, two ofAstragalus, and two ofTrifolium) have been studied. For the quantitative estimation of the flavonoids we used a spectrophotometric method permitting the determination of flavonols and isoflavones when they are present simultaneously. A comparatively high content of flavonoids (from 2.37 to 4.13%) was found. The sum of the flavonoid compounds from the species ofOnobrychis, Astragalus, andTrifolium investigated possesses a hypolipidemic activity.Pyatigorsk Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 43–45, January–February, 1984.     

Amino acid derivatives of 2-R-7-hydroxy-3′,4′-ethylenedioxyisoflavones

A number of 7-O-aminoacyl derivatives of isoflavones have been obtained by the interaction of 2-R-7-hydroxy-3,4-ethylenedioxyisoflavones with the symmetrical anhydrides of N-protected amino acids.Kiev Tara Shevshenko University, Ukraine, 252033, Kiev, Ul. Vladimirskaya, 64, tel./fax 225-12-73. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 334–338, May–June, 1999.     

Solute–Solvent Interactions of Flavonoids in Organic Solvents

The diffusion coefficients of one flavone and five isoflavones in methanol, ethanol, 2-propanol, and acetonitrile were measured at 25°C by the Taylor–Aris dispersion method. The observed variations of the D values were interpreted in terms of solute–solvent hydrogen-bond interactions and the interpretation was supported by molecular dynamics simulations of two solutes in methanol.     

Chemistry of isoflavone heteroanalogs.

Benzodioxane analogs of chalcones were isomerized to the corresponding flavanones and isoflavones. The PMR and IR spectra of these compounds were discussed.For Communication 11, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 319–323, March, 1989.     

Chemistry of heteroanalogs of isoflavones 14. Isoxazole analogs of isoflavones

Isoxazole analogs of isoflavones have been synthesized by the cyclization of -(3-isoxazolyl)-2-hydroxyacetophenones. Their alkylation, acylation, and electrophilic substitution reactions, and reactions with binucleophiles have been studied. 3-(3-Isoxazolyl)-7-methoxychromones are rearranged selectively into 2-aminochromone derivatives by the action of hydroxylamine as a result of a double recyclization and are recyclized into pyrazole derivatives by hydrazine. Preparations with hypolipidemic, anabolic, hypoglycemic, and antiarrhythmic action are found among the derivatives of 3-(3-isoxazolyl)chromones.For Communication 13, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 29–39, January, 1993.     

Protein Binding Study of Isoflavones by High-Performance Frontal Analysis

High-performance frontal analysis was used for protein binding study of isoflavones (daidzein, genistin, and genistein) to human serum albumin. The analysis was performed on a Develosil 100-Diol-5 column (10 cm × 4.6 mm). Sodium phosphate solution (pH 7.4, ionic strength 0.17) was used as the mobile phase at a flow rate of 1 mL min^–1. UV wavelength was set at 260 nm. To ensure the drug to be eluted as a trapezoidal peak with a plateau, injection volumes of 700 L for daidzein and genistin, 900 L for genistein were chosen, respectively. Experimental data were fitted by Scatchard equation. The binding constants (K) and binding affinities (nK) of isoflavones to HSA were: K=1.581 × 10⁵ (L mol^–1), nK=0.77 × 10⁴ (L mol^–1) for daidzein, K=1.082 × 10⁵ (L mol^–1), nK=0.32 × 10⁴ (L mol^–1) for genistein, and K=3.533 × 10⁵ (L mol^–1), nK=0.70 × 10⁴ (L mol^–1) for genistin, respectively.     

Antibacterial Activities of Prenylated Isoflavones from Maclura tricuspidata against Fish Pathogenic Streptococcus: Their Structure-Activity Relationships and Extraction Optimization

Streptococcus zoonotic bacteria cause serious problems in aquaculture with clinical effects on humans. A structure-antibacterial activity relationships analysis of 22 isoflavones isolated from M. tricuspidata (leaves, ripe fruits, and unripe fruits) against S. iniae revealed that prenylation of the isoflavone skeleton was an important key for their antibacterial activities (minimum inhibitory concentrations: 1.95–500 μg/mL). Through principal component analysis, characteristic prenylated isoflavones such as 6,8-diprenlygenistein (4) were identified as pivotal compounds that largely determine each part’s antibacterial activities. M. tiricuspidata ripe fruits (MTF), which showed the highest antibacterial activity among the parts tested, were optimized for high antibacterial activity and low cytotoxicity on fathead minnow cells using Box–Behnken design. Optimized extraction conditions were deduced to be 50%/80 °C/7.5 h for ethanol concentration/extraction temperature/time, and OE-MTF showed contents of 6,8-diprenlygenistein (4), 2.09% with a MIC of 40 µg/mL. These results suggest that OE-MTF and its active isoflavones have promising potential as eco-friendly antibacterial agents against streptococcosis in aquaculture.     

Chemistry of heteroanalogs of isoflavones

Pyrazole analogs of isoflavones were synthesized from substituted -(4-pyrazolyl)-2,4-dihydroxyacetophenones.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1108–1111, August, 1976.