Antioxidant Status, Antidiabetic Properties and Effects on Caco-2 Cells of Colored and Non-Colored Enriched Extracts of Sweet Cherry Fruits

Abstract

This study aimed to compare three different extracts of Saco sweet cherry, namely the non-colored fraction, colored fraction, and total extract concerning phenolic composition, antioxidant and antidiabetic potential, and erythrocytes’ protection and effects on Caco-2 cells. Twenty-two phenolic compounds were identified using high-performance liquid chromatography with diode-array detection. Hydroxycinnamic acids were the most predominant in both the non-colored fraction and total extract, while cyanidin-3-O-rutinoside was the main anthocyanin found in the colored fraction. The total extract was the most effective against 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, and superoxide radicals, and in the inhibition of α-glucosidase enzyme. The colored fraction revealed the best activity against hemoglobin oxidation and hemolysis. Regarding to Caco-2 cells, the colored extract exhibited the highest cytotoxic effects, while the total extract was the most efficient in protecting these cells against oxidative damage induced by tert-butyl hydroperoxide.

Polyphenol Extraction by Different Techniques for Valorisation of Non-Compliant Portuguese Sweet Cherries towards a Novel Antioxidant Extract

“…Among flavonols, only 3 derivatives were identified: Kaempferol-3-rutinoside, kaempferol-3-glucoside, and quercetin derivative, which were reported previously by Martini, Conte, and Tagliazucchi [5] in exotic varieties and Portuguese varieties, for instance, Saco sweet cherry for Gonçalves, Bento, Silva, and Silva [47], and in Saco cherry polyphenol-rich extracts [8,17]. Regarding anthocyanins, a total of 5 were identified in antioxidant polyphenol-rich extracts: Cyanidin-3-glucoside, cyanidin-3-rutinoside, peonidin-3-rutinoside, peonidin-3-glucoside, and pelargonidin-3-glucoside.…”

“…Regarding anthocyanins, a total of 5 were identified in antioxidant polyphenol-rich extracts: Cyanidin-3-glucoside, cyanidin-3-rutinoside, peonidin-3-rutinoside, peonidin-3-glucoside, and pelargonidin-3-glucoside. These anthocyanins had been already identified in the Saco variety [47] and in polyphenol-rich extracts produced from Saco cherry [17], being that these anthocyanins are the most reported in cherries, in spite of the variety. All the extraction methodologies showed to be able to recover all phenolic compounds except on MAE extracts, where three of the hydroxycinnamic acids were not detected.…”

“…On the other hand, Martini, Conte, and Tagliazucchi [5] identified 12 more flavanols in cherry exotic varieties, including procyanidins, and Serra, Duarte, Bronze, and Duarte [4] identified two flavanols in Saco cherries ((+)-catechin and (−)-epicatechin). Furthermore, Matias, Rosado-Ramos, Nunes, Figueira, Serra, Bronze, Santos, and Duarte [8] reported the presence of (+)-catechin and procyanidin B2 in antioxidants extracts from Saco cherry produced by recovery (poly)phenols from extracts by adsorption process, although, Gonçalves, Rodrigues, Santos, Alves, and Silva [17] did not identify any flavanols in Saco cherry hydro-alcoholic extracts.…”

“…Since one of the main purposes of this work was to produce extracts, by the application of four different methodologies, following the evaluation of their bioactivities, the variables regarding type of solvent and ratio were fixed. For that, a mixture of water:ethanol (50:50, v/v) was selected, because (i) these are food grade solvents, and thus are considered to be safe for the consumer even if not completely removed from the final ingredient, (ii) are environmentally friendly, (iii) could be reused in the process, and finally, (iv) this mixture is one of the most common mixtures of solvents used to produce extracts rich in BCs [17]. The extraction yield of the different Saco cherry antioxidant polyphenol-rich extracts obtained by different extraction techniques are shown in Figure 1.…”

Anthocyanins as Antidiabetic Agents—In Vitro and In Silico Approaches of Preventive and Therapeutic Effects

“…Specifically, previous studies have proven the ability of phenolic-rich ingredients (berry extracts, soft-fruits, grape seeds and bitter melon to inhibit the activities of pancreatic α-amylase and intestinal α-glucosidase in the gut lumen [ 51 , 52 ]. Other studies have shown that anthocyanin-rich fractions from blueberry [ 53 ], blackberry [ 54 ], black legumes [ 55 ], black mulberry [ 56 ], bilberry and cranberry [ 57 ], red aril fruits [ 58 ], camelina and ophia seeds [ 59 ], royle fruits [ 60 ], fruits of Chilean berberis species [ 61 ], peach fruit and A. melanocarpa fruit juice extracts [ 62 , 63 ], colored extracts of Saco sweet cherry [ 64 ], and anthocyanin extracts from black bean hull, black currants and black rice [ 65 , 66 ] exhibited higher effectiveness to inhibit α-glucosidase. Therefore, diet-induced treatments from anthocyanin-based extracts, often combined with other polyphenols, may offer a natural alternative to achieve better glycemic control in T2DM.…”