Bioactivity of Sour Cherry Cultivars Grown in Denmark

Variability in the Qualitative and Quantitative Composition of Phenolic Compounds and the In Vitro Antioxidant Activity of Sour Cherry (Prunus cerasus L.) Leaves

Sour cherry (Prunus cerasus L.) is a deciduous tree belonging to the Rosaceae Juss. family. Cherry leaves are an underutilized source of biologically active compounds. The aim of this study was to determine the composition of the phenolic compounds, as well as the total antioxidant activity, in leaf samples of P. cerasus cultivars and to elucidate the cultivars with particular phytochemical compositions. The phytochemical profiles of P. cerasus leaves vary significantly in a cultivar-dependent manner. The total content of identified phenolic compounds varied from 8.254 to 16.199 mg/g in the cherry leaves. Chlorogenic acid ranged between 1413.3 µg/g ('North Star') and 8028.0 µg/g ('Note'). The total content of flavonols varied from 4172.5 µg/g ('Vytenu zvaigzde') to 9030.7 µg/g ('Tikhonovskaya'). The total content of identified proanthocyanidins varied from 122.3 µg/g ('Note') to 684.8 µg/g ('Kelleris'). The highest levels of phloridzin (38.1 ± 0.9 µg/g) were found in samples of 'Molodezhnaya', while the lowest level of this compound was determined in the leaf samples of 'Turgenevka' (6.7 ± 0.2). The strongest antiradical (138.0 ± 4.0 µmol TE/g, p < 0.05) and reducing (364.9 ± 10.5 µmol TE/g, p < 0.05) activity in vitro was exhibited by the cultivar 'Vytenu zvaigzde' cherry leaf sample extracts. 'Kelleris', 'Note', and 'Tikhonovskaya' distinguish themselves with peculiar phytochemical compositions.

Changes in bioavailability of sour cherry (Prunus cerasus L.) phenolics and anthocyanins when consumed with dairy food matrices

In this study, it is aimed to understand the changes in sour cherry phytochemicals when their co-digestions are simulated in dairy model systems comprising skim milk, non-fat-yoghurt, probiotic yoghurt or cream. These co-digestions were analyzed for their total phenolic and anthocyanin contents, total antioxidant activity (TAA) in addition to phenolic and anthocyanin profiles, individually. Sour cherry phenolics were stable during gastric conditions (120%); 54% lost in pancreatic digestion and being available (59%) in serum available fraction (IN). Anthocyanins were lost both in gastric (30%) and pancreatic digestions (16%), being only little available (0.6%) in IN. Soymilk had inhibitory effects on TAA. Dairy food matrix components evaluated were found to have distinct effects on the measured bioavailability of individual sour cherry phenolics. This study might aid both consumers and industry on selecting the food matrices to aiding increase in bioavailability.

Protective Effect of Pure Sour Cherry Anthocyanin Extract on Cytokine-Induced Inflammatory Caco-2 Monolayers

Anthocyanins have several beneficial effects, especially on inflammatory and oxidative conditions. The pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), induce damage in the intestinal barrier and participate in the pathogenesis of chronic bowel diseases. A number of fruits have high anthocyanin contents with strong biological activity which can support protective actions. Sour cherry (Prunus cerassus) is one of the richest fruits in anthocyanins; especially it has high content of cyanidins. The aim of this study was to test the biological effects of a pure sour cherry anthocyanin extract under inflammatory conditions on the intestinal barrier. Caco-2 monolayers were stimulated with 50 ng/mL TNF-α and 25 ng/mL IL-1β, and the protective effects of the anthocyanin extract were examined. We demonstrated the safety of 500, 50, 5 and 0.5 µM anthocyanin extracts through cell impedance measurements. The 50 µM anthocyanin extract inhibited the cytokine-induced Caco-2 permeability and the nuclear translocation of NF-κB p65 subunits. The extract significantly reduced the release of IL-6 and IL-8 production in intestinal cells and glutathione peroxidase activity stimulated by cytokines. We demonstrated, for the first time, the beneficial effects of pure sour cherry anthocyanin extract on inflammatory Caco-2 monolayers, indicating that this substance could be protective in inflammatory bowel diseases and is an excellent raw material for further applications and formulations.

Tart Cherries and health: Current knowledge and need for a better understanding of the fate of phytochemicals in the human gastrointestinal tract

Tart cherries are increasingly popular due to purported health benefits. This Prunus cesarus species is cultivated worldwide, and its market has increased significantly in the last two decades due to improvements in agricultural practices and food processing technology. Tart cherries are rich in polyphenols, with a very specific profile combining anthocyanins and flavonols (berries-like) and chlorogenic acid (coffee-like). Tart cherries have been suggested to exert several potentially beneficial health effects including: lowering blood pressure, modulating blood glucose, enhancing cognitive function, protecting against oxidative stress and reducing inflammation. Studies focusing on tart cherry consumption have demonstrated particular benefits in recovery from exercise-induced muscle damage and diabetes associated parameters. However, the bioconversion of tart cherry polyphenols by resident colonic microbiota has never been considered, considerably reducing the impact of in vitro studies that have relied on fruit polyphenol extracts. In vitro and in vivo gut microbiota and metabolome studies are necessary to reinforce health claims linked to tart cherries consumption.

Antioxidants: Characterization, natural sources, extraction and analysis

Recently many review papers regarding antioxidants from different sources and different extraction and quantification procedures have been published. However none of them has all the information regarding antioxidants (chemistry, sources, extraction and quantification). This article tries to take a different perspective on antioxidants for the new researcher involved in this field. Antioxidants from fruit, vegetables and beverages play an important role in human health, for example preventing cancer and cardiovascular diseases, and lowering the incidence of different diseases. In this paper the main classes of antioxidants are presented: vitamins, carotenoids and polyphenols. Recently, many analytical methodologies involving diverse instrumental techniques have been developed for the extraction, separation, identification and quantification of these compounds. Antioxidants have been quantified by different researchers using one or more of these methods: in vivo, in vitro, electrochemical, chemiluminescent, electron spin resonance, chromatography, capillary electrophoresis, nuclear magnetic resonance, near infrared spectroscopy and mass spectrometry methods.