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Tricin, a flavone isolated from rice bran, has been shown to be chemopreventive in a colorectal cancer (CRC) mouse model. This study aimed to illustrate the inhibitory activities of tricin in colon cancer cells and in a metastatic CRC mouse model. BALB/c mice injected with mouse Colon26-Luc cells into the rectum wall were treated with tricin (37.5 mg/kg) daily for 18 days. Orthotopic colon tumor growth and metastasis to lungs were assessed by in vivo bioluminescence imaging. Results showed that tricin suppressed Colon-Luc cells motility and downregulated phosphorylated Akt, Erk1/2 and NF-κB expressions of human colon cancer HT-29 cells. While tricin treatment suppressed tumor growth and lung metastasis as well as altered the populations of myeloid-derived suppressor cells and regulatory T cells in spleens. In summary, the tumor microenvironment modulatory and anti-metastatic effects of tricin in colon cancer mouse model were shown for the first time, suggesting the potential development of tricin-containing food supplements for CRC patients.

Use of enhanced LC-MS/MS methods to identify common glycosyl groups of flavonoid glycosides enabled better characterization of the flavonoids in fruits of sea buckthorn (Hippophae rhamnoides). The saccharide moieties of 48 flavonol O-glycosides detected in a methanol extract were identified by these methods. Several of the flavonol glycosides were acylated, two of which were isolated and found to be new compounds. Their structures were determined using spectroscopic and chemical methods as isorhamnetin 3-O-(6-O-E-sinapoyl-β-D-glucopyranosyl)-(1→2)-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (24) and isorhamnetin 3-O-(6-O-E-feruloyl-β-D-glucopyranosyl)-(1→2)-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (30). Analysis of the acylated glycosyl groups of 24 and 30 by serial mass spectrometry provided evidence to suggest the acylation position of 11 other minor flavonol glycosides acylated with hydroxycinnamic or hydroxybenzoic acids. The nitric oxide scavenging activities of 24 and 30 were compared with those of other flavonoids and with ascorbic acid and the potassium salt of 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3-oxide (carboxy-PTIO).

Increasing interest in phenolic compounds in olives is due to their antioxidant and health-enhancing properties. In this study the phenolics in fruits of the Tunisian olive cultivar Chemlali were extracted by methanol-water and fractionated using Sephadex LH-20 column chromatography. The identification of phenolic monomers and flavonoids was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analysis. Oleuropein, a secoiridoid glycoside esterified with a phenolic acid, was the major compound. Eight phenolic monomers and 12 flavonoids were also identified in Chemlali olives. Five flavonoids were isolated and purified using Sephadex LH-20 column chromatography and preparative paper chromatography. The antioxidant activity of the extract and the purified compounds was evaluated by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and by using the beta-carotene-linoleate model assay. Acid hydrolysis of the extract enhanced its antioxidant activity. Hydroxytyrosol and quercetin showed antioxidant activities similar to that of 2,6-di-tert-butyl-4-methylphenol. A hydroxyl group at the ortho position at 3' on the B ring of the flavonoid nucleus could contribute to the antioxidant activity of the flavonoids.

Two flavonol O-glycosides identified as the 3-O-alpha-arabinopyranosyl(1'''-->6'')-beta-glucopyranoside 7-O-beta-glucopyranosides of kaempferol and quercetin were isolated from the whole plant of Corydalis bungeana Turcz. together with eight known flavonol O-glycosides. Two isoquinolinone alkaloids were also obtained from the same source, including the new derivative, 6,7-methylenedioxy-2-(6-acetyl-2,3-methylenedioxybenzyl)-1(2H)-isoquinolinone. The structures were determined by spectroscopic methods (NMR and high-resolution MS).

A new flavone C-glycoside, apigenin 6-C-alpha-L-arabinopyranosyl-8-C-beta-L-arabinopyranoside, has been isolated from Viola yedoensis together with the known compounds, apigenin 6,8-di-C-alpha-L-arabinopyranoside, apigenin 6-C-alpha-L-arabinopyranosyl-8-C-beta-D-glucopyranoside (isoschaftoside), apigenin 6-C-beta-D-glucopyranosyl-8-C-alpha-L-arabinopyranoside (schaftoside), apigenin 6-C-beta-D-glucopyranosyl-8-C-beta-L-arabinopyranoside (neoschaftoside), apigenin 6,8-di-C-beta-D-glucopyranoside (vicenin-2), apigenin 6-C-alpha-L-arabinopyranosyl-8-C-beta-D-xylopyranoside, apigenin 6-C-beta-D-xylopyranosyl-8-C-alpha-L-arabinopyranoside, luteolin 6-C-beta-D-glucopyranoside (isoorientin) and luteolin 6-C-alpha-L-arabinopyranosyl-8-C-beta-D-glucopyranoside (isocarlinoside). The structures were determined by spectroscopic methods and new or revised (1)H- and (13)C-NMR spectral assignments are proposed for some compounds.

Recent contributions to the role of phenolics, especially flavonoids, in different aspects of insect-plant interactions are reviewed, including data on the effects of rutin on the feeding behaviour of a range of noctuid larvae.

A new flavonol triglycoside, isorhamnetin 3-O-beta-D-xylopyranosyl-(1""-->3)-alpha-L-rhamnopyranosyl-(1'''-->6")-beta-D-galactopyranoside, has been isolated from the leaves of Hammada scoparia together with two known compounds, isorhamnetin 3-O-beta-D-apiofuranosyl-(1'''-->2")[alpha-L-rhamnopyranosyl-(1""-->6")]-beta-D-galactopyranoside and isorhamnetin 3-O-alpha-L-rhamnopyranosyl-(1'''-->2")[alpha-L-rhamnopyranosyl-(1""-->6")]-beta-D-galactopyranoside. The structures were determined by spectroscopic methods.

Leaves of Hyparrhenia hirta yielded the rare diastereoisomeric flavonolignans tricin 4'-O-(erythro-beta-guaiacylglyceryl) ether and tricin 4'-O-(threo-beta-guaiacylglyceryl) ether together with their 7-O-glucosides, which are the first flavonolignan glycosides to be isolated as natural products. A complete set of (1)H and (13)C NMR resonance assignments obtained for both flavonolignan aglycones indicates the need for revision of data published previously for these compounds and for a reassessment of their original stereochemical designation.

Pelargonium graveolens (Geraniaceae) was characterized with respect to its chemical composition, antioxidant potential and antimicrobial activities. This is the first investigation focusing on the comparison of both essential oil and polar extracts from this species. The chemical composition of the essential oil of the aerial parts of P. graveolens was analyzed by gas chromatography/mass spectrometry. The main constituents of the oil were found to be β-citronellol (21.9%), citronellyl formate (13.2%), geraniol (11.1%), 10-epi-γ-eudesmol (7.9%), geranyl formate (6.2%) and (l)-linalool (5.6%). Nine flavonoids were identified by high-performance liquid chromatography-MS in leaf and flower extracts. Kaempferol 3- O-rhamnoside-glucoside, isorhamnetin aglycone, quercetin 3- O-glucoside, kaempferol 3,7-di- O-glucoside, quercetin 3- O-pentose and kaempferol 3- O-glucoside, quercetin 3- O-rhamnoside-glucoside, quercetin 3- O-pentoside-glucoside, myrisetin 3- O-glucoside-rhamnoside flavonoids were detected in methanolic and aqueous extracts, respectively. The total flavonoids ranged between 29.9 and 78.2 mg QE/g in flower water and methanol extracts, respectively, and 22.5 and 71.2 mg QE/g dry weight in leaf water and methanol extracts, respectively. The highest antioxidant activities using two methods of free radical scavenging capacities were obtained with the essential oil (9.16 mM of Trolox and 2.68 µg/ml). All P. graveolens essential oil and polar extracts were active against at least one bacterium. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]