Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Apigenin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1996

Involvement of monoamine oxidase and noradrenaline uptake in the positive chronotropic effects of apigenin in rat atria.

In rat isolated atria spontaneously beating and labelled with [3H]noradrenaline, exposure to the flavonoid apigenin increased the atrial rate in a concentration-dependent manner (0.01-30 microM). This increase was accompanied by a reduction of 60% in the uptake of [3H]noradrenaline as well as by a modification in the pattern of [3H]noradrenaline and metabolites spontaneously released. Sixty minutes after exposure to 30 microM apigenin, the proportion of unmetabolized [3H]noradrenaline increased from 11% to 45% of the total products collected in the organ bath whereas the tritiated O-methylated deaminated metabolites decreased from 33% to 14% of the total efflux. A small but significant decrease in the outflow of [3H]3,4-dihydroxymandelic acid as well as a tendency to a decrease in the efflux of [3H]3,4-dihydroxyphenylglycol was also observed. Furthermore, apigenin inhibited in a concentration-dependent manner the activity of monoamine oxidase in the rat atrial homogenates. The calculated IC50 (7.7 microM) was within the range that produced 50% of the maximal increase in atrial rate. It is concluded that apigenin possesses the property to increase the atrial rate, probably as a result of a reduction in noradrenaline uptake as well as in monoamine oxidase activity.

Animals↗
PubMed1998

Column-switching high-performance liquid chromatographic assay for determination of apigenin and acacetin in human urine with ultraviolet absorbance detection.

A high-performance liquid chromatographic (HPLC) method is described for the determination of apigenin and the 4'-methylated derivative acacetin in human urine using column-switching and ultraviolet (UV) absorbance detection. Urine samples were enzymatically hydrolysed and solid-phase extracted prior to injection onto the HPLC system. Prior to elution of apigenin and the internal standard, 5,7,8-trihydroxyflavone, from the first column used for sample clean-up, the six-port valve was switched to the second column for analysis with UV detection. Detection of apigenin was precise and reproducible, with a limit of quantification of 10 ng ml(-1) urine. Detection and quantification of acacetin was linear down to 70 ng ml(-1) urine. The method has been successfully applied to determine the level of apigenin in 100 human urine samples from an intervention study with parsley.

Anticarcinogenic Agents↗
PubMed1995

Apigenin, a component of Matricaria recutita flowers, is a central benzodiazepine receptors-ligand with anxiolytic effects.

The dried flower heads of Matricaria recutita L. (Asteraceae) are used in folk medicine to prepare a spasmolytic and sedative tea. Our fractionation of the aqueous extract of this plant led to the detection of several fractions with significant affinity for the central benzodiazepine receptor and to the isolation and identification of 5,7,4'-trihydroxyflavone (apigenin) in one of them. Apigenin competitively inhibited the binding of flunitrazepam with a Ki of 4 microM and had no effect on muscarinic receptors, alpha 1-adrenoceptors, and on the binding of muscimol to GABAA receptors. Apigenin had a clear anxiolytic activity in mice in the elevated plusmaze without evidencing sedation or muscle relaxant effects at doses similar to those used for classical benzodiazepines and no anticonvulsant action was detected. However, a 10-fold increase in dosage produced a mild sedative effect since a 26% reduction in ambulatory locomotor activity and a 35% decrement in hole-board parameters were evident. The results reported in this paper demonstrate that apigenin is a ligand for the central benzodiazepine receptors exerting anxiolytic and slight sedative effects but not being anticonvulsant or myorelaxant.

Animals↗
PubMed2007

Chlorpromazine and apigenin reduce adenovirus replication and decrease replication associated toxicity.

BACKGROUND: Adenoviruses can cause severe toxicity in immunocompromised individuals. Although clinical trials have confirmed the potency and safety of selectively oncolytic adenoviruses for treatment of advanced cancers, increasingly effective agents could result in more toxicity and therefore it would be useful if replication could be abrogated if necessary. METHODS: We analyzed the effect of chlorpromazine, an inhibitor of clathrin-dependent endocytosis and apigenin, a cell cycle regulator, on adenovirus replication and toxicity. First, we evaluated the in vitro replication of a tumor targeted Rb-p16 pathway selective oncolytic adenovirus (Ad5/3-Delta24) and a wild-type adenovirus in normal cells, fresh liver samples and in ovarian cancer cell lines. Further, we analyzed the in vitro cell killing efficacy of adenoviruses in the presence and absence of the substances. Moreover, the effect on in vivo efficacy, replication and liver toxicity of the adenoviruses was evaluated. RESULTS: We demonstrate in vitro and in vivo reduction of adenovirus replication and associated toxicity with chlorpromazine and apigenin. Effective doses were well within what would be predicted safe in humans. CONCLUSIONS: Chlorpromazine and apigenin might reduce the replication of adenovirus, which could provide a safety switch in case replication-associated side effects are encountered in patients. In addition, these substances could be useful for the treatment of systemic adenoviral infections in immunosuppressed patients.

Adenocarcinoma↗
PubMed2006

Differential modulation of cyclooxygenase-mediated prostaglandin production by the putative cancer chemopreventive flavonoids tricin, apigenin and quercetin.

OBJECTIVES: Diet-derived flavonoids possess cancer chemopreventive properties in preclinical models. The knowledge of the pharmacology of most flavonoids is insufficient to warrant their advancement to clinical evaluation. METHODS: Here the three flavonoids tricin from rice bran, apigenin from leafy vegetables, and quercetin from onions and apples, were compared in terms of their ability to modulate cyclooxygenase- (COX-) catalyzed prostaglandin E-2 (PGE-2) generation. Specifically their effects on the following parameters were studied: (1) COX enzyme activity, (2) COX-2 expression in human-derived colon cancer cells HCA-7, which express COX-2 constitutively, (3) phorbol ester-mediated COX-2 induction in human colon epithelial cells (HCEC), and (4) PGE-2 levels in cellular incubations. RESULTS: Tricin and quercetin inhibited enzyme activity in purified COX-1 and -2 preparations with IC50 values of near 1 (tricin) and 5 microM (quercetin). Apigenin at up to 25 microM did not affect COX enzyme activity. Flavonoids were incubated with cells for 6 or 24 h and COX-2 protein expression and PGE-2 levels were assessed by Western blot and competitive immunoassay, respectively. None of the agents affected constitutive COX-2 expression in HCA-7 cells. Apigenin, but not tricin or quercetin, down-regulated inducible COX-2 expression in HCEC cells on 6 h incubation. All three flavonoids reduced cellular levels of PGE-2 in the supernatant of HCA-7 cells at both time points and of HCEC cells at 6 h. CONCLUSIONS: The results demonstrate that these structurally similar flavonoids regulate COX-mediated PGE-2 production in different fashions. Their ability to attenuate prostanoid levels may contribute to their cancer chemopreventive efficacy.

Animals↗
PubMed2004

Isolation, identification and stability of acylated derivatives of apigenin 7-O-glucoside from chamomile (Chamomilla recutita [L.] Rauschert).

The major flavonoids in the white florets of chamomile (Chamomilla recutita [L.] Rauschert) were rapidly purified using a combination of polyamide solid-phase extraction and preparative HPLC. From the combined LC/MS, LC/MS/MS, and NMR data the apigenin glucosides were identified as apigenin 7-O-glucoside (Ap-7-Glc), Ap-7-(6"-malonyl-Glc), Ap-7-(6"-acetyl-Glc), Ap-7-(6"-caffeoyl-Glc), Ap-7-(4"-acetyl-Glc), Ap-7-(4"-acetyl,6"-malonyl-Glc), and a partially characterised apigenin-7-(mono-acetyl/mono-malonylglucoside) isomer. Malonyl and caffeoyl derivatives of Ap-7-Glc have not previously been identified in chamomile. The two mono-acetyl/mono-malonyl flavonoids have not previously been reported in any plant species. These acylated glucosides are unstable and degrade to form acetylated compounds or Ap-7-Glc. The degradation products formed are dependent on the extraction and storage conditions, i.e. temperature, pH and solvent.

Acetylation↗
PubMed1993

Skin anti-inflammatory activity of apigenin-7-glucoside in rats.

The effect of apigenin-7-glucoside on skin inflammation induced by different generators of reactive oxygen species and free radicals was studied. Skin inflammation in rats was induced by intradermal injection of glucose-oxidase (hydrogen peroxide), xanthine-oxidase/hypoxanthine (superoxide anion radical), and cumene hydroperoxide (peroxyl radical). Subsequent intradermal application of liposomal apigenin-7-glucoside inhibited in a dose dependent manner skin inflammation caused by xanthine-oxidase and cumene hydroperoxide. Glucose-oxidase induced dermatitis was not significantly inhibited. The results are in good agreement with the in-vitro superoxide anion radical and peroxyl radical scavenging properties of apigenin and indicate that its antioxidant properties contribute to the anti-inflammatory effect in this model system.

Animals↗
PubMed1999

Effect of parsley (Petroselinum crispum) intake on urinary apigenin excretion, blood antioxidant enzymes and biomarkers for oxidative stress in human subjects.

Seven men and seven women participated in a randomized crossover trial to study the effect of intake of parsley (Petroselinum crispum), containing high levels of the flavone apigenin, on the urinary excretion of flavones and on biomarkers for oxidative stress. The subjects received a strictly controlled diet low in flavones and other naturally occurring antioxidants during the 2 weeks of intervention. This basic diet was supplemented with parsley providing 3.73-4.49 mg apigenin/MJ in one of the intervention weeks. Urinary excretion of apigenin was 1.59-409.09 micrograms/MJ per 24 h during intervention with parsley and 0-112.27 micrograms/MJ per 24 h on the basic diet (P < 0.05). The fraction of apigenin intake excreted in the urine was 0.58 (SE 0.16)% during parsley intervention. Erythrocyte glutathione reductase (EC 1.6.4.1; GR) and superoxide dismutase (EC 1.15.1.1; SOD) activities increased during intervention with parsley (P < 0.005) as compared with the levels on the basic diet, whereas erythrocyte catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.11.1.9) activities did not change. No significant changes were observed in plasma protein 2-adipic semialdehyde residues, a biomarker of plasma protein oxidation. In this short-term investigation, an overall decreasing trend in the activity of antioxidant enzymes was observed during the 2-week study. The decreased activity of SOD was strongly correlated at the individual level with an increased oxidative damage to plasma proteins. However, the intervention with parsley seemed, partly, to overcome this decrease and resulted in increased levels of GR and SOD.

Adult↗
PubMed2001

Flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants.

Studies were conducted on the flavonoids (myricetin, quercetin, kaempferol, luteolin, and apigenin) contents of 62 edible tropical plants. The highest total flavonoids content was in onion leaves (1497.5 mg/kg quercetin, 391.0 mg/kg luteolin, and 832.0 mg/kg kaempferol), followed by Semambu leaves (2041.0 mg/kg), bird chili (1663.0 mg/kg), black tea (1491.0 mg/kg), papaya shoots (1264.0 mg/kg), and guava (1128.5 mg/kg). The major flavonoid in these plant extracts is quercetin, followed by myricetin and kaempferol. Luteolin could be detected only in broccoli (74.5 mg/kg dry weight), green chili (33.0 mg/kg), bird chili (1035.0 mg/kg), onion leaves (391.0 mg/kg), belimbi fruit (202.0 mg/kg), belimbi leaves (464.5 mg/kg), French bean (11.0 mg/kg), carrot (37.5 mg/kg), white radish (9.0 mg/kg), local celery (80.5 mg/kg), limau purut leaves (30.5 mg/kg), and dried asam gelugur (107.5 mg/kg). Apigenin was found only in Chinese cabbage (187.0 mg/kg), bell pepper (272.0 mg/kg), garlic (217.0 mg/kg), belimbi fruit (458.0 mg/kg), French peas (176.0 mg/kg), snake gourd (42.4 mg/kg), guava (579.0 mg/kg), wolfberry leaves (547.0 mg/kg), local celery (338.5 mg/kg), daun turi (39.5 mg/kg), and kadok (34.5 mg/kg). In vegetables, quercetin glycosides predominate, but glycosides of kaempferol, luteolin, and apigenin are also present. Fruits contain almost exclusively quercetin glycosides, whereas kaempferol and myricetin glycosides are found only in trace quantities.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Interactions of the monomeric and dimeric flavones apigenin and amentoflavone with the plasma membrane of L929 cells; a fluorescence study.

Flavonoids are ubiquitous polyphenolic compounds, found in vascular plants, which are endowed with a large variety of biological effects. Some of these effects have been assumed to result from interactions with the cell plasma membrane. In order to investigate the nature of these interactions a fluorescence study was performed with two flavonoids, currently used in one of the laboratories: apigenin and its homologous dimer amentoflavone. After preliminary assays with DPH in several types of phospholipid liposomes, the effects of these flavonoids on the membrane of mouse L929 fibroblasts were compared, using the non-permeant probe TMA-DPH. Amentoflavone, unlike apigenin, induced a static quenching effect, which denoted an important, but reversible, association of the molecule with the plasma membrane. In addition, amentoflavone treatment induced a dose-dependent increase in TMA-DPH fluorescence anisotropy, which could be interpreted as an increase in membrane lipidic order. For apigenin, the effect was much less important. Moreover, exploiting the capacity of TMA-DPH to label endocytic compartments, it was shown that, after association with the membrane, amentoflavone is not internalized into the cell. Possible correlations of these membrane effects with other biological properties are discussed.

Animals↗
PubMedDate not supplied

Apigenin glycosides from the flowers of Bellis perennis L.

Two next apigenin glycosides, apigenin 7-O-beta-D-glucuronide [III], apigenin 7-O-beta-D-glucoside [IV] were isolated from the flowers of Bellis perennis L. Their structures were determined by means of chemical and spectroscopic methods.

Chromatography↗
PubMed2006

Stimulatory effect of genistein and apigenin on the growth of breast cancer cells correlates with their ability to activate ER alpha.

Genistein and apigenin are phytoestrogens present in commercial preparations used for the treatment of postmenopausal symptoms. In this study, we assessed the influence of these compounds on mammary tumor growth. Both compounds stimulate the proliferation of MCF-7 and T47D cells [estrogen receptor alpha (ERalpha-positive)], but do not stimulate the proliferation of an ERalpha-negative cell line (MDA-MB-435 cells). Genistein appeared more efficient in this regard due to its higher binding affinity for ERalpha, a property explained by a structural analysis of the binding of these compounds to the ERalpha's ligand binding domain. As previously described for estradiol (E(2)), genistein and apigenin down regulated ERalpha and enhanced estrogen response element (ERE)-dependent gene expression. The additional finding that genistein antagonizes the anti-proliferative effect of hydroxytamoxifen suggests phytoestrogens may be detrimental in women with breast cancer who are being treated with tamoxifen. In addition, because of their ability to stimulate breast cell growth, the widespread use of phytoestrogens in postmenopausal women could be detrimental.

Apigenin↗
PubMed2006

Prenylation enhances cytotoxicity of apigenin and liquiritigenin in rat H4IIE hepatoma and C6 glioma cells.

Antioxidative as well as cytotoxic effects of the prenylated flavonoids licoflavone C (8-prenylapigenin) and isobavachin (8-prenylliquiritigenin) were investigated in comparison to the corresponding non-prenylated flavonoids (apigenin, liquiritigenin) and vitexin (apigenin-C8-glucoside) using metabolically active H4IIE hepatoma and metabolically poorly active C6 glioma cells. None of the substances showed radical scavenging activities in the 2,2-diphenyl-1-picrylhydrazyl (DPPH)-assay nor were they effective in protection against H2O2-induced intracellular 2',7'-dichlorodihydrofluorescein (H2DCF) oxidation (fluorescent probe for oxidative stress) in H4IIE and C6 cells. When the intrinsic effects of the substances were investigated, licoflavone C and isobavachin exerted a pronounced toxicity in both H4IIE (IC50 values of 42+/-5 and 96+/-19 micromol/L) and C6 cells (IC50 values of 37+/-6 and 69+/-3 micromol/L) while the non-prenylated analogues as well as the glycosylated derivate vitexin showed almost no cytotoxic effect up to 250 micromol/L. In H4IIE cells the induction of apoptotic cell death by licoflavone C and icobavachin was detected as an activation of caspase 3/7 (6- and 3.3-fold, respectively). Based on these experiments we suggest that C8-prenylation of a flavonoid enhances the cytotoxicity inducing an apoptotic cell death in H4IIE cells without affecting antioxidative properties.

Animals↗
PubMed2006

Evaluation of apigenin using in vitro cytochalasin blocked micronucleus assay.

High doses of flavonoids are reported to be clastogenic in contrast to their potential to reduce oxidative DNA damage, retard growth of leukemia cells, obstruct cell signal transduction and induce cellular differentiation in cancers. In the present study, we evaluated apigenin, a plant-derived flavonoid in doses of 10, 33, and 100 microM per 5 ml culture using cytochalasin-B blocked micronucleus (CBMN) assay in peripheral human lymphocytes. Apigenin was found to induce micronuclei in a dose dependent manner indicating potential genotoxic hazard in humans. Hence, flavonoids may act as mutagen, pro-oxidant or as inhibitor of key enzymes to produce clastogenic effects depending upon the levels consumed as well as the physiological parameters.

Apigenin↗
PubMed1994

(Delphinidin 3-gentiobiosyl) (apigenin 7-glucosyl) malonate from the flowers of Eichhornia crassipes.

A novel acylated delphinidin glycoside was isolated from the blue-purple flowers of Eichhornia crassipes as a major pigment, and was identified as (6'''-O-(delphinidin 3-O-(6''-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosyl))) (6''-O-(apigenin 7-O-(beta-D-glucopyranosyl)))malonate by spectral methods. The three dimensional structure of this pigment was suggested from the observation of the negative Cotton effect at lambda max 535 nm that delphinidin (chromophore) and apigenin (co-pigment) occupy a folding conformation as a binary complex.

Anthocyanins↗
PubMed2000

Behavioral characterisation of the flavonoids apigenin and chrysin.

The behavioral effects of acute administration of two flavonoids, apigenin and chrysin, contained in Matricaria chamomilla and in Passiflora incarnata, respectively, were studied in rats. The data demonstrate that in our experimental conditions, the two flavonoids were equally able to reduce locomotor activity when injected in rats at a minimal effective dose of 25 mg/kg. However, while chrysin exhibited a clear anxiolytic effect when injected at the dose of 1 mg/kg, apigenin failed to exert this activity. The sedative effect of these flavonoids cannot be ascribed to an interaction with GABA-benzodiazepine receptors, since it was not counteracted by the benzodiazepine antagonist Flumazenil. To the contrary, the anxiolytic effect of chrysin, which was blocked by the injection of Flumazenil, could be linked to an activation of the GABA(A) receptor unit.

Animals↗
PubMed2001

Peroxidative metabolism of apigenin and naringenin versus luteolin and quercetin: glutathione oxidation and conjugation.

GSH was readily depleted by a flavonoid, H(2)O(2), and peroxidase mixture but the products formed were dependent on the redox potential of the flavonoid. Catalytic amounts of apigenin and naringenin but not kaempferol (flavonoids that contain a phenol B ring) when oxidized by H(2)O(2) and peroxidase co-oxidized GSH to GSSG via a thiyl radical which could be trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to form a DMPO-glutathionyl radical adduct detected by ESR spectroscopy. On the other hand, quercetin and luteolin (flavonoids that contain a catechol B ring) or kaempferol depleted GSH stoichiometrically without forming a thiyl radical or GSSG. Quercetin, luteolin, and kaempferol formed mono-GSH and bis-GSH conjugates, whereas apigenin and naringenin did not form GSH conjugates. MS/MS electrospray spectroscopy showed that mono-GSH conjugates for quercetin and luteolin had peaks at m/z 608 [M + H](+) and m/z 592 [M + H](+) in the positive-ion mode, respectively. (1)H NMR spectroscopy showed that the GSH was bound to the quercetin A ring. Spectral studies indicated that at a physiological pH the luteolin-SG conjugate was formed from a product with a UV maximum absorbance at 260 nm that was reducible by potassium borohydride. The quercetin-SG conjugate or kaempferol-SG conjugate on the other hand was formed from a product with a UV maximum absorbance at 335 nm that was not reducible by potassium borohydride. These results suggest that GSH was oxidized by apigenin/naringenin phenoxyl radicals, whereas GSH conjugate formation involved the o-quinone metabolite of luteolin or the quinoid (quinone methide) product of quercetin/kaempferol.

Apigenin↗
PubMed2006

An apigenin-derived xanthine oxidase inhibitor from Palhinhaea cernua.

Fractionation of the ethanol extract of Palhinhaea cernua afforded a new (1) and two known p-coumaroylated apigenin glycosides (2, 3) in addition to dillenetin, rhamnazin, alpha-onocerin, beta-sitosterol, and (E)-2-hydroxy-5-methoxycinnamic acid. The structure of compound 1 was elucidated as apigenin-4'-O-(2' '-O-p-coumaroyl)-beta-D-glucopyranoside by a combination of its spectroscopic data. The new glycoside 1 inhibits xanthine oxidase (IC(50): 23.95 +/- 0.43 microM) in a competitive-noncompetitive manner with K(i) and K(I) values of 14.35 and 93.68 microM, whereas compounds 2 and 3 were inactive. The distribution and significance of acylated flavonoid glycosides are discussed.

Apigenin↗