Tronchuda cabbage flavonoids uptake by Pieris brassicae

The flavonoid pattern of larvae of cabbage white butterfly (Pieris brassicae L.; Lepidoptera: Pieridae) reared on the leaves of tronchuda cabbage was analysed by HPLC-DAD-MS/MS-ESI. Twenty flavonoids were identified or characterised, namely 16 kaempferol and four quercetin derivatives. Kaempferol 3-O-sophoroside, a minor component of tronchuda cabbage, was found to be the main component in P. brassicae (15.8%). Apart from this, only two other flavonoids present in significant amounts in tronchuda cabbage (kaempferol 3-O-sophoroside-7-O-glucoside and kaempferol 3-O-sophoroside-7-O-sophoroside) were found in the larvae. The larvae have high amounts of quercetin derivatives (18.5%), which were present only in trace amounts in tronchuda cabbage extracts, suggesting that P. brassicae is able to selectively sequester these flavonoids. The occurrence of a high content of flavonoids not detectable in tronchuda cabbage extracts indicates that P. brassicae larvae are able to metabolize dietary flavonoids.     

Regioselective synthesis of plant (iso)flavone glycosides in <Emphasis Type="Italic">Escherichia coli</Emphasis>

The flavonoids genistein, biochanin A, luteolin, quercetin, and kaempferol are plant natural products with potentially useful pharmacological and nutraceutical activities. These natural products usually exist in plants as glycosides, and their glycosylation has a remarkable influence on their pharmacokinetic properties. The glycosyltransferases UGT71G1 and UGT73C8 from Medicago truncatula are excellent reagents for the regioselective glycosylation of (iso)flavonoids in Escherichia coli grown in Terrific broth. Ten to 20 mg/L of either genistein or biochanin A 7-O-glucoside was produced after feeding genistein or biochanin A to E. coli expressing UGT71G1, and similar levels of luteolin 4'-O- and 7-O-glucosides were produced after feeding luteolin to cultures expressing UGT73C8. For the production of kaempferol 3-O-glucoside or quercetin 3-O-glucoside, the Phe148Val or Tyr202Ala mutants of UGT71G1 were employed. Ten to 16 mg/L of either kaempferol 3-O- or quercetin 3-O-glucosides were produced on feeding kaempferol or quercetin to E. coli expressing these enzymes. More than 90% of the glucoside products were released to the medium, facilitating their isolation.     

三种山茶属金花茶组植物花朵类黄酮成分研究

该研究以山茶属金花茶组的金花茶、凹脉金花茶和崇左金花茶为材料,利用超高效液相色谱-四极杆-飞行时间质谱联用技术定性定量分析其花朵中类黄酮成分与含量。结果表明:三种植物中检测到15种类黄酮,其中天竺葵素-3-O-葡萄糖苷、木犀草素、木犀草素-7-O-芸香糖苷、槲皮素-3,7-O-二葡萄糖苷、芸香柚皮苷、圣草素和染料木苷为金花茶组首次发现;槲皮素-3-O-葡萄糖苷、槲皮素-7-O-葡萄糖苷、槲皮素-3-O-芸香糖苷和山萘酚-3-O-葡萄糖苷为凹脉金花茶和崇左金花茶中首次发现。儿茶素、表儿茶素、槲皮素-3-O-葡萄糖苷、槲皮素-7-O-葡萄糖苷、槲皮素-3-O-芸香糖苷和山萘酚-3-O-葡萄糖苷为三个物种主体成分;天竺葵素-3-O-葡萄糖苷为金花茶特有,槲皮素-3,7-O-二葡萄糖苷为崇左金花茶特有;木犀草素-7-O-芸香糖苷主要存在于金花茶和崇左金花茶;木犀草素主要存在于凹脉金花茶和崇左金花茶。类黄酮类型主要为儿茶素类、槲皮素类、木犀草素类和山萘酚类;崇左金花茶中槲皮素类、木犀草素类及类黄酮总量远高于金花茶和凹脉金花茶,凹脉金花茶和崇左金花茶儿茶素类高于金花茶,金花茶和崇左金花茶山萘酚类高于凹脉金花茶。     

崇左金花茶花朵和叶片类黄酮UPLC-Q-TOF-MS分析

以崇左金花茶（Camellia chuangtsoensis）为材料,利用超高效液相色谱-四极杆-飞行时间质谱（UPLC-Q-TOF-MS）联用技术定性定量分析其花朵（花瓣、雄蕊）和叶片（老叶、新叶）中类黄酮成分与含量。结果表明,崇左金花茶中共检测到14种类黄酮成分,木犀草素、木犀草素-7-O-芸香糖苷、槲皮素-3,7-O-二葡萄糖苷、芸香柚皮苷、圣草素和染料木苷为山茶属金花茶组植物中首次发现,其中槲皮素-3,7-O-二葡萄糖苷、芸香柚皮苷、圣草素和染料木苷主要存在于花朵中,木犀草素和木犀草素-7-O-芸香糖苷在花朵中含量高于叶片,雄蕊中高于花瓣;槲皮素-3-O-葡萄糖苷、槲皮素-7-O-葡萄糖苷、槲皮素-3-O-芸香糖苷和山柰酚-3-O-葡萄糖苷为金花茶组植物叶片中首次发现,其叶片中含量远低于花朵,老叶中远低于新叶,雄蕊中远低于花瓣;儿茶素和表儿茶素在花朵中含量高于叶片,雄蕊中高于花瓣;槲皮素和山萘酚在花朵和叶片中含量均较低。崇左金花茶花瓣和雄蕊中含量较高的类黄酮为儿茶素类、木犀草素类和槲皮素类,主要是表儿茶素、木犀草素和槲皮素-3-O-葡萄糖苷;叶片中为儿茶素类和木犀草素类,主要是表儿茶素、木犀草素和木犀草素-7-O-芸香糖苷。崇左金花茶花瓣和雄蕊中儿茶素类、木犀草素类及类黄酮总量均高于叶片,且雄蕊高于花瓣;花瓣和雄蕊中槲皮素类远高于叶片,且花瓣中远高于雄蕊。     

Regioselective formation of quercetin 5-O-glucoside from orally administered quercetin in the silkworm, Bombyx mori

The cocoons of some races of the silkworm, Bombyx mori, have been shown to contain 5-O-glucosylated flavonoids, which do not occur naturally in the leaves of their host plant, mulberry (Morus alba). Thus, dietary flavonoids could be biotransformed in this insect. In this study, we found that after feeding silkworms a diet rich in the flavonol quercetin, quercetin 5-O-glucoside was the predominant metabolite in the midgut tissue, while quercetin 5,4'-di-O-glucoside was the major constituent in the hemolymph and silk glands. UDP-glucosyltransferase (UGT) in the midgut could transfer glucose to each of the hydroxyl groups of quercetin, with a preference for formation of 5-O-glucoside, while quercetin 5,4'-di-O-glucoside was predominantly produced if the enzyme extracts of either the fat body or silk glands were incubated with quercetin 5-O-glucoside and UDP-glucose. These results suggest that dietary quercetin was glucosylated at the 5-O position in the midgut as the first-pass metabolite of quercetin after oral absorption, then glucosylated at the 4'-O position in the fat body or silk glands. The 5-O-glucosylated flavonoids retained biological activity in the insect, since the total free radical scavenging capacity of several tissues increased after oral administration of quercetin.     

A new hepatoprotective flavone glycoside from the flowers of Onopordum alexandrinum growing in Egypt

A bioactivity-guided fractionation of the ethyl acetate fraction of the flowers of Onopordum alexandrinum L. (Asteraceae) yielded a new flavonoidal glycoside designated as acacetin-7-O-galacturonide (9), alongside with nine known flavonoids; 6-methoxy-apigenin (hispidulin) (1), acacetin (2), apigenin (3), luteolin (4), kaempferol (5), eriodictyol (6), apigenin-7-O-glucoside (7), luteolin-7-O-glucoside (8), and kaempferol-3-O-rutinoside (10). The compounds were assayed for their hepatoprotective activity against CCl4-induced hepatic cell damage in rats and free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH). Compounds 4, 6, 9, and 10 have not been previously reported from flowers of O. alexandrinum L., and this is the first report of acacetin-7-O-galacturonide (9) in nature which has also shown significant hepatoprotective and free radical scavenging effects. The isolated compounds were identified using different spectroscopic methods (UV, 1H NMR, 13C NMR, HMQC, HMBC, and COSY).     

Polyphenols from Cornulaca monacantha

The aerial parts of the Egyptian herb Cornulaca monacantha have yielded two new galloyltannin analogs (named monacanthin A and monacanthin B) characterized by protoctechuoyl moiety at C-6, and also a new flavonol glycoside, quercetin-4'-O-beta-D-galactoside. The structures of the new compounds were established by conventional analytical methods and confirmed by spectral analyses. Two known flavonoids, luteolin-7-O-rhamnoside, luteolin-7-O-glucoside, and two known gallotannins, penta-O-galloyl-beta-D-glucose and 1,2,3,6-tetra-O-galloyl-beta-D-glucose were also isolated.     

Anti-inflammatory and antinociceptive potential of major phenolics from Verbascum salviifolium Boiss

The potential effects of flavonoids, phenylethanoid and neolignan glycosides from the aerial parts of Verbascum salviifolium Boiss. were studied in the p-benzoquinone-induced writhing reflex, for the assessment of the antinociceptive activity, and in carrageenan- and PGE1-induced hind paw edema and 12-O-tetradecanoyl-13-acetate (TPA)-induced ear edema models in mice, for the assessment of the anti-inflammatory activity. Through bioassay-guided fractionation and isolation procedures ten compounds from the aqueous extract of the plant, luteolin 7-O-glucoside (1), luteolin 3'-O-glucoside (2), apigenin 7-O-glucoside (3), chrysoeriol 7-O-glucoside (4), beta-hydroxyacteoside (5), martynoside (6), forsythoside B (7), angoroside A (8), dehydrodiconiferyl alcohol-9'-O-beta-D-glucopyranoside (9) and dehydrodiconiferyl alcohol-9-O-beta-D-glucopyranoside (10), were isolated and their structures were elucidated by spectral techniques. Results have shown that 1, 2, 3 and 5 significantly inhibited carrageenan-induced paw edema at a 200 mg/kg dose, while 1, 2 and 5 also displayed anti-inflammatory activity against the PGE1-induced hind paw edema model. However, all the compounds showed no effect in the TPA-induced ear edema model. The compounds 1 and 2 also exhibited significant antinociceptive activity.     

A new kaempferol triglycoside from Fagonia taeckholmiana: cytotoxic activity of its extracts

In addition to apigenin, apigenin 7-O-glucoside, kaempferol 3-O-glucoside, kaempferol 3,7-di-O-rhamnoside, quercetin, and quercetin 3-O-glucoside, the methanolic extract of Fagonia taeckholmiana afforded a new compound identified as kaempferol 3-O-beta-l-arabinopyranosyl-(1-->4)-alpha-l-rhamnopyranoside-7-O-alpha-l-rhamnopyranoside. Identification of the isolated compounds was based on chemical and spectroscopic analyses including UV, FABMS, (1)H, (13)C and 2D NMR, and DEPT. The cytotoxic activities of the compounds against several cancer cell lines were determined.     

Phytochemical studies and effect on urine volume of Glossostemon bruguieri Desf. constituents

Two new flavonoids, takakin 7-O-glucoside (1) and (2) bucegin 7-O-glucoside, and six other known compounds (3-8), takakin, isosctullarien, its 7-O-glucoside, takakin 8-O-glucoside, xanthotoxin and esculetin, were separated and identified from Glossostemon bruguieri. The new compounds were characterized using modern spectroscopic techniques, including UV spectroscopy, proton nuclear resonance (1HNMR), carbon thirteen nuclear resonance (13CNMR), homomolecular quantum coherance (HMQC), heteromolecular bonding connectivity (HMBC) and chemical ionization mass spectra (CI). The effect on rats urine volume of the plant powder, its ethanolic extract, (500 mg kg(-1)) along with four of the purified compounds (1,4-6), (100 mg kg(-1)) are described. Eight groups of albino rats (200-300 g body weight) (n=5 for each group) were used in the tests for a one-time treatment, and other seven groups (150-180 g body weight) (n=5 for each group) were tested using the same dose with repeated administration for 15 days. The rat sera were collected and used to determine liver and kidney functions based on alanine amino transferase (ALT) and aspartate amino transferase (AST) for both single and repeated administration. Levels of urea, creatinine and uric acid were determined for both sets of experiments. The toxic effects of both the powder and its alcoholic extract were also studied on mice to determine their LD50, both materials proved to be non-toxic up to 2500 mg kg(-1) body weight.     

Triterpene saponins and flavonoids in the seeds of Trifolium species

Seeds of 57 species of the genus Trifolium have been studied for the occurrence and concentration of soyasapogenol B glycosides and flavonoids. It was shown that all tested species contained soyasaponin I and in some species astragaloside VIII and/or 22-O-glucoside and 22-O-diglucoside of soyasaponin I were also present. Total concentration of saponins ranged from trace amounts up to 10 mg/g(DM). It was suggested that soyasapogenol B glycosides could be recognized as chemotaxonomic character of Fabaceae family. All but three tested species contained flavonoids. The majority of species contained quercetin as a sole flavonoid or in the mixture with a number of unidentified flavonoid components. Concentration of quercetine in some species was at the level of about 3 mg/g(DM). This high quercetin concentration and soyasaponin occurrence makes the seeds of some Trifolium species a potential source of health beneficial phytochemicals, to be used in human nutrition.     

Flavonoids as chemotaxonomic markers for Erythroxylum australe

Methanolic leaf extracts of Erythroxylum australe F. Muell. produced eight O-conjugated flavonoids. Six of the flavonoid aglycones were dihydroisoflavones (all dihydro-orobol derivatives), one a flavanone, eriodictyol, and one a flavonol, quercetin. The major glycosides of the flavonoids included mono-glucosyl-rhamnosyls and dirhamnosyl-glucosides with either 3, 5, 7 or 3', 4' linkage or a combination thereof The array of flavonoids present in E. australe suggests kinship to E. ulei and linkage to the four cultivated alkaloid-bearing Erythroxylum, especially the ancestral E. coca var. coca. Because of the uniqueness of the flavonoids present in leaf tissue of E. australe they are unambiguously useful as chemotaxonomic markers for the taxon.     

Multi-substrate flavonol O-glucosyltransferases from strawberry (Fragaria x ananassa) achene and receptacle

In an effort to characterize fruit ripening-related genes functionally, two glucosyltransferases, FaGT6 and FaGT7, were cloned from a strawberry (Fragaria x ananassa) cDNA library and the full-length open reading frames were amplified by rapid amplification of cDNA ends. FaGT6 and FaGT7 were expressed heterologously as fusion proteins in Escherichia coli and target protein was purified using affinity chromatography. Both recombinant enzymes exhibited a broad substrate tolerance in vitro, accepting numerous flavonoids, hydroxycoumarins, and naphthols. FaGT6 formed 3-O-glucosides and minor amounts of 7-O-, 4'-O-, and 3'-O-monoglucosides and one diglucoside from flavonols such as quercetin. FaGT7 converted quercetin to the 3-O-glucoside and 4'-O-glucoside and minor levels of the 7- and 3'-isomers but formed no diglucoside. Gene expression studies showed that both genes are strongly expressed in achenes of small-sized green fruits, while the expression levels were generally lower in the receptacle. Significant levels of quercetin 3-O-, 7-O-, and 4'-O-glucosides, kaempferol 3-O- and 7-O-glucosides, as well as isorhamnetin 7-O-glucoside, were identified in achenes and the receptacle. In the receptacle, the expression of both genes is negatively controlled by auxin which correlates with the ripening-related gene expression in this tissue. Salicylic acid, a known signal molecule in plant defence, induces the expression of both genes. Thus, it appears that FaGT6 and FaGT7 are involved in the glucosylation of flavonols and may also participate in xenobiotic metabolism. The latter function is supported by the proven ability of strawberries to glucosylate selected unnatural substrates injected in ripe fruits. This report presents the first biochemical characterization of enzymes mainly expressed in strawberry achenes and provides the foundation of flavonoid metabolism in the seeds.     

Antiplasmodial activity of sesquilignans and sesquineolignans from Bonamia spectabilis

Phytochemical re-investigation of the aerial parts of Bonamia spectabilis (Convolvulaceae) led to the isolation of four minor tetrahydrofuran-type sesquilignans (bonaspectins E-H) together with the known neolignan virolongin A and the known lignan rel-(7S,8R,7'R,8'R)-3,3',4,4',5,5'-hexamethoxylignan. Their structures were established on the basis of spectral data. These six compounds as well as further seven lignanoids from B. spectabilis, characterised previously, were tested for their antiplasmodial activity against a chloroquine-sensitive strain (PoW) and a chloroquine-resistant clone (Dd2) of Plasmodium falciparum. Bonaspectin C 4"-O-glucoside, its aglycone, and bonaspectin D 4"-O-glucoside revealed the highest antiplasmodial activities (IC50 values: 1.3, 2.0, 6.5 microM [PoW]; 1.7, 4.6, 3.7 microM [Dd2], respectively).     

Three labdane diterpenoids from Aframomum sceptrum (Zingiberaceae)

Three labdane diterpenoids, 8beta,17-epoxy-3beta,7beta-dihydroxy-12(E)-labden-16,15-olide (1), methyl 8beta,17-epoxy-3beta,7beta,15-trihydroxy-12(E)-labden-16-oate (2) and 3beta,7beta,8beta,12zeta,17-pentahydroxylabdan-16,15-olide (3) have been isolated from the seeds of Afromomum sceptrum K. Schum (Zingiberaceae) and their structures assigned on the basis of their spectroscopic properties. Nerolidol, and the known flavonoids 3-acetoxy-4',5,7-trihydroxyflavanone, and 3,4',5,7-tetrahydroxyflavanone were also obtained.     

4'-Acetylvitexin-2'-O-rhamnoside, isoorientin, orientin, and 8-methoxykaempferol-3-O-glucoside as markers for the differentiation of Crataegus monogyna and Crataegus pentagyna from Crataegus laevigata (Rosaceae)

In our chemotaxonomic investigation of pharmaceutically relevant Crataegus species, the qualitative and quantitative flavonoid fingerprint of Crataegus monogyna and C. pentagyna is presented. Six flavonoids were identified as vitexin-2'-O-rhamnoside (1), vitexin (2), isovitexin (3), rutin (4), hyperoside (5), and isoquercitrin (6). Besides the verification of the main compounds isoorientin (7) and orientin (8) in C. pentagyna, further four flavonoids were isolated and identified as isoorientin-2'-O-rhamnoside (9), orientin-2'-O-rhamnoside (10), isovitexin-2'-O-rhamnoside (11), and 8-methoxykaempferol-3-O-glucoside (12) by means of 1D- and 2D-NMR, MS, and UV analyses. Compound 12 was isolated for the first time from C. pentagyna. In contrast to C. pentagyna, C. monogyna samples were predominated by 4'-acetylvitexin-2'-O-rhamnoside (13), which was missing in C. pentagyna. Hence, 13 represents an interesting compound for chemotaxonomy of C. monogyna, whereas the main flavonoids 7, 8, and 12 could be proposed as markers for C. pentagyna. The absence of 7, 8, 12, and 13 in C. laevigata offers an appropriate tool for additional differentiation from C. monogyna and C. pentagyna, and for sample identification and quality control of the three main Crataegus species used in European phytotherapy.     

Antimicrobial evaluation of coumarins and flavonoids from the stems of Daphne gnidium L.

The antimicrobial activity of stems methanol extract from Daphne gnidium L. collected from Sardinia (Italy) was evaluated against 6 strains of standard and clinical isolated gram (+/-) bacteria. The antimicrobial effect on two strains of fungi was also tested. The extract in toto exhibited antibacterial activity against Bacillus lentus and Escherichia coli, but was inactive against fungi. Four coumarins (daphnetin, daphnin, acetylumbelliferone, daphnoretin) and seven flavonoids (luteolin, orientin, isoorientin, apigenin-7-O-glucoside, genkwanin, 5-O-beta-D-primeverosyl genkwanine, 2,5,7,4'-tetrahydroxyisoflavanol) present in the plant extract were also investigated against the same strains of bacteria and fungi assayed for the crude extract. The most active compounds were daphnetin, genkwanin, and 2,5,7,4'-tetrahydroxyisoflavanol.     

Flavonoids from Andrographis lineata

Three flavonoids, 5,7,2',3',4'-pentamethoxyflavone (1), 2'-hydroxy-2,4',6'-tri methoxychalcone (2) and dihydroskullcapflavone I (3), together with 17,19,20-trihydroxy-5beta, 8alpha H, 9beta H,10alpha-labd-13-en-16,15-olactone (4), a known diterpenoid and six known flavonoids, 5-hydroxy-7,8-dimethoxyflavanone (5), 5-hydroxy-7,8,2',3',4'-pentamethoxyflavone (6), 5,2'-dihydroxy-7-methoxyflavanone (7), 5,2'-dihydroxy-7,8-dimethoxyflavone (8), 5,2'-dihydroxy-7-methoxyflavone (9) and 5,2'-dihydroxy-7-methoxyflavone 2'-O-beta-D-glucopyranoside (10) were isolated from the whole plant of Andrographis lineata. The structures of these compounds were elucidated on the basis of spectral and chemical studies.     

Luteolin and luteolin-7-O-glucoside from dandelion flower suppress iNOS and COX-2 in RAW264.7 cells

Both reactive oxygen- and nitrogen-derived reactive species play important roles in physiological and pathophysiological conditions. Flavones, luteolin and luteolin-7-O-glucoside along with a rich plant source of both flavones, namely dandelion (Taraxacum officinale) flower extract were studied for antioxidant activity in different in vitro model systems. In this current study, luteolin and luteolin-7-O-glucoside at concentrations lower than 20 microM, significantly (p < 0.05) suppressed the productions of nitric oxide and prostaglandin E2 (PGE2) in bacterial lipopolysaccharide activated-mouse macrophage RAW264.7 cells without introducing cytotoxicity. The inhibitory effects were further attributed to the suppression of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression, and not reduced enzymatic activity. Similar suppression for both inducible enzymes was also found with the presence of dandelion flower extract, specifically, the ethyl acetate fraction of dandelion flower extract which contained 10% luteolin and luteolin-7-O-glucoside.     

Protein glycosylation in Haloferax volcanii: partial characterization of a 98-kDa glycoprotein

Eubacterium ramulus, a flavonoid-degrading anaerobic bacterium from the human gastrointestinal tract, was tested for its ability to transform the isoflavonoids genistein-7-O-glucoside (genistin), genistein and daidzein. Genistein was completely degraded by E. ramulus via 6'-hydroxy-O-desmethylangolensin to 2-(4-hydroxyphenyl)-propionic acid. Dihydrogenistein was neither observed as an intermediate in this transformation nor converted itself by growing cells or cell-free extracts of E. ramulus. Genistein-7-O-glucoside was partially transformed by way of genistein to the product 2-(4-hydroxyphenyl)-propionic acid. Daidzein was in part degraded to O-desmethylangolensin, the corresponding metabolite to 6'-hydroxy-O-desmethylangolensin. The hydroxyl group in position 6' of O-desmethylangolensin is crucial for further degradation.