Blackcurrant press cake by-product: Increased chemical bioaccessibility and reduced antioxidant protection after in vitro simulation of gastrointestinal digestion.

This study describes the bioaccessibility in terms of total phenolic content (TPC) and antioxidant capacity before and after in vitro digestion from blackcurrant press cake extracts (BPC) and the bioactivity in cell culture, human erythrocytes as well as the in silico analysis. Chemical analysis of BPC presented an increase in TPC (270%) and anthocyanins (136%) after in vitro digestion, resulting in an improvement of antioxidant activity (DPPH 112%; FRAP: 153%). This behavior may be related to the highest activity of cyanidin-3-rutinoside, as confirmed by in silico analysis. The digested BPC did not exert cytotoxicity in cells and showed less antioxidant activity against the oxidative damage induced in endothelial cells and human erythrocytes compared to the non-digested extract. The results raise a question about the reliability we should place on results obtained only from crude samples, especially those that will be used to produce foods or nutraceuticals.

Influence of spontaneous and inoculated fermentation of açai on simulated digestion, antioxidant capacity and cytotoxic activity.

This work describes the kinetic study of different types (spontaneous, lactic and alcoholic) of açai fermentation in terms of total phenolics and total anthocyanins, as well as antioxidant capacity, before and after simulated digestion (SD). Cytotoxicity (A549, HCT8 and IMR90 cells) and formation of reactive oxygen species (A549 cells) were also evaluated. The results revealed that spontaneous fermentation (SF) for 24 h, followed by SD, generated a product with greater bioaccessibility of phenolics (52.68%) and cyanidin-3-glucoside (27.01%) than unfermented açai. Likewise, lactic fermentation (LF) for 72 h improved the bioavailability of phenolics (64.49%) and cyanidin-3-rutinoside (20.00%). On the other hand, alcoholic fermentation (AF) decreased the bioaccessibility of phenolic compounds and anthocyanins after SD. The SF 24 h (10.16 ± 1.25 µmol Trolox /g) and LF 72 h (15.90 ± 0.51 µmol Trolox /g) significantly increased the antioxidant capacity after SD, when compared to unfermented açai (SF 0 h, 4.00 ± 0.09 µmol Trolox /g; LF 0 h, 10.57 ± 0.91 µmol Trolox /g). It was concluded that the samples did not show cytotoxicity in the cell lines tested and, in addition, AF 24 h showed antioxidant and antimutagenic effects in vitro, reducing about 40% of chromosomal aberrations. The results obtained provide important information that can be used to produce foods with greater bioaccessibility of bioactive compounds.

Sustainable and effective approach to recover antioxidant compounds from purple tea (Camellia sinensis var. assamica cv. Zijuan) leaves.

Camellia sinensis var. assamica cv. Zijuan (purple tea) is known for its content of anthocyanins, flavan-3-ols, and bioactivities. This study aimed to verify the influence of solvent polarity, in a solid-liquid extraction, on the content of phenolic compounds and chlorophylls, instrumental color, and antioxidant activity. Different proportions of water and ethanol (0:100, 25:75, 50:50, 75:25, and 100:0 v/v) were used for extraction. The results showed that the hydroalcoholic extract (75 % ethanol + 25 % water) had the highest contents of total flavonoids, total anthocyanins, chlorophyll A, and total carotenoids, as well as presenting the highest color intensity, proportion of yellow pigments, and antioxidant activity (total reducing capacity and scavenging of the DPPH free radical). Twenty-two compounds were identified, with chlorogenic acid, hesperidin, (-)-epicatechin, (-)-epigallocatechin gallate, and isoquercitrin being the main phenolics. This phenolic-rich extract inhibited lipoperoxidation induced in egg yolk homogenate (IC50 = 455 mg/L), showed no hemolytic behavior when human erythrocytes were subjected to osmotic stress, and exerted in vitro cytotoxic effects against cancer and hybrid cells. The extract obtained with the mixture of non-toxic solvents presented critical bioactivities, as well as a comprehensive identification of phenolic compounds in the cultivar, and has potential to be used in technological applications.

Optimizing the extraction of bioactive compounds from pu-erh tea (Camellia sinensis var. assamica) and evaluation of antioxidant, cytotoxic, antimicrobial, antihemolytic, and inhibition of α-amylase and α-glucosidase activities.

The aims of this study were to quantify and optimize the extraction of total phenolic content (TPC), total flavonoids (TF) and antioxidant activity (AA) of aqueous pu-erh (Camellia sinensis var. assamica) extracts, as well as to compare the optimized pu-erh tea extract (OPT) with toasted mate (Ilex paraguariensis), black and green (Camellia sinensis) teas. The optimization process increased the TPC and the ferric reducing antioxidant power (FRAP). The results showed that the green tea extract presented the highest values for TPC and antioxidant capacity. The pasteurized OPT showed lower TPC and TF, and higher FRAP, DPPH and Cu2+ chelating ability compared to the non-pasteurized OPT. The lyophilized OPT showed inhibition of lipid peroxidation in Wistar rat brain homogenate and displayed antibiofilm activity against Enterococcus faecalis ATCC 25212 and 19433, and Staphylococcus aureus ATCC 25923. Additionally, lyophilized OPT presented cytotoxic and antiproliferative effects against tumor cell lines (Caco-2, A549 and HepG2), inhibited the production of reactive oxygen species in A549 and IMR90 cells, and presented antihemolytic activity in human erythrocytes. The lyophilized OPT inhibited α-glucosidase (IC50 = 47.0 µg/mL) and α-amylase at 30.0 mg/mL. The main compounds detected in OPT were gallic acid, caffeine and theobromine.

From byproduct to a functional ingredient: Camu-camu (Myrciaria dubia) seed extract as an antioxidant agent in a yogurt model.

This work aimed to characterize the phenolic composition and in vitro antioxidant and antiproliferative properties of lyophilized camu-camu (Myrciaria dubia) seed extract (LCE), and to assess the effects of LCE on the antioxidant and sensory traits of yogurt. The LCE contained 46.3% (wt/wt) total phenolic content; the main compounds quantified were vescalagin, castalagin, gallic acid, procyanidin A2, and (-)-epicatechin. The LCE had antioxidant activity, as measured by different chemical assays (2,2-diphenyl-1-picrylhydrazyl, Folin-Ciocalteu reducing capacity, total reducing capacity, ferric reducing antioxidant power, and Cu2+ chelating capacity), and inhibited the cell proliferation of HepG2 cells (human hepatoma carcinoma; IC50 = 1,116 µg/mL) and Caco-2 cells (human colorectal adenocarcinoma epithelial cells; IC50 = 608.5 µg/mL). In addition, LCE inhibited the in vitro activity of α-amylase, α-glucosidase, and angiotensin-converting enzyme, and protected DNA from peroxyl radical-induced scission. When added to yogurts, different concentrations of LCE (0, 0.25, 0.5, 0.75, and 1.0 g/100 g) increased the chemical antioxidant and reducing capacities. The camu-camu yogurt containing LCE at 0.25 g/100 g had an acceptance index of 84%, showing that camu-camu seed extract may be a potential ingredient for addition to yogurts.