The role of lipophilic and polar flavonoids in the classification of temperate members of the Anthemideae

Lipophilic and vacuolar flavonoids were separately identified in representative temperate species of the genera Anthemis, Chrysanthemum, Cotula, Ismelia, Leucanthemum and Tripleurospermum. The four Anthemis species investigated variously produced four main surface constituents, in leaf and flower: santin, quercetagetin 3,6,3′-trimethyl ether, scutellarein 6,4′-dimethyl ether and 6-hydroxyluteolin 6,3′-dimethyl ether. By contrast, surface extracts of disc and ray florets of the species of Chrysanthemum, Cotula, Ismelia, Leucanthemum and Tripleurospermum surveyed yielded five common flavones in the free state: apigenin, luteolin, acacetin, apigenin 7-methyl ether and chrysoeriol. Polar flavonoids were isolated and identified in leaf, ray floret and disc floret of all the above plants. Anthemis species were distinctive in having flavonol glycosides in the leaves, whereas the leaf flavonoids of the other taxa were generally flavone O-glycosides. The 3-glucoside and 3-rutinoside of patuletin were characterised for the first time from Anthemis tinctoria ssp. subtinctoria. Two new flavonol glycosides, the 5-glucuronides of quercetin and kaempferol, were obtained from the leaf of Leucanthemum vulgare, where they co-occur with the related 5-glucosides and with several flavone glycosides. The ray florets of these Anthemideae generally contain apigenin and/or luteolin 7-glucoside and 7-glucuronide, whereas disc florets have additional flavonol glycosides, notably the 7-glucosides of quercetin and patuletin and the 7-glucuronide of quercetin. A comparison of the flavonoid pattern encountered here with those previously recorded for Tanacetum indicate some chemical affinity between Anthemis and Tanacetum. Flavonoid patterns of the other five genera are more distinct from those of Tanacetum and suggest that those genera form a related group. All 14 species surveyed for their flavonoid profiles have distinctive constituents and the chemical data are in harmony with modern taxonomic treatments of the “Chrysanthemum complex” as a series of separate genera.     

Sesquiterpene lactones,flavonoids and anthraquinones from Asphodeline globifera and Asphodeline Damascena

The known compounds chrysoeriol, apigenin, luteolin, acacetin, scutellarein, 6-methoxyluteolin, apigenin 7-glucoside, luteolin 7-glucoside, esculetin, chrysophanol, asphodeline, mircocarpin, sitosterol, 1-β-acetoxyeudesman-4(15),7(11)dien-2α,12-olide and 1-β-acetoxy-8β-hydroxyeudesman-4(15),7(11)-dien-8α,12-olide were isolated from Asphodeline globifera and A. damascena. A new sesquiterpene lactone 1-β-acetoxy-8β-ethoxyeudesman-4(15),7(11)dien-8α, 12-olide was also characterized. These are the first reports of sesquiterpene lactones in Asphodeline and in the Liliaceae.     

A chemotaxonomic survey of flavonoids in leaves of the Oleaceae

Leaves of 97 taxa representing all the genera at present recognized in the family Oleaceae were surveyed for flavonoids. Four flavonol glycosides were found to be common, the 3-glucmides and 3-rutinosides of quercetin and kaempferol, as were four flavone glycosides, namely the 7-glurosides arid 7-rutinosides of luteolin and apigenin. Among rarer constituents detected were luteolin 4'-glucoside, eriodictyol 7-glucoside, chrysoeriol 7-glucoside, an apigenin-di-C-glycoside and several higher glycosides of quercetin. The species and genera surveyed fell into two groups: those with flavonol glycosides alone; and those with both flavonol and flavone glycosides. The most striking correlation was with chromosome number (and subfamily division) since almost all taxa with a basic number of 11, 13 and 14 had only flavonol glycosides, whereas most taxa with x = 23 had both types of flavonoid. Evolutionary advancement in the family appears to involve the gradual replacement of flavonol by flavone glycosides. Indeed, a few tam, notably Nestegis apelala, Picconia excelsa and Tesserandra fluminense , lacked flavonol glycosides in the leaves completely. At the lower levels of classification, the distribution of flavonoids is of less interest. However, the patterns in Linociera and Chionanthus , two taxa recently made congeneric, are sufficiently different to suggest that this decision might have to be reconsidered when more is known of their chemistry. Otherwise leaf patterns generally fit in with the existing generic classification in the family.     

The comparative pollen morphology of genera Matricaria L. and Tripleurospemum Sch. Bip. (Asteraceae) in Turkey

Pollen morphology of four Matricaria species and 28 Tripleurospermum species was investigated with light microscopies (LM) and scanning electron microscopies (SEM). Pollen slides were prepared using Wodehouse technique. Measurements were based on 20 or more pollen grains per specimen. For SEM studies, dried pollen grains were transferred on aluminum stubs and coated with gold for 4 min in a sputter-coater. The pollen grains of Matricaria and Tripleurospermum are radially symmetric and isopolar. The pollen grains of the Matricaria are oblate-spheroidal with the polar axes 16.6–31.2 μm and the equatorial axes 18.7–23.9 μm. Tripleurospermum is oblate-spheroidal, suboblate and prolate-spheroidal with the polar axes 15.6–32.2 μm and the equatorial axes 17.7-38.5 μm. The pollen grains of Tripleurospermum are operculate and tricolporate. Matricaria is operculate and usually tricolporate or rarely syncolporate, tricolpate and tetracolporate. The pollen grain of both taxa shows echinate ornamentation. The spines are commonly conical with a broadened base and a tapered apical portion. The spine length varies between 1.8–4 μm in Tripleurospermum and 2.3–3.3 μm in Matricaria. The width of spines varies between 2.8–4.6 μm in Tripleurospermum and 2.4–3.6 μm in Matricaria. Inter-spinal area shows granulate–perforate, reticulate–perforate, rugulate–perforate ornamentations and the tectum surrounding the spine base is micro perforate. Overall exine thickness ranges from 2.8 to 4.8 μm in Tripleurospermum, 3.6 to 5.2 μm in Matricaria. Intine is thicker under pores in Tripleurospermum (0.3–0.62 μm) than in Matricaria (0.6–0.8 μm). Inter-spinal ornamentations, pollen shape and the numbers of perforations at the spin base have been observed as important morphological characters.     

A chemosystematic study of the phenolics of Sonchus

Thirty-three Sonchus, one Embergeria, one Babcockia and five Taeckholmia species were surveyed for their phenolic constituents. The coumarins scopoletin and aesculetin were found as major constituents of Embergeria, Babcockia and Taeckholmia species, and in lesser amount in some Sonchus species. Six flavone glycosides were identified: apigenin 7-glucuronide, apigenin 7-rutinoside, luteolin 7-glucoside, luteolin 7-glucuronide, luteolin 7-rutinoside and luteolin 7-glucosylglucuronide and the systematic significance of their distribution is discussed.     

Species Specific Flavone Glucuronides in Elodea Species

The flavonoid patterns of plants of Elodea canadensis, E. ernstae and E. nuttallii apigenin were investigated. The main flavonoids of E. canadensis are apeginin, luteolin and chrysoeriol 7-O-diglucuronides, of E. nuttalli apigenin and luteolin 7-O- diglucuronides, and of E. ernstae apigenin and luteonin 7-O-monoglucoronides. The qualitative stability of these flavonoid patterns is checked by chromatographic comparison of various populations from a wide area of the three species, it is shown that the flavonoid patterns are valuable criteria for the separation of these species.     

Flavonoid variation in the liverwort Conocephalum conicum: Evidence for geographic races

The flavonoids of 2 samples of Conocephalum conicum gametophyte tissue have been studied, one from U.S.A. and the other from Germany. Common to both samples were vicenin-2, lucenin-2, the 7-O-glucuronides of apigenin, chrysoeriol and luteolin and the previously unknown 7-O-glucuronide 4′-O-rhamnosides of apigenin, chrysoeriol and luteolin. Additionally the German sample contained the 7,4′-di-O-glucuronides of apigenin and luteolin and a new compound, apigenin 7-O-diglucuronide 4′-O-glucuronide. The North American sample contained, additionally, luteolin 7,3′-di-O-glucuronide, luteolin 7-O-glucuronide 3′,4′-di-O-rhamnoside (a new triglycoside) and 2 further derivatives of luteolin 7-O-glucuronide. Evidence is presented for the existence of geographic faces of C. conicum and for the qualitative invariability of the flavonoid patterns with changing season or environment.     

Evidence of biosynthetic simplicity in the flavonoid chemistry of the ricciaceae

The major flavonoids in Riccia crystallina are naringenin and its 7-O-glucoside, apigenin 7-O-glucoside and apigenin 7-O-glucuronide and derivatives. Ricciocarpus natans is a rich source of luteolin 7,3′-di-O-glucuronide and also contains the 7-O-glucuronides of apigenin and luteolin and the 3′-O-glucuronide of luteolin. A parallel between the production of biosynthetically simple flavonoids and reduced morphology is evident among these liverworts.     

Effects of drought stress on phenolic accumulation in greenhouse-grown olive trees (Olea europaea)

The present study evaluates the effects of severe drought stress on the content of phenolic compounds in olive leaves, namely hydroxytyrosol, tyrosol, p-hydroxybenzoic acid, catechin, luteolin 7-O-rutinoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside, quercetin, apigenin, pinoresinol, oleuropein and verbascoside in greenhouse-grown plantlets. The results showed that oleuropein, verbascoside, luteolin 7-O-glucoside and apigenin 7-O-glucoside were the most important phenolic compound of stressed olive plants and can represent up to 84% of the total amount of the identified phenolic compounds. Application of drought stress caused a significant increase in the level of oleuropein (87%), verbascoside (78%), luteolin 7-O-glucoside (72%) and apigenin 7-O-glucoside (85%), when compared to the control. The elevated values of these phenolic compounds can help controlling the water status of olive plants and avoiding serious oxidative damage induced by water deficit stress. To our knowledge, this is the first report to show the boost in the concentrations of verbascoside, luteolin 7-O-glucoside and apigenin 7-O-glucoside in the leaves of olive trees after water deficit stress.     

A comparative study of the flavonoids of Medicago radiata with other Medicago and related Trigonella species

The flavonoid glycosides of Medicago radiata as well as M. arabica, M. polymorpha, M. sativa, Trigonella coerulescens, T. foenum-graecum and T. spicata were studied in detail. Major glycosides identified were the 7-glucuronides of apigenin, luteolin, chrysoeriol and tricin, as well as lesser amounts of di- and triglucuronides of chrysoeriol and tricin. Also identified were the 3-robinobioside and 3,7-diglucoside of kaempferol, along with lesser amounts of quercetin-3,7-diglucoside, 4′,7-dihydroxyflavone, 3′,4′,7-trihydroxyflavone, formononetin and daidzein. Twelve other Medicago and Trigonella species were also studied for their flavonoid aglycones. The systematic position of M. radiata is discussed.     

A chemotaxonomic study of flavonoids in the leaves of six Trichosanthes species

The 7-, 3′- and 4′-glucosides of luteolin, the 7-glucoside and 6,8-di-C-glucoside of apigenin were isolated from Trichosanthes kirilowii var. japonica. Kaempferol 3,7-di-rhamnoside and 3-glucoside-7-rhamnoside were identified from T. cucumeroides, kaempferol 3-galactoside and 3-sophoroside were also identified from T. anguina. Quercetin-3-rutinoside was detected from T. multiloba and T. rostrata. T. bracteata afforded luteolin 3′-glucoside and kaempferol 3-rutinoside, and T. kirilowii afforded luteolin 7-, 3′- and 4′-glucosides and apigenin 7-glucoside.     

Flavonoids of Helichrysum chasmolycicum and its antioxidant and antimicrobial activities

From the aerial parts of Helichrysum chasmolycicum P.H Davis, which is an endemic species in Turkey, the flavonoids apigenin, luteolin, kaempferol, 3,5-dihydroxy-6,7,8-trimethoxyflavone, 3,5-dihydroxy-6,7,8,4′-tetramethoxyflavone, apigenin 7-O-glucoside, apigenin 4′-O-glucoside, luteolin 4′-O-glucoside, luteolin 4′,7-O-diglucoside, kaempferol 3-O-glucoside, kaempferol 7-O-glucoside and quercetin 3-O-glucoside were isolated. The methanol extract of the aerial parts of H. chasmolycicum showed antioxidant activity by DPPH method (IC₅₀ 0.92 mg/mL). Antimicrobial activity test was performed on the B, D, E extracts and also 3,5-dihydroxy-6,7,8-trimethoxyflavone and kaempferol 3-O-glucoside which were the major flavonoid compounds obtained from aerial parts of H. chasmolycicum by microbroth dilutions technique. The E (ethanol-ethyl acetate) extract showed moderate antimicrobial activity against Pseudomonas aeruginosa, B (petroleum ether-60% ethanol-chloroform) extract and 3,5-dihydroxy-6,7,8-trimethoxyflavone showed moderate antifungal activity against Candida albicans.     

Flavonoid pigments of butterflies in the genus Melanargia

Flavonoid pigments (18) were identified in the wings and body of Melanargia galathea: tricin, tricin 7-glucoside, tricin 7-diglucoside, tricin 4′-glucoside, luteolin, luteolin 7-glucoside, luteolin 7-diglucoside, luteolin 7-triglucoside, apigenin, apigenin 7-glucoside, orientin, orientin 7-glucoside, iso-orientin, iso-orientin 7-glucoside, vitexin 7-glucoside, vitexin 7-glucoside, isovitexin, isovitexin 7-glucoside and a novel but incompletely identified tricin 4′-conjugate. Examination of the wings and bodies of individual M. galathea, M. galathea var. procida, M. lachesis, M. russiae, M. larissa, M. occitanica and M. ines butterflies from a number of different populations in Europe by 2D PC revealed that variation in their flavonoid patterns was so minor that the flavonoid pattern of these Melanargia spp. may be considered constant. The concentration of flavonoids in the wings of each butterfly was greater than that in the body, as is the covering of scales. Not all flavonoids are located in the scales; some are also located in the reproductive tissues of the female. With the exception of the tricin 4′-conjugate which was absent from the egg and first instar larvae before feeding commences, these flavonoids were present in all the life stages of M. galathea. The presence of tricin 4′-conjugate in Melanargia but its absence from the larval food plants suggests that this compound is synthesized by the insect and that flavonoids are not merely sequestered from the diet but are also partly metabolized.     

Flavone glycosides of some Launaea species

Eight flavone glycosides were isolated from Launaea nudicaulis and identified as apigenin 7-glucoside and 7-gentiobioside, luteolin 7-glucoside, 7-     

Anaerobic Degradation of Flavonoids by Clostridium orbiscindens

An anaerobic, quercetin-degrading bacterium was isolated from human feces and identified as Clostridium orbiscindens by comparative 16S rRNA gene sequence analysis. The organism was tested for its ability to transform several flavonoids. The isolated C. orbiscindens strain converted quercetin and taxifolin to 3,4-dihydroxyphenylacetic acid; luteolin and eriodictyol to 3-(3,4-dihydroxyphenyl)propionic acid; and apigenin, naringenin, and phloretin to 3-(4-hydroxyphenyl)propionic acid, respectively. Genistein and daidzein were not utilized. The glycosidic bonds of luteolin-3-glucoside, luteolin-5-glucoside, naringenin-7-neohesperidoside (naringin), quercetin-3-glucoside, quercetin-3-rutinoside (rutin), and phloretin-2′-glucoside were not cleaved. Based on the intermediates and products detected, pathways for the degradation of the flavonol quercetin and the flavones apigenin and luteolin are proposed. To investigate the numerical importance of C. orbiscindens in the human intestinal tract, a species-specific oligonucleotide probe was designed and tested for its specificity. Application of the probe to fecal samples from 10 human subjects proved the presence of C. orbiscindens in 8 out of the 10 samples tested. The numbers ranged from 1.87 × 10⁸ to 2.50 × 10⁹ cells g of fecal dry mass⁻¹, corresponding to a mean count of 4.40 × 10⁸ cells g of dry feces⁻¹.     

Acylated luteolin glucosides from Salix gilgiana

Besides apigenin and luteolin 7-glucoside, four novel luteolin glucosides acylated with acetic,trans-cinnamic,p-coumaric andferulic acids, re acyl groups was determined to be at C-6″ by the¹³C NMR spectral data.     

Flavonoid glycosides and the chemosystematics of Eucalyptus camaldulensisis

Leaf flavonoid glycosides of Eucalyptus camaldulensis were identified as kaempferol 3-glucoside and 3-glucuronide; quercetin 3-glucoside, 3-glucuronide, 3-rhamnoside, 3-rutinoside and 7-glucoside, apigenin 7-glucuronide and luteolin 7-glucoside and 7-glucuronide. Two chemical races were observed based on the flavonoid glycosides. These races correspond to the northern and southern populations of species growing in Australia. The Middle Eastern species examined were found to belong to the southern Australian chemical race. The major glycosides of E. occidentalis proved to be quercetin and myricetin 3-glucuronide.     

Flavonoids from the leaves and flowers of the Himalayan Cathcartia villosa (Papaveraceae)

Five flavonols, four flavones and one C-glycosylflavone were isolated from the leaves of Cathcartia villosa which is growing in the Himalayan Mountains. They were characterized as quercetin 3-O-vicianoside (1), quercetin 7,4′-di-O-glucoside (3), quercetin 3-O-rutinoside (4), quercetin 3-O-glucoside (5), quercetin 3-O-arabinosylarabinosylglucoside (6) (flavonols), luteolin (7), luteolin 7-O-glucoside (8), apigenin (9), chrysoeriol (10) (flavones), and vicenin-2 (11) (C-glycosylflavone) by UV, LC-MS, acid hydrolysis, NMR and/or HPLC and TLC comparisons with authentic samples. On the other hand, two flavonols 1 and kaempferol 3-O-vicianoside (2) were isolated and identified from the flowers of the species. Flavonoids were reported from the genus Cathcartia in this survey for the first time. Their chemical characters were chemotaxonomically compared with those of related Papaveraceous genera, Meconopsis and Papaver.     

Negatively charged flavones and tricin as chemosystematic markers in the palmae

A survey of 125 species of the Palmae revealed a complex pattern of flavonoids in the leaf. C-Glycosylflavones, leucoanthocyanins and tricin, luteolin and quercetin glycosides were common, being present in 84, 66, 51, 30 and 24% of the species respectively. Apigenin and kaempferol were recorded in only a few species and isorhamnetin only once. Eighteen flavonoids were identified: the 7-glucoside, 7-diglucoside and 7-rutinoside of both luteolin and tricin, tricin 5-glucoside, apigenin 7-rutinoside, quercetin 3-rutinoside-7-galactoside, isorhamnetin 7-rutinoside, orientin, iso-orientin, vitexin, isovitexin and vitexin 7-O-glucoside. Many of the C- and O-flavonoid glycosides were present as the potassium bisulphate salts and negatively charged compounds were detected in 50% of the species. The distribution patterns are correlated with the taxonomy of the family in several ways. Thus, the Phoenicoideae and Caryotoideae have distinctive flavonoid patterns, there is evidence to support the separation of the subfamilies Phytelephantoideae and Nypoideae, and tricin is a useful marker at tribal level. At the generic level, Cocos is clearly separated from Butia, and other Cocoseae and Mascarena and Chamaedorea form well defined groups within the Arecoideae. A numerical analysis of these biochemical data, together with morphological characters, produces a new classification which suggests that the flavonoid data may have more systematic value than is indicated when they are applied to the traditional classification.     

Flavonoids in the leaves of Hillebrandia and Begonia species (Begoniaceae)

The fresh leaves of Hillebrandia sandwicensis and 126 Begonia taxa were chemotaxonomically surveyed for flavonoids. Of their taxa, H. sandwicensis and 119 species, one variety and three hybrids were analyzed for flavonoids for the first time. Ten flavonols and eleven C-glycosylflavones were isolated and characterized as quercetin 3-O-rutinoside (1), kaempferol 3-O-rutinoside (2), isorhamnetin 3-O-rutinoside (3), quercetin 3-O-glucoside (4), quercetin 3-methyl ether 7-O-rhamnosylglucoside (5), quercetin 3,3'-dimethyl ether 7-O-rhamnosylglucoside (6), quercetin glycoside (13), quercetin glycoside (acylated) (14), kaempferol glycoside (17) and quercetin 3-O-rhamnoside (18) as flavonols, and isovitexin (7), vitexin (8), isoorientin (9), orientin (10), luteolin 6-C-pentoside (11), luteolin 8-C-pentoside (12), schaftoside (15), isoschaftoside (16), chrysoeriol 6,8-di-C-pentoside (19), apigenin 6,8-di-C-arabinoside (20) and isovitexin 2''-O-glucoside (21) as C-glycosylflavones. Quercetin 3-O-rutinoside (1) alone was isolated from H. sandwicensis endemic to Hawaii. Major flavonoids of almost Begonia species was also 1. Begonia species were divided into two chemotypes, i.e. flavonol containing type and C-glycosylflavone containing type. Of 14 section of the Begonia, almost species of many section, i.e. sect. Augustia, Coelocentrum, Doratometra, Leprosae, Loasibegonia, Monopteron and Ruizoperonia, were flavonol types. On the other hand, C-glycosyflavone type was comparatively most in sect. Platycentrum.