Composition and Biological Activity of Vitis vinifera Winter Cane Extract on Candida Biofilm

Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as one of the possible approaches. We have investigated the total phenolic content, composition, antioxidant activity, and antifungal activity against Candida biofilm of an extract from winter canes and a commercially available extract from blue grapes. Light microscopy and confocal microscopy imaging as well as crystal violet staining were used to quantify and visualize the biofilm. We found a decrease in cell adhesion to the surface depending on the concentration of resveratrol in the cane extract. The biofilm formation was observed as metabolic activity of Candida albicans, Candida parapsilosis and Candida krusei biofilm cells and the minimum biofilm inhibitory concentrations were determined. The highest inhibition of metabolic activity was observed in Candida albicans biofilm after treatment with the cane extract (30 mg/L) and blue grape extract (50 mg/L). The composition of cane extract was analyzed and found to be comparatively different from blue grape extract. In addition, the content of total phenolic groups in cane extract was three-times higher (12.75 gGA/L). The results showed that cane extract was more effective in preventing biofilm formation than blue grape extract and winter canes have proven to be a potential source of polyphenols for antimicrobial and antibiofilm treatment.

Grape Extract Promoted α-MSH-Induced Melanogenesis in B16F10 Melanoma Cells, Which Was Inverse to Resveratrol

Melanin is a natural pigment produced by cells to prevent damage caused by ultraviolet radiation. Previously, resveratrol was shown to reduce melanin synthesis. As a natural polyphenol with various biological activities, resveratrol occurs in a variety of beverages and plant foods, such as grapes. Therefore, we investigated whether grape extracts containing resveratrol also had the ability to regulate melanin synthesis. In this study, we used mouse B16F10 melanoma cells as a model for melanin synthesis with the melanogenesis-inducing α-melanocyte-stimulating hormone (α-MSH) as a positive control. Our results confirmed previous reports that resveratrol reduces melanin synthesis by reducing the activity of the rate-limiting enzyme tyrosinase. In contrast, the grape extract could not reduce melanin synthesis, and in fact promoted melanogenesis in the presence of α-MSH. The expression of genes related to melanin synthesis, such as tyrosinase, tyrosinase-related protein-1, tyrosinase-related protein-2, and microphthalmia-associated transcription factor, also supports these phenomena, which means that even in the presence of resveratrol, grape extract will strengthen the function of α-MSH in promoting melanin synthesis. Therefore, these results also provide a point of view for research on cosmetics.

Potential of Grape Extract in Comparison with Therapeutic Dosage of Antibiotics in Weaning Piglets: Effects on Performance, Digestibility and Microbial Metabolites of the Ileum and Colon

Enteric diseases in piglets, such as post-weaning diarrhea (PWD), often require antibiotic treatment of the entire litter. Grape polyphenols may help overcome PWD and thereby reduce the need for antibiotics. The potential of a grape extract (GE; continuous in-feed supplementation) on performance of weaning piglets, compared with both negative (NC; corn-based diet) and positive control (PC; NC + in-feed antibiotic (amoxicillin) in a therapeutic dosage for day 1–day 5 post weaning) was assessed. Apparent total tract digestibility (ATTD) and microbial metabolites were also evaluated on two sampling points (day 27/28 and day 55/56). We assigned 180 weaning piglets (6.9 ± 0.1 kg body weight (BW)) to 6 male and 6 female pens per treatment with 5 piglets each. Animals from PC showed higher BW on day 13 compared with NC and GE, and a tendency for higher BW on day 56 (p = 0.080) compared to NC. Furthermore, PC increased the average daily feed intake in the starter phase (day 1–day 13), and the average daily gain in the early grower phase (day 14–day 24). Overall, GE improved the ATTD at the same level as PC (ash, acid-hydrolyzed ether extract), or at a higher level than PC (dry matter, organic matter, gross energy, crude protein, P). There were no effects on microbial metabolites apart from minor trends for lactic acid and ammonia. Dietary inclusion of GE may have beneficial effects compared to therapeutic antibiotics, as frequently used at weaning.

Polyphenol-Rich Muscadine Grape Extract Reduces Triple Negative Breast Cancer Metastasis in Mice with Changes in the Gut Microbiome

Background Triple negative breast cancer (TNBC) has a high propensity to metastasize and no treatments are available to slow or prevent metastatic progression. The goal of this study is to determine whether a proprietary high-polyphenol content muscadine grape extract (MGE) inhibits TNBC metastasis. Methods 4T1 TNBC cells were injected into the mammary fat pad of 6-week-old female Balb/c mice. After 2 weeks, tumors were surgically removed and mice were placed into a control (n=8) or treatment group that received 0.1 mg/mL total phenolics MGE in the drinking water (n=8) for 4 weeks. Immunohistochemistry (Ki67, α-SMA) and hemotoxylin and eosin staining were used to quantify metastases. Gut microbial composition was determined by 16S rRNA sequencing and short chain fatty acids (SCFAs) were detected by gas chromatography. MDA-MB-231, BT-549 and 4T1 TNBC cell motility and cytoskeletal organization was assessed in vitr o by scratch wound migration and confocal microscopy, respectively. Data were evaluated by student’s t -test. Results MGE reduced metastatic proliferation in mouse lungs (33.3%) and livers (58.3%) and decreased the number (51.1%) and size (17.4%) of liver metastases, resulting in a 55.7% reduction in metastatic tumor burden ( P < 0.01). Serum IL-6 was reduced 99.6% in MGE-treated mice ( P = 0.06). MGE attenuated migration, altered cytoskeletal organization, and reduced RHAMM expression in TNBC cells ( P < 0.05). The gut microbiota, a mediator of polyphenolic bioactivities, was altered significantly in MGE-treated mice; MGE increased the alpha diversity (7.14%), Firmicutes/Bacteroidetes ratio (2-fold), relative abundance of butyrate-producing genera, and butyrate (3-fold) ( P < 0.05). Butyrate inhibited 4T1 cell proliferation and migration, suggesting butyrate contributes to MGE’s anti-metastatic activities ( P < 0.05). Conclusion Our results indicate that MGE may be an effective adjuvant therapy to reduce TNBC metastatic progression.