Non-polar flavonoids of perityle vaseyi (asteraceae)

Ten flavonoids have been isolated from a dichloromethane leafwash of Perityle vaseyi. Trace amounts of 7,4′-dimethylnaringenin were observed along with nine O-methylated flavonols. Two kaempferol, four 6-hydroxykaempferol and three 6-hydroxyquercetin O-methylated derivatives were identified. 5,7,4-Trihydroxy-3,6-dimethoxyflavone and 5,4′-dihydroxy-3,6,7-trimethoxyflavone were the major components.     

Highly oxygenated flavones from Mentha piperita

Six highly oxygenated flavones have been isolated from the leaves of Mentha piperita. Five known compounds, 5-hydroxy-6,7,8,4′-tetramethoxyflavone, 5,4′-dihydroxy-6,7,8-trimethoxyflavone, 5,3′-dihydroxy-6,7,8,4′-tetramethoxyflavone, 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavone and 5,3′,4′-trihydroxy-6,7,8-trimethoxyflavone, are reported for the first time in the genus Mentha. The sixth compound has been identified as 5,6-dihydroxy-7,8,3′,4′-tetramethoxyflavone by UV, NMR and mass spectra.     

Chemistry of toxic range plants. Highly oxygenated flavonol methyl ethers from Gutierrezia microcephala

The perennial American desert shrub, Gutierrezia microcephala, contains 20 flavonol methyl ethers displaying nine different oxygenation patterns. These include 11 new flavonols: 5,7-dihydroxy-3,6,8,3′,4′,5′-hexamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′,5′-pentamethoxyflavone, 5,7,3′-trihydroxy-3,6,8,4′,5′-pentamethoxyflavone, 5,7,2′,4′-tetrahydroxy-3,6,8,5′-tetramethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,6,8-trimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3,6-dimethoxyflavone, 3,5,7,3′,4′-pentahydroxy-6,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone, 5,7,8,4′-tetrahydroxy-3,3′-dimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3-methoxyflavone and 5,7,8,4′-tetrahydroxy-3-methoxyflavone. In addition, the following known flavonols were isolated: 5,7-dihydroxy-3,8,3′,4′,5′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,8,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,4′-dihydroxy-3,6,7,8,3′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′-tetramethoxyflavone and 3,5,7,4′-tetrahydroxy-6,8,3′-trimethoxyflavone.     

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.     

Flavonoids from Gutierrezia texana var. texana

Eleven flavonoids, including two new compounds, were isolated from Gutierrezia texana: the structures of the new compounds are 5,7,2′,5′-tetrahydroxy-3,4′-dimethoxyflavone and 5′-acetoxy-5,7,2′-trihydroxy-3,4′-dimethoxyflavone. The nine known compounds are 5,4′,5′-trihydroxy-3,6,7,8-tetramethoxyflavone, 5,7,2′,5′-tetrahydroxy-3,6,4′-trimethoxyflavone, 5,7,3′-trihydroxy-3,4′-dimethoxyflavone, 5,7,3′,4′-tetrahydroxyflavone, 3,5,7,3′,4′- pentahydroxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,6,7,3′,4′,-pentahydroxy-3-methoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone 7-O-glucoside and 3,5,7,3′,4′-pentahydroxyflavanone.     

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.     

Four 6-hydroxyflavonols from Blumea malcomii

Four new 6-hydroxyflavonols have been isolated from Blumea malcolmii and identified as 6-hydroxy-3,5,7,4′-tetramethoxyflavone, 6,2′,5′-trihydroxy-3,5,7-trimethoxyflavone, 6,5′-dihydroxy-3,5,7,2′-tetramethoxyflavone and 6-hydroxy-3,5,7,2′,5′-pentamethoxyflavone, by spectral data coupled with some chemical correlations.     

Two new flavone glycosides from Cirsium lineare

An examination of four species of Cirsium disclosed the presence of two new flavonoids in C. lineare. The structure of one was 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (cirsilineol) 4′-monoglucoside and the other 5,3′,4′-trihydroxy-6,7-dimethoxyflavone (cirsiliol) 4′-monoglucoside. Luteolin 7-glucoside was found in C. suffultum, and pectolinarin and linarin in C. kamtschaticum and C. pectinellum.     

Antioxidant and α-Amylase Inhibitory Compounds from Aerial Parts of Varthemia iphionoides Boiss

Various extracts of aerial parts of Varthemia (Varthemia iphionoides Boiss) were investigated for radical-scavenging activity, antioxidative activity, and porcine pancreas α-amylase inhibitory activity. The ethanol and water extracts showed a pronounced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, with inhibition of about 90% at a concentration of 100 μg/ml, and α-amylase inhibitory activity of about 70% at a concentration of 200 μg/ml by the 2-chloro-4-nitrophenyl α-maltotrioside (CNP-G₃) degradation method. The ethanol extract was purified by column chromatography to give seven 3-methoxyflavones (1–7) and eudesmane sesquiterpene, selina-4,11(13)-dien-3-on-12-oic acid (8). The structures of these compounds were established by NMR, MS, and UV spectroscopy. Of 3-methoxyflavones, 5,7,4′-trihydroxy-3,6-dimethoxyflavone (1), 5,7,4′-trihydroxy-3,3′-dimethoxyflavone (2), and 5,4′-dihydroxy-3,7,3′-trimethoxyflavone (3,7,3′-tri-O-methyl-quercetin) (7) exhibited pronounced radical-scavenging activity. The antioxidative activity in the linoleic acid system was considerable in compounds 1, 2, and 5,4′-dihydroxy-3,6,7-trimethoxyflavone (4). Compounds 1, 2, 4, 5 (5,7,4′-trihydroxy-3-methoxyflavone), and 6 (5,4′-dihydroxy-3,7-dimethoxyflavone) showed markedly high inhibitory activity against porcine pancreas α-amylase. Eudesmane sesquiterpene did not show any activity.     

Revised structure of a flavonoid from the fern notholaena aschenborniana

The structure of a flavonoid from the fern Notholaena aschenborniana, previously described as 5,4′,6′-trihydroxy-6,7,2′,3′-tetramethoxyflavone, is revised to 5,2′,4′-trihydroxy-3,7,8,5′-tetramethoxyflavone on the basis of current studies on 2′-oxygenated flavonoids. Identity of the natural product with the proposed structure is confirmed by synthesis.     

外来入侵植物假臭草的黄酮类成分研究

从外来入侵植物假臭草的70%乙醇提取物的乙酸乙酯萃取物中分离得到5个黄酮化合物,利用波谱方法鉴定为5,6,7,4′-四甲氧基黄酮(1),7-羟基-5,6,4′-三甲氧基黄酮(2),4′-羟基-5,6,7-三甲氧基黄酮(3),5,4′-二羟基-6,7-二甲氧基黄酮(4),5,7,4′-三羟基-6-甲氧基黄酮(5).化合物1～5均首次从该植物中分离得到.     

Flavonoid aglycones from Xanthocephalum gymnospermoides var. gymnospermoides

Six known flavonoid aglycones and the newly described 5,7,4′-trihydroxy-3,3′,5′-trimethoxyflavone were isolated from Xanthocephalum gymnospermnoides var. gymnospermnoides.     

Flavonols of parthenium section bolophytum

Casticin (V), 5,7,3′,4′-tetrahydroxy-3,6-dimethoxyflavone-7-glycoside (I), 5,7,4′-trihydroxy-6-methoxyflavone-7-glycoside (hispidulin 7-glycoside) (IV), 5,4′-dihydroxy-3,6,7,3′-tetramethoxyflavone (VII) and 5,7-dihydroxy-3,6,3′,4′-tetramethoxyflavone (XII) were found, with the coumarin scopoletin (IX), in various combinations in the three species of Parthenium section Bolophytum. No infraspecific variation was detected in these calciphilic relicts.     

Three methylated flavones from Thymus vulgaris

Three highly oxygenated flavones were isolated from leaves of Thymus vulgaris. Their structures were determined by spectroscopic methods as 5, 6, 4′-trihydroxy- 7, 8, 3′-trimethoxyflavone (thymonin), 5, 4′-dihydroxy-6, 7, 3′-trimethoxyflavone (cirsilineol) and 5, 4′-dihydroxy-6, 7, 8, 3′-tetramethoxyflavone. These flavones are reported for the first time in the genus Thymus.     

Flavonoids of Balsamorhiza deltoidea and Wyethia mollis

Eleven O-methylated derivatives of kaempferol, quercetin and quercetagetin were isolated from the dichloromethane leaf-wash of Balsamorhiza deltoidea. Four of these compounds represent new reports from either Balsamorhiza or Wyethia: 6-hydroxykaempferol 7-O-methyl ether, quercetin 3′,4′-O-dimethylether, quercetagetin 7-O-methyl ether, and quercetagetin 3,6,7-O-trimethyl ether. We also confirmed the presence of two isoflavones, santal and orobol 3′-O-methyl ether, in W. mollis. The 8-C-prenylated derivatives of naringenin, eriodictyol, and dihydroisorhamnetin were also identified as constituents of W. mollis. The vacuolar flavonoid fraction of Balsamorhiza deltoidea and Wyethia helenioides was shown to consist of simple mono and diglycosides of kaempferol and quercetin.     

New prenylated isoflavones and a prenylated dihydroflavonol from Millettia pachycarpa

Extraction of Millettia pachycarpa Benth. gave 5,7,4′-trihydroxy-6,8-diprenylisoflavone (1a), 5,7,4′-trihydroxy-6,3′-diprenylisoflavone (2a), 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (3a) and (2R, 3R)-5,4′-dihydroxy-8-prenyl-6″,6″-dimethylpyrano[2″,3″: 7,6]-dihydroflavonol (4a) whose structures were established by chemical transformations and spectroscopic means. Pectolinarigenin and salvigenin were isolated from Buddleia macrostachya Benth.     

Two methylated flavones from Artemisia frigida

Two new highly oxygenated flavones were isolated from Artemisia frigida. Their structures were determined by spectroscopic methods as 5,7,4′-trihydroxy-6,3′,5′-trimethoxyflavone and 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone.     

Flavonoids of Gardenia cramerii and G. fosbergii bud exudates

From the bud exudates of Gardenia cramerii and G. fosbergii, two species endemic to Sri Lanka, a new flavonoid with an unusual B-ring oxidation pattern, 5,5′-dihydroxy-6,7,2′,3′-tetramethoxyflavone, was characterized. Two other rare flavonoids, 5,3′,5′-trihydroxy-3,6,7,4′-tetramethoxyflavone and 5-hydroxy-6,7,3′,4′,5′-pentamethoxyflavone were also isolated from both Gardenia species.     

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.     

Isolation and synthesis of two new flavones from Conoclinium coelestinum

Two new flavones, 3′,4′-methylenedioxy-5,6,7,8,5′-pentamethoxyflavone and 5,7,4′-trihydroxy-6,3′,5′-trimethoxyflavone, have been isolated from Conoclinium coelestinum. Final structure proof was accomplished by synthesis.