Flavonoids from Artemisia ludoviciana var. ludoviciana

Nineteen flavonoids were isolated from Artemisia ludoviciana var. ludoviciana, including a new 2′- hydroxy- 6-methoxyflavone, 5,7,2′,4′-tetrahydroxy-6,5′-dimethoxyflavone. The known compounds include quercetagetin 3,6,3′,4′-tetramethyl ether, eupatilin, 5,7-dihydroxy-3,6,8,4′-tetramethoxyflavone, luteolin 3′,4′-dimethyl ether, jaceosidin, 5,7,4′-trihydroxy-3,6-dimethoxyflavone, tricin, hispidulin, chrysoeriol, kaempferol 3-methyl ether, apigenin, axillarin, eupafolin, selagin and luteolin together with three flavones which were previously isolated for the first time from Artemisia frigida: 5,7,4′-trihydroxy-6, 3′,5′-trimethoxyflavone, 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone and 5,7,3′,4′-tetrahydroxy-6,5′- dimethoxyflavone.     

Brickellin,a novel flavone from brickellia veronicaefolia and b. chlorolepis

A new highly oxygenated flavone methyl ether has been isolated from Brickellia veronicaefolia and B. chlorolepis. It has been identified as 5,6′-dihydroxy-6,7,2′,3′,4′-pentamethoxyflavone and given the name brickellin.     

Variations in flavonoid patterns within the genus Chondropetalum (restionaceae)

HPLC and chemical analyses of the flavonoids in culms of 11 Chondropetalum species divide the genus into two groups: seven, with glycosides of myricetin larycitin and syringetin; and four, with glycosides of kaempferol, quercetin, gossypetin, gossypetin 7-methyl ether and herbacetin 4′-methyl ether. This chemical dichotomy is correlated with anatomical differences and confirms the view that the genus requires taxonomic revision. HPLC measurements on those species with myricetin derivatives show that taxa with a qualitatively similar pattern of glycosides can be readily separated on quantitative grounds. Syringetin 3-arabinoside and a glycoside of herbacetin 4′-methyl ether are reported for the first time from the genus.     

Methylated Chalcones from Bidens torta

Four new natural products, all methylated chalcones, including an acetylated glycoside, were isolated from Bidens torta. Their structures were determined by spectroscopic methods as okanin 3,4,3′,4′-tetramethyl ether, okanin 3,4,3′-trimethyl ether 4′-glucoside, okanin 4-methyl ether 4′-glucoside and okanin 4-methyl ether 4′-glucoside monoacetate. Okanin 3,4-dimethyl ether 4′-glucoside was also isolated.     

Flavonoids from the exudate of Acacia neovernicosa

2′,4′-Dihydroxychalcone, 4′-hydroxy-2′-methoxychalcone and 2′,4′-dihydroxy-3′-methoxychalcone were isolated and characterized from the resinous exudate produced by Acacia neovernicosa. Smaller amounts of isoliquiritigenin, pinocembrin and chrysin were also found and identified by their chromatographic properties and UV spectra. The material of one collection contained galangin, 3-methylkaempferol and 3,3′ -dimethylquercetin.     

Polyphenols of Intsia heartwoods

Robinetin is the main polyphenol of the heartwood of Intsia bijuga and is accompanied by smaller amounts of 3,5,4′-tri- and 3,5,3′,4′-tetra-hydroxystilbenes, dihydromyricetin, myricetin and naringenin. The wood contains large amounts of water soluble polymers including leucocyanidin. The stilbenes are absent from the sapwood. Samples of I. bijuga and I. palembanica from several countries revealed differences in composition.     

Flavonoids in leaves and inflorescences of australian Cyperus species

A survey of the flavonoids of some 92 species of Australian Cyperus, mainly of subtropical or tropical origin, has confirmed a correlation previously reported in this family between flavonoid pattern and plant geography. The pattern found was similar to that of African and South American Cyperaceae, particularly in the occurrence of the rare marker substance, luteolin 5-methyl ether. Tricin and luteolin are relatively common, in glycosidic form, in the leaves while the flavonol quercetin is infrequent. When present, quercetin occurs either in glycosidic form or free as a methyl ether. The 3-monomethyl and 3, 7-dimethyl ethers of kaempferol and quercetin and the 3, 7, ?-trimethyl ether of quercetin are reported for the first time from the Cyperaceae. The flavonoid pattern of inflorescences is distinct from that of the leaves in that tricin is not detectable and that luteolin 5-methyl ether appears to be replaced by 7, 3′, 4′-trihydroxyflavone. In addition, the aurone aureusidin is more commonly present than in the leaves and is occasionally accompanied by two further aurones. The glycoxanthones mangiferin and isomangiferin occur rarely in all three species examined in the section Haspani, i.e. in C. haspan, C. prolifer and C. tenuispica. In general, however, the flavonoid data do not offer any markers which separate off different sections within the genus; there are, however, some significant correlations between the frequency of the flavonoid classes and subgeneric groupings.     

Flavonoids of Elaeocarpus lanceofolius

4′-Methylmyricetin has been isolated from the leaves of Elaeocarpus lanceofolius together with myricetin and its 3-O-rhamnoside. This is the second report of the natural occurrence of a 4′-methyl ether of myricetin and the first in the family, Elaeocarpaceae.     

Flavonol glycosides of Limnanthes douglasii

Eighteen flavonol glycosides were isolated from petal and leaf-stem of Limnanthes douglasii. There were six aglycones: kaempferol, quercetin, isorhamnetin, myriectin, syringetin and a new flavonol, myricetin 3′-methyl ether. Each occurred as the 3-rutinoside, 3-rhamnosylrutinoside and 3-rutinoside-7-glucoside.     

Chalcone glycosides of Antirrhinum majus

Three chalcones have been found in yellow flowers of A. majus, two of which have been identified as chalcononaringenin 4′-glucoside and 3,4,2′,4′,6′-pentahydroxychalcone 4′-glucoside.     

Flavonoids of four species of Parthenium (compositae)

Kaempferol and quercetin 3-O-glycosides were found in the closely related species, Parthenium hysterophorus, P. bipinnatifidum and P. glomeratum; the major aglycone flavonols in P. hypterophorus are quercetagetin 3,7-dimethyl ether and a new flavonoid, 6-hydroxykaempferol 3,7-dimethyl ether. The North-South American species-pair P. glomeratum (Argentina) and P. bipinnatifidum (Mexico) yielded quercetagetin 3,7,3′-trimethyl ether as the major aglycone. The desert species P. rollinsianum yielded five methylated flavonols: quercetin 3,3′-dimethyl ether, penduletin, quercetagetin 3,6,7-trimethyl ether, polycladin and artemetin.     

Three highly oxygenated flavone glucuronides in leaves of Spinacia oleracea

Droplet counter-current chromatographic separation and subsequent TLC demonstrated the existence of at least 14 phenolics in the leaves of Spinacia oleracea. Three have now been isolated and identified, respectively, as the 4′-glucuronides of 5,7,4'-trihydroxy-3,6,3′-trimethoxyflavone (jaceidin), 5,3′,4′-trihydroxy-3-methoxy-6:7-methylene-dioxyflavone and 5,4′-dihydroxy-3,3′-dimethoxy-6:7-methylenedioxyflavone.     

6-Hydroxyflavones from Thymbra spicata

Four flavonoids, including two new compounds, were isolated from the leaf extract of Thymbra spicata. The new compounds were the 7,3′-dimethyl and 7,3′,4′-trimethyl ethers of 6-hydroxyluteolin. All the compounds were identified by spectral methods.     

The structure and synthesis of neobavachalcone,a new component of Psoralea corylifolia.

Reinvestigation of the seeds of P. corylifolia has given, besides known compounds, a new formylated chalcone named neobavachalcone whose structure has been deduced as 5′-formyl-2′,4-dihydroxy-4′-methoxychalcone from spectral data and confirmed by synthesis. Its dimethyl ether has also been synthesised by an alternative procedure.     

Myricetin methyl ethers from Solanum pubescens

3,7,3′,5′-Tetramethoxy-5,4′-dihydroxyflavone and a novel flavonol 3,7,3′-trimethoxy-5,4′,5′-trihydroxyflavone were isolated from the leaves of Solanum pubescens and characterized by both physical and chemical methods.     

5-Methyl ether flavone glucosides from the leaves of Bruguiera gymnorrhiza

Two new 5-methyl ether flavone glucosides (7,4′,5′-trihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside and 7,4′-dihydroxy-5-methoxyflavone 7-O-β-D-glucopyranoside) were isolated from the leaves of Thai mangrove Bruguiera gymnorrhiza together with 7,3′,4′,5′-tetrahydroxy-5-methoxyflavone, 7,4′,5′-trihydroxy-5,3′-dimethoxyflavone, luteolin 5-methyl ether 7-O-β-D-glucopyranoside, 7,4′-dihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranoside, rutin, kaempferol 3-O-rutinoside, myricetin 3-O-rutinoside and an aryl-tetralin lignan rhamnoside. The structure of a lignan rhamnoside was found to be related to racemiside, an isolated compound from Cotoneaster racemiflora, and also discussed. Structure determinations were based on analyses of physical and spectroscopic data including 1D- and 2D-NMR.     

Two new C-methylated flavonoids from Myrica gale

From the leaves of Myrica gale 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone has been isolated. The fruits yielded 2′-hydroxy-4′,6′-dimethoxy-3′-methyldihydrochalcone. The constitutions were deduced from spectroscopic data and confirmed by synthesis.     

Methoxyspheroidene and methoxyspheroidenone,two carotenoids from Rhodopseudomonas spheroides

Two new carotenoids isolated from Rhodopseudomonas spheroides (Rhodospirillaceae) have been identified as methoxyspheroidene (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7$\text{,}\text{?}$8′-hexahydro-ψ,ψ-carotene) obtained from anaerobic cultures and methoxyspheroidenone (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7′,8′-hexahydro-ψ,ψ-caroten-2-one) recovered from aerobic cultures.     

Flavonoids from Haplophyllum pedicellatum, H. robustum AND H. glabrinum

Haplophyllum pedicellatum, H. robustum and H. glabrinum all yielded the known compound gossypetin 8,3′-dimethyl ether 3-rutinoside. In addition the first two species afforded isorhamnetin and its 3-rutinoside. A new glycoside, gossypetin 8,3′-dimethyl ether 3-glucoside was obtained from H. pedicellatum together with the 3-malonylrutinoside, 3-malonylglucoside and 3-galactoside of isorhamnetin plus kaempferol 3-malonylglucoside. H. robustum yielded isorhamnetin 7-glucoside and 3-glucoside and quercetin 3-galactoside, while H. glabrinum was found to contain gossypetin 8-methyl ether 3-malonylrutinoside in addition to kaempferol and isorhamnetin 3-glucoside.     

Octasubstituted flavones from Ageratum houstonianum

Two new highly oxygenated flavones, were isolated from aerial parts of Ageratum houstonianum. Their structures were established as 3′-hydroxy-5,6,7,8,2′,4′,5′-heptamethoxyflavone and 5,3′-dihydroxy-6,7,8,2′,4′,5′-hexamethoxyflavone on the basis of spectral data and chemical degradation. The structure of the latter compound was confirmed by X-ray analysis.