Antiradical

Following the action of extraordinary stimulants (hypoxic hypoxia, hypoxia + hyperoxia, hypodynamia + hyperthermia), animals demonstrate an accumulation of malonic dialdehyde with a simultaneous fall of antiradical activity of the liver tissue. A preliminary introduction to rats of acetylene amine 3,4,5-tris(morpho-linopropynyl)-l-methylpyrazole 103 and also of tocopherol antioxidant and gutumine antihypoxant averts activation of the lipid peroxidation processes. The inhibition of peroxidation with this agent is mediated by stabilization of ly-zosomal and mitochondrial membranes. Unsaturated amines prevent destruction of the organelle membranes provoked by UV irradiation and incubation at 37°C (pH4.7)(78MIl). 

Polymers can be radiation protected by stabilizing additives (antirads) through two principal... 

Effect of Antirad Agents on the Scission Yield of a Natural Rubber Compound... 

The antirads, including numerous commercial antioxidants, having labile hydrogens in their stmc-mre intermpt the radical chain reactions, through transfer of the labile hydrogen and yield a highly stabilized radical from them, e.g., with a hindered phenol. 

EB irradiation of polymeric materials leads to superior properties than the 7-ray-induced modification due to the latter having lower achievable dose rate than the former. Because of the lower dose rate, oxygen has an opportunity to diffuse into the polymer and react with the free radicals generated thus causing the greater amount of chain scissions. EB radiation is so rapid that there is insufficient time for any significant amount of oxygen to diffuse into the polymer. Stabilizers (antirads) reduce the dose-rate effect [74]. Their effectiveness depends on the abUity to survive irradiation and then to act as an antioxidant in the absence of radiation. 

Efforts to achieve a retardation of cross-linking in elastomers are based on the general assumption of a radical mechanism for retardation cross-linking and the possibility of its inhibition by a deactivation of the reactive macromolecular radical [33]. These compounds generally contain one or more labile hydrogen atoms, which after, donation of this atom, will form relatively inactive radicals. Typical antirad agents are quinones, hydroquinones, and aromatic amines (phenyl and napthylamines). 

RACCHI M, DAGLIA M, LANNi c, PAPETTi A, GovoNi s and GAZZANi G (2002) Antiradical activity of water soluble components in common diet vegetables , JAgric Food Chem, 50 (5) 1272-7. 

Pedreno, M.A. and Escribano, J., Correlation between antiradical activity and stability of betanine from Beta vulgaris L roots under different pH, temperature and light conditions, J. Sci. Food Agric., 81, 627, 2001. 

Sanchez-Moreno and others (1998 1999a,b) proposed a new methodology for the evaluation of the antiradical efficiency toward DPPH. Their procedure takes into account not only the concentration of the antioxidant but also the reaction time to reach the plateau of the scavenging reaction, a modification that could be an advantage... 

Espin JC, Soler-Rivas C, Wichers HJ and Garcia-Viguera C. 2000. Anthocyanin-based natural colorants a new source of antiradical activity for foodstuff. J Agric Food Chem 48(5) 1588—1592. 

Heimler D, Vignolini P, Dini MG, Vincieri FF and Romani A. 2006. Antiradical activity and polyphenol composition of local Brassicaceae edible varieties. Food Chem 99(3) 464-469. 

Kefalas P, Kallithraka S, Parejo I and Makris DP. 2003. A comparative study on the in vitro antiradical activity and hydroxyl free radical scavenging activity in aged red wines. Food Sci Technol Int 9(6) 383-385. 

Lo Scalzo R, Iannoccari T, Summa C, Morelli R and Rapisarda P. 2004. Effect of thermal treatments on antioxidant and antiradical activity of blood orange juice. Food Chem 85(1) 41—47. 

Popov IN and Lewin G. 1994. Photochemiluminescent detection of antiradical activity. II. Testing of nonenzymic water-soluble antioxidants. Free Radic Biol Med 17(3) 267—271. 

Popov IN, Lewin G and von Baehr R. 1987. Photochemiluminescent detection of antiradical activity. I. Assay of superoxide dismutase. Biomed Biochim Acta 46(11) 775—779. 

Sanchez-Moreno C, Larrauri, JA and Saura-Calixto, F. 1998. A procedure to measure the antiradical efficiency of polyphenols. J Sci Food Agric 76(2) 270-276. 

The reaction partners for antiradical substances are products of the first reaction. The SOD reacts selectively with 02" the nonenzymic antioxidants can react with both superoxide and luminol radicals. Theoretically, the carbonate radicals can also be involved in the PCL [25, 26],... 

In the context of the theoretically existing problems, a need exists to investigate the antiradical efficacy of compounds independent of pH value or polarity of the solvent, respectively. These problems are particularly relevant in the design of new pharmaceutical antioxidant preparations for specialized therapeutic applications. 

ACW—Integral Antiradical Capacity of Water-Soluble Compounds... 

During determination of the integral antiradical capacity of blood plasma (ACW) by the PCL method, the above-mentioned substances, among others, will be detected primarily. 

Figure 9 Antiradical capacity in the lipid phase of blood plasma (ACL) determined with the PCL method versus vitamin E (VE) as a sum of a- and y-tocopherols determined with HPLC. (From Ref. 28.)...

Modified procedure (ACP kit) Total plasma protein is isolated from low-molecular-weight plasma antioxidants in a single-step liquid gel chromatography procedure and its antiradical capacity ACP is measured in the ACW assay. 

The antiradical capacity of proteins is thought to be an important component of the total antioxidant capacity of blood plasma. Analysis of the ACW of blood plasma showed, that under normal conditions, its main components are the UA and ASC. The rest of the total antiradical capacity (ACR), which can be... 

Investigations of the effects of UV- and hypochlorite-induced oxidative modification of 20 amino acids and human serum albumin (HSA) on their antiradical properties showed unexpected results [36], Seven amino acids (cystine, histidine, methionine, phenylalanine, serine, tryptophan, and tyrosine) and HSA developed ACW following oxidation (see examples in Fig. 14). The fresh (produced in 1998) HSA from Serva had no antiradical capacity, but it acquired this quality during irradiation. The out-of-date HSA sample (Dessau, GDR, 1987, expiration date 7/1/1992) showed a remarkable ACW even in an unirradiated state. 

Figure 15 Antiradical capacity of histidine (2 mmol/L) undergoing chemical (NaOCI) and physical (UV, 254 nm) oxidation in equivalent concentrations of ascorbic acid used as calibrator. For UV dose 1 = 60 s, dose 2 = 120 s. For NaOCI after 45 min of incubation with 16 (dose 1) or 32 (dose 2) mg/L NaOCI.

Figure 17 Time course of the antiradical parameters ACL0 and ACW of LDL measured by the PCL method its a-tocopherol content (AT) measured by the HPLC technique and conjugated dienes (LDL-abs. at 234 nm) during Cu2+-initiated oxidation in vitro. (From Ref. 36.)...

As isolation of LDL for determination of its antiradical properties is a tedious task, it was alternatively selectively removed from the blood plasma. 

Modified procedure HDL plasma—plasma depleted with apo B-con-taining lipoproteins by pretreatment with dextran sulfate/Mg2+ HDL reagent (Sigma, procedure 352-3). Plasma LDL-bound antiradical parameters can be calculated as the difference between ACW/ACL/ACL0 for whole plasma and for HDL plasma as well. 

Table 2 Antiradical Activity of Red and White Wines (ACWw) and Their Antioxidative Protective Effectiveness in the Test System of the Cu2+-Initiated LDL Oxidation...

The plasma LDL/VLDL-bound antiradical parameter was calculated as the difference between ACP for whole plasma and for HDL plasma as well. 

Figure 22 shows an example of the impact of a modified mash treatment (heating, storage) on antiradical properties of resulting wines (the authors thanks Dr. Voigt for support of these investigations). 

Obviously the amount of antiradical-effective substances in wine can be raised by optimizing the technology under PCL monitoring. 

Figure 23 Comparison of antiradical properties of different tea types. 1, Sage tea 2, green tea 3, black tea 4, peppermint tea 5, bladder tea 6, dandelion tea 7, Saint-John s-wort tea 8, tea for cough 9, nettle tea 10, rosehip tea 11, chamomile tea 12, horsetail tea 13, linden flowers tea 14, marigold tea 15, fennel tea 16, cumin tea.

Tea also contains phenolic substances and carotenoids. The long-living Caucasian population regularly consume wine and tea. The aim of the studies was to compare the antiradical properties of different tea types. The results of measurements of ACW and ACL0 for 16 various types are shown in Figure 23. 

---