Phenolic composition, antioxidant properties, and endothelial cell function of red and white cranberry fruits.

The effects of phenolic constituents in red cranberry extracts (RCE) and white cranberry extracts (WCE) on the endothelial cell function were investigated. Peonidin-3-O-galactoside, cyanidin-3-O-arabinoside, and cyanidin-3-O-galactoside were the predominant anthocyanins characterized, whereas a procyanidin tetramer was the predominant proanthocyanidin identified. The antioxidant properties of RCE and WCE were not significantly different regardless of antioxidant assays (DPPH, FRAP, and TEAC) used. Both RCE and WCE induced the phosphorylation of Akt in vitro in human umbilical endothelial cells (HUVEC), resulting in the phosphorylation of endothelial nitric oxide synthase, cell migration, and tube formation. The enhanced phosphorylation of PI3/Akt kinase in HUVEC, endothelial cell wound healing, and tube formation elicited by RCE and WCE suggest that overall phenolic constituents rather than individual phenolic compounds within the cranberry matrix may be responsible for these biological effects.

Berry fruits modulated endothelial cell migration and angiogenesis via phosphoinositide-3 kinase/protein kinase B pathway in vitro in endothelial cells.

Polyphenolic-rich berry fruits are known to activate redox-sensitive cellular signaling molecules such as phosphatidylinositol-3-kinase (PI3 kinase)/kinase B (Akt), resulting in a cascade of downstream signaling pathways. This study investigated the ability of strawberry (SB), wild blueberry (WBB), and cranberry (CB) extracts to induce the activation of PI3 kinase/Akt signaling in vitro in human umbilical endothelial cells (HUVECs) and whether this activation would enhance cell migration and angiogenesis. Anthocyanin profiles of the extracts were characterized using HPLC-ESI/MS, and Akt activation was investigated using the Alpha Screen SureFire assay. The total anthocyanin contents of SB, WBB, and CB extracts were 81.7, 82.5, and 83.0 mg/100 g fresh weight, respectively. SB, WBB, and CB extracts activated Akt in a dose-dependent manner via PI3 kinase and induced cell migration and angiogenesis in vitro in HUVECs. The results from this study suggest that polyphenolics in berry fruits may play a role in promoting vascular health.

Modeling relationships among active components in black raspberry (Rubus occidentalis L.) fruit extracts using high-resolution (1)H nuclear magnetic resonance (NMR) spectroscopy and multivariate statistical analysis.

A process was developed to ascertain the bioactive components of black raspberry (Rubus occidentalis L.) fruit extracts by relating chemical constituents determined by high-field nuclear magnetic resonance (NMR) spectroscopy to biological responses using partial least-squares regression analysis. To validate our approach, we outlined relationships between phenolic signals in NMR spectra and chemical data for total monomeric anthocyanin (TMA) content and antioxidant capacity by the ferric-reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Anthocyanins, cyanidin 3-O-rutinoside (Cy 3-rut), cyanidin 3-O-(2(G))-xylosylrutinoside (Cy 3-xylrut), and cyanidin 3-O-glucoside (Cy 3-glc), were significant contributors to the variability in assay results, with the two most important NMR bins corresponding to the methyl peaks in Cy 3-rut (6''') and/or Cy 3-xylrut (6(IV)). Many statistically important bins were common among assay models, but differences in structure-activity relationships resulted in changes in bin ranking. The specificity of these results supported the application of the process to investigate relationships among health-beneficial natural products and potential biological activity.

Cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside as primary phenolic antioxidants in black raspberry.

Anthocyanin constituents in black raspberries (Rubus occidentalis L.) were investigated by HPLC-DAD, and their involvement as potent, significant antioxidants in black raspberries was demonstrated by three common antioxidant assays (FRAP, DPPH, ABTS) in this study. Five anthocyanins were present in black raspberries: cyanidin 3-sambubioside, cyanidin 3-glucoside, cyanidin 3-xylosylrutinoside, cyanidin 3-rutinoside, and pelargonidin 3-rutinoside. Their identities and structures, with particular emphasis on cyanidin 3-xylosylrutinoside, were confirmed by NMR spectroscopy. Two of these anthocyanins, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside, predominated, comprising 24-40 and 49-58%, respectively, of the total anthocyanins in black raspberries. On the basis of both potency and concentration, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside were found to be the significant contributors to the antioxidant systems of black raspberries. These findings indicate that these two anthocyanin compounds may function as the primary phenolic antioxidants in black raspberries. These two compounds exhibit potential biological activities that may be exploited in conjunction with other naturally occurring bioactive compounds in black raspberry fruit-based products used in clinical trials for the treatment of various types of cancer.

Modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (abts) method to measure antioxidant capacity of Selected small fruits and comparison to ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods.

The measurement of antioxidant capacity in fruits differs from that of other biological samples due to their low pH and very low lipophilic antioxidant capacity. In this report, we present a modified 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method for fruits and compare its performance with the other commonly used antioxidant methods of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The antioxidant capacity and reaction kinetics of four phenolic compounds, two antioxidant standards, and five fruits were also investigated. The modified ABTS method prepared at a pH of 4.5 with sodium acetate buffer is highly stable and easily applied to fruit samples as compared to the standard (pH 7.4) version. The measured antioxidant capacity of samples varied with the assay method used, pH, and time of reaction. Traditional antioxidant standards (trolox, ascorbic acid) displayed stable, simple reaction kinetics, which allowed end point analysis with all of assays. Of the phenolic compounds examined, chlorogenic and caffeic acids exhibited the most complex reaction kinetics and reaction rates that precluded end point analysis while gallic acid and quercetin reached stable end points. All fruit extracts exhibited complex and varied kinetics and required long reaction times to approach an end point. Because the antioxidant capacity of fruit extracts is a function of the array of individual antioxidants present, accurate comparisons among fruit samples require that reaction times be standardized and of sufficient length to reach steady state conditions and that more than one assay be used to describe the total antioxidant activity of fruit samples.

Reversible and irreversible emission of methanethiol and dimethyl disulfide from anaerobically stored broccoli.

The reversible and irreversible emission of methanethiol (MT) and dimethyl disulfide (DMDS) from broccoli florets was demonstrated during anaerobic storage at 20 degrees C for up to 24 h. Reversible emission of MT and DMDS was feasible only in broccoli stored for between 0 and 12 h under entirely anaerobic condition. Beyond that, the emission was completely irreversible. This irreversible process was demonstrated through significant reductions in the chlorophyll fluorescence values and rate of carbon dioxide production and significant increase in the membrane permeability of induced broccoli tissues after exposure to air and incubation. Irreversible emission was also demonstrated through significant change in color from the characteristic bright green to olive green as well as the conversion of chlorophyll a to pheophytin a and chlorophyll a' contents of the induced florets after hot-water treatment. These findings suggest that the irreversible emission of MT and DMDS is a function of permanent membrane damage and loss of intracellular compartmentation in the broccoli tissues as a result of the anaerobic induction. The off-odor formation can still be reversed if the affected tissue is only temporarily impaired by anaerobic condition, thereby maintaining the quality of stored broccoli.

Formation of methanethiol and dimethyl disulfide in crushed tissues of broccoli florets and their inhibition by freeze-thawing.

The formation of methanethiol and dimethyl disulfide in crushed, homogenized, and frozen-thawed tissues of broccoli florets was investigated. These volatile sulfur compounds were produced in crushed florets, but their formation was inhibited in frozen-thawed tissues. Only dimethyl disulfide was formed in homogenized tissues. High pH treatment triggered the release of dimethyl disulfide in frozen-thawed tissues and also enhanced the action of cysteine sulfoxide lyase in all disrupted tissues. Methyl methanethiosulfinate and methyl methanethiosulfonate were not detected in crushed florets; thus, the favored mechanism for the formation of methanethiol and dimethyl disulfide is the chemical disproportionation of methanesulfenic acid. In contrast, the formation of dimethyl disulfide in frozen-thawed and homogenized tissues occurs from the chemical disproportionation of methyl methanethiosulfinate that was detected in these tissues. The inhibition of dimethyl disulfide production during freeze-thawing must be caused by a sudden drop in the pH of the tissue, adherence of dimethyl disulfide on the tissue surfaces, and weakening of the cysteine sulfoxide lyase activity under acidic conditions.