6-methoxyflavonoids from Brickellia laciniata (compositae)

One new and fourteen known flavonoids, including thirteen containing 6-methoxy groups, were isolated from Brickellia laciniata. The new flavonol is quercetagetin 6,4′-dimethyl ether. Among the known compounds identified were the 4′-methyl and 7,4′-dimethyl ethers of eupafolin and luteolin 4′-methyl ether, and the flavonols: patuletin, spinacetin, eupatolitin, eupatin, centaureidin, casticin, patuletin 3-glucoside and 3-galactoside, eupatolitin 3-galactoside, patuletin 3-SO₃K and eupatin 3-SO₃Ca_1/2.     

Flavonoids from Brickellia chlorolepis and B. dentata

Eleven flavonoids including three new glycosides were isolated from Brickellia chlorolepis and one new and nine known flavonoids were obtained from B. dentata. The new glycosides from B. chlorolepis are 6-methoxykaempferol 3-rhamnoglucoside, spinacetin 3-rhamnogalactoside and veronicafolin 3-rhamnoglucoside. The known compounds identified from B. chlorolepis are patuletin, casticin, artemetin, eupatolitin 3-galactoside, quercetin 3-rhamnogalactoside, rutin, isorhamnetin 3-galactoside and eupatin 3-SO₃Ca_{$\text{1}\text{2}$}. B. dentata contains the new glycoside eupalitin 3-galactoside and nine known compounds: pectolinarigenin, salvigenin, eupafolin, cirsiliol, eupatorin, eupatolitin, eupatolitin 3-glucoside, eupatolitin 3-galactoside and eupatin.     

6-Methoxyflavonoids from Brickellia californica

Two new and eleven known 6-methoxyflavonoids were identified in leaf tissue of Brickellia californica. The new flavonols are eupatin 3-SO₃ Ca_1/2 and patuletin 3-SO₃K. The known compounds include the flavones hispidulin and eupafolin and their respective 7- and 4′-monomethyl ethers and the flavonols; spinacetin, eupatin, patuletin 3-glucoside and 3-galactoside, and eupatolitin 3-galactoside.     

6-Hydroxy- and 6-methoxyflavonoids from Neurolaena lobata and N. macrocephala

Twelve flavonoids including one new sulfate were isolated from Neurolaena lobata, and six known flavonoids were obtained from N. macrocephala. The new compound isolated from N. lobata is 6-hydroxykaempferol 3-methyl ether 7-sulfate, and the known flavonoids are 6-hydroxykaempferol 3,7-di-dimethyl ether, 6-hydroxykaempferol, 3-methyl ether 7-glucoside, 6-hydroxykaempferol 7-glucoside, quercetagetin and its 7-glucoside, quercetagetin 3,6- and 3,7-dimethyl ethers, quercetagetin 3-methyl ether 7-glucoside and 7-sulfate, 6-hydroxyluteolin 3′-methyl ether and 6-hydroxyluteolin 7-glucoside. The known flavonoids identified from N. macrocephala are quercetagetin 3,6- and 3, 7-dimethyl ethers, quercetagetin 6-methyl ether 7-glucoside, quercetagetin 3,6-dimethyl ether 7-glucoside, quercetagetin 7-glucoside and quercetagetin 3-methyl ether 7-sulfate.     

Flavonoid methyl ethers on the external leaf surface of Larrea tridentata and L. Divaricata

The external phenolic resin on the leaves of Larrea tridentata contains eighteen flavone and flavonol aglycones (mostly as methyl ethers), one dihydroflavonol and two lignans (including nordihydroguaiaretic acid). Except for a few isolated 2n populations which exhibited minor differences, a single chemical type was observed for all three ploidy levels (2n, 4n and 6n) in the North American L. tridentata suggesting an autoploid origin for the tetraploid and hexaploid races. The resin chemistry of the North American taxon was most similar to that of the Argentinian diploid L. divaricata, although the resin of the latter taxon did not contain the three 8-hydroxyflavonols; however, 8-hydroxyflavonol aglycones were detected in Peruvian populations of L. divaricata.     

New 6-hydroxyflavonoids and their methyl ethers and glycosides from Neurolaena oaxacana

Six new and nine known flavonoids were obtained from Neurolaena oaxacana. The known flavonoids are 6-hydroxykaempferol 3,7-dimethyl ether, quercetagetin 3,7-dimethyl ether, quercetin 3-methyl ether, axillarin, nodifloretin, 6-hydroxyluteolin 7-glucoside, kaempferol 3-glucoside, quercetagetin 7-glucoside and patulitrin. The new compounds are 6-hydroxykaempferol 3-methyl ether, quercetagetin 3,7-dimethyl ether 6-galactoside, quercetagetin 3-methyl ether 7-glucoside, the 6- and 7-glucosides of 6-hydroxykaempferol 3-methyl ether and quercetagetin 3-methyl ether 7-sulfate.     

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.     

Sulfated and 6-methoxyflavonoids from Brickellia baccharidea (compositae)

Thirteen known flavonoids, all containing 6-methoxyl substitution, were identified from leaves of Brickellia baccharidea.     

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.     

6-Methoxyflavonols from Brickellia veronicaefolia (compositae)

Three new and eight known flavonols, all containing 6-methoxyl groups, were isolated from Brickellia veronicaefolia. The new compounds were eupatolitin 3-sulfate, 6-methoxyquercetin 7,3′-dimethyl ether (veronicafolin) 3-digalactoside and veronicafolin 3-sulfate. The known flavonoids were eupatolitin, quer-cetagetin 3,6,7-trimethyl ether, eupatin, casticin, artemetin, eupatolitin 3-galactoside, patuletin 3-sulfate and eupatin 3-sulfate.     

6-Hydroxyflavonoids from Pulicaria dysenterica (compositae)

Methyl ethers of 6-hydroxykaempferol and quercetagetin, together with scutellarein, were isolated from the leaves of Pulicaria dysenterica. The pattern of compounds is different from that previously recorded in the flowers.     

Isoprenoid dihydroquinones from a brown alga,Cystophora sp.

The lipids-soluble extract of the brown alga Cystophora sp. has yielded three new derivatives of geranyltoluquinol.     

Flavonoids in leaves and inflorescences of australian cyperaceae

A survey of 170 Australian species of Cyperaceae belonging to 35 genera has confirmed that this family has a highly characteristic flavonoid pattern in leaf and inflorescence. Aurone pigments, the most distinctive family constituents, were found in the leaves of 25% of the sample and in the inflorescences of 40%. Sulphuretin was found for the first time in the family, in Carex appressa. Flavones, such as tricin and luteolin, are very common; in addition, a variety of methyl ethers were detected. Luteolin 5-methyl ether was found in further genera, while luteolin 7-methyl ether, diosmetin and acacetin were detected for the first time in the Cyperaceae. Flavonols and their methyl ethers occurred in over one-third of the species, particularly in the leaves, being especially well represented in the genera Fuirena, Gahnia, Lepidosperma and Mesomelaena. Myricetin was found only twice, in two Baumea species. The 3-desoxyanthocyanidin carexidin was found in the inflorescences of eight species, i.e. in 5% of the sample. Taxonomically, the results are mainly of interest at the generic and specific level, where the patterns sometimes show useful correlations with morphology. At the tribal level, the Sclerieae are the most distinctive, with higher than average frequency of flavone C-glycosides, flavonols, proanthocyanidins and aurones, and lower than average frequency of flavones.     

Isoetine,nouvelle flavone isolee de Isoetes delilei et de Isoetes durieui

A new flavone isolated from Isoetes has been identified as 2′,4′,5,5′,7-pentahydroxy flavone.     

C-glycosylflavones from Oryza sativa

Eight flavone C-glycosides isolated from rice plant were found to act as probing stimulants for planthoppers. They have been identified as the known compounds schaftoside, neoschaftoside, carlinoside, isoorientin 2″-glucoside and the new constituents neocarlinoside (6-C-β-D-glucopyranosyl-8-C-β-L-arabinopyranosylluteolin), isoscoparin 2″-glucoside (chrysoeriol 6-C-β-D-(2-O-β-D-glucopyranosyl)glucopyranoside) and its 6?-p-coumaric and ferulic acid esters.     

Triterpene methyl ethers of Chionochloa (Gramineae)

The leaf wax of twenty species of Chionochloa was examined for triterpene methyl ethers; twelve species gave positive yields. The known pentacyclic methyl ethers arundoin, miliacin, lupeol methyl ether and β-amyrin methyl ether were identified and the methyl ethers of the tetracyclic alcohols, cycloartenol and parkeol are reported as new natural products. Arundoin and miliacin occur in many species while the remaining compounds may be suitable chemotaxonomic markers.     

Isopongaglabol and 6-methoxyisopongaglabol,two new hydroxyfuranoflavones from Pongamia glabra

Isopongaglabol and 6-methoxyisopongaglabol, two new hydroxyfuranoflavones, together with two furanoflavones 5-methoxyfurano(8,7-4″,5″)flavone and 5-methoxy-3′,4′-methylenedioxyfurano(8,7-4″,5″)flavone, two simple flavones, desmethoxykanugin and fisetin tetramethyl ether, a chromenoflavanone, ovalichromene B, two triterpenes, cycloart-23-ene-3β,25-diol and friedelin, and β-sitosterol-β-d-glucoside were isolated from the petrol and CHCl₃ extracts of the flowers of Pongamia glabra. The structures of isopongaglabol and 6-methoxyisopongaglabol have been established as 4′-hydroxyfurano(8,7-4″,5″)flavone and 4′-hydroxy-6-methoxyfurano(8,7-4″,5″)flavone, respectively, on the basis of the spectral evidence and they have been confirmed by synthesis.     

6-Methoxyflavonols from disjunct populations of Brickellia cylindracea (compositae)

Eight identical 6-methylated flavonols including aglycones and glycosides were isolated from two geographically disjunction population of Brickellia cylindracea from Mount Livermore and Austin, Texas, suggesting that they are best treated as a single taxon. Among the flavonol aglycones identified were patuletin, centaureidin, quercetagetin 3,6,3′,4′-tetramethyl ether and artemetin. The flavonol glycosides were patuletin and its 3-galactoside, 3-galactogalactoside, 3-rhamnogalactoside and a 3-rhamnogalactoside derivative.     

Biflavones from the leaves of Araucaria excelsa

Eight biflavones have been isolated from the leaf extracts of Araucaria excelsa. 7″-O-Methylamento-flavone, 7,7″-di-O-methylamentoflavone, 4′ or 4″', 7-di-O-methylcupressuflavone, 7,7″,4″'-tri-O-methyl agathisflavone and 7,4′,7″-tri-O-methylamentoflavone are new compounds and are being reported for the first time. The others are 7,7″-di-O-methylagathisflavone,7,4′,7″,4″'-tetra-O-methylamentoflavone and 7,4′,7″,4″'-tetra-O-methyl-cupressuflavone. Mass and NMR spectral studies are used for structural elucidation. In addition, the presence of several other biflavones has been indicated by TLC examination of methylated products.     

Asplenetin,a flavone and its glycoside from Launaea asplenifolia

A new flavone, asplenetin, has been isolated from Launea asplenifolia and characterized as 5,7,3′,4′,5′-pentahydroxy-3-(3-methylbutyl)flavone. Its glycoside, asplenetin 5-O-neohesperidoside, is also reported.