Grape Skin Extract Research Articles

Effects of Defoliation on Phenolic Concentrations, Antioxidant and Antibacterial Activity of Grape Skin Extracts of the Varieties Blaufränkisch and Merlot (Vitis vinifera L.).

Vitis vinifera L. has been highlighted by its many positive effects on human health, including antibacterial, anti-inflammatory and antioxidant activity due to its rich phytochemical content. Removing six basal leaves has great potential to influence the production of phytochemicals. The purpose of this study was to determine the impact of different terms of defoliation on the antioxidant and antibacterial activity of grape skin extracts of the Blaufränkisch and Merlot varieties. The total phenolic concentration, total and individual anthocyanin concentration, antioxidant activity and antibacterial activity on gram-positive and gram-negative human pathogens have been determined. The study was conducted on three treatments (control treatment without defoliation, defoliation immediately after bloom and defoliation before the start of the véraison phase). The results showed statistically significant enhancement of the total phenolic concentration as well as the antioxidant and antibacterial activity in both studied cultivars. Defoliation just after blooming was the preferable defoliation term in the Merlot variety for achieving the highest total anthocyanin concentration, antioxidant activity and significant increase of antibacterial activity against all four investigated bacteria. Defoliation before the start of the véraison phase was the preferable defoliation term for achieving the highest total anthocyanin concentration in the Blaufränkisch variety. In general, treatment of defoliation immediately after bloom was more beneficial compared with the defoliation before the start of the véraison phase.

Abstract 1047: Novel roles for manganese superoxide dismutase polymorphisms in prostate cancer

Abstract Prostate Cancer is the most common non-cutaneous cancer and second leading cause of cancer related death in American men. Epithelial Mesenchymal Transition (EMT), a key event in prostate cancer metastasis, is a process in which polarized epithelial cells undergo biochemical changes, allowing them to assume mesenchymal morphologies, enhancing invasiveness and migration. Reactive Oxygen Species (ROS) are chemically reactive molecules of cellular metabolism that induce oxidative stress, and increase levels of SNAI1 (Snail) transcription factor while also promoting EMT. In Phase II clinical trials, patients were treated with natural product, Muscadine Grape Skin Extract (MSKE), and patients with SOD2 Ala/Ala single nucleotide polymorphism (SNP) responded better than those with Val/Val SNP. Ala/Ala SNP is associated with higher dismutase activity [superoxide (O2-) to hydrogen peroxide (H2O2)] than Val/Val. We hypothesize that SOD2 Ala/Ala genotype is associated with increased H2O2 and EMT, potentially antagonized by MSKE in prostate cancer cells. Prostate cancer cell lines were analyzed for SOD2 SNPs by pyrosequencing. Site-directed mutagenesis was conducted to create the Ala/Ala and Val/Val SNP vectors. LNCaP prostate cancer cells were transiently and subsequently stably transfected with SOD2 Val/Val cDNA, as well as empty vector (Neo) control, and verified through western blot analysis. ROS activity was evaluated for baseline ROS activity. Our results showed that most prostate cancer cell lines were heterozygous for SOD2 SNP (Ala/Val), although several had extra copies, for example, LNCaP had Val/Val/Ala, suggesting multiple copy numbers. Only metastatic MDA PCa 2a and MDA PCa 2b contained Ala/Ala homozygous SNP. LNCaP cells transiently and stably transfected with Val/Val showed partial induction of EMT, concomitant with higher levels of Snail and Vimentin, as compared to LNCaP Neo control. Furthermore, data also suggested that transient transfection marginally affected ROS activity while stable transfection caused significant changes in ROS activity compared to LNCaP Neo cells. We have begun to stably transfect Ala/Ala cDNA into LNCaP cells and are interested to see the differences in ROS activity and EMT induction between the two clone cell types (LNCaP Ala/Ala and Val/Val). As previous data suggests, we believe that Ala/Ala will show a higher expression of SOD2 and mesenchymal markers Snail and Vimentin, demonstrating full induction of EMT. In future we will test ROS activity, EMT marker expression in response to treatment of LNCaP Ala/Ala and Val/Val cells with MSKE. These studies may uncover the differential functions and response to treatment of SOD2 SNPs. Acknowledgements: These studies were supported by the NIH/NIMHD/RCI Grant #5G12MD007590-31, NIH/NIGMS/RISE Grant #5R25GM060414, and https://www.thecommunityfoundation.org/ Citation Format: Janae D. Sweeney, Valerie Odero-Marah, Channing Paller. Novel roles for manganese superoxide dismutase polymorphisms in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1047.

88-LB: Effects of Grape Skin Extract (GSE) on Glycemic Response to a Starch Challenge in Prediabetic Subjects

Prediabetes is a condition leading to increased risk of diabetes and its complications and cardiovascular disease. Annually, ∼10% prediabetic subjects progress to T2D. We, and other investigators, reported that grape skin extract (GSE) impacts postprandial glycemia through alpha glucosidase inhibition. This study aims to examine the effect of GSE on glycemic response to a starch challenge in healthy prediabetic subjects. The study was approved by the IRB of Hamad Medical Corporation. Subjects were screened from a high-risk population based on family history and/or fasting glucose (5.7-7.3 mmol) and IGT confirmed with 75 gram OGTT. Subjects were randomized to GSE capsule 600 (N=4), 1200 (N=8), 1800 (N=15) or 2400 mg (N=14). Each received a meal of 35 gram (uncooked weight) rice with or without the assigned dose of GSE and blood glucose was measured at time 0, 15, 30, 60 and 120 minutes. Area under the curve (AUC) was calculated using the trapezoidal method and the subjects were classified into “responders” or “non-responders” if AUC after GSE was reduced by at least 1 SD. A total of 41 eligible subjects (83% male; age 29±8 years; BMI 23.2%±5.9, 34% Arab, 24% African, 17% Asian, 24% Indian) with prediabetes were enrolled. A total of 4 (9.7%)subjects decreased AUC by 2SD; 24% decreased by 1 SD and the remainder had no positive response to a single dose of GSE. There were no responders to 600 mg; 2 in 1200 mg; 4 in 1800 mg; and 3 in 2400 mg dose. There were no differences between the responders and non-responders in clinical or biochemical characteristics. In conclusion, 24% of prediabetic subjects had a positive response to GSE in a starch challenge test. The value of the test in characterizing prediabetic subjects who may benefit from GSE to reverse their prediabetic condition is currently under further investigation. In Qatar, the prevalence of diabetes is 17% and expected to increase. Studies to develop natural products to prevent diabetes are of great public health interest. Disclosure M. Alkasem: None. I. Abdalhakam: None. N.N. Suleiman: None. A.N. Iskandarani: None. T.A. Samra: None. F.A. Mir: None. R.M. Mohammad: None. A. Abou-Samra: None. K. Zhou: None. M.C. Skarulis: None. Funding Qatar National Research Fund

마우스 안구건조증 모델에서 포도껍질 추출물인 안토시아닌 올리고머의 효과에 관한 연구

본 연구에서는 안토시아닌 올리고머(50 mg/kg)가 염화벤잘코늄으로 유발된 안구건조증에서 다양한 안구건조증 지표의 개선에 효과가 있음을 보여주었다. 본 연구에서 염화벤잘코늄을 안구에 점안하였을 때 안구표면에 다양한 반응이 나타났다. 염화벤잘코늄이 각막상피세포에 직접적인 손상을 주어서 각막상피세포의 편평상피화생(squamous metaplasia)이 나타났고 다양한 염증세포의 각막침윤이 관찰되었다. 이상의 결과로 보아 염화벤잘코늄을 이용한 안구건조증 유발 모델에서 안토시아닌 올리고머는 염화벤잘코늄의 점안 이후에 나타나는 다양한 염증성 사이토카인의 증가 및 이로 인한 세포 사멸을 억제함으로써 각막표면상피세포의 편평상피화생을 막아 안구건조증에 나타나는 다양한 변화를 개선시키는 것으로 추정해볼 수 있다. 이러한 안구건조증에서 안토시아닌 올리고머의 효과는 항염 작용과 더불어 안토시아닌이 본래 가지고 있는 강력한 항산화 작용에 의한 것으로 생각된다. 특히 본 연구에 사용된 안토시아닌은 단량체가 아닌 중합체로써 기존의 단량체보다 생리활성이 높을 것으로 생각되는데, 향후 추가적인 연구를 통하여 중합체의 우수한 생리활성이 추가로 규명된다면 다양한 안과영역에서 관심을 받을 것으로 생각된다. 안구건조증은 치료가 쉽지 않고 환자의 삶의 질까지 영향을 미치는 질환이다. 치료가 잘 되지 않는 이유 중에 하루에도 수차례씩 치료 약제를 점안하여야 하므로 환자의 순응도가 떨어지는 점이 있는데 경구 약제가 이러한 점을 보완해줄 수 있을 것이라 생각된다. 향후 좀 더 장기적인 연구, 염증 관련 단백질 분석 등과 점안제와 동시에 복용했을 경우의 효과 등에 대한 추가적인 연구가 필요할 것으로 생각된다.

CCAAT-displacement protein/cut homeobox transcription factor (CUX1) represses estrogen receptor-alpha (ER-α) in triple-negative breast cancer cells and can be antagonized by muscadine grape skin extract (MSKE).

Triple-Negative Breast Cancers (TNBCs) are the most difficult to treat subtype of breast cancer and are often associated with high nuclear expression of Snail and Cathepsin L (Cat L) protease. We have previously shown that Snail can increase Cat L expression/activity in prostate and breast cancer cells. This study investigated the role of CUX1 (a downstream substrate of Cat L) in TNBC. We showed that Cat L and CUX1 were highly expressed in TNBC patient tissue/cell lines, as compared to ER-positive samples, using cBioportal data and western blot/zymography analyses. Additionally, luciferase reporter and chromatin immunoprecipitation assays showed that CUX1 directly bound to estrogen receptor-alpha (ER-α) promoter in MDA-MB-468, a representative TNBC cell line, and that CUX1 siRNA could restore ER-α transcription and protein expression. Furthermore, Snail and CUX1 expression in various TNBC cell lines was inhibited by muscadine grape skin extract (MSKE, a natural grape product rich in anthocyanins) or Cat L inhibitor (Z-FY-CHO) leading to decreased cell invasion and migration. MSKE decreased cell viability and increased expression of apoptotic markers in MDA-MB-468 cells, with no effect on non-tumorigenic MCF10A cells. MSKE also decreased CUX1 binding to ER-α promoter and restored ER-α expression in TNBC cells, while both MSKE and CUX1 siRNA restored sensitivity to estradiol and 4-hydoxytamoxifen as shown by increased cell viability. Therefore, CUX1 activated by Snail-Cat L signaling may contribute to TNBC via ER-α repression, and may be a viable target for TNBC using natural products such as MSKE that targets cancer and not normal cells.

Comparison of protective supports and antioxidative capacity of two bio-based films with revalorised fruit pomaces extracted from blueberry and red grape skin

Abstract This work aimed to develop novel food packaging materials following eco-friendly concept. Chitosan (CS) and carboxymethyl cellulose (CMC) based films were developed with blueberry (B) and red grape skin pomace extracts (P) rich in antioxidants at different concentrations (1, 2 and 4% w/v). Physico-chemical (thickness, oxygen and water vapour permeability, solubility and moisture content) and antioxidant film properties and activities were determined. Adjustments in film formulations and quantity of plasticizer were done in order to obtain smooth films that are easy to manipulate and without cracks and mechanical failures. The extract of blueberry had higher levels of total phenolics, however films had lower antioxidant activity compared to red grape skin extracts, and the CMC resulted in more active films in the three concentrations of bioactives incorporation tested. On the other hand, with the extract of grape skin that had lower content of total phenolics, the films presented greater antioxidant activity, and the CS matrix, in general, showed more active efficacy. Both matrices showed antioxidant activities directly proportional to total phenolic contents incorporated into the films, being more effective those of CS containing 4% red grape skin pomace extract. The addition of red grape skin extracts increased oxygen permeability for 3 orders of magnitude in CMC films while it didn’t influence OTR in CS films expect for 4% extract. Similarly, addition of blueberry extract significantly increased OTR only in 4% CMC films and one order of magnitude in CS films. The addition of extracts slightly changed WVP of control films.

Antihypertensive effects of the Vitis vinifera grape skin (ACH09) extract consumption elicited by functional improvement of P1 (A1) and P2 (P2X1) purinergic receptors in diabetic and hypertensive rats

Cross-talk between hypertension and diabetes associated with red wine consumption triggering cardioprotective and antihypertensive effects have been well established; nevertheless, the role of isolated total polyphenols from extracts of Vitis vinifera grape skin (ACH09) and the possible correlation with cardiovascular functionality mediated by purinergic receptors remain poorly understood. We evaluate how ACH09 extract causes an antihypertensive effect by modulation of purinergic receptors. Male Wistar Kyoto (WKY), streptozotocin-induced diabetic WKY and SHR (spontaneously hypertensive) rats were subjected to intake of ACH09 extract 200 mg/kg/v.o. for 21 days. Systolic blood pressure (SBP), blood glucose levels were measured; cardiovascular functionality of sympathetic neurotransmission, represented by purinergic (P1-A1/P2-P2X1) and adrenergic receptors (α1/β1), was evaluated by isometric contraction. Compared to their respective controls, we found that ACH09 extract exposure decreased SBP in both groups, primarily by functional improvement of the following receptors: (1) P1 purinergic (A1), augmenting vascular endothelium-dependent relaxation; (2) P2 purinergic (P2X1), decreasing vasoconstriction; and (3) P1 purinergic (A1), increasing atrial negative inotropism. In conclusion, these findings suggest that dietary supplementation with polyphenolic-rich foods (lentil, citrus fruit and/or red wine) may inspire new pharmacologic and dietetic therapeutic approaches for treatment of hypertension and diabetes.

Enrichment of Whole Wheat Cocoa Biscuits with Encapsulated Grape Skin Extract.

Grape pomace is one of the major waste products generated by the wine-making process and it contains seeds and skins still rich in bioactive compounds. Skins can be separated from the seeds and valorised for the recovery of antioxidant extracts with different potential applications. The aim of this study was to evaluate the influence of the addition of an extract obtained from waste grape skins and encapsulated in maltodextrins on the antioxidant properties and sensory acceptability of whole wheat cocoa biscuits. Different levels of enrichment (1.2, 2.3, and 3.5% on dough weight) were tested, and the obtained doughs and biscuits were analysed for total phenols content and antioxidant capacity (based on different radical assays). Extract addition increased the phenolic content (up to 134% increase) and antioxidant capacity (up to 244%) of both doughs and biscuits. Extract containing biscuits were also characterised by a different colour. However, oxidation stability, evaluated at accelerated temperature and oxygen conditions, was not improved by the extract incorporation. Cooking led to an average (not always significant) 16% decrease in phenolic content for both enriched and reference recipes. The enrichment level significantly influenced the sensory acceptability, with identification of two clusters of consumers, with one cluster preferring the biscuits with the highest enrichment level and one cluster preferring the biscuits with the lowest level. The results showed that whole wheat cacao biscuits represent an appropriate food matrix to develop pleasant novel products enriched in phenolic compounds from waste grape skins and likeable for regular biscuits consumers.

Application of gum Arabic, β-cyclodextrin, and hydroxypropyl-β-cyclodextrin to microencapsulation by molecular inclusion of grape skin extract (Vitis labrusca var. Isabel)

Gum Arabic (GA), β-cyclodextrin (β-CD), and hydroxypropyl-β-cyclodextrin were used in different proportions to microencapsulate polyphenols obtained by aqueous extraction from a grape skin. Phenol contents of the microcapsules were evaluated for anthocyanins, flavonoids and total flavanols, antioxidant activity, color, moisture, water activity (Aw), solubility, hygroscopicity, and glass transition temperature (Tg). The microcapsules prepared with either 5% GA or a mixture of 3% GA and 2% β-CD had the highest retention of phenolic (78.9 and 67.5%, respectively), anthocyanins (35.3 and 29%, respectively) and antioxidant activity greater than 50% measured by the DPPH and CUPRAC methods. Treatment with 3% GA and 2% β-CD showed the highest retention of flavonoids (67.2%) and total flavanols (51.1%), as well as physical properties suitable for this type of product, such as Aw of 0.175, solubility greater than 90%, hygroscopicity of 17.3%, and Tg of 32.8°C, which may contribute to a greater stability of the powder. Practical applications Grape processing by-products have a great feasible commercial, and this is due at high concentrations of phenolic compounds in grape skin. It was possible to obtain inclusion complexes powder of phenolic compounds from grape skin, using cyclodextrin and its derivates in mixture with Arabic gum as carriers. This way, the stability of bioactive compounds may be improved during food processing, storage and pass through the gastrointestinal tract. In addition, it is possible to enhance solubility of phenolics compounds in aqueous dispersions. Powders obtained have antioxidant properties and potential prebiotic activity.

Influence of supplementation with two specific inactivated dry yeast and grape-skin extract on the color and composition of red wine

Wines from grapes of Cabernet Sauvignon of the AOC Tarragona were elaborated with supplementation or not of two specific inactivated dry yeasts (Optired®and Optimum Red®; Lallemand Inc.) or with an experimental grape-skin extract. All the wines treated were significantly less astringent than the control wine because both inactivated dry yeast and the skin extract released polysaccharides which probably inhibit interactions between salivary proteins and tannins, and because their presence decrease the proportion of seed tannins and increase the proportion of skin tannins in the final wines.

Muscadine grape skin extract inhibits prostate cancer cells by inducing cell-cycle arrest, and decreasing migration through heat shock protein 40

Previously we demonstrated that muscadine grape skin extract (MSKE), a natural product, significantly inhibited androgen-responsive prostate cancer cell growth by inducing apoptosis through the targeting of survival pathways. However, the therapeutic effect of MSKE on more aggressive androgen-independent prostate cancer remains unknown. This study examined the effects of MSKE treatment in metastatic prostate cancer using complementary PC-3 cells and xenograft model. MSKE significantly inhibited PC-3 human prostate cancer cell tumor growth in vitro and in vivo. The growth-inhibitory effect of MSKE appeared to be through the induction of cell-cycle arrest. This induction was accompanied by a reduction in the protein expression of Hsp40 and cell-cycle regulation proteins, cyclin D1 and NF-kBp65. In addition, MSKE induced p21 expression independent of wild-type p53 induced protein expression. Moreover, we demonstrate that MSKE significantly inhibited cell migration in PC-3 prostate cancer cells. Overall, these results demonstrate that MSKE inhibits prostate tumor growth and migration, and induces cell-cycle arrest by targeting Hsp40 and proteins involved in cell-cycle regulation and proliferation. This suggests that MSKE may also be explored either as a neo-adjuvant or therapeutic for castration resistant prostate cancer.

Evaluation of the Chemopreventive Activity of Grape Skin Extract Using Medium-term Oral Carcinogenesis Assay Induced by 4-Nitroquinoline 1-Oxide.

The aim of this study was to evaluate the chemoprotective potential of grape skin extract following rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). Male Wistar rats were distributed into four groups (n=5, per group): Control Group: free access to commercial diet and drinking water for 12 weeks; 4NQO Group: received 4NQO diluted in drinking water daily, for 12 weeks; Grape Skin Extract Group: free access to water and received grape skin extract incorporated with diet for 12 weeks; 4NQO + Grape Skin Extract Group: received 4NQO in drinking water daily and grape extract incorporated with diet for 12 weeks. Animals treated with grape skin extract revealed a significant reduction in epithelial dysplasia. Also, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and ki-67 immunoexpression was reduced in animals treated with grape skin extract. Western blot analysis showed a significant decrease of p-NFκB p50 and MyD88 protein expression in the groups treated with grape skin extract. Copper-zinc superoxide dismutase, manganese superoxide dismutase, and catalase gene expression did not present any statistically significant differences (p>0.05). Grape skin extract displayed chemopreventive activity in oral carcinogenesis assays as depicted by its antioxidant, anti-proliferative and anti-inflammatory properties.

“Green” synthesis of nanoparticles of precious metals: antimicrobial and catalytic properties

The paper presents the use of agricultural products, namely grape skins, in the “green” synthesis of monometallic (Au, Ag) and bimetallic (Au-Ag) nanoparticles (NPs) from aqueous solutions of metal ions of the corresponding precursors. At present, there exist urgent problems of utilization of waste from the agro-industrial complex, rational use of nature and transition to the use of environment-friendly and energy-efficient technologies. Therefore, there is a tendency to use “green” technologies in obtaining nanomaterials that are considered environment-friendly and resource-saving. The study has proved the efficiency of using food waste (grape skins) as a reducing and stabilizing agent in forming nanoparticles of precious metals of mono- and bimetallic structures. Biological raw materials were extracted in an aqueous medium under a short-term effect of low-temperature plasma discharges. On the basis of the complex analysis of the extract composition, it was proved that the hydroxyl, carbonyl and carboxyl functional groups of the organic compounds of the grape skin extract are responsible for the recovery of the metal ions and stabilization of the resulting NPs. The research has proved that mono- and bimetallic NPs are formed with the following peaks: for Ag 0 (λ max =440 nm), Au 0 (λ max =540 nm), and Ag-Au (λ max =510 nm). The size and stability of the nanoparticles obtained by the “green” synthesis were assessed in comparison with the same parameters for the plasmochemical method of nanoparticles’ formation. The study has revealed antibacterial, catalytic and anti-corrosion properties of the synthesized nanoparticles. The resulting monometallic (Au, Ag) and bimetallic (Au–Ag) nanoparticles show excellent catalytic activity while recovering p-nitrophenol (4-NPh) to p-aminophenol (4-APh) in the presence of NaBH 4 . The synthesized NPs demonstrate their antibacterial activity against gram-positive and gram-negative bacteria. The findings allow to expand the practical application of metal nanoparticles in various industries and enhance the processing and reuse of non-liquid waste

Grape skin extract improves muscle function and extends lifespan of a Drosophila model of Parkinson's disease through activation of mitophagy.

Recent studies suggest that moderate red wine consumption may confer several health benefits, including protection against heart disease, certain cancers and multiple age-related neurological diseases such as Alzheimer's disease. These health benefits are assumed to come from a compound from grape skin called resveratrol, which has been proposed to be a pro-longevity agent. Whether resveratrol accounts for all the health benefits of grape-derived nutrients and the molecular and cellular mechanisms underlying the beneficial effects of such nutrients are not well understood. Here we investigated the effect of supplementing grape skin extract (GSE) left from red wine-production process to the daily food intake of a Drosophila melanogaster model of Parkinson's disease (PD) associated with PTEN-induced kinase 1 (PINK1) loss-of-function. Consumption of GSE resulted in rescue of mitochondrial morphological defects, improvement of indirect flight muscle function and health-span, and prolonged lifespan of the PINK1 mutant flies. Further biochemical and genetic studies revealed a link between activation of mitophagy and the beneficial effects of GSE. Our results indicate that GSE can promote autophagy activation, preserve mitochondria function, and protect against PD pathogenesis, and that the beneficial effect of GSE in mitophagy activation is not accounted for by resveratrol alone.

Determination of Total Phenolic Content Using the Folin-C Assay: Single-Laboratory Validation, First Action 2017.13.

A single-laboratory validation of a method using Folin & Ciocalteu's phenol reagent (Folin-C reagent) for determination of total phenolic content of selected dietary supplement extracts was performed. The method is composed of a water extraction of dried extracts with sonication followed by reaction with the Folin-C reagent. The resulting colorimetric reaction is measured at 765 nm and compared with a standard curve generated with gallic acid standard solutions. The validation results were compared with Standard Method Performance Requirement (SMPR®) 2015.009, developed by the Stakeholder Panel on Dietary Supplements. The method demonstrated acceptable within-day RSDr of 1.96-7.47% for the five matrixes studied (grape seed extract, grape skin extract, black tea extract, green coffee extract, and cocoa extract). When gallic acid was spiked into maltodextrin (a surrogate dietary supplement carrier) at 30 or 70%, the recovery ranged from 91 to 104%, within the acceptable range established by SMPR 2015.009. Selectivity testing with glucose, fructose, and sucrose demonstrated no positive interference by these compounds. Finally, ruggedness studies demonstrated no significant effects due to changes in the heating apparatus, test material weight, read time after reaction, amount of Folin-C reagent, reaction time, reaction temperature, and amount of Na2CO3. The single-laboratory validation results support adoption of the method as First Action Official MethodSM 2017.13 and further evaluation in a collaborative study.

Stability of polyphenolic extracts from red grape skins after thermal treatments

Considering the potential of applying grape skin extract (GSE) as functional ingredients in products that must be thermally processed, the aim of this study was to evaluate the stability of individual polyphenols in grape skin extracts submitted to heating at different temperatures. Polyphenolic compounds were extracted by applying 20% aqueous ethanol containing 1% acetic acid for 1 h at 50 °C on a magnetic stirrer. The obtained extract was divided into aliquots and submitted to heating at different temperatures for a various time. The content of individual phenolic compounds in all incubated extract was determined by the HPLC method. All studied compounds were very stable during heating at 40 °C. Among analyzed anthocyanins, diglucosides were more stable than corresponding monoglucosides. Gallocatechin and procyanidins B1 and B2 contents were decreased, while catechin and epicatechin contents were increased during thermal treatments. At both incubation temperature contents of caftaric and coutaric acid were decreased, while in the same time contents of caffeic and coumaric acids were raised which could be due to hydrolysis. A significant increase of gallic, protocatechuic, vanillic, and syringic acid contents was due to thermal degradation of delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, and malvidin-3-O-glucoside, respectively. trans-Piceid showed high stability toward thermal treatments.

Syrah grape skin valorisation using ultrasound‐assisted extraction: Phenolic compounds recovery, antioxidant capacity and phenolic profile

SummaryThe influence of ultrasound power (1000–3000 W/L), citric acid concentration (0–3%) and solid:liquid ratio (1:5–1:15) on the phenolic compounds recovery and antioxidant capacity of Syrah grape skin extracts were evaluated. Total phenolic compounds varied from 6485 to 11732 mg gallic acid/100 g and monomeric anthocyanin content from 453 to 685 mg malvidin‐3‐glucoside/100 g. The antioxidant capacity measured by ORAC and ABTS methods ranged from 230 to 516 μmol Trolox/g and from 442 to 939 μmol Trolox/g, respectively. The most suitable conditions chosen for extraction, within the studied ranges, were 3000 W/L of power, 2.5% citric acid and solid:liquid ratio of 1:15. The extraction yield was satisfactory, with a recovery of 59% of the quantified phenolic compounds, with only 3 min of processing. Ultrasound was considered a suitable method as compared to the conventional extraction, improving the extraction of phenolic acids and facilitating their release.

Biochemical evaluation of selected grape varieties (Vitis vinifera L.) grown in Jordan and in vitro evaluation of grape seed extract on human prostate cancer cells

A chemical and biological approach was used for quality assessment of 16 different eating grape varieties collected in Jordan. A validated LC-ESI-MS/MS method was used for quantitative analysis of resveratrol in grape skin and grape seed extracts. Grape skin extracts showed higher resveratrol content than that of seeds. The antioxidant activity and total phenolic content of seed, skin, and whole berry extracts of the grape varieties were evaluated using the DPPH radical scavenging assay and Folin–Ciocalteu colorimetric method, respectively. Seed extracts showed the highest total phenolic content and antioxidant activity. The in vitro effects of Golden Scatt grape seed extract on human prostate cancer cell migration and colony-genic potential were assayed. Golden Scatt seed extract modulated the colony formation potential and inhibited the migratory potential of prostate cancer cells in a dose-dependent manner.

Efficacy of sodium dodecyl sulphate and natural extracts against E. coli biofilm

The aim of this study was to determine and compare the efficacy of a standard cleaning agent, sodium dodecyl sulphate, and natural extracts from pomegranate peel grape skin and bay laurel leaf against E. coli biofilm. The biofilm was exposed for 10 minutes to three different concentrations of each tested compound. The results show that bay laurel leaf extract is the most efficient with 43% biofilm biomass reduction, followed by pomegranate peel extract (35%); sodium dodecyl sulphate and grape skin extract each have 30% efficacy. Our study demonstrated that natural extracts from selected plants have the same or even better efficacy against E. coli biofilm removal from surfaces than the tested classical cleaning agent do. All this indicates that natural plant extracts, which are acceptable from the health and environment points of view, can be potential substitutes for classical cleaning agents.

MUSCADINE GRAPE SKIN EXTRACT INHIBITS ANDROGEN‐INDEPENDENT PROSTATE CANCER CELL GROWTH, INDUCING CELL‐CYCLE ARREST, AND DECREASING MIGRATION BY TARGETING HEAT SHOCK PROTEIN 40

Previously we demonstrated that muscadine grape skin extract (MSKE), a natural product, significantly inhibited prostate cancer cell growth by inducing apoptosis through the targeting of phosphatidylinositol 3‐kinase‐Akt and mitogen‐activated protein kinase survival pathways in androgen‐responsive transformed human prostate cancer epithelial cell lines. However, the preventive effect of MSKE on more aggressive androgen‐independent prostate cancer remains unknown. This study examined the effects of MSKE treatment using complementary PC‐3 prostate cancer cell culture and xenograft models. MSKE significantly inhibited PC‐3 human prostate cancer cell tumor growth in vitro and in vivo. The growth‐inhibitory effect of MSKE appeared to be through the induction of cell‐cycle arrest. This induction was accompanied by a reduction in the protein expression of Hsp40 protein and cell‐cycle regulation proteins, cyclin D1 and NF‐kBp65. In addition, MSKE induced p21 expression independent of wild‐type p53 induced protein expression. Moreover, we demonstrated that MSKE significantly inhibited cell migration in PC‐3 prostate cancer cells which was complimented by siRNA‐HSP40 knock‐down that also inhibited cell migration and growth. Overall, these results demonstrate that MSKE inhibits prostate tumor growth and migration, and induces cell‐cycle arrest by targeting Hsp40 and proteins involved in cell‐cycle regulation and proliferation. This suggests that MSKE may also be explored as a novel therapeutic in castration resistant prostate cancer.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.