•Food matrix (FM) contains significant amount of phenolic acids and flavonols.•Total recovery of polyphenols of grape extracts was significantly influenced by FM.•Low recovery of proantocyanidins and ...total flavonoids of seed extracts was observed.•FM and digestive fluids increased total polyphenol content of grape digests.•FM and digestive fluids contributed to ABTS+ scavenging activity of grape digests.
The aim of this study was to evaluate the effect of enriching a complex food matrix (FM) with grape extracts on polyphenol content, composition, bioaccessibility and antioxidant activity during digestion. The grape extracts and FM were separately tested under the same conditions as controls. The FM by itself contains a significant amount of phenolic acids and flavonols, influencing the final recovery of polyphenols from grape extracts. The FM significantly increased the total recovery of polyphenols after digestion of grape seed extracts compared to those digested without the FM; however, a low recovery of proantocyanidins and total flavonoids was observed. Digestive fluids and FM compounds significantly increased the total polyphenol content of grape digests and significantly contributed to their ABTS+ scavenging activity and ferrous-ion-chelating capacity. The present study suggested that enrichment of meat- and cereal-based products with grape polyphenol extracts could be a good strategy to formulate a healthier diet.
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•HPLC analysis showed that TTSG milk/pollen powder is good source of polyphenols.•After in vitro digestion of sample, the total polyphenols recovery was 30.71%.•TTSG milk/pollen ...powder exhibited good antioxidant properties.•TTSG milk/pollen powder could be a good functional ingredient.
The aim of research was to determine polyphenols bioaccessibility and antioxidant properties of thermally-treated skimmed goat milk enriched with sunflower bee-collected pollen through in vitro digestion. HPLC analysis confirmed that pollen-enriched milk contained flavonols as the main phenolic fraction (80.7–76.2%) followed by phenolic acids (14.2–17.4%). Among individual compounds quercetin-3-O-glucoside (155.1–197.2 μg/L) and p-coumaric acid (29.5–30.7 μg/L) were the main quantified flavonols and phenolic acids, respectively. After digestion of milk/pollen sample, total polyphenols recovery was 30.71% with higher phenolic acids recovery (40.1%) compared to flavonols (28.3%) indicating strong interactions between caprine milk casein micelles and pollen polyphenols. Applied antioxidant assays (phosphomolybdenum, ABTS•+scavenging activity and ferrous-ion-chelating capacity) have confirmed complexity of prepared product- it had high ability to quench ABTS•+ radicals and to form chelating complexes with Fe2+ ions. Digestion provoked 20% reduction in total antioxidant capacity compared to the initial sample. TTSG milk/pollen powder could be good functional ingredient.
The aim of this study was to investigate the bioaccessibility of pesticide residues in blueberries (commercial and sample from controlled field trial) from Serbia, involving the presence of a complex ...food matrix and to assess the potential risk to human health. The presence of nine active substances (azoxystrobin, boscalid, fludioxonil, cyprodinil, pyrimethanil, pyridaben, pyriproxyfen, acetamiprid and thiametoxam) in initial blueberry samples was determined in concentration range from 5.15 μg/kg for thiametoxam to 187 μg/kg for azoxystrobin. Clothianidin, metabolite of thiametoxam, was not detected in any blueberry sample. However, after in vitro digestion, the content of initially detected pesticides residues was significantly decreased or it was below limit of quantification resulting in the total bioaccessibility of about 15%. Azoxystrobin, pyrimethanil and fludioxonil was quantified in digestive juice at concentrations which were about 81%, 37% and 10% less than the inital concentration, respectively. The presence of food matrix during digestion of blueberries even more severely reduced concentration of pesticide residues (total bioaccessibility was about 7%) compared to digestion without the food matrix. Only azoxystrobin was quantified after digestion with food matrix in concentration of 27 μg/kg in sample from controlled field trial and detected in two commercial samples but below the limit of quantification. Furthermore, chronic risk assessment indicated that risk is acceptable for the health of different human subpopulation groups. The current study on pesticides residues, most commonly applied on blueberries, provides for the first time an insight into their bioaccessibility under conditions that mimic physiological environment of human digestive tract.
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•Pesticide residues concentration before and after in vitro digestion were analyzed.•Nine different pesticide residues were quantified in initial blueberry samples.•Azoxystrobin, pyrimethanil and fludioxonil were detected after in vitro digestion.•Azoxystrobin was bioaccessible after in vitro digestion with the food matrix.•Health risk via blueberry consumption for different consumer groups was acceptable.
Phenolic compounds and biopotential (antioxidant, cellular antioxidant and cytotoxic activity) of grape pomace (GP) skin, seed, stem and whole GP originating from indigenous red grape variety ...Prokupac were evaluated. The UHPLC-Orbitrap MS4 analysis showed the presence of 75 phenolic compounds (57 non-anthocyanins and 18 anthocyanins), among which considerable content of ethyl gallate was observed and malvidin-3-O-hexoside-(8,8)-methylmethyne-(epi)catechin was identified. The stem had significant content of stilbenoids. The GP seed and the whole GP showed the highest antioxidant activity estimated by ABTS•+ DPPH• and H2O2 scavenging assays that were strongly correlated with the presence of flavan-3-ols, phenolic acids and ethyl gallate. The GP skin exerted cellular antioxidant activity on adenocarcinoma cells (EC50 = 56.4 mg TPCs/mL) which was strongly correlated with the presence of flavonols and anthocyanins. These by-products of Prokupac red grape variety are a notable source of phenolic compounds with good antioxidant activity that can be extensively used in food and pharmaceutical industry.
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•Seventy five phenolic compounds were quantified in grape pomace of Prokupac variety.•Considerable amount of ethyl gallate was observed in the grape pomace extracts.•The stem contained significant amount of stilbenoids.•The seed and whole pomace showed the highest radicals and H2O2 scavenging activities.•The extracts of grape pomace skin exerted the cellular antioxidant activity.
Anticancer activity of Pd complexes 1–5 with bidentate N-heteroaromatic hydrazone ligands was investigated on human acute monocytic leukemia (THP-1; cells in a suspension) and human mammary ...adenocarcinoma (MCF-7; two-dimensional layer and three-dimensional spheroid tumor model) cell lines. For the Pd(II) complexes with condensation products of ethyl hydrazainoacetate and quinoline-8-carboxaldehyde (complex 1) and 2-formylpyridine (complex 3), for which apoptosis was determined as a mechanism of anticancer activity, further investigation revealed that they arrest the cell cycle in G0/G1 phase, induce generation of reactive oxygen species and inhibit Topoisomerase I in vitro. In silico studies corroborate experimental findings that these complexes show topoisomerase inhibition activity in the micromolar range and indicate binding to a DNA's minor groove as another potential target. Based on the results obtained by circular dichroism and fluorescence spectroscopy measurements, the most active complexes are suitable to be delivered to a blood stream via human serum albumin.
A cytotoxic potential of Pd(II)-complexes with bidentate N-heteroaromatic chelators was investigated. Complexes 1 and 3 showed strong pro-apoptotic activity with the production of reactive oxygen species. The complexes interfere with DNA replication process causing DNA damage directly by binding to a minor groove and indirectly by Topoisomerase I inhibition. Display omitted
•Cytotoxic potential of Pd(II) complexes with N-heteroaromatic chelators was investigated.•Complexes 1 and 3 were revealed as more potent apoptosis inducers than cisplatin.•1 achieves a superior inhibition of mammary adenocarcinoma MCF-7 spheroids' growth.•1 and 3 cause DNA damage by binding to a minor groove and Topoisomerase I inhibition.•1 and 3 are suitable to be delivered to a blood stream via human serum albumin.
Pseudomonas aeruginosa
, which is a clinically important representative of
Pseudomonas
spp., has been recognized as causative agent of severe nosocomial infections worldwide. An increase in ...antibiotic resistance of
P. aeruginosa
clinical strains could be attributed to their capacity to acquire resistance through mobile genetic elements such as mobile integrons that are present in one-half of multidrug-resistant
P. aeruginosa
strains. Mobile class 1 integrons are recognized as genetic elements involved in the rapid dissemination of multiple genes encoding for antibiotic resistance. The LexA protein is a major repressor of integrase transcription, but differences in transcription regulation among bacterial species have also been noted. In this study, the promoter activity of class 1 integron integrase gene (
intI1
) and its variant lacking the LexA binding site in
Pseudomonas putida
WCS358 wild type,
ΔrpoS
and
ΔpsrA
was analysed. The results show that the activity of the
intI1
gene promoter decreased in the
rpoS
and
psrA
mutants in the stationary phase of growth compared to the wild type, which indicates the role of RpoS and PsrA proteins in the positive regulation of integrase transcription. Additionally, it was determined that the activity of the
lexA
gene promoter decreased in
ΔrpoS
and
ΔpsrA
, and thus, we propose that PsrA indirectly regulates the
intI1
gene promoter activity through regulation of
lexA
gene expression in co-operation with some additional regulators. In this study,
intI1
gene expression was shown to be controlled by two major stress response (SOS and RpoS) regulons, which indicates that integrase has evolved to use both systems to sense the cell status.
Lactococcus lactis subsp. lactis biovar. diacetylactisS50 je prirodni izolat iz maslacne maje. Soj S50 sintetise bakteriocin uskog spektra delovanja i proteinazu PI tipa. Soj S50 poseduje tri ...vidijiva plazmida koji se mogu izolovati (pS50-7, pS50-10a i pS50-10b). Ciscenjem plazmida iz soja S50 istovremenim tretmanom subletalnom temperaturom i novobiocinom (10u:g/m!) dobijen je Bac- i Prt- derivat (S50-1).Analizom genoma soja S50 i derivata S50-1 na elektroforezi u pulsirajucem polju (PFGE) nakon digestije restrikcionim enzimima ustanovijeno je da se geni za sintezu proteinaze PI tipa i bakteriocina S50 nalaze na plazmidu velicine oko 290kb koji je oznacen kao plazmid pS50-290. Na osnovu razdvajanja secene DNK na PFGE i hibridizacije sa probama za proteinazni (Q; i Qo) i bakteriocinski gen (LenA) odredjena je restrikciona mapa plazmida pS50-290 i odredjen je polozaj gena na njemu. Plazmid pS50-290 pokazuje visok stepen retardacije na PFGE sto moze biti posledica vezivanja proteina za njega.Soj S50 je ukrstan sa vecim brojem recipijentnih sojeva (MG7284, 1L1403, VEL1122 i ocisceni derivati soja S50) u kojima su dobijani Bact konjugnti sa priblizno istom frekvencom. Na osnovu toga se moze tvrditi da je plazmid pS50-290 autokonjugabilan ili Tra+ plazmid, odnosno da na sebi poseduje sve neophodne gene za sopstveni transfer. Pored sinteze bakteriocina ustanovljeno je da svi dobijeni konjuganti sintetisu i proteinazu PI tipa istih karakteristika kao i soj S50. Analizom plazmidnog sastava konjuganata ustanovijeno je da i drugi plazmidi soja S50 (pS50-7 i pS50-10b) poseduju sposobnost konjugacionog transfera, najverovatnije zato sto poseduju gen za Mob protein i oriT sekvencu.Restrikcionom analizom plazmida izolovanih iz konjuganata, rekonjuganata i derivata S50- 20 (digestijia Smal restrikcionim enzimom i razdvajanje dobijenih fragmenata na PFGE) ustanovijeno je da je u njima plazmid pS50-290 (oznacen kao pS50-290A) skracen i da poseduje samo jedno Smal restrikciono mesto za razliku od plazmida pS50-290 izolovanog iz sojaS50 koji poseduje dva. Fragment koji se deletira je velicine nekoliko kilobaza i pokazuje homologiju sa ostalim plazmidima soja S50 (pS50-7, pS50-10a i pS50-10b). Hibridizacionim ekspeimentima u kojima je plazmid pS50-7 koriscen kao proba pokazano je da svi plazmidi soja S50 poseduju homologe sekvence cije prisustvo govori o zajednickom poreklu ovih plazmida.U procesu izolacije spektinomicin-rezistentnih derivata soja S50 izolovani su mutanti koji pokazuju visok nivo rezistencije na spektinomicin i koji ujedno poseduju inverziju u hromozomu velicine izmedju 180 i 790kb. Istu inverziju je posedovao i mutant derivata S50-20-62 rezistentan na visoku koncentraciju spektinomicina.
A natural isolate of Lactococcus lactis was shown to produce two narrow spectrum class II bacteriocins, designated LsbA and LsbB. The cognate genes are located on a 5.6-kb plasmid within a gene ...cluster specifying LmrB, an ATP-binding cassette-type multidrug resistance transporter protein. LsbA is a hydrophobic peptide that is initially synthesized with an N-terminal extension. The housekeeping surface proteinase HtrA was shown to be responsible for the cleavage of precursor peptide to yield the active bacteriocin. LsbB is a relatively hydrophilic protein synthesized without an N-terminal leader sequence or signal peptide. The secretion of both polypeptides was shown to be mediated by LmrB. An L. lactis strain lacking plasmid-encoded LmrB and the chromosomally encoded LmrA is unable to secrete either of the two bacteriocins. Complementation of the strain with an active LmrB protein resulted in restored export of the two polypeptides across the cytoplasmic membrane. When expressed in an L. lactis strain that is sensitive to LsbA and LsbB, LmrB was shown to confer resistance toward both bacteriocins. It does so, most likely, by removing the two polypeptides from the cytoplasmic membrane. This is the first report in which a multidrug transporter protein is shown to be involved in both secretion and immunity of antimicrobial peptides.
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