In an attempt to study the biological activities of flavonoids, a flavone, flavanone and series of chalcones were synthesized and characterized by IR and 1 H NMR and elemental analysis. All the targeted compounds were screened for their antibacterial activity against Bacillus cereus, Enterococcus faecalis, Kleibsiella pneumonia and Pseudomonas aeroginosa and antifungal activity against Aspergil...

Two new flavanone glucosides, (2R)- and (2S)-5-O-beta-D-glucopyranosyl-7,4'-dihydroxy-3',5'-dimethoxyflavanone[pervianoside I (3), peruvianoside II(4)] and a new flavonol glycoside, quercetin 3-O-[beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-galactopyranoside] (peruvianoside III, 13) were isolated from the leaves of Thevetia peruviana Schum., together with nine known f...

The ethyl acetate extract of the stem bark of Erythrina abyssinica showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC(50) values of 7.9+/-1.1 and 5.3+/-0.7 microg/ml, respectively. From this extract, a new chalcone, 2',3,4,4'-tetrahydroxy-5-prenylchalcone (trivial name 5-prenylbutein) and a new flavanone...

Streptomyces graminofaciens BA14348, isolated from a soil sample, was found to produce new specific inhibitors of estrogen binding to its receptor. Five related substances, BE-14348A approximately E, were isolated, and their structures were determined by analyses of spectral properties. Of these substances, A was identical with the known flavanone, naringenin. On the other hand, B, C, D and E w...

A new flavanone, 7-hydroxy-5,6-dimethoxyflavanone (1), together with three other flavonoids, didymocarpin (2), 2',4'-dihydroxy-5',6'-dimethoxychalcone (3), and isodidymocarpin (4), had been isolated from the methanol extract of the tree bark of Cryptocarya costata. The structures of these compounds were determined based on spectral evidence, including UV, IR, 1-D and 2-D NMR, and mass spectra. ...

Five geranylflavonoids, one prenylated flavonoid, and a simple flavanone were isolated from an ethanolic extract of Paulownia tomentosa fruit. Tomentodiplacol (1), 3'-O-methyl-5'-methoxydiplacol (2), 6-isopentenyl-3'-O-methyltaxifolin (3), and dihydrotricin (4) are reported from a natural source for the first time and 3'-O-methyldiplacone (6) for the first time from the genus Paulownia. The str...