(±) Erysectin A, a new isoprenylated isoflavone with a rare acetonyl group from Erythrina secundiflora Hassk

(±) Erysectin A (1), a new isoprenylated isoflavone with a rare acetonyl group, along with 15 known compounds including eight isoprenylated isoflavones (2-9), two isoprenylated flavanones (10-11), three flavanones (12-14), a flavone (15), and a chalcone (16), was isolated from the twigs and leaves of Erythrina secundiflora Hassk. Their structures were identified based on their 1 D and 2 D NMR spectral data. All the compounds were isolated from this plant for the first time. Compound 1 showed moderate cytotoxicity on several cancer cell lines.

Bio- and chemo- transformations of glabranin and 7-O-methylglabranin and cytotoxic evaluations of the transformed products

The biotransformation of glabranin (1) with Aspergillus niger and Cunninghamella blakesleeana favoured the formation of benzofuran derivatives (3 and 4), while in contrast, its acid-catalysed chemical transformation favoured the formation of benzopyran derivatives (6 and 7). Compound 6 was further biooxidised at C-4'. Biotransformation of 7-O-methylglabranin (2) proceeded via oxidation of the prenyl group and C-4' by the same fungi, and the obtention of 11 mimics the biosynthesis of this last compound. Some compounds displayed moderate antiproliferative activity against selected human cancer cell lines, with glabranin being the most active, suggesting that the prenyl group and the phenol at C-7 are important structural determinants for cytotoxicity.

Transformation of 8-prenylnaringenin by Absidia coerulea and Beauveria bassiana

Beauveria bassiana AM278 and Absidia coerulea AM93 converted 8-prenylnaringenin (1) into two glycoside derivatives (7-O-β-D-glucopyranoside) (2) and 7-O-β-D-4'''-O-methylglucopyranoside) (3) in high yields in processes conducted in Saboraud medium. 8-Prenylnaringenin 7-O-β-D-4'''-O-methylglucopyranoside (3) is a new compound. 8-Prenylnaringenin-7-sulfate (4) was obtained in transformation of 1 by Absidia coerulea AM93 in a buffer. Formation of conjugated products in this study proceeds in a manner analogous to mammalian systems which indicates the potential use of microbes to mimic mammalian metabolism.

Constituents from the Leaves of Phellodendron amurense and Their Antioxidant Activity

Three new coumarins, phellodenols F-H (1-3) and a new glutaric acid derivative, phellodendric acid-A (4) were isolated from the leaves of Phellodendron amurense together with twenty-nine known compounds. Extensive 1D and 2D NMR experiments and other spectroscopic studies were employed to determine the structures of 1-4. The isolated compounds were screened for their antioxidant activity through DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) radical scavenging assay. Compounds quercetin, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-D-galactoside and kaempferol-3-O-beta-D-glucoside demonstrated significant radical scavenging activity comparable to vitamin E.

Furanoflavonoids: an overview

The review covers the phytochemistry and pharmacology of furanoflavonoids describing 291 compounds and containing 228 references.

Constituents of Leaves of Phellodendron japonicum MAXIM. and Their Antioxidant Activity

Three new flavonoid derivatives, 6'''-O-acetyl amurensin (1), 6'''-O-acetyl phellamurin (3) and (2R)-phellodensin-F (5), together with thirty known compounds have been isolated from the leaves of Phellodendron japonicum MAXIM. Their structures were established by means of spectroscopic analysis, including extensive 2D NMR and Mass spectra. The known compounds were identified by comparison with published physical and spectral data. The isolated compounds were screened for their in vitro antioxidant activity through DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. Compounds quercetin and phellodenin-A demonstrated significant radical scavenging activity.