STUDIES ON THE PRENYLFLAVONOIDS PART V.SYNTHESIS OF(±)LESPEDEZAFLAVANONE D

(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxy- acetophenone with 2,4-dimethoxymethoxy-5-(γ,γ-dimethylallyl)benzaldehydc followed by cyclization and demethoxymethylation.

STUDIES ON THE PRENYLFLAVONOIDS PARTⅡ.SYNTHESIS OF EUCHRENONE A_7

Euchrcnonc a_7 has been prcparcd by condensation of 2-hydroxy-4- mcthoxy-3-prcnylacctophcnone with 2,4-dimethoxymethoxybenzaldehyde followed by cyclization and demethoxymethylation.

STUDIES ON THE PRENYLFLAVONOIDS PART Ⅲ.SYNTHESIS OF(±)EUCHRENONE A_8

(±)Euchrenonc a_8,7,2'-dihydroxy-8,5'-di(γ,γ-dimethylallyl)-4'-methoxyflavanone,has been synthesized by the condensation of 2-hydroxy-4-methoxymethoxy-3-(γ,γ-dimethylallyl) acctophenonc with 4-methoxy-2-methoxymethoxy-5-(γ,γ-dimethylallyl)benzaldchyde followed by cyclization and demethoxymethylation.

STUDIES ON THE PRENYLFLAVONOIDS PART X IX SYNTHESIS OF EXIGUAFLAVANONE K

K was first synthesized via the Condensation of 2-hydroxy-3-prenyl-4, 6-dimethoxymethoxyacetophenone 3- methoxy-4methoxymethoxybenzaldehyde followed by cyclixation

Two new prenylflavonoids from Morus nigra L.

Two new prenylflavonoids, momigrol E（1） and mornigrol F（2） were isolated from Morus nigra L. Their structures were elucidated on the basis of spectroscopic methods, especially 2D-NMR techniques.

Analysis of antioxidant prenylflavonoids in different parts of Macaranga tanarius,the plant origin of Okinawan propolis

Objective:To analyze the antioxidant prenylilavonoids in different parts of Macaranga tanarius(M.tanarius)(Euphorbiaceae)including the leaf,petiole,stem,leaflet,flower and fruit(only in female plant),and to evaluate their antioxidant properties.Methods:Methanol extracts of each part of M.tanarius were prepared and five prenylilavonoids in them were quantitatively analyzed using HPLC.The fruits from female plant were further separated into seed,pericarp,and glandular trichome.After the quantitative analyses of prenylflavonoids in each part of M.tanarius,antioxidant activity of the extracts was evaluated by 2,2-diphenyl-l-picryI-hydrazyl(DPPH)radical scavenging assay.Results:The leaf of M.tanarius contained two prenylflavonoids as main components in both male and female plants.Both flowers(male and female)contained five kinds of prenylflavonoids.In the petiole,stem and leaflet of both male and female plants,the prenylflavonoids were not delected or their amounts were very low.Five kinds of prenylflavonoids were detected in the seed,pericarp and glandular trichome of female M.tanarius.In particular,the glandular trichome had the highest level of total prenylflavonoids(235 mg/g of fresh plant).DPPH radical scavenging activity of all parts was more than 30%.Conclusions:We found that different parts of M.tanarius contained antioxidant prenylflavonoids.In particular,not only the glandular trichome but also the leaf contained prenylflavonoids,which indicated that M.tanarius may be developed as a functional plant,because the leaves of this plant can be easily collected.

Biocatalytic access to diverse prenylflavonoids by combining a regiospecific C-prenyltransferase and a stereospecific chalcone isomerase

Prenylflavonoids are valuable natural products that have diverse biological properties, and are usually generated biologically by multiple metabolic enzymes in nature. In this study, structurally diverse prenylflavonoids were conveniently synthesized by enzymatic catalysis by combining GuILDT, a regiospecific chalcone prenyltransferase, and Gu CHI, a stereospecific chalcone isomerase that has promiscuous activity for both chalcones and prenylchalcones as substrates. Our findings provided a new approach for the synthesis of natural/unnatural bioactive prenylflavonoids, including prenylchalcones and optical prenylflavanones with chalcone origins.

New anti-pulmonary fibrosis prenylflavonoid glycosides from Epimedium Koreanuin

Four new prenylflavonoid glycosides,namely koreanoside H-K(1-4),together with eleven known ones(5-15)were isolated from the leaves of Epimedium koreanum Nakai.Their structures were elucidated by ID NMR,2D NMR,HR-ESI-MS,IR and UV.The identification of the sugar moieties was carried out by means of acid hydrolysis and HPLC analysis of their derivatives.It is worth noting that compound 3 and compound 4 were elucidated to contain fucose and quinovose moieties,which were two extremely rare sugar units from the genus Epimedium.The anti-pulmonary fibrosis activity of the new compounds was evaluated using A549 cell line.Compounds 1,2 and 4 showed significant anti-pulmonary fibrosis activities.