Flavonoids from Artemisia frigida

Twelve flavonoids including a new flavone were isolated from Artemisia frigida. The structure of the new highly oxygenated flavone was determined b     

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-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.     

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.     

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.     

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.     

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-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.     

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.     

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.     

Flavonols of Pulicaria arabica

Three quercetagetin methyl ethers, quercetin 3-glucoside, quercetin 3-glucuronide and a sulphated flavonoid were identified in leaves and flowers of Pulicaria arabica.     

Flavonoid and ceroptin pigments from frond exudates of Pityrogramma triangularis

Two chemically distinct golden-yellow flavonoid exudates occur on the underside of fronds of Pityrogramma triangularis: ceroptin and a newly described flavonol, 6-methyl-8-methoxy-3,5,7-trihydroxyflavone were detected in one of the exudates and two methylated kaempferol derivatives, 4′-methoxy-3,5,7-trihydroxyflavone and 3,5-dihydroxy-7,4′-dimethoxyflavone were isolated from the other.     

Flavonoids in the black rhizomes of Boesenbergia panduta

5-Hydroxy-7-methoxyflavanone, 5,7-dimethoxyflavanone, 5-hydroxy-7-methoxyflavone 5-hydroxy-7,4′-dimethoxyflavone, 5,7-dimethoxyfiavone, 5,7,4′-trimethoxyflavone, 5,7,3′,4′-tetramethoxyflavone, 5-hydroxy-3,7-dimethoxyflavone, 5-hydroxy-3,7,4′-trimethoxyflavone, 3,5,7-trimethoxyflavone and 5-hydroxy-3,7,3′,4′-tetramethoxyflavone have been isolated from the black rhizomes of Boesenbergia pandurata.     

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.     

Inheritance of triterpene methyl ethers in Cortaderia (Gramineae)

The distribution of triterpene methyl ethers in several generations of interspecific hybrids of Cortaderia indicates dominant gene control of their synthesis. The hybrid C. richardii × C. toetoe is an exception because synthesis of α- and β-amyrin methyl ethers is suppressed in F₁ and F₂, but is restored in the backcross F₁ × C. toetoe; this backcross generation was heterozygous for genes for the amyrin methyl ethers, and on selfing segregated in a simple Mendelian ratio.     

Constitution of the santalin pigments A and B

The heartwood of Pterocarpus santalinus contains two major red pigments, santalin-A and santalin-B which are partial methyl ethers of the same polyphenol (santalin). For locating the position of the methoxyl groups, alkali fission and permanganate oxidation of the mixed ethyl methyl ethers are the most convenient. By this method santalin-A has been shown to be 9,1O,12- tri-O-methylsantalin and santalin-B, 9,10,12,4′-tetra-O-methylsantalin.     

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.     

Triterpene methyl ethers in leaf waxes of Saccharum and related genera

The triterpene methyl ethers in the leaf waxes of over 80 clones of Saccharum officinarum, S. edule, S. robustum, S. spontaneum and a limited number of related species were compared as possible chemotaxonomic markers by GLC. The principal components were arundoin, crusgallin and cylindrin. The overall interspecific variation was small, but arundoin was particularly characteristic of S. officinarum. However, each species showed marked interclonal variation, which was related to chromosome numbers and geographical origin. Most S. spontaneum clones from India were atypical containing no triterpene methyl ethers.