Luteolin as an anti-inflammatory and anti-allergic constituent of Perilla frutescens.
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Oral administration of the perilla leaf extract (PLE) to mice inhibits inflammation, allergic response, and tumor necrosis factor-alpha production. We also found that PLE suppressed the tumor necrosis factor-alpha (TNF-alpha) production in vitro. Using the inhibitory activity of TNF-alpha production in vitro as the index for isolation, we searched the active constituents from PLE and isolated luteolin, rosmarinic acid and caffeic acid as active components. Among the isolated compounds, only luteolin showed in vivo activity: inhibition of serum tumor necrosis factor-alpha production, inhibition of arachidonic acid-induced ear edema, inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced ear edema and inhibition of oxazolone-induced allergic edema. These results suggest that luteolin is a genuinely active constituent which is accountable for the oral effects of perilla. (+info)
Inhibitory effect of Perilla leaf extract and luteolin on mouse skin tumor promotion.
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In the present study, the effects of perilla leaf extract (PLE) and luteolin on 7,12-dimethylbenz[a]anthracene (DMBA)- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin papillomas in mice were investigated. Topical application of PLE prior to TPA treatment in DMBA-initiated mouse skin resulted in a significant reduction in tumor incidence and multiplicity. An even more potent preventive effect was observed with topical application of luteolin, which we previously identified as an antiinflammatory constituent. PLE was dissolved in drinking water at a 0.05% dose and mice ingested it ad libitum; no significant difference was observed in tumor incidence or multiplicity but there was a significant reduction in tumor volume between the PLE-treated and untreated groups. These results suggest that PLE has potent antipromotion activity and ingesting it as a daily food may provide a beneficial chemopreventive effect. (+info)
Developmental transition of the flavonoid contents in safflower leaves during stress-loaded cultivation.
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We have previously reported that strong visible light with limited water caused a significant increase in the polyphenol contents of safflower seedlings (Carthamus tinctrius L.), suggesting that the appropriate stress loading could be applied to effectively cultivate flavonoid-rich plants. In this present study, we investigated in detail the time-dependent transition in the flavonoid contents of safflower leaves during the stress-loaded cultivation. In the cotyledons, the light/water stress continuously increased the content of luteolin 7-O-glucoside, which is a strong antioxidant, whereas the content of acacetin 7-O-glucuronide, a weak antioxidant, generally remained unchanged. In the foliage leaves under the stress condition, the contents of the flavonoid glucosides (luteolin 7-O-glucoside and quercetin 7-O-glucoside) markedly increased on the 2nd day and then decreased to the level before stress loading on the 5th day. These results indicate that appropriate selection of the time for stress loading could provide more flavonoid-rich plants during the practical cultivation of vegetables. (+info)
Anaerobic degradation of flavonoids by Clostridium orbiscindens.
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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 x 10(8) to 2.50 x 10(9) cells g of fecal dry mass(-1), corresponding to a mean count of 4.40 x 10(8) cells g of dry feces(-1). (+info)
Antimutagenic activity of flavonoids from Chrysanthemum morifolium.
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A methanol extract from the flower heads of Chrysanthemum morifolium showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract was re-extracted with hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction showed a suppressive effect. Suppressive compounds in the ethyl acetate fraction were isolated by silica gel column chromatography and identified as the flavonoids acacetin (1), apigenin (2), luteolin (3), and quercetin (4) by EI-MS, IR, and (1)H and 13C NMR spectroscopy. Compounds 1-4 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1-4 suppressed 60.2, 75.7, 90.0, and 66.6% of the SOS-inducing activity at a concentration of 0.70 micromol/ml. The ID50 (50% inhibitory dose) values of 1-4 were 0.62, 0.55, 0.44, and 0.59 micromol/ml. These compounds had the suppressive effects on umu gene expression of the SOS response against other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver-metabolizing enzymes. These compounds also showed the suppression of SOS-inducing activity against the other mutagens aflatoxin B1 (AfB1) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver-metabolizing enzymes, and UV irradiation. In addition to the antimutagenic activities of these compounds against furylfuramide, Trp-P-1 and activated Trp-P-1 were also assayed by the Ames test using S. typhimurium TA100. (+info)
Production of unnatural glucosides of curcumin with drastically enhanced water solubility by cell suspension cultures of Catharanthus roseus.
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Catharanthus roseus cell suspension cultures converted exogenously supplied curcumin to a series of glucosides, none of which has been found in nature so far. The efficiency of glucosylation was dependent on culture stage of the cells and medium sucrose concentration. Methyl jasmonate and salicylic acid enhanced the glucoside formation only when they were added to the cultures prior to the addition of curcumin. The glucoside yield was 2.5 micromol/g fresh weight of the cells at an optimal culture condition. The water solubility of curcumin-4',4"-O-beta-D-digentiobioside was 0.65 mmol/ml, which was 20 million-fold higher than that of curcumin. (+info)
Metabolism of apigenin by rat liver phase I and phase ii enzymes and by isolated perfused rat liver.
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The metabolism of apigenin, a low estrogenic flavonoid phytochemical, was investigated in rat using liver models both in vitro (subcellular fractions) and ex vivo (isolated perfused liver). In vitro, phase I metabolism led to the formation of three monohydroxylated derivatives: luteolin which was the major metabolite (K(m) = 22.5 +/- 1.5 microM; V(max) = 5.605 +/- 0.090 nmol/min/mg protein, means +/- S.E.M.), scutellarein, and iso-scutellarein. These oxidative pathways were mediated by cytochrome P450 monooxygenases (P450s). The use of P450 inhibitors and inducers showed that CYP1A1, CYP2B, and CYP2E1 are involved. In vitro studies of phase II metabolism indicated that apigenin underwent conjugation giving three monoglucuronoconjugates and one monosulfoconjugate. Luteolin led to the formation of four monoglucuronoconjugates, two sulfoconjugates, and one methylconjugate identified as diosmetin. Ex vivo during the apigenin perfusion of an isolated rat liver, none of the phase I metabolites could be recovered. In contrast, two monoglucuronoconjugates and one of the sulfoconjugates of apigenin already identified in vitro were recovered. Moreover, two new derivatives were isolated and identified as a diglucuronoconjugate and a glucuronosulfoconjugate. This work provides new data about the metabolism of apigenin and shows the interest value of using various experimental models in metabolic studies. (+info)
A hydroxyl group of flavonoids affects oral anti-inflammatory activity and inhibition of systemic tumor necrosis factor-alpha production.
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We previously reported that oral administration of luteolin can inhibit serum tumor necrosis factor (TNF)-alpha production and several inflammatory and allergic models. We investigated here the effect of various flavonoids which resemble luteolin in structure. Lipopolysaccharide (LPS)-induced TNF-alpha production from macrophages was inhibited by treatment with flavone (luteolin, apigenin, and chrysin), flavonol (quercetin and myricetin), flavanonol (taxifolin), and anthocyanidin (cyanidin chloride) in vitro. Most of these, however, did not affect mice when administered orally. Serum TNF-alpha production was inhibited only by luteolin or apigenin, and only luteolin or quercetin inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema. These results suggest that the structure of luteolin: 3',4',5,7-tetrahydroxyflavone, is most suitable for the oral anti-inflammatory activity and that existence or disappearance of a hydroxy group may cause a loss of efficiency. (+info)