Nicholi Vorsa

The structure of cranberry proanthocyanidins which inhibit adherence of uropathogenic P-fimbriated Escherichia coli in vitro.

Ethyl acetate extracts of Sephadex LH20-purified proanthocyanidins of American cranberry (Vaccinium macrocarpon Ait.) exhibited potent biological activity by inhibiting adherence of uropathogenic isolates of P-fimbriated Escherichia coli bacteria to cellular surfaces containing alpha-Gal(1-->4)beta-Gal receptor sequences similar to those on epithelial cells in the urinary tract. The chemical structures of the proanthocyanidins were determined by 13C NMR, electrospray mass spectrometry, matrix-assisted laser absorption time-of-flight mass spectrometry and by acid catalyzed degradation with phloroglucinol. The proanthocyanidin molecules consisted predominantly of epicatechin units with mainly DP of 4 and 5 containing at least one A-type linkage. The procyanidin A2 was the most common terminating unit occurring about four times as frequently as the epicatechin monomer.

Influence of cranberry proanthocyanidins on formation of biofilms by streptococcus mutans on saliva-coated apatitic surface and on dental caries development in vivo

Cranberry crude extracts, in various vehicles, have shown inhibitory effects on the formation of oral biofilms in vitro. The presence of proanthocyanidins (PAC) in cranberry extracts has been linked to biological activities against specific virulence attributes of Streptococcus mutans, e.g. the inhibition of glucosyltransferase (Gtf) activity. The aim of the present study was to determine the influence of a highly purified and chemically defined cranberry PAC fraction on S. mutans biofilm formation on saliva-coated hydroxyapatite surface, and on dental caries development in Sprague-Dawley rats. In addition, we examined the ability of specific PAC (ranging from low-molecular-weight monomers and dimers to high-molecular-weight oligomers/polymers) to inhibit GtfB activity and glycolytic pH drop by S. mutans cells, in an attempt to identify specific bioactive compounds. Topical applications (60-second exposure, twice daily) with PAC (1.5 mg/ml) during biofilm formation resulted in less biomass and fewer insoluble polysaccharides than the biofilms treated with vehicle control had (10% ethanol, v/v; p < 0.05). The incidence of smooth-surface caries in rats was significantly reduced by PAC treatment (twice daily), and resulted in less severe carious lesions compared to the vehicle control group (p < 0.05); the animals treated with PAC also showed significantly less caries severity on sulcal surfaces (p < 0.05). Furthermore, specific A-type PAC oligomers (dimers to dodecamers; 0.1 mg/ml) effectively diminished the synthesis of insoluble glucans by GtfB adsorbed on a saliva-coated hydroxyapatite surface, and also affected bacterial glycolysis. Our data show that cranberry PAC reduced the formation of biofilms by S. mutans in vitro and dental caries development in vivo, which may be attributed to the presence of specific bioactive A-type dimers and oligomers.

Influence of cranberry phenolics on glucan synthesis by glucosyltransferases and Streptococcus mutans acidogenicity

Aims:  To investigate the influence of several phenolic compounds isolated from cranberry fruit (Vaccinium macrocarpon) on some of the virulence properties of Streptococcus mutans associated with glucan synthesis and acidogenicity.

Human glycemic response and phenolic content of unsweetened cranberry juice.

This cross-sectional study determined the phenolic composition of an over-the-counter cranberry juice (CBJ) with high-performance liquid chromatography and examined the effects of low- and normal-calorie CBJ formulations on the postprandial glycemic response in healthy humans. The CBJ used in this study contained seven phenolic acids, with 3- and 5-caffeoylquinic acid being the primary components, and 15 flavonol glycosides, with myricetin-3-galactoside and quercetin-3-galactoside being the most prevalent. CBJ proanthocyanidins consisted of three different tetramers and a heptamer, which were confirmed with matrix-assisted laser desorption ionization-time of flight-mass spectrometry analysis. Participants received one of the following six treatments: nothing (no water/beverage), water (480 mL), unsweetened low-calorie CBJ (38 Cal/480 mL), normal-calorie CBJ (280 Cal/480 mL), isocaloric normal calorie (high fructose corn syrup [HFCS]), or isocaloric low-calorie beverages. No significant differences in postprandial blood glucose or insulin were observed in the groups receiving nothing, water, or low-calorie treatments. In contrast, the ingestion of normal-calorie CBJ and normal-calorie control beverage resulted in significantly higher blood glucose concentrations 30 minutes postprandially, although the differences were no longer significant after 180 minutes. Plasma insulin of normal-calorie CBJ and control (HFCS) recipients was significantly higher 60 minutes postprandially, but not significantly different 120 minutes postprandially. CBJ ingestion did not affect heart rate or blood pressure. This study suggests that the consumption of a low-calorie CBJ rich in previously uncharacterized trimer and heptamer proanthocyanidins is associated with a favorable glycemic response and may be beneficial for persons with impaired glucose tolerance.

Determination of ploidy level and nuclear DNA content in blueberry by flow cytometry

The technique of DNA flow cytometry was used to study variation in DNA content among different ploidy levels, as well as among diploid species, of Vaccinium section Cyanococcus. In a sample of plants of varying ploidy level, the relative fluorescence intensity (RFI) of nuclei stained with propidium iodide was a function of the number of chromosome sets (x), as represented by the linear equation RFI=3.7x-2.3 (r2=95%). The data indicated that DNA flow cytometry could be useful for the determination of ploidy level at the seedling stage in blueberry. They also suggest that “conventional polyploid evolution” has occurred in this section of the genus Vaccinium with an increase in nuclear DNA content concurrent with the increase in chromosome number. The nuclear DNA content of diploid species of Vaccinium section Cyanococcus was estimated from the relationship of the observed RFI to an internal known DNA standard (trout red blood cells). A nested analysis of variance indicated significant variation among species, as well as among populations within species, in nuclear DNA content, although this variation was small compared to the variation among ploidy levels. The variation in nuclear DNA content corresponded to the phylogenetic relationships among species determined from previous studies.

Tracing the history of plant traits under domestication in cranberries: potential consequences on anti-herbivore defences

The process of selecting certain desirable traits for plant breeding may compromise other potentially important traits, such as defences against pests; however, specific phenotypic changes occurring over the course of domestication are unknown for most domesticated plants. Cranberry (Vaccinium macrocarpon) offers a unique opportunity to study such changes: its domestication occurred recently, and we have access to the wild ancestors and intermediate varieties used in past crosses. In order to investigate whether breeding for increased yield and fruit quality traits may indirectly affect anti-herbivore defences, the chemical defences have been examined of five related cranberry varieties that span the history of domestication against a common folivore, the gypsy moth (Lymantria dispar). Direct defences were assessed by measuring the performance of gypsy moth caterpillars and levels of phenolic compounds in leaves, and indirect defences by assaying induced leaf volatile emissions. Our results suggest that breeding in cranberry has compromised plant defences: caterpillars performed best on the derived NJS98-23 (the highest-yielding variety) and its parent Ben Lear. Moreover, NJS98-23 showed reduced induction of volatile sesquiterpenes, and had lower concentrations of the defence-related hormone cis-jasmonic acid (JA) than ancestral varieties. However, induced direct defences were not obviously affected by breeding, as exogenous JA applications reduced caterpillar growth and increased the amounts of phenolics independent of variety. Our results suggest that compromised chemical defences in high-yielding cranberry varieties may lead to greater herbivore damage which, in turn, may require more intensive pesticide control measures. This finding should inform the direction of future breeding programmes.

Allozyme evidence for genetic autopolyploidy and high genetic diversity in tetraploid cranberry, Vaccinium oxycoccos (Ericaceae).

Polyploidy has been important in the evolution of angiosperms and may significantly affect population genetic diversity and structure. Nineteen isoenzyme loci were studied in diploid and tetraploid populations of Vaccinium oxycoccos (Ericaceae), and the results are compared with data previously reported for the related V. macrocarpon. Diploid V. oxycoccos and V. macrocarpon were readily discriminated based on their allozymic variation. No evidence for fixed heterozygosity was found in tetraploid V. oxycoccos. In contrast, all polymorphic loci exhibited both balanced and unbalanced heterozygotes, with some individuals exhibiting a pattern consistent with the presence of three alleles. These results support an autopolyploid origin for tetraploid V. oxycoccos. However, tetraploid V. oxycoccos possessed a suite of alleles not found in diploid V. oxycoccos; half of these alleles were shared with V. macrocarpon. This suggests that autotetraploid V. oxycoccos may have undergone hybridization with V. macrocarpon or that the autotetraploid retained the genetic variation present in an ancestral diploid species. Following theoretical expectations, proportion of polymorphic loci, mean number of alleles, and observed heterozygosity were significantly higher for the autotetraploid than for the diploid. Mean inbreeding (F(IS)) was similar for diploid and tetraploid V. oxycoccos. The latter exhibited population differentiation (F(ST)) exceeding both diploid species.

Polyploidy and sexual polyploidization in the genus Vaccinium

Genus Vaccinium,consisting of blueberries, cranberries, lingonberries and many related wild species, includes diploid, tetraploid, and hexaploid species. Most evidence indicates that the tetraploid species are autotetraploids, with non-preferential bivalent chromosome pairing. Although homoploid interspecific crosses usually produce numerous fertile hybrids if the parents are from the same section of the genus, inter sectional crosses at the diploid level normally produce no seedlings, weak seedlings, or seedlings that are very low in fertility. There is a strong but not complete triploid block within Vaccinium. Even with insections, tetraploid × diploid (and the reciprocal) crosses normally give only a few tetraploid and a few triploid hybrids. Hexaploid × diploid crosses within sections are very hard to make, and the few hybrids that have been obtained are pentaploid. The frequency of 2n gametes varies,both among genotypes within species and among species. Vaccinium pollen is normally shed in tetrads, and the frequency of large pollen grains shed in dyads can be used to estimate 2n gamete frequency. Cultivated blueberries occur at both the tetraploid and the hexaploid levels, and there are important genetic resources in the diploids. Unreduced gamete production has permitted transfer of genetic material from the diploid to the tetraploid level and from the diploids and tetraploids to the hexaploid level via triploid hybrids. Intersectional crosses can occasionally produce tetraploid Vaccinium hybrids that appear to behave as amphidiploids and have medium to high fertility. CommercialVaccinium cultivars are normally propagated by cuttings. Intersectional hybridization, chromosome doubling, and asexual propagation could permit the production of novel hybrid combinations with value as ornamentals or in fruit production.

RAPDs identify varietal misclassification and regional divergence in cranberry [Vaccinium macrocarpon (Ait.) Pursh]

The majority of cultivated cranberry varieties were selected from native populations in the 1800s and early 1900s from sites in Massachusetts, New Jersey, and Wisconsin. Since their initial selections 100–150 years ago, varietal identities have become increasingly confused; primarily the result of there being a paucity of qualitative markers to effectively distinguish among varieties. Random amplified polymorphic DNA (RAPD) technology has the potential for allowing a more definitive classification of varieties and was used in this study to characterize 22 cranberry varieties. Twenty-two decamer primers amplified 162 scorable DNA fragments, of which 66 (41%) were polymorphic. On the basis of these 66 silver-stained RAPDs (ssRAPDs), 17 unique profiles were identified rather than the expected 22. Fourteen varieties had unique ssRAPD profiles, while the remaining 8 were represented by 3 ssRAPD profiles. Permuational analyses of the data suggest that the observed ssRAPD profile duplications are examples of varietal misclassification. Further analyses identified 2 ssRAPD markers that were found only in Eastern varieties (from Mass. and N. J.) and not in Wisconsin varieties. With varieties differing on average by 22 bands, ssRAPDs are shown to be effective in varietal identification and the assessment of genetic diversity in cranberry.

Cranberry proanthocyanidins are cytotoxic to human cancer cells and sensitize platinum-resistant ovarian cancer cells to paraplatin.

Polyphenolic extracts of the principal flavonoid classes present in cranberry were screened in vitro for cytotoxicity against solid tumor cells lines, identifying two fractions composed principally of proanthocyanidins (PACs) with potential anticancer activity. Matrix‐Assisted Laser Desorption/Ionization Time‐Of‐Flight Mass Spectrometry (MALDI‐TOF‐MS) analysis of the proanthocyanidins (PACs) fractions indicated the presence of A‐type PACs with 1–4 linkages containing between 2–8 epicatechin units with a maximum of 1 epigallocatechin unit. PACs exhibited in vitro cytotoxicity against platinum‐resistant human ovarian, neuroblastoma and prostate cancer cell lines (IC50 = 79–479 µg/mL) but were non‐cytotoxic to lung fibroblast cells (IC50 > 1000 µg/ml). SKOV‐3 ovarian cancer cells treated with PACs exhibited classic apoptotic changes. PACs acted synergistically with paraplatin in SKOV‐3 cells. Pretreatment of SKOV‐3 cells with PACs (106 µg/ml) resulted in a significant reduction of the paraplatin IC50 value. Similarly, in a BrdU incorporation assay, co‐treatment of SKOV‐3 cells with PACs and paraplatin revealed reduced cell proliferation at lower concentrations than with either individually. In SKOV‐3 cell cultures co‐treated with PAC‐1 and paraplatin, an HPLC analysis indicated differential quantitative presence of various PAC oligomers such as DP‐8, ‐9, ‐11 and ‐14 indicating either selective binding or uptake. Cranberry proanthocyanidins exhibit cell‐line specific cytotoxicity, induce apoptotic markers and augment cytotoxicity of paraplatin in platinum‐resistant SKOV‐3 ovarian cancer cells. Copyright