Synthesis and characterization of antioxidants and detergent dispersant based on some polyisobutylene copolymers

Polyisobutylene succinic anhydride-urea/polyamines (PIBSA) copolymers were synthesized as potential antioxidants and detergent dispersant agents for lubricating oils samples (SAE-30). Homogeneity, thermal stability and dispersancy of the solutions were determined. Fully soluble oil compounds that are thermally stable up to 250 °C were achieved. The oxidation stability of lube oil samples in the presence of four designed PIBSA additives (varying in the number of amine groups) was determined for a time period of up to 72 hours. The dependence of the additive efficiency on its concentration was studied to achieve maximum stability. Some PIBSA additives at concentration 3.0 · 10⁴ ppm exhibit the best results. Dispersivity values were measured at predetermined oxidation times. The results proved reliable dispersion capability as the nitrogen content of the additive is increased, i.e. the increase in the basic character of the additive leads to the increase in the neutralization capability. Moreover, the designed PIBSA additives retain their efficiency after long oxidation times, confirming their role as multifunctional nitrogen containing polymeric additive. Electronic Publication     

Preparation and properties of polyamines. Part I. Polymers containing dinitro substituted aromatic groups

Relatively high molecular weight polyamines with aromatic nitro groups in the repeat units were prepared by the reactions of aliphatic diamines, and 1,5-difluoro-2,4-dinitrobenzene, at elevated temperatures in diphenyl sulfone. The physical characteristics, including solubility, thermal stability, and viscosity of the resulting polyamines were found to be strongly dependent on the aliphatic chain length of the diamines used. All polymers exhibited exceptional solvent resistance. Except for strong acids with bulky counter-ions, including sulfuric, perchloric, and nitric acids, the polymers were found to be insoluble in all common organic solvents at room temperature.     

Antioxidative effects of polyamines

The antioxidative effects of spermine, spermidine and putrescine were determined by measurement of primary and secondary oxidation products of polyunsaturated fatty acids, using gas and liquid chromatography as well as spectrophotometric recordings. It was demonstrated that polyamines inhibit the oxidation of polyunsaturated fatty acids,α-tocopherol and carotenoid pigments. Both linear and nonlinear dose/response relationships have been observed. The efficiency of a given polyamine was correlated with the number of amine groups in the molecule. Spermine was, thus, more efficient than spermidine, which in turn had a higher efficiency than putrescine. The relative antioxidative effect was as follows: spermine (100.0), spermidine (61.0), putrescine (23.0), ethoxyquin (27.6), ascorbyl palmitate (18.3), octyl gallate (7.9), tert butylhydroquinone (6.3), butylated hydroxyanisole (3.6) andα-tocopherol (3.4).     

Contents of polyamines in selected foods

Dietary polyamines, putrescine, spermidine and spermine, participate in many biochemical processes, mainly in cell proliferation and differentiation. Polyamines were determined as N-benzamides by micellar electrokinetic capillary chromatography in 153 samples of 21 foods, mostly culinary processed. Very low putrescine contents were observed in processed meats, pork liver and kidney, while the highest mean contents exceeded 55 mg kg⁻¹ in stewed green pea, grapefruit and fresh green pepper. Higher spermine than spermidine contents were typical for foods of animal origin, while the opposite was observed in plant products. Mean spermidine contents, exceeding 20 mg kg⁻¹, were found in dry soybean, stewed green pea, yellow pea puree and roasted chicken breast. Roasted chicken breast, stewed pork kidney, roasted pork liver and roasted pork neck had mean spermine contents above the same level. Polyamine content varies widely within individual food items, what makes application of the results by dietitians rather difficult.     

Biogenic Amine Content of Tarhana: A Traditional Fermented Food

Tarhana is a traditional fermented cereal food consumed in nearly all regions of Turkey as a soup having a delicious and desired taste. There are some other products similar to tarhana in Syria, Jordan, Egypt, Iraq, Hungary, Finland, Greece, and Scotland. Fifteen homemade and 5 commercially produced tarhana samples were analyzed for the first time to determine biogenic amine contents. Tyramine was the prevailing biogenic amine. Average tyramine concentrations of homemade and commercially produced tarhana samples were 92.8 and 55.0 mg/kg of tarhana, respectively. Concentrations of biogenic amines were below the permissible limits except for two homemade samples. The pH values of tarhana samples were in the range from 3.43 to 5.03; acidities were from 0.60 to 3.89 g/100 g tarhana (as lactic acid); total dry matters were from 86.42 to 92.32 g/100 g tarhana; and total free amino acid contents were from 0.035 to 1.427 g/100 g tarhana (as leucine).     

Polyamine determination in different strains of the yeast Debaryomyces hansenii by high pressure liquid chromatography

Polyamines (putrescine, spermidine and spermine) participate in many biochemical processes that are indispensable for cell differentiation and proliferation. In the present study, polyamine types were determined in 13 Debaryomyces hansenii strains isolated from different sources by high pressure liquid chromatography. Very low putrescine levels were observed in the strains DhhBCS007, DhfBCS001 and DhfBCS002. Spermidine and spermine were the most prevalent amines detected in all the yeasts, ranging from 7.71 to 18.42 mg/kg of spermidine in the strain L2 and 9.39–18.96 mg/kg for spermine in strain DhhCBS004. D. hansenii strain L2 and CBS004 isolated from citrus fruit and marine water, respectively, were the main polyamine-secreting yeasts. The results will contribute to our ability to select the most appropriate strains for use, as dietary complement (probiotic) in the animal food industry, including aquaculture.     

Biogenic amine content in dry fermented sausages as influenced by a producer,spice mix,starter culture,sausage diameter and time of ripening

Sixteen types of dry fermented sausages were commercially produced as combinations of two producers (designated K and R), two starter cultures (Pediococcus pentosaceus, C; Lactobacillus curvatus + Staphylococcus carnosus, F), two spicing mixtures (H; P) and two casing diameters (4.5 cm, T; 7 cm, W), and were sampled at days zero, 14, 28 (end of ripening), 49, 70, 91 and 112 (samples were stored at 15 °C and relative humidity of 70% between days 28 and 112). Tyramine and putrescine content (Y, mg kg⁻¹) increased (P < 0.01) with increasing time of ripening/storage (X, days): Y = 52.0 + 5.19X − 0.0275X² (R² = 0.60) and Y = 37.0 + 3.45X − 0.0192X² (R² = 0.23), respectively. Smaller diameter (T), spice mix containing red pepper (P) and starter culture C decreased (P < 0.05) both tyramine and putrescine content in the sausages as compared to the W, H and F counterparts, respectively; content of both amines was lower (P < 0.05) in the K-sausages than in the R-sausages. Tyramine content in the sausages at the time interval 28 days of ripening + 21 days of storage was in the range from 170 (KHCU sausage combination) to 382 (RHFS) mg kg⁻¹.     

Bioactive amines in fresh, canned and dried sweet corn, embryo and endosperm and germinated corn

The types and levels of free bioactive amines in different corn products were determined. The amines were analyzed by ion pair-HPLC, post-column derivatization with o-phthalaldehyde and fluorimetric detection. Fresh sweet corn contained mainly spermidine followed by putrescine. Spermine, cadaverine, phenylethylamine, histamine and agmatine were also present at low levels. The profile and levels of amines changed significantly in canned and dried corn. Putrescine was the prevalent amine in canned corn whereas spermine was prevalent in dried corn. Germinated corn had significantly higher spermidine, spermine and putrescine levels. The embryo of the corn contained significantly higher spermine levels compared to the endosperm. These results indicate that corn is a good source of polyamines and that the different types of corn products available can be used to provide a profile of amines according to specific dietary need.     

Dietary flavonoids fisetin,luteolin and their derived compounds inhibit arginase,a central enzyme in Leishmania (Leishmania) amazonensis infection

Fisetin, quercetin, luteolin and 7,8-hydroxyflavone show high activity in Leishmania cultures and present low toxicity to mammalian cells. In this work, the structural aspects of 13 flavonoids were analyzed for their inhibition of the arginase enzyme from Leishmania (Leishmania) amazonensis  . A higher potency of arginase inhibition was observed with fisetin, which was four and ten times greater than that of quercetin and luteolin, respectively. These data show that the hydroxyl group at position 3 contributed significantly to the inhibitory activity of arginase, while the hydroxyl group at position 5 did not. The absence of the catechol group on apigenin drastically decreased arginase inhibition. Additionally, the docking of compounds showed that the inhibitors interact with amino acids involved in the Mn⁺²-Mn⁺²${\text{Mn}}^{+2}-{\text{Mn}}^{+2}$ metal bridge formation at the catalytic site. Due to the low IC₅₀ values of these flavonoids, they may be used as a food supplement in leishmaniasis treatment.