Imidacloprid – olive orchard “guardian”

Pojava otpornosti populacije štetnika na organofosfate i metilkarbamate, inhibitore acetilkolinesteraze, dovela je do njihove slabije učinkovitosti i uvjetovala da ih neonikotinoidni insekticidi istisnu iz uporabe. Imidakloprid je najvažniji neonikotinoid, a odlikuje se niskom postojanosti u tlu, visokom insekticidnom aktivnosti i niskom toksičnosti u sisavaca. Neurofiziološke studije su potvrdile da je on agonist postsinaptičkih nikotinskih acetilkolinskih receptora, pri čemu izaziva najprije stimulaciju postsinaptičkih membrana, a nakon toga para lizu prijenosa živčanih impulsa. U Hrvatskoj se imidakloprid često koristi u maslinicima Istre i kvarnerskih otoka kao efi kasno sredstvo u zaštiti nasada maslina protiv različitih nametnika. Progresivno povećanje proizvodnje i primjene pesticida u poljoprivredi predstavlja veliku opasnost za onečišćenje okoliša, osobito podzemnih voda. Kada pesticid uđe u okoliš ovisan je o mnogim fi zikalnim i kemijskim procesima. Procesi sorpcije jedni su od glavnih faktora koji utječu na postojanost i pokretnost pesticida u okolišu. U ovome radu opisani su postupci sorpcije i razgradnje imidakloprida i njihova ovisnost o karakteristikama tla u četiri maslinika Istre i kvarnerskih otoka. Sastav i svojstva tla (veličina čestica, udio organskih tvari, kiselost tla) imaju izrazit utjecaj na postupke sorpcije i razgradnje imidakloprida. Sorpcija imidakloprida je jača, a razgradnja brža u tlu s višim udjelom gline i humusa te nižoj kiselost tla. Razgradnja imidakloprida u tlu se odvija sporo i kontinuirano. S vremenom poluraspada iznad 110 dana, imidakloprid se može svrstati u postojane pesticide. Uslijed česte primjene ipak predstavlja potencijalnu opasnost zbog ulaska u ciklus kruženja tvari u okolišu s posljedičnim štetnim djelovanjem na biljni i životinjski svijet, a time i na čovjeka.Neonicotinoids are increasingly replacing the organophosphate and methylcarbamate acetylcholinesterase inhibitors which are losing their eff ectiveness due to the selection for resistant pest populations. Imidacloprid is the most important neonicotinoid with low soil persistence, high insec cidal potency and rletively low mammalian toxicity. Neurophysiological studies have confi rmed that imidacloprid is an agonist at the postsynaptic nicotinic acetylcholine receptors which stimulates the postsynaptic membrane first and then paralyses nerve conduction. In Croatia, imidacloprid is commonly used in olive growing areas, including Istria and Kvarner islands, as an eff ective mean of olive fruit fly infestation control. Once a pesticide is introduced into the environment it can be infl uenced by many physical and chemical processes. Pesticide sorption processes are undoubtedly one of the major factors aff ecting the persistence and movement in the environment. This paper describes sorption and degradation processes of imidacloprid and investigates the relationships between soil properties and sorption and degradation characteristics in four soils, representative of northern Adriatic region, namely island Krk and a coastal Istrian region. Soil content and properties (particle size, content of organic matter, acidity) have a great eff ect on sorption of imidacloprid onto soil particle. Sorption and degradation of imidacloprid increase in soil with higher clay and organic matter content and with lower acidity. The imidacloprid degradation processes are continuous, though not very rapid. According to half-life of more than 110 days, imidacloprid is classified as persistant pesticide. However, it’s liberate usage can disturb environmental cycling and thus adversely aff ect non-target organisms, including plant and animal species. In this way, imidacloprid may also impose a risk to the human health

Antioxidant activity and kinetic analysis of tocopherol extract obtained from different types of vegetable oils

Cilj: Utvrditi razliku u antioksidativnoj aktivnosti maslinovog, suncokretovog, bučinog i crnog ulja i njihovih tokoferolnih ekstrakata te proučiti kinetiku i mehanizam reakcije između slobodnih radikala i antioksidansa. Materijali i metode: Antioksidativna aktivnost ulja i tokoferolnih ekstrakata mjerena je spektrofotometrijski uz uporabu DPPH˙ (2,2-difenil-1-pikril-hidrazil), dok je Trolox ekvivalent poslužio kao referentni standard za kvantifikaciju rezultata dobivenih DPPH˙ testom. Pomoću kinetičkih monofaznih i bifaznih matematičkih modela procijenjena je i analizirana inhibicija signala DPPH˙. Rezultati: Vrijednost TEAC-a ukazuje da maslinovo i suncokretovo ulje (2,16 mmol/L) posjeduju jaču antioksidativnu aktivnost u odnosu na crno (1,85 mmol/L) i bučino ulje (1,68 mmol/L), a ujedno i intenzivniju inhibiciju DPPH˙ radikala. Tokoferolni ekstrakti imaju puno slabiji antioksidativni učinak od analiziranih biljnih ulja, pri čemu je najdjelotvorniji ekstrakt suncokretova ulja koji čini 22,1 % antioksidativne aktivnosti ulja, a najslabiji ekstrakt bučina ulja sa samo 13,9 %. Nestanak DPPH˙ radikala u uzorcima ulja odvija se u dva susljedna koraka, početnog eksponencijalnog koji se odvija unutar 7 min reakcije, ovisno o vrsti ulja, i drugog sporog, gdje su promjene proporcionalne s vremenom. Kod tokoferolnih ekstrakata brzi korak reakcije nije uočen, ukazujući time da se reakcija odvija mehanizmom kinetike prvog reda. Zaključak: Rezultati ukazuju da biljna ulja imaju jači učinak u inhibiciji radikala u odnosu na tokoferolne ekstrakte, pa se njihovom pravilnom konzumacijom potpomaže organizmu u „borbi“ protiv slobodnih radikala. Zapravo, najvažniji dio antioksidacijskog sustava obrane organizma od slobodnih radikala čini sinergističko djelovanje antioksidansa, odnosno antioksidansi u sinergiji imaju jači učinak nego sumarni učinak svih pojedinačnih antioksidansa.Aim: To determine the difference in the antioxidant activity of the olive, sunflower, pumpkin and black oil and their tocopherol extracts as well as to examine the kinetics and mechanism of reactions between free radicals and antioxidants. Materials and Methods: Antioxidant activity of the oils and tocopherol extracts was measured spectrophotometrically using DPPH˙ (2,2-diphenyl-1-picrylhydrazil) while Trolox equivalent was used as a reference standard for the quantification of the results obtained by the DPPH˙ test. DPPH˙ signal inhibition was evaluated and analyzed by monophasic and biphasic kinetics mathematical models. Results: The TEAC values suggest that olive and sunflower oil (2.16 mmol/L) have a stronger antioxidant activity than black (1.85 mmol/L) and pumpkin oil (1.68 mmol/L) and they possess stronger inhibition of the DPPH˙ radical. Tocopherol extracts have a much weaker antioxidant effect than the analyzed vegetable oils, where the sunflower extract is most effective, making 22.1 % of the antioxidant oil activity, while the weakest extract is the pumpkin oil extract oil with only 13.9 %. DPPH˙ radical disappearance in oil samples takes place in two successive phases, the initial exponential which takes place within 7 min of the reaction, depending on the oil type, and the second slow phase where the changes are proportional to the time. The rapid reaction phase by tocopherol extracts was not noticed, indicating that the reaction takes places by the mechanism of the first order kinetics. Conclusion: The results indicate that vegetable oils have a stronger effect on the radical inhibition than the tocopherol extracts, and by their proper consumption they will support the organism in the “fight” against free radicals. In addition, the most important role of the antioxidant defense system against free radicals makes the synergic interactions among the different molecules present in the food, indicating that antioxidants in synergy have a stronger potential than the sum of all individual antioxidants

Uloga izomera α-, γ- i δ-tokoferola u bifaznoj kinetici uklanjanja DPPH radikala iz uzoraka bučinog ulja i uljnih mješavina

The antioxidant activity of three types of pumpkin seed oil or oil mixtures (cold-pressed, produced from roasted seed paste and salad) produced in the northern part of Croatia and the kinetics of their behaviour as free radical scavengers were investigated using DPPH˙. In addition, the involvement of oil tocopherol isomers (α-, γ- and δ-) in different steps of DPPH˙ disappearance and their impact on the rate of reaction were analysed. The kinetics of DPPH˙ disappearance is a two-step process. In the first step, rapid disappearance of DPPH˙ occurs during the first 11 min of the reaction, depending on the oil type, followed by a slower decline in the second step. To describe DPPH˙ disappearance kinetics, six mathematical models (mono- and biphasic) were tested. Our findings showed that γ- and δ-tocopherols affected DPPH˙ disappearance during the first step, and α-tocopherol in the second step of the reaction. Moreover, α-tocopherol demonstrated 30 times higher antioxidant activity than γ- and δ-tocopherols. The results indicated the biphasic double-exponential behaviour of DPPH˙ disappearance in oil samples, due to the complexity of reactions that involve different tocopherol isomers and proceed through different chemical pathways.U ovom su radu ispitani antioksidacijska aktivnost i kinetika uklanjanja DPPH radikala iz bučinih ulja ili uljnih mješavina (iz hladno-prešanog, zatim ulja dobivenog prešanjem prženih bučinih sjemenki i salatnog ulja), proizvedenih na području Sjeverne Hrvatske. Osim toga, ispitan je utjecaj različitih izomera vitamina E (α-, γ- i δ-tokoferola) na brzinu reakcije tijekom različitih stupnjeva nestanka DPPH radikala iz tih ulja. Postupak uklanjanja radikala odvija se u dva stupnja: u prvom stupnju se tijekom početnih 11 minuta reakcija odvija brzo, nakon čega slijedi sporiji, drugi stupanj. Za opisivanje kinetike nestanka radikala upotrijebljeno je šest monofaznih i bifaznih matematičkih modela. Iz dobivenih se rezultata može zaključiti da γ- i δ-izomeri tokoferola sudjeluju u prvom stupnju, dok je α-tokoferol uključen u drugi stupanj procesa uklanjanja radikala. Osim toga, utvrđeno je da α-tokoferol ima 30 puta veću antioksidacijsku aktivnost od γ- i δ-izomera. Rezultati pokazuju da je bifazna kinetika nestanka DPPH radikala posljedica niza složenih reakcija koje se odvijaju različitim mehanizmima, a u kojima sudjeluju izomeri tokoferola

Effect of dietary fatty acid variation on mice adipose tissue lipid content and phospholipid composition

The objective of our research was to determine the effects of five different diets as a source of various groups of fatty acids on mice adipose tissue lipid content, phospholipid composition and fatty acid composition of adipose tissue total lipids and phospholipids. Beside the standard diet, diets enriched either with pumpkin-seed, olive or fish oil or lard were used for feeding wild type C57Bl/6 male mice aged 8-10 weeks for 3 weeks. In mice fed with diets enriched with oils/lard, relative adipose tissue mass decreased, comparing to standard diet fed mice. Adipose tissue total lipid content decreased significantly in olive and fish oil diet comparing to pumpkin-seed oil and standard diet. Analysis of the phospholipid classes showed that phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and sphingomyelin were common components in all diet types. The dominant storage form of fatty acids in adipose tissue total lipids were unsaturated fatty acids (oleic and linoleic acid prevailed), while in phospholipids, C18 acids prevailed (stearic acid was the main fatty acid) in all diets. Enrichment of the diet with specific oil or lard significantly changed the n-6/n-3 ratio. Fish oil diet provoked the highest reduction of that ratio, both in adipose tissue total lipids and in phospholipids. Obtained results imply that diet modification has an influence on adipose tissue lipid content and composition as well as remodelling process occurring in the adipose tissue phospholipids

Preexposure to Olive Oil Polyphenols Extract Increases Oxidative Load and Improves Liver Mass Restoration after Hepatectomy in Mice via Stress-Sensitive Genes

Polyphenols can act as oxidants in some conditions, inducing redox-sensitive genes. We investigated the effect of preexposure to the olive oil polyphenols extract (PFE) on time-dependent changes in the hepatic oxidative state in a model of liver regeneration—a process in which oxidative stress associated with the metabolic overload accounts for the early events that contribute to the onset of liver self-repair. Liver regeneration was induced by one-third hepatectomy in mice. Prior to hepatectomy, mice were intraperitoneally given either PFE (50 mg/kg body weight) or saline for seven consecutive days, while respective controls received vehicle alone. Redox state-regulating enzymes and thiol proteins along with the mRNA levels of Nrf2 gene and its targets γ-glutamylcysteine synthetase and heme oxygenase-1 were determined at different time intervals after hepatectomy. The liver mass restoration was calculated to assess hepatic regeneration. The resulting data demonstrate the effectiveness of preexposure to PFE in stimulating liver regeneration in a model of a small tissue loss which may be ascribed to the transient increase in oxidant load during the first hours after hepatectomy and associated induction of stress response gene-profiles under the control of Nrf2

Kinetic Evaluation of Imidacloprid Degradation in Mice Organs Treated with Olive Oil Polyphenols Extract

Imidacloprid is a highly effective insecticide, acting as agonists at the insect nicotinic acetylcholine receptor. Nevertheless, imidacloprid itself or its metabolites could exhibit toxicity in mammals. Imidacloprid biotransformation involves oxidative cleavage, releasing the 6-chloronicotinic acid. Therefore, the concentration of imidacloprid and 6-chloronicotinic acid was used to characterize degradation kinetics and distribution of imidacloprid in mice liver, kidneys and lungs. Additionally, the influence of olive oil polyphenols on imidacloprid metabolism was evaluated. Experimental animals were divided into three groups: control, IMI – imidacloprid treated mice (5 mg/kg) and (IMI + PP) – mice treated with polyphenols (10 mg/kg) for seven days before the administration of imidacloprid. Neither imidacloprid nor 6-chloronicotinic acid could be detected 48 hours after administration in IMI group, while complete degradation in the (IMI + PP) group was accomplished within 24 hours. Significantly higher rate constant and shorter half-life in (IMI + PP) group emphasize that polyphenols may diminish the toxicity of this pesticide

Natural enrichment of refined rapeseed oil with phenols and chlorophylls from olive leaves of Oblica cultivar

Olive leaves as by-products of olive farming are rich natural source of bioactive compounds with antioxidant properties. In this study, the efficiency of the natural maceration of fresh and steam blanched olive leaves in refined rapeseed oil was investigated, as well as the effect of degree of leaf fragmentation (whole, cut, ground) and maceration time on transfer of bioactive compounds (polyphenols) and pigments (chlorophylls) in oil. In oils obtained by maceration, changes of total phenolic compounds and total chlorophylls were determined spectrophotometrically. The effect of these oil preparation procedures on oil quality indicators was also investigated through free fatty acid content and spectrophotometric indices. The content of total phenols and chlorophylls increased in oils obtained by maceration of fresh and steam blanched olive leaves, and were in statistically significant correlation with leaf fragmentation degree. The highest content of total phenols was achieved in oils with whole fresh leaves (220.4 mg/kg) after seven days of maceration while the chlorophylls transfer to oils was the most efficient when ground steam blanched leaves were macerated for 28 days (79.10 mg/kg). Maceration of olive leaves slightly deteriorated the quality of refined rapeseed oil, equally in oils with fresh and steam blanched olive leaves. This simple preparation procedure can be efficiently used for enrichment of refined oils with natural antioxidants

Influence of essential oil Helichrysum italicum (Roth) G. Don on the formation of non-tuberculous mycobacterial biofilm

Cilj: Ispitati antimikrobni i antioksidacijski učinak te sposobnost inhibicije biofilma eteričnog ulja (EU) smilja [Helichrysum italicum (Roth) G. Don (H. italicum)] prema netuberkuloznim mikobakterijama M. avium i M. intracellulare. Materijali i metode: Za određivanje minimalne inhibicijske koncentracije (MIK) i minimalne baktericidne koncentracije (MBK) EU H. italicum prema M. avium i M. intracellulare korištena je metoda mikrodilucije u bujonu. Preživljavanje mikobakterija u Middlebrook 7H9 bujonu pod utjecajem EU smilja praćeno je subkultivacijom suspenzija 0, 1, 4 i 8 dan. Za određivanje inhibicije stvaranja biofilma u vodi primjenjena je metoda bojenja biofilma s kristal violetom. Antioksidacijski učinak MIK koncentracije EU određen je DPPH (2,2-difenil-1-pikril-hidrazil) metodom. Rezultati: MIK i MBK vrijednost EU smilja iznosila je 3,2 mg/ml. Koncentracija ½ MIK vrijednosti dovela je nakon prvog dana do redukcije vijabilnosti M. avium za približno 2 log10 odnosno 2,5 log10 za M. intracellulare, dok je četvrti dan zabilježena potpuna inhibicija porasta obje vrste mikobakterija. M. avium je pokazao veću tendenciju stvaranja biofilma. Koncentracija od ¼ i ½ MIK vrijednosti dovela je do statistički značajne inhibicije stvaranja biofilma ispitivanih mikobakterija. MIK koncentracija EU H. italicum je nakon 60 minuta inhibirala 38,2 % DPPH radikala. Zaključak: Subinhibitorne koncentracije EU smilja značajno reduciraju vijabilnost M. avium i M. intracellulare i dovode do značajne inhibicije stvaranja biofilma ispitivanih mikobakterija u vodi što bi omogućilo primjenu niskih efektivnih koncentracija ovog EU, koje nemaju citotoksični učinak, kao prirodnog dezinficijensa u vodi.Objective: To investigate the antimicrobial and antioxidative effect of the essential oil (EO) of immortelle [Helichrysum italicum (Roth) G. Don (H. italicum)] and its ability to inhibit biofilm of nontuberculous mycobacteria, M. avium and M. intracellulare. Materials and methods: a broth microdilution method was used to determine the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the H. italicum EO. Survival of mycobacteria in Middlebrook 7H9 broth under the influence of H. italicum EO was monitored by subcultivation of suspension of 0, 1, 4 and 8 days. For determination of the inhibition of biofilm formation in water, the biofilm coloring method with crystal violet was applied. The antioxidant effect of MIC concentrations of H. italicum EO was determined by DPPH (2,2-diphenyl-1-picrylhydrazil) method. Results: MIC and MBC value of immortelle EO was 3.2 mg/ml. Treatment of mycobacteria with H. italicum EO at one half times the MIC resulted in approximately 2 log10 reduction of M. avium and 2.5 log10 M. intracellulare respectively over 24 h, and complete reduction of both mycobacteria on the fourth day. M. avium showed a greater tendency to form biofilms. The concentration of one-quarter and one-half of the MIC values resulted in statistically significant inhibition of biofilm production of the tested mycobacteria. MIC concentrations of H. italicum EU after 60 minutes inhibited 38.2% of DPPH radicals. Conclusion: The subinhibitory concentrations of H. italicum EO significantly reduce the viability of M. avium and M. intracellulare and result in substantial inhibition of biofilm production of the tested mycobacteria in water, which would allow the application of low effective concentrations of this EO that do not have a cytotoxic effect as a natural disinfectant in water