Prenylated Flavanones fromDerris laxiflora

Kangaroo Island propolis types originating from two Lepidosperma species and Dodonaea humilis

The endemic Australian plants Lepidosperma sp. Flinders Chase (Cyperaceae), Lepidosperma viscidum (Cyperaceae) and Dodonaea humilis (Sapindaceae) were found to be the botanical origin of three propolis types found on Kangaroo Island identified by TLC and ¹H NMR matching of propolis and plant resin analytical profiles. Resin samples extracted from the plant, Lepidosperma sp. Flinders Chase, were chromatographically fractionated to give: methyl 3-phenyl-2-(E-cinnamoyloxy)propanoate (1), 3-(E-8-methoxy-8-oxo-3,7-dimethyloct-2-enyl)-4-hydroxy-E-cinnamic acid (2), 3-(E-6,7-dihydroxy-3,7-dimethyloct-2-enyl)-4-hydroxy-E-cinnamic acid (3), previously undescribed; and the known stilbenes, 2-prenyl-3,5-dihydroxy-E-stilbene (6) and 2-prenyl-3-methoxy-5-hydroxy-E-stilbene (7). The resin from L. viscidum gave: 5'-(E-4-hydroxy-3-methylbut-2-enyl)-4,2',4'-trihydroxydihydrochalcone (4); 5'-(E-4-hydroxy-3-methylbut-2-enyl)-4'-methoxy-4,2'-dihydroxydihydrochalcone (5), previously undescribed; and three known flavanones, farrerol (8), 5,7,3',5'-tetrahydroxy-6,8-dimethylflavanone (9) and 5,7,3',5'-tetrahydroxy-6-methylflavanone (10). The major constituent in the propolis identified as being sourced from D. humilis was identified as 6,8-diprenyl-5,7,3',4'-tetrahydroxyflavanone (11), a known compound identified in several unrelated plant species.

α-Glucosidase inhibitory, antibacterial, and antioxidant activities of natural substances from the wood of Derris reticulata Craib

Derris reticulata (Leguminosae-Papilionoideae) has been used for the treatment of diabetes in Thai folk remedies. The phytochemical investigation of the wood of D. reticulata revealed the isolation of two new pyranoflavanones, 4'-methoxydereticulatin (1) and 2'''-hydroxy,3'''-ethoxylupinifolin (2), along with five known compounds namely lupinifolin (3), 2''',3'''-dihydroxylupinifolin (4), genistein (5), lupeol (6), and β-sitosterol (7). Compounds 1-4 were selected for antibacterial assay using broth microdilution method, and displayed good activity against four out of five tested pathogenic bacterial strains, with MIC values ranging from 0.78 to 128 μg/mL. The result from spectrophotometric assay of α-glucosidase inhibition showed that 5 exhibited promising α-glucosidase inhibitory activity, compared with the positive control acarbose. Additionally, it was found that compounds 4 and 5 showed moderate DPPH and NO radicals scavenging activity. Modeling studies were also performed to suggest the interaction modes of compounds 3-5 in the α-glucosidase enzyme active site.

Two new diprenylated flavanones from Derris laxiflora Benth

Phytochemical reinvestigation on the whole plants of Derris laxiflora Benth. afforded two new diprenylated flavanones, derriflavanones B and C (1-2), together with thirty-two known compounds, including sixteen flavonoids (3-18), eleven aromatic compounds (19-29), and five chlorophylls (30-34). All known compounds were first isolated from this plant. The structures of these compounds were determined by analysis of the NMR spectroscopy, mass data, IR spectra, UV spectra, optical rotation and by comparison with literature data.

Flavonoid Constituents of Pistacia integerrima

Pistacides A and B (1–2), two new flavonoid glycosides, have been isolated from the methanolic extract of the aerial parts of Pistacia integerrima, along with 2′-hydroxyisoorientin (3), echioidinin 2′- O-β-D-(6″- O-acetyl) glucopyranoside (4), chrysoeriol (5), and diandraflavone A (6), reported for the first time from this species. Their structures were elucidated by spectroscopic analysis including 2D NMR, FAB-MS, and acidic hydrolysis.

A new prenylated flavanone from the roots of Sophora flavescens

A new prenylated flavanone was isolated from the roots of Sophora flavescens. The structure of the new compound was elucidated as (2S)-7,4'-dihydroxy-5-methoxy-8-(gamma,gamma-dimethylallyl)-flavanone (1) on the basis of chemical and spectral evidence.