Showing papers on "Flavanone published in 1987"

Flavonoids from Andrographis paniculata

Abstract: A new flavanone glucoside, named andrographidine A (1), and five new flavone glucosides, named andrographidines B (2), C (3), D (4), E (5) and F (6), were isolated from the root of Andrographis paniculata. Their structures were determined on the basis of spectral data, especially carbon-13 and proton nuclear magnetic resonance spectra, and chemical derivatization. They have uncommon O-substitution patterns involving 5-, 7-, 8-, 2'-, 3'-and 4'-O-substituents.

Medicinal plants of Southern Africa. Part 1. Dimeric chalcone-based pigments from Brackenridgea zanguebarica

Abstract: From the bark of Brackenridgea zanguebarica four novel biflavonoids have been identified. These include a chalcone-benzofuran dimer, its dihydrobenzofuran derivative, a known dimeric flavanone, and a chalcone-flavanone dimer.

Effect of flavanone on mixed-function oxidase and conjugation reactions in rats.

Abstract: 1. Flavanone administered to female Fischer 344 rats (1.00mmol/kg per day for seven days) did not induce ethylmorphine demethylation, aniline hydroxylation, hexobarbital oxidation or aldrin epoxidation.2. Flavanone at 0.05mmol/kg per day for seven days increased glutathione-S- transferase activity with 1,2-dichloro-4-nitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy) propane as substrates.3. Flavanone at 0.05 mmol/kg per day for seven days increased the glucuronidation of 1-naphthol, and at 0.20 mmol/kg increased the glucuronidation of chloramphenicol.4. Flavanone administration did not alter sulphotransferase activity with 2-naphthol as the substrate and did not enhance glutathione-S-transferase or glucuronyltransferase activity when added in vitro.

A New Prenylated Flavanone from Erythrina suberosa Roots.

Abstract: The roots of ERYTHRINA SUBEROSA were found to contain a new prenylated flavanone by combined physico-chemical studies

Two novel flavanones, methyllinderatone and isolinderatone, from lindera umbellata thunb. var. membranacea (maxim.) momiyama

Abstract: From the fresh leaves of Lindera umbellata Thunb. var. membranacea (Maxim.) Momiyama two new flavanones, methyllinderatone (1) and isolinderatone (2), were isolated. Their structures were established by chemical and spectroscopic means.

Flavonoids of Tephrosia procumbens—revised structure for praecansone A and conformation of praecansone B

Abstract: Two rotenoids (rotenone and sumatrol), a flavanone (obovatin), a β-diketone (praecansone B), and its isomeric methyl ether (praecansone A) have been isolated from the chloroform extract of roots of Tephrosia procumbens. Furthermore, an unusual flavonol (7-ethoxy-3,3′,4′-trihydroxyflavone; fisetin 7-ethyl ether) and an isoflavone (7,4′-dihydroxy-3′-methoxyisoflavone) have been isolated from an ethyl acetate fraction of the alcoholic extract of the roots. The structures of all the compounds were established spectroscopically.The structure of praecansone A has been revised as (3) on the basis of 13C and 1H n.m.r. data, and confirmed by an n.O.e. experiment. The possible conformations of praecansone B in CDCl3 are discussed on the basis of 1H n.m.r. data and D2O-exchange studies.

Flavonoids of Ammothamnus lehmannii. Structure of lehmannin and of ammothamnidin

Abstract: The new flavanon lehmannin (I) has been isolated from the roots ofAmmothamnus lehmannii Bunge. On the basis of chemical transformations and with the aid of physicochemical characteristics it has been established that compound (I) has the structure of 2′,4′,7-trihydroxy-8-(2″-isopropenyl-5″-methylhex-4″-enyl)flavanone. The alkaline cleavage of lehmannin gave ammothamnidin (V). The structure proposed previously for the chalcone ammothamnidin has been corrected. It has been shown that it has the structure of 2,2′-4,4′-tetrahydroxy-3′-(2″-isopropenyl-5″-methylhex-4″- enyl)chalcone. A comparative study of the13C NMR spectra of a number of flavanones has revealed an empirical law permitting the prediction of the presence or absence of substituents (OH and OCH3) at C-2′ from the value of the chemical shift of the signal of the C-2 carbon atom.

Synthesis and characterization of homoeriodictyol and its five analogs of b-ring

Abstract: The preparation and structure characterization of homoeriodictyoland its five analogs of B-ring were described.Five of them possessed inhibitoryeffect on platelets aggregation and increased coronary flow.Three of them areunreported compounds.

Synthesis of n-isonicotinoyl flavanone hydrazones as possible antibacterial and antitubercular agents.

Abstract: Some N-isonicotinoyl flavanone hydrazones (IIIa-f) have been synthesized by condensing isonicotinic acid hydrazide (INH,II) with suitably substituted chalcones (Ia-f) at pH 4.2 (approx). The compounds when screened in-vitro, exhibited recordable antitubercular activity.