Kaempferol 3-methyl Ether Research Articles

Chemotaxonomic value of flavonoids in Chromolaena congesta (Asteraceae)

The phytochemical investigation on the aerial parts of Chromolaena congesta led to the isolation of nine flavonoids, known in the literature as genkwanin (1) kumatakenin (2) acacetin (3), kaempferol 3-methyl ether (4), apigenin (5), apigenin 5,7-dimethyl ether (6), apigenin 5-methyl ether (7), luteolin (8) and kaempferol (9). The chemical structures were established on the basis of spectral evidence. All the compounds were isolated from this species for the first time. The results from the present study provide further information about the flavonoids as taxonomic marker of the genus Chromolaena, and the chemotaxonomic significance of these compounds were also summarized.

Anthocyanins and Other Flavonoids as Flower Pigments from Eleven Centaurea Species

Anthocyanins and other flavonoids were isolated from the flowers of eleven Centaurea species, C. macrocephala, C. rupestotilis and C. suaveolens, which produce yellow flowers, and C. achtarovii, C. dealbata, C. montana, C. nigra, C. scabiosa, C. simplicicaulis, C. hypoleuca and C. triumfetti, which have cyanic flowers. Four anthocyanins, cyanidin 3,5-di-O-glucoside, cyanidin 3-O-(6"-malonylglucoside)-5-O-glucoside, cyanidin 3-O-(6"-succinylglucoside)-5- O-glucoside and cyanidin glycoside, were detected in the cyanic flowers of seven Centaurea species. Of these anthocyanins, the first two were found as major anthocyanins. In the cyanic species, four other flavonoids, apigenin 7-O-glucuronide-4'-O-glucoside, malonylated apigenin 7,4'-di-O-glucoside, apigenin 7-0- glucuronide and kaempferol glycoside, were also isolated. On the other hand, nine flavonols and four flavones were isolated from the three yellow-flowered species, and identified as quercetagetin, quercetagetin 7-O-glucoside, quercetagetin 3'-methyl ether 7-O-glucoside, patuletin, patuletin 7-O-glucoside, quercetin 7-O-glucoside, kaempferol 3-methyl ether, kaempferol 3-methyl ether 4'-O-glucuronide and isorhamnetin 3-O-galactoside, and apigenin, apigenin 7- O-glucuronide, luteolin 7-O-glucoside and apigenin 6,8-di-C-glucoside (vicenin-2). Of these flavonoids, the former five flavonols are "yellow flavonols", and it was shown that their flower colors are due to these compounds.

Synthesis of Some 4'-O Substituted Derivatives of Natural Naringin and Their Biological Screening

Rhynchosia pseudo-cajan Cambess. (papilionaceae) is a common weed which is medicinally important. It is an erect shrub having whitish leaflets on lower side. Its common name is Lahrr. It is distributed in Jammu & Kashmir and Pakistan. Its leaves are used as tonic and stomach disorders, leaves and bark powder is useful for peptic ulcer and other digestive problems. The crude drugs of Rhynchosia are used in the formation of fermented liquor having antioxidative, antitumor, skin whitening and arthritis preventing and treating effects. Since now no phytochemical studies have been carried out on this species but many important compounds have been discovered from other species of genus Rhynchosia. Tirumalin, a prenylated dihydroflavanol was isolated from Rhynchosia cyanosperma. Rhynchosin, a new 5-deoxyflavonol was isolated from leaves of Rhynchosia beddomei. The leaves of Rhynchosia rufescenes contain methylated flavonols such as kaempferol, kaempferol 3-methyl ether and quercetin 3-methyl ether, which are of chemotaxonomic importance. Many flavonoides have been Synthesis of Some 4'-O Substituted Derivatives of Natural Naringin and Their Biological Screening

Flavonoids and coumarins from Hieracium pilosella L. (Asteraceae)

Typical chromatographic methods were successfully applied to isolate nine flavonoid compounds and two coumarin glycosides from the inflorescences and the herb of <em>Hieracium pilosella</em> L. Repeated column chromatography, occasionally paper chromatography and recrystallization made the separation of three flavonoid aglycones and six glycosides - possible. Coumarin glycosides were isolated by preparative thin layer chromatography. Subsequent UV, NMR and MS analyses have led to identification of the following flavonoid derivatives: known for the species - apigenin, luteolin, luteolin 7-O- ß-glucopyranoside, luteolin 4’-O-ß-glucopyranoside, isoetin 7-O-ß- -glucopyranoside, isoetin 4’-O-ß-glucuronide and new for the species – kaempferol 3-methyl ether and apigenin 7-O-ß-glucopyranoside. Third isoetin glycoside contained two different sugar moieties: xylose and glucose, probably attached to the hydroxyl groups at C-4’ or C-4’ and C-2’(or 5’) of an aglycone. Umbelliferone 7-O-ß-glucopyranoside (skimmin) and new for the genus Hieracium esculetin 7-O-ß-glucopyranoside (cichoriin) were determined by NMR and MS methods.

The utility of leaf flavonoids as taxonomic markers for some Malaysian species of the tribe Shoreae (Dipterocarpaceae)

A flavonoid survey was carried out on 45 taxa from the genera Shorea, Hopea, Parashorea, Neobalanocarpus, and Dryobalanops of the tribe Shoreae in the Dipterocarpaceae. The study showed significant chemotaxonomic differences in leaf flavonoid aglycone patterns and the presence of tannins in these taxa. The flavonoid patterns are useful in the delimitation of some taxa. For example, the genus Parashorea is distinguished by the universal presence of kaempferol 3-methyl ether, and the monotypic genus Neobalanocarpus is unique in not producing ellagic and gallo tannins. The presence of chalcones and flavone C-glycosides supports the separation of the genus Hopea into two sections, section Dryobalanoides and section Hopea in Ashton's classification, which is based on the type of venation. The flavonoid distributions in this study show that they can be very useful for differentiating between the Balau group in the genus Shorea, and some scaly barked Hopea species, particularly H. helferi (lintah bukit), H. nutans (giam), and H. ferrea (malut). (C) 2008 The Linnean Society of London.

Constituents of the stems and fruits of Opuntia ficus-indica var. saboten.

From the stems and fruits of Opuntia ficus-indica var. saboten, eight flavonoids, kaempferol (1), quercetin (2), kaempferol 3-methyl ether (3), quercetin 3-methyl ether (4), narcissin (5), (+)-dihydrokaempferol (aromadendrin, 6), (+)-dihydroquercetin (taxifolin, 7), eriodictyol (8), and two terpenoids, (6S,9S)-3-oxo-alpha-ionol-beta-D-glucopyranoside (9) and corchoionoside C (10) were isolated and identified by means of chemical and spectroscopic. Among these isolates, compounds 3-5 and 8-10 were reported for the first time from the stems and fruits of O. ficus-indica var. saboten.

Antiinflammatory and antibacterial activities of C-methylflavonols fromPiliostigma thonningii

Newly described C-methylflavonols, 6,8-di-C-methylquercetin 3-methyl ether, 6-C-methylquercetin 3,7-dimethyl ether, 6,8-di-C-methylquercetin 3,7-dimethyl ether together with the known compounds quercetin, quercitrin, 6-C-methylquercetin 3-methyl ether, 6-C-methylquercetin 3,7,3′-trimethyl ether, 6,8-di-C-methyl- kaempferol 3-methyl ether and 6,8-di-C-methylkaempferol 3,7-dimethyl ether isolated from the leaves of Piliostigma thonningii, were tested for their ability to inhibit prostaglandin synthesis in vitro and antibacterial activity against Staph. aureus. The influence of the B ring 3′,4′ diol group on the activity of C-methylflavonols in the inhibition of prostaglandin synthesis differ from that observed for a series of flavonoids without C-methyl groups. The antibacterial activity in the series mirror those of methylated antimicrobial flavonoids. The traditional uses of the plant in infections and inflammatory conditions were rationalized on the basis of the activities of these compounds. © 1997 John Wiley & Sons, Ltd.

Variations in the lipophilic and vacuolar flavonoids of the genus Vellozia

Five lipophilic flavonoids were identified in Vellozia aff. scoparia: kaempferol, kaempferol 3-methyl ether, luteolin, chrysoeriol and a new compound, 6-prenylherbacetin 3,8-dimethyl ether. Five such substances were identified in V. phalocarpa: luteolin, chrysoeriol, eriodictyol, 6- C-methylquercetin 3-methyl ether and 8- C-methylquercetagetin 3,6,7,4′-tetramethyl ether. Five compounds were identified in V. laevis: velloquercetin 3,3′-dimethyl ether, 8- C-methyl-6-hydroxykaempferol 3,6,7-trimethyl ether and the 3,6,7,3′- and 3,6,7,4′-tetramethyl ethers of 8- C-methylquercetagetin. A method for distinguishing these latter two isomers is described. All three species also contained a range of vacuolar flavone O- and C-glycosides; two contained a new conjugate of orientin, the 7-caffeate. These lipophilic and vacuolar flavonoid patterns were compared with those of seven other Vellozia species and the results used to prepare similarity indices within the genus. Although all 10 species have distinctive profiles, there is no evidence to suggest that any of these species should be transferred to a different genus.

Flavones and other constituents from Centaurea species

Roots, green parts and flower heads of Centaurea nervosa and C. phrygia were examined separately. Eight flavones, nine polyacetylenes and four tetraenic aldehydes of known structures, together with aplotaxene and the lignan (−)-aretigenin were isolated and characterized. The flavones apigenin, kaempferol 3-methyl ether, kaempferol 3,6-dimethyl ether, centaureidin, jaceidin and hispidulin were found in appreciable amounts in both plants.

Seasonal variation in leaf exudate flavonoids of Isocoma acradenia (Asteraceae)

The four major flavonoid aglycones (apigenin, luteolin 7-methyl ether, kaempferol 3-methyl ether, quercetin 3,3'dimethyl ether) in the external leaf resin of Isocoma acradenia were examined monthly over a one year period. Ten plants in one population were sampled repeatedly; each month 10 leaves per plant were collected (i.e. one leaf each from the tenth node of ten stems). Flavonoids were examined using reverse phase HPLC in acetonitrile and water. No qualitative variation was found among the four flavonoids. Analysis of variance of integrated peak areas revealed significant seasonal variation in relative per cent composition among apigenin, luteolin 7-methyl ether and quercetin 3,3'-dimethyl ether. Kaempferol 3-methyl ether did not vary significantly. The flavonoid aglycone composition showed no clear relationship with the amount of exudate.

6α-Acetoxy-16β,22-dihydroxyhopan-24-oic acid, a triterpene from the fern Notholaena candida var. copelandii

Farinose exudates on fronds of gymnogrammoid ferns generally consist of flavonoid aglycones. In Notholaena candida var. copelandii a new triterpene was found as a major component of the farina besides galangin 3-methylether and kaempferol 3-methylether. Extensive mass spectral and NMR studies revealed this triterpene to be a new natural product, 6α-acetoxy-16β,22-dihydroxyhopan-24-oic acid.

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.

Methyläther des myricetins, quercetins und kämpferols im knospenöl von aesculus hippocastanum

Zusammenfassung In addition to the recently published free flavonol aglycones in the oil secreted by buds of horse chestnut we now identified myricetin 7,3′,4′-trimethyl ether (a hither- to unknown substance), quercetin 7,3′,4′-trimethyl ether, quercetin 3,3′-dimethyl ether, kaempferol 3-methyl ether, rhamnazin and isorhamnetin and there also seem to be traces of kaempferol 7,4′-dimethyl ether.

The synthesis of 3-methylfisetin and some methyl ethers of kaempferol

The naturally occurring flavones, 3′,4′,7-trihydroxy-3-methoxyflavone (3-methylfisetin), 4′,5-dihydroxy-3,7-dimethoxyflavone (kumatakenin), 4′,5,7-trihydroxy-3-methoxyflavone (kaempferol 3-methyl ether) and 3,5-dihydroxy-4′,7-dimethoxyflavone, have been synthesized by the Allan-Robinson method.