The tyrosinase inhibitory activity of methanol extracts of the leaves of 39 plant species growing on the seashore of Iriomote island (Okinawa, Japan) was investigated. The extracts of Hibiscus tiliaceus, Carex pumila, and Garcinia subelliptica showed potent activity among them. The inhibitors in the extract of Garcinia subelliptica were purified by assay-guided fractionation to give two biflavo...

Chlorophyll-type contaminants are commonly encountered in the isolation and determination of flavones of plant aerial plant parts. Heme is also a difficult background substance in whole blood analysis. Both chlorophyll and heme are porphyrin type compounds. In this study, a rapid method for isolating flavones with 5-hydroxyl or ortho-hydroxyl groups from biological samples was developed based o...

Within the secondary metabolite class of flavonoids, which consist of more than 10,000 known structures, flavones define one of the largest subgroups. The diverse function of flavones in plants as well as their various roles in the interaction with other organisms offers many potential applications including in human nutrition and pharmacology. We used two genes, flavone synthase (PFNS-1) that ...

T he m ajo r constituent of the yellow frond exudate of the fern Notholaena sulphurea was iden tified by spectroscopic m ethods as 3 ,5 ,2 '-trihydroxy-7-m ethoxy-8-acetoxy flavone and its struc tu re was confirm ed by synthesis. This novel natural flavonoid was also de tected in the frond exudate of five o ther Notholaena species. In the yellow form of N. sulphurea, the rare 5 ,2 'dihydroxy-7,...

Rye Primary Leaf, Phenylalanine Ammonia-Lyase Inhibitor, 2-Aminoindan-2-phosphonic Acid, Photosystem II Damage, Ultraviolet-B In the epidermal layers of rye primary leaves two flavone glycosides and several hydroxycinnamoyl esters are localized, whereas the mesophyll contains two flavone glucuronides and two anthocyanins. The concentrations of all these potential UV-B protective phenylpropanoid...

Flavones correspond to a flavonoid subgroup that is widely distributed in the plants, and which can be synthesized by different pathways, depending on whether they contain C- or O-glycosylation and hydroxylated B-ring. Flavones are emerging as very important specialized metabolites involved in plant signaling and defense, as well as key ingredients of the human diet, with significant health ben...