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Significance of polyphenols for cancer prevention
No full textPolifenoli su izuzetno velika i raznovrsna skupina bioaktivnih spojeva prisutnih u biljkama, poznati po antioksidacijskim svojstvima. Nalaze se u vo u, povr u, aju, crnom vinu i drugim prehrambenim proizvodima. Zna aj polifenola u prevenciji raka proizlazi iz njihove sposobnosti da neutraliziraju slobodne radikale, btite i organizam od oksidacijskog stresa koji mo~e dovesti do nastanka raka. Dokazana je njihova u inkovitost u inhibiranju proliferacije stanica raka, aktiviranja apoptoze i sprje avanju metastaza. Neki polifenoli su se posebno istaknuli po svojim antikancerogenim svojstvima, poput resveratrola iz gro~đa i epigalokatehin-3-galata iz zelenog aja. Međutim, job uvijek se provode istra~ivanja koja e u potpunosti objasniti mehanizme djelovanja polifenola na stanice raka te time omogu iti u inkovitu primjenu polifenola u samom lije enju raka.Polyphenols are a group of natural bioactive compounds, known for their antioxidative properties. They are present in fruits, vegetables, tea, red wine and other foods. The significance of polyphenols in cancer prevention stems from their ability to neutralize free radicals, protecting organisms from oxidative stress that can lead to cancer. Their function in inhibition of cancer cell proliferation, apoptosis activation and metastasis prevention has been proven. Some polyphenols have better anticarcinogenic properties than other, such as resveratrol from grapes and epigallocatechin-3- gallate from green tea. However, studies underlying mechanisms of polyphenol activity towards cancer cells are still being conducted and will hopefully enable efficient implementation of polyphenols in cancer treatment
Kojic acid and derivatives: preparation and biological activity
No full textHidroksipiranoni pripadaju skupini heterocikli kih spojeva koji sadržavaju aromatski bestero lani prsten s endocikli kim kisikovim atomom. Na prstenu su, kao supstituenti, naj eb e vezane karbonilna i hidroksilna skupina. Kojinska kiselina jedan je od važnijih predstavnika ove skupine spojeva, koja osim navedenih supstituenata, na atomu C-2 sadrži vezanu hidroksimetilnu skupinu, koja je ujedno i najreaktivniji dio spomenute molekule. Zbog mogu nosti strukturne modifikacije, danas je poznat velik broj derivata kojinske kiseline, koji svoju primjenu najve im dijelom pronalaze u medicini, kao potencijalni agensi za supresiju rasta tumorskih stani nih linija te kao depigmentacijska sredstva. U ovom radu predstavljeni su zna ajni rezultati iz novije literature u kojima je vidljiva raznovrsnost priprave derivata kojinske kiseline kao i njihove biolobke primjene.Hydroxypyranones are a group of heterocyclic compounds containing an aromatic six-membered ring with one endocyclic oxygen atom per atom. As a rule, carbonyl and hydroxyl groups are attached to the ring. One of the most important representatives of this group is kojic acid, which contains a bound hydroxymethyl group in addition to the substituents mentioned on the C-2 atom, which also represents the most reactive part of the molecule mentioned. Due to the possibility of structurally modifying the molecules, a large number of kojic acid derivatives are known today, most of which are used in medicine as potential agents to suppress the growth of tumor cell lines and as depigmenting agents. This paper presents the most important findings from the recent literature, emphasizing the diversity in the production of kojic acid derivatives and their biological evaluation
Characterization of the new all-solid-state potentiometric sensor for determination of anionic surfactants
No full textTenzidi ili povrbinski aktivne tvari su vrsta molekula koje smanjuju povrbinsku napetost između dvije faze. Klasificiraju se na anionske, kationske, amfolitske i neionske tenzide. Anionski tenzidi su povrbinski aktivne tvari koje imaju negativan naboj na svom hidrofilnom kraju. Neke od metoda određivanja anionskih tenzida su spektrofotometrijske, potenciometrijske, kromatografske, titrimetrijske metode i druge. Cilj ovog rada bila je karakterizacija novog all-solid-state potenciometrijskog senzora za određivanje anionskih tenzida. Metoda koja je koribtena u radu je direktna potenciometrija. Selektivnost novog all-solid-state potenciometrijskog senzora ispitana je metodom stalne koncentracije interferenata. Od deset ispitanih otopina smetaju ih tvari (interferenata) samo se natrijev dodecilbenzensulfonat (NaDBS) pokazao kao mogu i interferent, ime je potvrđena dobra selektivnost novog senzora prema natrijevom dodecil sulfatu (NaDDS). Pri ispitivanju dinami kog odziva dobiveno vrijeme odziva iznosilo je oko 9 sekundi ime se potvrđuje brz odziv senzora prema NaDDS-u. Nadalje je ispitan utjecaj pH vrijednosti na odziv senzora te je iz dobivenih rezultata vidljivo da je mjerno pH podru je pri pH od 2 do 8. Zadnji ispitan parametar bio je tijek signala koji je iznosio 2,7 mV/h.Surfactants or surface active agents are a type of molecules that reduce the surface tension between two phases. They are classified as anionic, cationic, ampholytic and nonionic surfactants. Anionic surfactants have a negative charge at their hydrophilic end. Some of the methods for determination of anionic surfactants are spectrophotometric, potentiometric, chromatographic, titrimetric methods and others. The aim of this paper was the characterization of a new all-solid-state potentiometric sensor for the determination of anionic surfactants. The method used in the paper is the direct potentiomety. The selectivity of the new all-solid-state potentiometric sensor was tested using the fixed interference method. Of the ten interferent solutions tested, only sodium dodecylbenzenesulfonate (NaDBS) proved to be a possible interferent, thereby confirming the good selectivity of the new sensor towards sodium dodecyl sulfate (NaDDS). When testing the dynamic response, the obtained response time was about 9 seconds, which confirms the fast response of the sensor toward NaDDS. Furthermore, the influence of the pH value on the response of the sensor was examined, and the obtained results show that the measuring pH range was between pH 2 and 8. The last parameter tested was the signal drift, which was 2.7 mV/h
Green synthesis of silver nanoparticles using Fomes Fomentarius (L.) extract
No full textZelena sinteza nanočestica srebra zbog svojih načela pridonosi održivom razvoju bez štetnog utjecaja na okoliš. Nanočestice srebra zbog svojih specifičnih antimikrobnih svojstava nalaze sve veću primjenu u medicinske svrhe. Cilj ovoga rada je sintetizirati nanočestice srebra iz vodenog ekstrakta gljive Fomes fomentarius i otopine AgNO3. Morfologija, stanište, upotreba gljive i zelena sinteza nanočestica srebra opisani su u literaturnom pregledu. Karakterizacija nanočestica izvršena je metodama UV-Vis, FT-IR, PXRD i TEM analize. UV-Vis analizom utvrđen je maksimum apsorbancije pri 410 nm. Rezultati FT-IR analize ukazali su na biomolekule koje su sudjelovale u procesu sinteze nanočestica. Prosječna veličina kristalita iznosila je 24 nm. Nanočestice srebra pokazale su dobru sposobnost razgradnje boje metilenskog plavila. Najbolju antibakterijsku aktivnost uzorak nanočestica srebra pokazao je na sojeve bakterija S. auerusa i E. coli, dok najmanju na soj bakterija P. aeruginosa.Due to its principles, the green synthesis of silver nanoparticles contributes to sustainable development without harmful impact on the environment. Silver nanoparticles are increasingly used for medical purposes due to their specific antimicrobial properties. The aim purpose of this work is to synthesize silver nanoparticles from the aqueous extract of the fungus Fomes fomentarius and AgNO3 solution. The morphology, habitat, use of the fungus and green synthesis of silver nanoparticles are described in the literature review. Nanoparticles were characterized by UV-Vis, FT-IR, PXRD and TEM analysis methods. UV-Vis analysis determined the maximum absorbance at 410 nm. The results of the FT-IR analysis indicated that the biomolecules had participated in the process of nanoparticle synthesis. The average crystallite size was 24 nm. Silver nanoparticles showed a good ability to degrade the color of methylene blue. The sample of silver nanoparticles showed the best antibacterial activity against bacteria S. auerus and E. coli, while the least activity against the strain of bacteria P. aeruginosa
Methamphetamine toxicity
No full textToksičnost metamfetamina odnosi se na štetne učinke uzrokovane zlouporabom ili predoziranjem metamfetaminom, snažnim lijekom za stimulaciju središnjeg živčanog sustava. Ovaj rad daje pregled toksičnosti metamfetamina, uključujući njegovo farmakološko djelovanje, kliničke manifestacije i liječenje. Metamfetamin izražava svoje toksične učinke povećanjem oslobađanja i inhibicijom ponovnog preuzimanja neurotransmitera kao što su dopamin (DA), norepinefrin i serotonin (5HT) u mozgu, što dovodi do kaskade fizioloških odgovora. Akutna toksičnost metamfetamina može rezultirati širokim rasponom simptoma, uključujući intenzivnu euforiju, povećanu energiju, uznemirenost, paranoju, halucinacije, ubrzan rad srca i povišen krvni tlak, hipertermiju, proširene zjenice i napadaje. U teškim slučajevima može dovesti do kardiovaskularnog kolapsa, rabdomiolize, zatajenja bubrega pa čak i smrti.Methamphetamine toxicity refers to the adverse effects caused by the misuse or overdose of methamphetamine, a powerful central nervous system stimulant. This paper provides an overview of methamphetamine toxicity, including its pharmacological actions, clinical manifestations, and treatment. Methamphetamine exerts its toxic effects by increasing the release and inhibiting the reuptake of neurotransmitters such as dopamine (DA), norepinephrine, and serotonin in the brain, leading to a cascade of physiological responses. Acute methamphetamine toxicity can result in a wide range of symptoms, including intense euphoria, increased energy, agitation, paranoia, hallucinations, increased heart rate and high blood pressure, hyperthermia, dilated pupils, and seizures. In severe cases, it can lead to cardiovascular collapse, rhabdomyolysis, kidney failure and even death
Lead and nickel in environment of eastern Croatia
No full textCilj ovog rada bio je procijeniti koncentracije olova i nikla u uzorcima vode, zemlje, maslačka i uzorcima kose, urina i seruma stanovnika s područja istočne Hrvatske, a metodama multivarijantne obrade podataka istražiti grupiranja i međusobne korelacije. Istraživanje je provedeno na ukupno 358 ispitanika u Vladislavcima, Dalju, Čepinu, Našicama i Osijeku. Vrijednosti za nikal kretale su se: serum 7,27 μg/L, urin 7,16 μg/L, kosa 4,95 mg/kg, zemlja od 19,24 mg/kg, voda 2,78 μg/L, maslačak 315,62 μg/kg. Vrijednosti za olovo kretale su se: serum 10,40 μg/L, urin 16,65 μg/L, kosa 17,23 mg/kg, zemlja 17,40 mg/kg, voda 0,60 μg/L, maslačak 77,22 μg/kg. Rezultat metode analize glavnih komponenata ukazao je na klaster koji se sastojao od dva grada i jednog naselja (Osijek, Našice, Čepin) okarakteriziranog nižim koncentracijama olova i nikla. Vrijednosti za biološke uzorke nalazile su se u rasponu referentnih vrijednosti ili su bile bliske njihovoj gornjoj granici. Vrijednosti koncentracija Ni i Pb za vodu, zemlju i maslačak nalazile su se u rasponu literaturnih vrijednosti za uzorke prikupljene na područjima koja nisu bila izložena antropogenim utjecajima. S obzirom na to da je istraživanje provedeno na velikom broju uzoraka, rezultati mogu poslužiti kao referentne i literaturne vrijednosti za koncentracije olova i nikla u istočnoj Hrvatskoj.The aim of this study was to assess the concentrations of lead and nickel in samples of water, soil, dandelions, and hair, urine, and serum samples from residents of eastern Croatia, and to explore clustering and mutual correlations using multivariate data analysis methods. The research was conducted on a total of 358 participants in Vladislavci, Dalj, Čepin, Našice, and Osijek. The values for nickel were as follows: serum 7.27 µg/L, urine 7.16 µg/L, hair 4.95 mg/kg, soil 19.24 mg/kg, water 2.78 µg/L, dande lions 315.62 µg/kg. The values for lead were as follows: serum 10.40 µg/L, urine 16.65 µg/L, hair 17.23 mg/kg, soil 17.40 mg/kg, water 0.60 µg/L, dandelions 77.22 µg/kg. The result of the principal component analysis method indicated a cluster consisting o f two cities and one settlement (Osijek, Našice, Čepin) characterized by lower concentrations of lead and nickel. Values for biological samples were within the range of reference values or close to their upper limit. Concentration values of Ni and Pb for w ater, soil, and dandelions were within the range of literature values for samples collected in areas not exposed to anthropogenic influences. Given that the research was conducted on a large number of samples, the results can serve as reference and literat ure values for concentrations of lead and nickel in eastern Croatia
Artificial enzymes
No full textPod pojmom "enzim" podrazumijevamo specifične organske spojeve, čija je uloga ubrzavanje kemijskih reakcija u organizmu. Svi enzimi, osim ribozima su proteini. Svi metabolički procesi imaju svoje specifične enzime, zahvaljujući kojima organizam može normalno funkcionirati. Od tisuće i tisuće enzima u organizmu čovjeka, odsustvo samo jednog enzima može predstavljati veliki problem za cjelokupno zdravlje i čitav život. Kada bi se uspjela razviti metoda za sintezu enzima riješili bi veliki broj najvećih i najkompleksnijih zdravstvenih problema. Upravo neke od najtežih bolesti ljudi su uzrokovane nedostatkom određenih enzima. Proteinsko inženjerstvo i svijet znanosti nastoje zaobići problem nedostatka prirodnih enzima dizajnirajući umjetne enzime. Umjetno dobiveni enzimi predstavljaju budućnost u svijetu znanosti i medicine. Katalitička aktivnost, specifičnost i kompleksnost strukture prirodnih enzima predstavljaju veliki izazov u sintezi umjetnih enzima. Cilj je dizajnirati i sintetizirati enzime koji će imati jednaka ili čak bolja svojstva od prirodnih enzima. Prostor za rast i razvoj, u svijetu umjetnih enzima, je pronašla i nanotehnologija sa svojim nanoenzimima. Nanoenzimi bi mogli ubrzo postati dio svakodnevne medicine i znanosti. Budućnost umjetnih enzima je svijetla i prostor za razvoj je jako veliki. Buduća istraživanja imaju zadatak poboljšati već sintetizirane umjetne enzime, ali i dizajnirati i sintetizirati nove.By the term "enzyme" we mean specific organic compounds whose role is to accelerate chemical reactions in the body. All enzymes except ribozymes are proteins. All metabolic processes have their own specific enzymes, thanks to which the body can function normally. Out of thousands and thousands of enzymes in the human body, the absence of just one enzyme can represent a big problem for the whole health and the whole life. If a method for enzyme synthesis could be developed, a large number of the biggest and most complex health problems would be solved. Some of the most serious human diseases are caused by a lack of certain enzymes. Protein engineering and the world of science are trying to circumvent the problem of lack of natural enzymes by designing artificial enzymes. Artificially obtained enzymes represent the future in the world of science and medicine. Catalytic activity, specificity and complexity of the structure of natural enzymes are a great challenge in the synthesis of artificial enzymes. The goal is to design and synthesize an enzyme that will have the same or even better properties than natural enzymes. Space for growth and development, in the world of artificial enzymes, has also been found by nanotechnology with its nanoenzymes. Nanoenzymes could soon become part of everyday medicine and science. The future of artificial enzymes is bright and the room for development is very large. Future research has the task of improving already synthesized artificial enzymes, but also designing and synthesizing new ones
Synthesis of quaternary salts of N-acylhydrazine derivatives of heterocyclic compounds
No full textZbog svoje važne biološke aktivnosti promatran je i ispitivan vitamin B6 i njegovi derivati. Važnost vitamina B6 očituje se u normalnom funkcioniranju živčanog sustava te normalnom funkcioniranju metabolizma lipida, glukoze, aminokiselina. Bitnu ulogu ima i u brojnim enzimskim aktivnostima. Molekula piridoksala pruža široke mogućnosti za kemijske modifikacije i pripravu derivata sa značajnim farmakološkim djelovanjem. U radu se pripravljeni derivati piridoksal hidroklorida. Prvo su sintetizirani N-acilhidrazoni (1-8), reakcijom piridoksala sa N-acilhidrazinima aromatskih i heteroaromatskih spojeva. Reakcije su rađene klasičnim putem, miješanjem u etanolu na sobnoj temperaturi 24 sata. U drugom dijelu rada se dobiveni hidrazoni kvaterniziraju s ciljem dobivanja kvaternih soli. Za kvaternizaciju se koriste fenacil-bromidi i supstituirani fenacil-bromidi. Sinteza se izvodi klasičnim putem, miješanjem i zagrijavanjem pri temperaturi refluksa otapala. Svi dobiveni spojevi su pročišćeni i snimljeni su im IR, MS, 1H i 13C NMR spektri, te im je određena temperatura tališta.Because of its important biological activity, vitamin B6 and its derivatives have been observed and investigated. The importance of vitamin B6 is manifested in the normal functioning of the nervous system and the normal functioning of the metabolism of lipids, glucose, and amino acids. It also plays an important role in numerous enzymatic activities. The pyridoxal molecule offers wide possibilities for chemical modifications and the preparation of derivatives with significant pharmacological activity. Pyridoxal hydrochloride derivatives are prepared in this work. First, N-acylhydrazones (1-8) were synthesized, by reacting piridoxal with N-acylhydrazines of aromatic and heteroaromatic compounds. The reactions were carried out in the classic way, by stirring in ethanol at room temperature for 24 hours. In the second part of the work, the obtained hydrazones are quaternized with the aim of obtaining quaternary salts. Phenacyl bromides and substituted phenacyl bromides are used for quaternization. The synthesis is carried out in the classical way, by mixing and heating at the reflux temperature of the solvent. All obtained compounds were purified and their IR, MS, 1H and 13C NMR spectra were recorded, and their melting point was determined
Electrochemical characterization of vitamin B12
No full textU ovom diplomskom radu ispitivana su elektrokemijska svojstva vitamina B12 cikličkom i diferencijalnom pulsnom voltametrijom. Cilj rada bio je ispitati utjecaj pH, brzine polarizacije elektrode i koncentracije vitamina B12 na njegova oksido-redukcijska svojstva, istražiti moguću adsorpciju vitamina B12 na površinu radne elektrode te detektirati vitamin B12 u realnom uzorku. Elektrokemijska mjerenja provedena su u troelektrodnoj elektrokemijskoj ćeliji s radnom elektrodom od staklastog ugljika, referentnom Ag/AgCl elektrodom i platinskom žicom kao protuelektrodom. Ciklički voltamogrami ispitivanog vitamina B12 pokazali su jedan oksidacijski strujni vrh koji odgovara oksidaciji Co2+ u Co3+ te jedan redukcijski strujni vrh koji odgovara redukciji Co3+ u Co2+. Utvrđeno je da je oksidacija Co2+ u Co3+ adsorpcijski kontroliran proces dok redukcija Co3+ u Co2+ difuzijski kontroliran proces jer je logaritam struje anodnog i katodnog strujnog vrha linearna funkcija logaritma brzine polarizacije elektrode (nagib pravca je oko 1 za anodni i oko 0,5 za katodni strujni vrh). Diferencijalni pulsni voltamogrami pokazali su da je anodni strujni vrh vitamina B12 linearna funkcija koncentracije u rasponu koncentracije od 1,00·10-6 mol dm-3 do 1,2·10-4 mol dm-3. Diferencijalnom pulsnom voltametrijom također je detektiran vitamin B12 u realnom uzorku kapsula B-kompleksa.In this diploma thesis, the electrochemical properties of vitamin B12 were determined by cyclic and differential pulse voltammetry. The aim of this study was to investigate the influence of pH, scan rate and concentration of vitamin B12 on its oxido-reduction properties, to study the possible adsorption of vitamin B12 on the working electrode surface and to detect vitamin B12 in a real sample. Electrochemical measurements were performed in a three-electrode electrochemical cell with a working glassy carbon electrode, reference Ag/AgCl electrode, and platinum wire counter electrode. The cyclic voltammograms of vitamin B12 have shown one oxidation peak which corresponds to the oxidation of Co2+ to Co3+ and one reduction peak which corresponds to a reduction of Co3+ to Co2+. It was determined that the oxidation of Co2+ to Co3+ is an adsorption-controlled process, while the reduction of Co3+ to Co2+ is a diffusion-controlled process, because the logarithm of the anodic and cathodic current peaks is a linear function of the logarithm of the electrode polarization speed (the slope of the line is about 1 for the anodic and about 0.5 for the cathodic peak current). Differential pulse voltammograms have shown that the anodic peak current of vitamin B12 was a linear function of concentration in a concentration range from 1.0·10 -6 mol dm-3 till 1.2 ·10 -4 mol dm-3. Differential pulse voltammetry was used to detect Vitamin B12 in a real sample of B-complex capsules
The influence of cadmium on the antioxidant activity of corn (Zea mays, L.)
No full textKukuruz (Zea mays, L.) je jednogodišnja vrsta žitarica prilagođena na različite vrste tla. Osim što je nutritivno vrijedan, kukuruz obogaćuju brojni fitokemijski spojevi, zbog kojih posjeduje snažna antioksidativna svojstva. Antioksidativni mehanizmi u kukuruzu, su u ovom radu, promatrani kao obrambeni mehanizmi. Kadmij je toksični metal koji, akumuliranjem u biljke, izaziva, ne samo abnormalnosti u rastu i razvoju biljke, već utječe i na njihova antioksidativna i druga svojstva. U ovom radu istraživan je utjecaj kadmija na antioksidativnu aktivnost dviju linija (84-28A i OS 942) kukuruza (Zea mays, L.) te njihova hibrida (OS 404). Uočeno je povećanje koncentracije proteina u biljkama tretiranim s koncentracijom kadmija od 150 μmol/L, dok su isti uzorci pokazali smanjenje sadržaja polifenola. Obje su linije kukuruza pokazale povećanje ukupne antioksidativne aktivnosti nakon tretmana s koncentracijom kadmija od 375 μmol/L, dok je u ostalim slučajevima antioksidativna aktivnost bila smanjena. Dobiveni rezultati upućuju na to da kadmij uvelike ima utjecaj na antioksidativnu aktivnost kukuruza (Zea mays, L.).Maize (Zea mays, L.) is an annual grain, adapted to different types of soil. Besides being nutritionally valuable, maize is also very rich in phytochemical compounds and therefore having strong antioxidant properties. Antioxidant mechanisms in maize, in this paper, were observed as defense mechanisms. Cadmium is a toxic metal which, when accumulated in plants, causes not only abnormalities in plant growth and development, but also impacts their antioxidant and other properties. The influence of cadmium on the antioxidant activity of two maize (Zea mays, L.) lines (84-28A i OS 942) and their hybrid (OS 404) was investigated in this study. The increase in protein concentration in plants treated with cadmium concentration of 150 μmol/L was observed, while the same samples showed a decrease in polyphenol content. Both maize lines showed an increase in total antioxidant activity when treated with cadmium concentration of 375 μmol/L. Total antioxidant activity was decreased in other samples of maize. The obtained results indicate that cadmium has a great influence on the antioxidant activity of maize