Biochemical markers of oxidative stress in maize seedlings exposed to rose-grass aphids

We studied the influence of rose-grass aphid (Metopolophium dirhodum L.) infestation on the biochemical markers of oxidative stress in seedlings of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and resistant Plomyk). We compared the generation of superoxide anion radicals O2-, level of hydrogen peroxide (H2O2), lipid peroxidation products (MDA) as well as markers of protein damage (protein-bound carbonyl groups). The studied parameters were measured at 24, 48, 72 and 96 h post-initial aphid infestation compared to the non-infested control seedlings. Our studies indicated that the rose-grass aphid feeding evoked oxidative stress in the maize seedlings. Investigated Z. mays cultivars exhibited excessive generation of superoxide anion radicals in response to insect treatments. Rose-grass aphid feeding increased the H2O2 level in maize tissues with similar levels observed at most periods post-infestation with M. dirhodum, also increased lipid peroxidation products with the maximal levels at 48 and 72 h for Ambrozja and 48, 72 and 96 h post-infestation for Plomyk varieties. Further at 48 and 72 h post-initial aphid infestation, there was an increase in protein bound carbonyl groups content in the maize seedlings after infestation with aphids.

Green Synthesis of Cobalt and Iron Incorporated Citric Acid/β-cyclodextrin Composites: Efficient H2O2 Scavengers

Sonochemical procedure was used to synthesize Co/β-cyclodextrin complex. For the first time Fe/β-cyclodextrin complex was also synthesized in alkaline media. Moreover, β-cyclodextrin was modified by citric acid (CA) and reacted with metal salts under ultrasonic irradiation. The prepared catalysts were characterized by using EDX, UV-vis and FTIR analytical techniques. The highest incorporation of metal into β-cyclodextrin was observed in the citric acid cross linked β-CD. The catalase like activity (peroxide scavenging) of Co/β-CD and Fe/β-CD complexes and composites was evaluated by UV–visible spectrophotometer and their superoxide scavenging capacity were measured using the pyrogallol method. The Co3/CA-β-CD complex showed the best catalase mimetic activity (93.2%) even in comparison to catalase enzyme extracted from potato. By contrast Fe3/CA-βCD complex had stronger capability to eliminate superoxide anion radicals.

The study on the antioxidant activity of polysaccharides isolated from Polygonatum odoratum (Mill.) Druce

The polysaccharides isolated from Polygonatum odoratum (Mill.) Druce (POPs) by water extraction, after precipitation with ethanol were purified through deproteinization, decolorization, dialysis, and column chromatography leading to a purified polysaccharide (POPs-I) content of 90.7 %. The scavenging of oxygen free radicals and inhibition of lipid peroxidation (LPO) by POPs-I were analyzed using a colorimetric method. The results showed that the hydroxyl radical scavenging ability of the polysaccharides was weaker than that of benzoic acid, but stronger than those of ascorbic acid and mannitol, and that the superoxide anion radical scavenging ability was inferior to those of all three. When the concentration was higher than 1.0 mg/mL, the POPs-I could inhibit LPO by superoxide anion radicals to a certain degree. Therefore, this work suggests that POPs-I are potential antioxidant agents in medicine and functional food.

DETERMINATION OF ANTIOXIDANT POTENTIAL OF SUBSTANCES OF DIFFERENT NATURE IN THE SYSTEM GENERATING SUPEROXIDE ANION RADICAL USING THE METHOD OF MATHEMATICAL MODELING

С использованием метода математического моделирования кинетики люминолзависимой хемилюминесценции изучено действие некоторых антиоксидантов (АО) на реакцию окисления люминола супероксидными анион-радикалами, образующимися в системе ТЕМЭД-рибофлавин. Установлено, что для описания вклада антиоксидантов в изменение кинетики люминолзависимой хемилюминесценции (ХЛ) достаточно использовать единственную реакцию взаимодействия антиоксиданта со свободным радикалом. Предложено использование константы скорости этой реакции в качестве меры «антиоксидантной активности». Using the method of mathematical modeling of the kinetics of luminol-dependent chemiluminescence, the effect of certain antioxidants on the reaction of oxidation of luminol by superoxide anion radicals formed in the TEMED-Riboflavin system was studied. It was found that to describe the contribution of antioxidants to the change in the kinetics of luminol-dependent chemiluminescence (ChL), it is sufficient to use a single reaction of the interaction of an antioxidant (AO) with a free radical. It is proposed to use the rate constant of this reaction as a measure of «antioxidant activity».

MALONDIALDEHYDE (MDA) (ZAT OKSIDAN YANG MEMPERCEPAT PROSES PENUAAN)

Malondialdehyde (MDA) is the end product of fat peroxidation due to the breakdown of fatty acid chains which are compounds that toxic to cells. Fat peroxidation is caused by body fat bound to free radicals such as hydroxyl radicals, superoxide anion radicals, and hydrogen peroxide, which are compounds or atoms that have unpaired electrons in their outer orbitals so that they are very reactive to cells or surrounding cell components including lipids. As a result of the lipid peroxidation reaction which is continuous which can cause various diseases and accelerate the aging process, because malondialdehyde causes cell damage. The aging process is the weakening of cells and organs as a whole starting from adulthood slowly and progressing quickly after the age of 50 years, marked by the body begins to ache and wrinkled skin. Naturally, the aging process will occur in every human being, but the process is different, some are fast (the process of premature aging) and some are slow (ageless). Although the aging process occurs for several reasons, free radicals such as melondialdehyde also contribute to accelerating the aging process. Efforts to slow down premature aging due to free radicals, namely antioxidants. As an active ingredient, antioxidants are used to protect skin from oxidation damage and prevent premature aging.