Phytochemical-rich antioxidant extracts of <i>Vaccinium vitis-idaea L</i>. leaves inhibit the formation of toxic Maillard reaction products in food models

Thermal treatment of proteinaceous foods generates heat-induced Maillard reaction substances including toxic advanced glycation end products (AGEs) and heterocyclic amines (HAs). It is known that plant phenolic compounds may influence Maillard reaction. This study investigated the impact of lingonberry leaf extracts on the formation of Nε-(carboxymethyl)lysine (CML) and Nε-(2-furoylmethyl)-L-lysine (furosine) in milk model system and HAs in meat-protein and meat model systems. In addition, lingonberry leaf extracts obtained by different solvents were characterized by radical scavenging, Folin-Ciocalteu assays and ultra-high pressure liquid chromatography quadruple-time-of flight mass spectrometry (UPLC-qTOF-MS). Water extract (WE) stronger suppressed CML than furosine formation in milk model system: CML levels were reduced by nearly 40%. Moreover, quinic acid and catechin which were abundant in WE, were effective in inhibiting CML and furosine formation. WE and acetone extract (AE) at 10 mg/mL significantly inhibited HAs formation in both model systems. However, higher suppressing effect on HAs formation showed AE which had lower antioxidant capacity and total phenolic content values than WE. WE contained higher amounts of hydroxycinnamic acids, proanthocyanidins and flavonols, while AE was richer in flavan-3-ols and arbutin derivatives. It indicates that the composition of phenolics might be a major factor for explaining different effect of extracts from the same plant on HAs formation. In general, the results suggest that lingonberry leaves is a promising source of phytochemicals for inhibiting toxic Maillard reaction products and enriching foods with plant bioactive compounds

Qualitative and quantitative anthocyanins composition and properties of half-highbush blueberry (Vaccinium × covilleanum) extracts

Sodinių šilauogių uogos yra vertingų biologiškai aktyvių medžiagų šaltinis ir turi didelę perspektyvą tiek maisto, tiek farmacijos pramonėje. Buvo tiriamos VDU Botanikos sode išaugintos Toro, Herbert, Coville ir North Blue veislių šviežios uogos. Chromatografijos ir masių spektrometrijos metodais ištyrus kokybinę bei kiekybinę antocianinų sudėtį nustatyta, kad Toro, Herbert ir Coville veislėse vyrauja cianidin-3-arabinozidas. Toro ir Coville veislėse jis sudaro apie 25 % visų antocianinų. North Blue ekstrakte vyrauja petunidin-3-gliukozidas, kuris sudaro 13 %. Antocianinų koncentracija tirtų veislių šilauogių uogose kito nuo 0,18 iki 0,27 g/100 g uogų, didžiausia buvo Toro veislės uogose. Išspaudose, kuriose kaupiama daugiausia pigmentų, antocianinų koncentracija buvo nuo 1,42 iki 2,06 g/100 g išspaudų, didžiausia nustatyta Coville veislės. Fenoliniai junginiai taip pat kaupiasi daugiausia uogų odelėse – išspaudose vidutinė nustatyta koncentracija buvo 2,7 g/100 g. Uogose ji buvo atitinkamai tik 0,72 g/100 g. Didžiausia fenolinių junginių koncentracija buvo Coville veislės uogose ir išspaudose, atitinkamai 0,79 ir 3,22 g/100 g. Visi tirti sodinių šilauogių uogų bei išspaudų ekstraktai pasižymėjo pakankamu antioksidaciniu aktyvumu. 10 kartų skiesti ekstraktai 2,2-difenil-1-pikrilhidrazilo radikalą (DPPH·) slopino 79–87 %Interest in fruit composition has intensified because of increased awareness of the possible health benefits of some of their micronutrients. Blueberries are a source of biologically active substances such as anthocyanins, phenolic compounds and vitamins. Few reports exist on the composition of anthocyanins and phenolic compounds in lowbush blueberries. In ripe highbush blueberries of the Croatan variety 14 anthocyanins were characterized. The major anthocyanins, in order of decreasing amounts, were identified to be malvidin and delphinidin 3-galactoside, delphinidin 3-arabinoside, petunidin 3-galactoside, petunidin and malvidin 3-arabinoside. The aim of this study was to quantitatively determine the anthocyanins present in half-highbush blueberries of Toro, Herbert, Coville and North Blue varieties by RP-HPLC-MS and to evaluate the antioxidative properties of extracts from berry and berry cakes. The major anthocyanin in the Herbert, Toro and Coville varieties was cyanidin 3-arabinoside. Petunidin 3-glucoside was the dominant anthocyanin in the North Blue variety berries. Total anthocyanins in blueberries ranged from 0.18 to 0.27 g/100 g of fresh berries and in berry cakes from 1.42 to 2.06 g/100 g. Toro berries and Coville berry cakes contained the highest level. The average concentration of phenolic compounds was 0.72 g/100 g of berries and 2.7 g/100 g in berry cakes. The highest level was determined in Coville berries and berry cakes (0.79 and 3.22 g/100 g respectively). All the study extracts showed antioxidative properties. The DPPH free radical scavenging capacity was 79−87%KTU Maisto institutasKauno technologijos universitetas, [email protected] Didžiojo universiteta

Health Beneficial Phytochemicals in <i>Dioscorea caucasica</i> Lipsky Leaves and Tubers and Their Inhibitory Effects on Physiologically Important Enzymes

Dioscorea caucasica Lipsky is a tertiary relict endemic plant naturally growing in the western part of the trans-Caucasus regions; it has adapted and successfully grows in the temperate region of the Baltic countries. Information about its phytochemical composition and bioactivities is rather scarce. This study reports the results of the identification of 41 compounds in D. caucasica leaf and tuber hydroethanolic extracts using UPLC-QTOF/MS. Organic acids were found in both extracts; hydroxycinnamates and flavonoids were the main phytochemicals in the leaves, while steroidal glycosides, fatty acids (mainly hydroxylated) and carbohydrates were found in the tubers. Leaf extracts inhibited enzymes in a dose-dependent manner and were remarkably stronger inhibitors of physiologically important enzymes, namely α-amylase (48.6% at 480 µg/mL), α-glucosidase (IC50 = 41.99 and 47.95 µg/mL with and without 0.1 M Na2CO3), acetylcholinesterase (45.85% at 100 µg/mL) and angiotensin-converting enzyme (IC50 = 829.7 µg/mL), most likely due to the presence of some quantified polyphenolic antioxidants. The mode of inhibition of α-glucosidase and acetylcholinesterase was assessed via kinetic studies based on Lineweaver–Burk inhibition plots. Leaf and tuber extracts acted as mixed-type and competitive inhibitors of α-glucosidase, respectively; the leaf extract demonstrated an uncompetitive inhibition mode of acetylcholinesterase. It is expected that this new knowledge of D. caucasica will serve for its valorization in developing new health beneficial ingredients for functional foods and nutraceuticals

Mangiferin Rich Products from Aphloia theiformis (Vahl) Benn Leaves: Extraction, Fractionation, Phytochemical Characterization, and Antioxidant Properties

International audienceAphloia theiformis is traditionally used in Mauritius, Madagascar, and Reunion Island for treating several diseases. In this study, various extraction solvents and schemes were applied for the recovery of antioxidant rich fractions from the leaves of A. theiformis. The products were evaluated for their antioxidant capacity using well known in vitro assays. Major compounds were characterized by UPLC-QTOF-MS. Hydrophilic extracts of A. theiformis demonstrated strong antioxidant properties, which are comparable with the synthetic antioxidant Trolox. UPLC analysis confirmed mangiferin as the main secondary metabolite of A. theiformis. Tormentic and hydroxytormentic acids as well as their isomers were also abundant in A. theiformis extracts and fractions, while their amounts were determined for the first time. The most potential extract was further separated into the fractions by liquid-liquid extraction and by precipitation at low temperature. Antioxidant capacity and composition of secondary metabolites of derived fractions were determined. Some of the fractions possessed remarkable antioxidant capacity, comparable to pure mangiferin. The results obtained reveal high potential of A. theiformis for recovery of natural antioxidants and other bioactive phytochemicals, particularly mangiferin

Bioactives and phytochemical composition of Dioscorea nipponica Makino and D. caucasica Lipsky extracts as possible sources of functional ingredients

P. 83Kauno technologijos universitetasVytauto Didžiojo universiteta

Antioxidant properties and phytochemical composition of fruits of different Viburnum opulus genotypes

Botanikos sodasKauno technologijos universitetasVytauto Didžiojo universiteta

Protective effects of Phyllanthus phillyreifolius extracts against hydrogen peroxide induced oxidative stress in HEK293 cells.

Phyllanthus phillyreifolius, a plant species indigenous to Reunion Island, is used in folk medicine for treating diarrhea and as a diuretic. In the present study acetone and hydroethanol extracts of P. phillyreifolius were evaluated for their cytotoxicity and antioxidant effects using in vitro (TPC, ABTS, DPPH, FRAP, ORAC) and in cellulo (MTT, DCFH-DA, RT-qPCR) assays. Major compounds were evaluated using UPLC-QTOF-MS. MTT cell viability assay showed low cytotoxicity of extracts towards human embryonic kidney 293 (HEK293) cell line. Both extracts were rich in polyphenols (mainly ellagitannins) and showed high antioxidant potential and intracellular ROS decreasing effect. Preconditioning of HEK293 cells with extracts influenced gene expression of antioxidant enzymes, however ROS level decreasing effect was more related to their capacity to scavenge free radicals and with their reducing power. Strong antioxidant activity of extracts as well as the presence of geraniin supports the use of P. phillyreifolius in traditional medicine

Selection of new blueberry cultivars with higher contents of biologically active compounds

Botanikos sodasKauno technologijos universitetasVytauto Didžiojo universiteta

Breeding of half-highbush blueberry in Lithuania

Botanikos sodasKauno technologijos universitetasVytauto Didžiojo universiteta

Redox Properties of Novel Antioxidant 5,8-Dihydroxycoumarin: Implications for its Prooxidant Cytotoxicity

The aim of this work was to characterize the redox properties of the new antioxidant 5, , isolated from sweet grass (Hierochloë odorata L.), and to determine its impact on its cytotoxic action. Reversible electrochemical oxidation of 5,8-DHC at pH 7.0 was characterized by the midpoint potential (E p/2 ) of 0.23 V vs. the normal hydrogen electrode. 5,8-DHC was slowly autoxidized at pH 7.0, and it was active as a substrate for peroxidase (POD, EC 1.11.1.7) and tyrosinase (TYR, EC 1.14.18.1). Oxidation of 5,8-DHC by POD/H 2 O 2 yielded the product(s) which reacted with reduced glutathione and supported the oxidation of NADPH by ferredoxin:NADP + reductase (FNR, EC 1.18.1.2) and NAD(P)H:quinone oxidoreductase (NQO1, DT-diaphorase, EC 1.6.99.2). The concentration of 5,8-DHC for 50% survival of bovine leukemia virus-transformed lamb kidney fibroblasts (line FLK) during a 24-h incubation was (60 ð 5.5) µm. Cytotoxicity of 5,8-DHC was decreased by desferrioxamine, catalase, the antioxidant N,N&apos;-diphenyl-p-phenylene diamine, and potentiated by 1,3-bis-(2-chloroethyl)-1-nitrosourea and dicumarol, an inhibitor of NQO1. This shows that 5,8-DHC possesses the oxidative stress-type cytotoxicity, evidently due to the action of quinodal oxidation product(s). The protective effect of isoniazide, an inhibitor of cytochrome P-450 2E1, points to hydroxylation of 5,8-DHC as additional toxification route, whereas the potentiating effect of 3,5-dinitrocatechol, an inhibitor of catechol-omethyltransferase (COMT, EC 2.1.1.6), points to the o-methylation of hydroxylation products as the detoxification route