Grape is one of the oldest fruit crops domesticated by humans. The numerous uses of grape in making wine, beverages, jelly, and other products, has made it one of the most economically important plants worldwide. The complex phytochemistry of the berry is characterized by a wide variety of compounds, most of which have been demonstrated to have therapeutic or health promoting properties. Among them, flavonoids are the most abundant and widely studied, and have enjoyed greater attention among grape researchers in the last century. Recent studies have shown that the beneficial health effects promoted by consumption of grape and grape products are attributed to the unique mix of polyphenolic compounds. As the largest group of grape polyphenols, flavonoids are the main candidates considered to have biological properties, including but not limited to antioxidant, anti-inflammatory, anti-cancer, antimicrobial, antiviral, cardioprotective, neuroprotective, and hepatoprotective activities. Here, we discuss the recent scientific advances supporting the beneficial health qualities of grape and grape-derived products, mechanisms of their biological activity, bioavailability, and their uses as nutraceuticals. The advantages of modern plant cell based biotechnology as an alternative method for production of grape nutraceuticals and improvement of their health qualities are also discussed.

Research continues to show that many artificial pigments are actually detrimental to our health. According to [1], there is an increasing consumer preference for healthy foods, which has invited considerable demand for the use of anthocyanins as natural colorants, because of their natural pedigree and healthful properties. Anthocyanins are the most widely distributed group of water-soluble plant pigments in nature. They are mainly responsible for the mauve, red, blue, and purple colors in flowers, fruits, leaves, seeds and other organs in most of the flowering plants. The other important class of water-soluble pigments are betalains, which are present only in plants belonging to 13 families of Caryophyllales order [2-5]. An interesting phenomenon is the existence of mutual exclusiveness of anthocyanins and betalains in plant kingdom [3, 5-9]. Recent research demonstrated that simultaneous production of anthocyanins and betalains is possible in cell cultures and seedlings of anthocyanin producing plants by introduction and expression of genes encoding dihydroxyphenylalanine (L-DOPA) dioxygenases in combination with substrate precursor feeding [10]. However, the co-occurrence of both pigments in the same plant species have never been found in nature and the plants which produce anthocyanins never produce betalains and vice versa [6]. The commercial production of anthocyanin pigments is one of the fastest growing segments of the food colorant industry [2, 11]. The only industrial sources for anthocyanin pigments are from whole plant extracts [1], with the most common source being grape skins from the wine industry. According to [1], the demand of natural colorants continues to rise by 5-15% every year and this translated to the sales of anthocyanins isolated from grape skins in 2002, which was estimated to be US$200 million worldwide. The increase

Vitis has two subgenera: Euvitis, which includes commercially important Vitis vinifera and interspecific hybrid cultivars, and Muscadinia. Of note, the market for Muscadinia grapes remains small, and only Muscadinia rotundifolia is cultivated as a commercial crop. To establish a basis for the study of Muscadinia species, we generated chromosome-level whole-genome sequences of Muscadinia rotundifolia cv. Noble. A total of 393.8 Mb of sequences were assembled from 20 haploid chromosomes, and 26 394 coding genes were identified from the sequences. Comparative analysis with the genome sequence of V. vinifera revealed a smaller size of the M. rotundifolia genome but highly conserved gene synteny. A genome-wide association study of 12 Muscadinia berry-related traits was performed among 356 individuals from breeding populations of M. rotundifolia. For the transferability of markers between Euvitis and Muscadinia, we used 2000 core genome rhAmpSeq markers developed to allow marker transferability across Euvitis species. A total of 1599 (80%) rhAmpSeq markers returned data in Muscadinia. From the GWAS analyses, we identified a total of 52 quantitative trait nucleotides (QTNs) associated with the 12 berry-related traits. The transferable markers enabled the direct comparison of the QTNs with previously reported results. The whole-genome sequences along with the GWAS results provide a new basis for the extensive study of Muscadinia species.

Three muscadine grape genotypes (Muscadinia rotundifolia (Michx.) Small) were evaluated for their metabolite profiling and antioxidant activities at different berry developmental stages. A total of 329 metabolites were identified using UPLC-TOF-MS analysis (Ultimate 3000LC combined with Q Exactive MS and screened with ESI-MS) in muscadine genotypes throughout different developmental stages. Untargeted metabolomics study revealed the dominant chemical groups as amino acids, organic acids, sugars, and phenolics. Principal component analysis indicated that developmental stages rather than genotypes could explain the variations among the metabolic profiles of muscadine berries. For instance, catechin, epicatechin-3-gallate, and gallic acid were more accumulated in ripening seeds (RIP-S). However, tartaric acid and malonic acid were more abundant during the fruit-set (FS) stage, and malic acid was more abundant in the veraison (V) stage. The variable importance in the projection (VIP > 0.5) in partial least-squares–discriminant analysis described 27 biomarker compounds, representing the muscadine berry metabolome profiles. A heatmap of Pearson’s correlation analysis between the 27 biomarker compounds and antioxidant activities was able to identify nine antioxidant determinants; among them, gallic acid, 4-acetamidobutanoic acid, trehalose, catechine, and epicatechin-3-gallate displayed the highest correlations with different types of antioxidant activities. For instance, DPPH and FRAP conferred a similar antioxidant activity pattern and were highly correlated with gallic acid and 4-acetamidobutanoic acid. This comprehensive study of the metabolomics and antioxidant activities of muscadine berries at different developmental stages is of great reference value for the plant, food, pharmaceutical, and nutraceutical sectors.

Background/Aim: Triple-negative breast cancer (TNBC) is the most aggressive subtype, predominant in African American women. In this study, the antioxidant/anticancer activity of muscadine grape extracts and the role of their phenolic and flavonoid contents in exerting these properties were investigated in TNBC cells. Materials and Methods: Berry extracts from muscadine genotypes were investigated for total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity, and anticancer effects using breast cancer cell lines, representing Caucasians and African Americans. Results: The antioxidant activity was associated with high TPC content. Extracts showed cytotoxicity up to 78.6% in Caucasians and 90.7% in African American cells, with an association with high antioxidant capacity. There was a strong correlation between TPC and anticancer/antioxidant activities. Conclusion: The anticancer and antioxidant effects of muscadine grapes are attributed to the TPC of extracts, which showed a stronger positive correlation with growth inhibition of African American breast cancer cells compared to Caucasians.