Search results for "antioksidanti"
showing 10 items of 26 documents
Lignocelulozes pirolīzes blakusprodukti kā antioksidantu avots
2022
Lignocelulozes pirolīzes blakusprodukti kā antioksidantu avots. Evita Volkova, zinātniskie vadītāji Dr. chem. Arturs Vīksna (LU ĶF) un pētniece Dr. chem. Kristīne Meile (LVKĶI). Bakalaura darba saturs: 31 lappuses, 9 attēli, 20 tabulas, 21 literatūras avoti, 3 pielikumi, Latviešu valodā. Darbā ir veikta antioksidantu aktivitātes noteikšana lignocelulozes pirolīzes blakusproduktiem, izmantojot DFPH radikāli, kā arī noteikts kopējo fenolu daudzums, izmantojot Folina-Čikalto metodi. Antioksidantu aktivitāte un kopējo fenolu daudzums tika noteikts, izmantojot spektrofotometriju un augstefektīvo šķidruma hromatogrāfiju. PIROLĪZE, ANTIOKSIDANTI, SPEKTROFOTOMETRIJA, ŠĶIDRUMA HROMATOGRĀFIJA
Šķidruma hromatogrāfijas un masspektrometrijas metožu izstrāde un pielietojums antioksidantu noteikšanai
2017
Antioksidanti ir plaši izplatīti augu valsts pārtikas produktos un pēdējā desmitgadē tiem ir pievērsta pastiprināta uzmanība. Pateicoties to veselību uzlabojošajām īpašībām, ir radusies palielināta interese par to noteikšanas veidiem dažāda veida augos un augu izcelsmes produktos. Līdz ar augsti efektīvās šķidrumu hromatogrāfijas pieejamību apvienojumā ar augstas izšķirtspējas masspektrometriju, ir pavērti jauni apvāršņi analītisko metožu izstrādei sarežģītās paraugu matricās. Darbā dots ieskats par antioksidantu un polifenolu īpašībām, to izdalīšanu no pārtikas produktiem, paraugu sagatavošanas un noteikšanas metodēm, izmantojot augsti efektīvās šķidruma hromatogrāfijas metodes. Kā pētījum…
Effects of a glyphosate-based herbicide on survival and oxidative status of a non-target herbivore, the Colorado potato beetle (Leptinotarsa decemlin…
2018
Abstract Glyphosate is the globally most used herbicide against a wide range of weeds. Glyphosate has been considered safe to animals as it mainly targets physiological pathways in plants. However, recent toxicological studies have revealed that glyphosate can cause various toxic effects also on animals. In this study, we investigated the direct toxic effects of a glyphosate-based herbicide (GBH, Roundup® Bio) on 1) survival and 2) oxidative status of a non-target herbivore by using Colorado potato beetles (Leptinotarsa decemlineata), originating from Poland and USA, as model species. Larvae were randomly divided into three groups: 1) high concentration (100% Roundup Bio, 360 g/l), 2) low c…
Toxicological and bioactivity evaluation of blackcurrant press cake, sea buckthorn leaves and bark from Scots pine and Norway spruce extracts under a…
2021
Aqueous extracts from blackcurrant press cake (BC), Norway spruce bark (NS), Scots pine bark (SP), and sea buckthorn leaves (SB) were obtained using maceration and pressurized hot water and tested for their bioactivities. Maceration provided the extraction of higher dry matter contents, including total phenolics (TPC), anthocyanins, and condensed tannins, which also impacted higher antioxidant activity. NS and SB extracts presented the highest mean values of TPC and antioxidant activity. Individually, NS extract presented high contents of proanthocyanidins, resveratrol, and some phenolic acids. In contrast, SB contained a high concentration of ellagitannins, ellagic acid, and quercetin, exp…
Spectroscopic, crystal structural, theoretical and biological studies of phenylacetohydrazide Schiff base derivatives and their copper complexes
2020
Two phenylacetohydrazide Schiff base derivatives: N’-(1-(2-hydroxyphenyl)ethylidene)-2-phenylacetohydrazide, HL1, and N’-((1-hydroxynaphthalen-2-yl)methylene)-2-phenylacetohydrazide, HL2, were synthesized. HL1 dimerizes in presence of HCl, probably via radical mechanism to give (2,2’-((1E)-hydrazine-1,2-diylidenebis(ethan-1-yl-1-ylidene))diphenol (DIM). Thermal reactions of Cu(II) ions with the two Schiff base ligands resulted in formation of the binuclear complexes [(CuL1)2] and [(CuL2)2]. The stoichiometry and structures of the reported compounds were investigated by several spectroscopic and analytical techniques. The structure of the HL1 ligand and its complex [(CuL1)2] as well as the D…
Non-Thermal Ultrasonic Extraction of Polyphenolic Compounds from Red Wine Lees
2020
This study presents the results of conventional aqueous (CE) and non-conventional ultrasound-assisted (UAE) extractions of polyphenolic compounds from lees extracts of red wine varieties (Merlot and Vranac). The effect of ultrasound extraction time (t, s), and amplitude (A,%) from a 400 W ultrasound processor with different ultrasonic probes diameters (Ds, mm) on the amount and profile of polyphenolic compounds in the obtained extracts was investigated and compared to CE. The optimal conditions resulting in maximum extraction of phenolic compounds were: Probe diameter of 22 mm, amplitude 90% and extraction time for Vranac wine lees 1500 s and for Merlot wine lees extraction time of 1361 s. …
Glyphosate-based herbicide has soil-mediated effects on potato glycoalkaloids and oxidative status of a potato pest
2020
Glyphosate is the most used herbicide worldwide, targeting physiological pathways in plants. Recent studies have shown that glyphosate can also cause toxic effects in animals. We investigated the glyphosate-based herbicide (GBH)-induced changes in potato (Solanum tuberosum) plant chemistry and the effects of a GBH on the survival rate and oxidative status of the Colorado potato beetle (Leptinotarsa decemlineata). The beetles were reared on potato plants grown in pots containing soil treated with a GBH (Roundup Gold, 450 g/l) or untreated soil (water control). The 2nd instar larvae were introduced to the potato plants and then collected in 2 phases: as 4th instar larvae and as adults. The ma…
Plazmas biomarķieru izmaiņas žurku akūtas mezenteriālas išēmijas modelī
2022
Lai gan akūtu mezenteriālu išēmiju (AMI) uzskata par retu slimību, tā ir ātri progresējoša un visbiežāk noved pie pacienta nāves. Neskatoties uz pēdējo gadu medicīnas sasniegumiem, agrīna un pareiza diagnoze vēl joprojām ir apgrūtinoša. Šobrīd klīnikā lietotie laboratorijas testi nav gana specifiski, tādēļ agrīna un jutīga biomarķiera izstrādei ir izšķiroša nozīme, lai glābtu pacientu dzīvības. Darba mērķis ir izpētīt trīs biomarķieru un kopējās antioksidantu spējas izmaiņas žurku plazmā pirmo divu stundu laikā kopš sākusies AMI. D- laktāta un zarnu taukskābes saistošā proteīna (I-FABP) koncentrācijas no išēmijas laika atkarīgā veidā pieauga, savukārt citrulīna līmenis samazinājās. Starp an…
Fibroblasts from bank voles inhabiting Chernobyl have increased resistance against oxidative and DNA stresses
2018
Background Elevated levels of environmental ionizing radiation can be a selective pressure for wildlife by producing reactive oxygen species and DNA damage. However, the underlying molecular mechanisms that are affected are not known. Results We isolated skin fibroblasts from bank voles (Myodes glareolus) inhabiting the Chernobyl nuclear power plant accident site where background radiation levels are about 100 times greater than in uncontaminated areas. After a 10 Gy dose of gamma radiation fibroblasts from Chernobyl animals recovered faster than fibroblasts isolated from bank voles living in uncontaminated control area. The Chernobyl fibroblasts were able to sustain significantly higher do…
Vaccinium spp. ogu ekstraktu polifenolu saturs un antioksidatīvie efekti
2018
Brīvie radikāļi ķermenī rada oksidatīvo stresu un deģeneratīvus procesus, kuru rezultātā var tikt bojāti veselie audi un izraisīta šūnu nāve. Atklājumi par brīvo radikāļu negatīvo ietekmi uz šūnām un saistību ar dažādu slimību progresēšanu, piemēram, vēža, aknu cirozes, artrīta, aterosklerozes, sirds un asinsvadu slimību, neirodeģeneratīvo traucējumu, kā arī ievērojams skaits epidemioloģisko pētījumu par saslimšanas riska samazināšanos, lietojot uzturā ar antioksidantiem bagātus produktus, ļauj domāt par jaunu pavērsienu medicīnas zinātnē. Darba mērķis: Izpētīt melleņu, krūmmelleņu, lielogu dzērveņu, dzērveņu un brūkleņu ogu spiedatlieku ekstraktu antioksidatīvās īpašības un atrast to saist…