Cytotoxicity of Cholesterol Oxides and the Consequences of Relative Molecular Similarity to cGMP Nucleotide

Cholesterol and cholesterol oxides impact on the functional properties of cells, in respect of the intracellular and extracellular distribution of compounds across cell membranes, carcinogenesis and drug resistance. Abnormal levels of cholesterol oxides and steroids in cancerous tissues promote interest in steroid receptor cross-talk during cell-signalling and the steroid metabolome of cancer patients. The research literature links the cytotoxic properties of oxysterols to interference with the NO/cGMP pathway. cGMP participates in cell-signalling and has a molecular structure that relates to cancer-inducing and cancer-preventing agents. This study uses a molecular modelling approach to compare the structures of cholesterol oxides to cGMP. Cholesterol and cholesterol oxide structures fit to a cGMP structural template in several ways, some of which are replicated by corticosteroids and gonadal steroid hormones. The results of this study support the concept that cholesterol oxides modulate cell apoptosis and autophagy via the NO/cGMP pathway and in conjunction with steroid hormones participate in modulating regulation of cell function by cGMP.

Influence of dietary canola oil and palm oil blend and refrigerated storage on fatty acids,myofibrillar proteins,chemical composition,antioxidant profile and quality attributes of semimembranosus muscle in goats

Background： Improving the unsaturated fatty acid content of ruminant meat is essential due to the generally saturated nature of fatty acids in ruminant meat and the negative effects this can have on human health. Nonetheless, enhancing the unsaturated fatty acid content of ruminant meat can have adverse effects on the shelf life and quality attributes of the meat. This study assessed the effects of dietary 80 % canola oil and 20 % palm oil blend（CPOB） on fatty acid composition, antioxidants, oxidative spoilage, cholesterol and physicochemical properties of semimembranosus（SM）muscle from goats. Twenty four Boer bucks were randomly assigned to diets containing on dry matter basis 0, 4 and8 % CPOB, fed for 100 d and slaughtered. The carcasses were subjected to a 7 d postmortem refrigerated storage. Al analyses were conducted on the SM muscle.Results： Diet had no effect（P 〉 0.05） on the concentration of free thiol and carbonyl and the band intensity of myosin heavy chain, actin and troponin T. The muscle glycogen, p H, water holding capacity, tenderness, glutathione peroxidase（GPX） activity, total carotenoid, δ-tocopherol, cholesterol and proximate composition did not differ（P 〉 0.05） between diets. The SM muscle from goats fed 4 and 8 % CPOB had lower（P 〈 0.05） concentration of C14：0 and C16：0 and higher（P 〈 0.05） concentration of C18：1 trans-11, C18：1ω-9, C18：3ω-3, C20：5ω-3 and C22：5ω-3 than the SM muscle from the control goats. Dietary CPOB increased（P 〈 0.05） the concentration of α and γ tocopherol and meat redness（a＊） on d1 and 4 postmortem. Regardless of diet, antioxidant vitamins, and shear force decreased（P 〈 0.05） while drip loss, lipid and protein oxidation increased（P 〈 0.05） as postmortem storage progressed.Conclusion： Results evince that dietary CPOB can be used as a management tool to enhance the beneficial fatty acids and antioxidant contents of chevon without deleterious effects on its physicochemical properties and shelf life.

Biquinho pepper(Capsium chinense):Bioactive compounds,in vivo and in vitro antioxidant capacities and anti-cholesterol oxidation kinetics in fish balls during frozen storage

The present study reports bioactive constituents from biquinho pepper,such as carotenoids,capsaicinoids,and capsinoids,identified by UHPLC-MS.Biquinho pepper extract showed an antioxidant potential by DPPH(33.17±0.08%),ORAC(32.35±0.02μM TE/g),β-carotene/linoleic acid(55.80±1.30%),and FRAP(315.88±4.23μmol TE/g)assays.Additionally,in vivo antioxidant analyses demonstrated that the pepper extract(170μg/mL)decreased the damage promoted by H_(2)O_(2) in Saccharomyces cerevisiae cells.Fish balls were prepared using different concentrations of pepper(0.0%,0.5%,0.75%,1.0%)to investigate its antioxidant effect during frozen storage.Biquinho pepper effectively reduced the formation of cholesterol oxides and preserved essential fatty acids,mainly in samples containing 1.0%of pepper.Moreover,this treatment was more efficient than sodium erythorbate(p<0.05),which was used as standard.The kinetics of cholesterol oxidation was also determined,showing that both cholesterol degradation and cholesterol oxides formation fit a first-order kinetic model(R^(2)>0.8).