Antioxidant properties of resveratrol and piceid on lipid peroxidation in micelles and monolamellar liposomes.

The antioxidant activities of trans-resveratrol (trans-3,5,4′-trihydroxystilbene) and trans-piceid (trans-5,4′- dihydroxystilbene-3-O-β-D-glucopyranoside), its more widespread glycosilate derivative, have been compared measuring their inhibitory action on peroxidation of linoleic acid (LA) and the radical scavenging ability towards different free radicals (such as DPPH) and radical initiators. It has been found that the two stilbenes have similar antioxidant capacity, while the comparison with BHT (2,6-di-tert-butyl-4-methylphenol) and α-tocopherol (vitamin E, vit. E), taken as reference, points out a slower but prolonged protective action against lipid peroxidation. Furthermore, piceid appears more efficacious than resveratrol as a consequence of the reaction of the latter with its radical form. The DSC profiles of phosphatidylcholine liposomes of various chain lengths, and EPR measurements of spin labelled liposomes demonstrated that the susceptible hydroxyl group of these compounds are located in the\ud lipid region of the bilayer close to the double bonds of polyunsatured fatty acids, making these stilbenes particularly suitable for the prevention and control of the lipid peroxidation of the membranes

Synthesis of 1,1-Bis(3,5-Dimethyl-2-Furyl)Ethene - the Chemo-Selectivity and Site-Selectivity of Its Cycloadditions

The new polyene 1,1-bis(3,5-dimethyl-2-furyl)ethene (11) was derived from 2,4-dimethylfuran. Its reaction with dienophiles such as maleic anhydride, benzoquinone or 1-cyanovinyl acetate generated exclusively Diels-Alder adducts (9-oxabicyclo[4.3.0]nona-1,7-diene derivatives) involving the exocyclic double bond and one double bond of one furyl unit. The reaction of 11 with didehydrobenzene (benzyne) gave a 7-oxabicyclo[2.2.1]hepta-2,5-diene derivative resulting from the exclusive Diels-Alder addition of one furyl group, whereas dimethyl acetylenedicarboxylate added to 11 giving a mixture of the corresponding 7-oxabicyclo[2.2.1]hepta-2,5-diene and 9-oxabicyclo[4.3.0]nona-1,4,7-triene derivatives. With allenic acid, 11 added in a [2+2] fashion exclusively with its exocyclic double bond giving 2-[3,3-bis(3,5-dimethyl-2-furyl)cyclobutylidene]acetic acid with high selectivity

Reductive oxa ring opening of 7-oxabicyclo[2.2.1]heptan-2-ones. Synthesis of C-alpha-galactosides of carbapentopyranoses

Photoinduced electron transfer from Et(3)N to 7-oxabicyclo[2.2.1]heptan-2-ones can generate the corresponding 3-hydroxycyclohexanone derivatives. The method has been applied to the synthesis of C-alpha-D-galactopyranosides of carbapentopyranoses. Radical alpha-D-galactosidation of (+/-)-(1RS,4RS,5RS, 6RS)-6-endo-methoxy-3-methylidene-5-exo-(phenylseleno)-7-oxabicyclo[2.2. l]hept-2-one ((+)-51) followed by seleno-Pummerer rearrangement and reduction with Bu(3)SnH gave (+)- (1R,2S,3S,4R,6R)-((+)-58) and (+)-(1S,2R,3R,4S,6S)-3-endo-methoxy-5-oxo-6-endo-[(2',3',4',6'-tetra-0-a cetyl-alpha-D-galactopyranosyl)methyl]-7-oxabicyclo[2.2.1]hept-2-endo-yl acetate ((+)-59), which were separated by column chromatography. Irradiation (254 nn) in the presence of Et(3)N gave (+)-(1S,2R,3R,6R)-((+)-60) and (+)-(1R,2S,3S,6S)-2-hydroxy-6-methoxy-4-oxo-3-[(2',3',4',6'-tetra-0-acet yl-alpha-D-galactopyranosyl)methyl]cyclohexyl acetate (+)-61, respectively. NaBH4 reduction and acetylation provided (+)-(1S,2S,3R,4R,5R)-((+)-62) and (+)-(1R,2R,3S,4S,5S)-5-methoxy-2-[(2',3',4',6'-tetra-0-acetyl-alpha-D-ga lactopyranosyl)methyl]cyclohexa-1,3,4-triyl triacetate ((+)-64)

Biomarker of exposure level data set in smokers switching from conventional cigarettes to Tobacco Heating System 2.2, continuing smoking or abstaining from smoking for 5 days

Levels of biomarkers of exposure to selected harmful and potentially harmful smoke constituents found in cigarette smoke, in addition to nicotine were measured in 160 smokers randomized for 5 days to continuing smoking conventional cigarettes (41 participants), switching to Tobacco Heating System 2.2 (THS 2.2) (80 participants), or abstaining from smoking (39 participants). The data reported here are descriptive statistics of the levels of each biomarker of exposure expressed as concentrations adjusted to creatinine; at baseline, and at the end of the study, and their relative change from baseline. Reductions in the levels of biomarkers of exposure when expressed as quantity excreted, are also reported. Detailed descriptions of bioanalytical assays used are also provided. The data presented here are related to the article entitled “Evaluation of the Tobacco Heating System 2.2. Part 8: 5-Day randomized reduced exposure clinical study in Poland” (Haziza et al., 2016) [1]

Structure-Antioxidant Activity Relationships in a Series of NO-Donor Phenols

Recently we reported a new class of NO-donor phenols that could be of interest in the treatment of many forms of cardiovascular disease (CD). Their potencies as inhibitors of ferrous salt/ascorbate-induced peroxidation of membrane lipids of rat hepatocytes were assessed as pIC(50) values through the TBARS assay. In this work we aimed to find quantitative relationships between the antioxidant activity of these compounds and appropriate molecular descriptors. In particular, we determined their log P(oct), their reactivity (log Z) in reaction with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(.)), and the theoretical parameter DeltaH(abs), which describes the enthalpy of homolytic O--H bond cleavage. The QSAR equations found through the classical Hansch approach allowed us to draw interesting conclusions on the possible mechanisms of reaction with radicals in the various environments, while underlining the role of lipophilicity in antioxidant activity

Assessment of the reduction in levels of exposure to harmful and potentially harmful constituents in Japanese subjects using a novel tobacco heating system compared with conventional cigarettes and smoking abstinence: A randomized controlled study in confinement

AbstractSmoking conventional cigarettes (CCs) exposes smokers to harmful and potentially harmful constituents (HPHCs). The Tobacco Heating System 2.2 (THS 2.2), a candidate modified risk tobacco product, was developed to reduce or eliminate the formation of HPHCs, while preserving as much as possible the taste, sensory experience, nicotine delivery profile and ritual characteristics of CC. This randomized, controlled, open-label study in confinement for 5 day exposure aimed to demonstrate the reduction in exposure to selected HPHCs, to assess nicotine uptake and subjective effects, in participants switching to THS 2.2 (n = 80) compared to participants continuing smoking CCs (n = 40) and abstaining from smoking (n = 40). The subjects were randomized according to sex and daily CC consumption. The levels of biomarkers of exposure to HPHCs were significantly reduced in participants switching to THS 2.2, compared to CC use. More importantly, the magnitude of exposure reduction observed was close to that which was seen in participants who abstained from smoking for 5 days, while nicotine uptake was maintained. Reduction in urge-to-smoke was comparable between THS and CC groups, however THS 2.2 was slightly less satisfactory than CCs. The new, alternative tobacco product THS 2.2 was well tolerated