Total Free Radical Scavenging Activity Research Articles

Alterations in growth, antioxidative defense and medicinally important compounds of Curcuma caesia Roxb. under elevated ultraviolet-B radiation

Ultraviolet-B (UV-B) radiation is a well-known stress factor, as involved in the generation of free radicals, and induction factor which permutates growth, metabolic processes, and secondary metabolites synthesis of plants. However, its impact on medicinal plants is less explored particularly in relation to secondary metabolites associated with the medicinally important rhizomes. An endangered medicinal plant (Curcuma caesia Roxb.) grown under natural field conditions was exposed to elevated UV-B (ambient ± 9.6 kJ m−2 d-1) to assess changes in growth, antioxidant profile, defense strategy and the secondary metabolites of the rhizome. Results showed that eUV-B induced the generation of different reactive oxygen species (·O2- radical and H2O2) which were counteracted by induction of UV absorbing pigments (flavonoids and anthocyanin), non-enzymatic (ascorbic acid) and enzymatic antioxidants (peroxidase, ascorbate peroxidase and catalase) at different growth stages. However, phenol, thiol and superoxide dismutase activity showed reduction at all the growth stages. Protection from UV-B was also manifested by an increase in total free radical scavenging activity, metal chelation and reducing activity. Alterations in biomass allocation might be a possible mechanism of defense which persuaded to higher increment in above ground biomass and tuber biomass with 47 % diminution of rhizome biomass. Among the four classes of compounds identified, sterols were increased whereas reductions were more prominent in fatty acids followed by monoterpenes and sesquiterpenes. Increased production of epicurzereonone, elemene, pinandiol, and 1,8-cineole whereas curcumenol, D-camphor, eucalyptol, curcumenone, isocurcumenol, and zederone were reduced. Elevated UV-B also induced the production of some anti-cancerous compounds such as furanodiene and caryophyllene.

Responses of tropical tree species to urban air pollutants: ROS/RNS formation and scavenging

Air pollution in an urban environment is the major stress factor for vegetation due to the direct generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). To quantify urban air pollution-induced ROS/RNS formation, damage and detoxification, nine different biochemical parameters related to free radical formation, scavenging and membrane damage were estimated in twelve tropical tree species. The experiment was performed in three different seasons at four distinct urban environments in Varanasi city located in the Indo-Gangetic plain of India. Redundancy analysis was performed to statistically assess the relationship between air pollutants (PM2.5, NO2, SO2 and O3) and temperature with ROS/RNS generation and their detoxification. Significant effects of air pollution exposure and temperature on ROS/RNS formation, scavenging and membrane damage were recorded with increasing pollution load in the city for all the tree species. The extent of variability (47–87%) in responses of different tree species was due to their intrinsic ability to scavenge free radicals which minimized the membrane damage. PM2.5, NO2 and O3 were identified as major pollutants that influenced trees to different extents in regulating ROS/RNS. However, the response was maximum against NO2 (34–72%) followed by PM2.5 (16–64%) and O3 (3–31%), indicating that under urban environment, trees are considerably sensitive to the combined effects of both particulate and gaseous pollutants. Reactive oxygen intermediate release, total free radical scavenging activity, NO scavenging activity and membrane stability index were identified as major parameters which showed distinct responses with increasing pollution load. Caesalpinia sappan, Ficus religiosa and Albizia lebbeck were identified as most tolerant tree species having higher ROS/RNS scavenging potential resulted in lower membrane damage. Thus responses of urban trees to air pollution are governed by their intrinsic defence mechanisms to scavenge ROS/RNS by maintaining the membrane integrity through integrated cross-talk between different antioxidative pathways.

HPTLC – Bioautographic methods for selective detection of the antioxidant and a-amylase inhibitory activity in plant extracts

A high-performance thin-layer chromatography (HPTLC) method was developed for quantification of a-amylase inhibitory activity and stigmasterol content in ant plant extracts. An improved HPTLC method for the determination of total free radical scavenging activity in samples using DPPH is also reported. For quantification of a-amylase inhibitory activity, the developed HPTLC plate is dipped into an a-amylase solution, and the bioautogram is then incubated at 25?°C for 30?min under humid conditions. For visualization of enzyme inhibitory activity, the starch test with an iodine indicator solution is used. The blue zone observed comes from the starch-iodine complex formed from starch that was not hydrolyzed by the amylase due to enzyme inhibition by the compound(s) present in the sample. The area of the blue zones was used to compare and quantify relative a-amylase inhibitory activity in different extracts. Location of the blue zones (hRF) on the plate was used to detect compounds that are responsible for the a-amylase inhibitory activity. Relative a-amylase activity was not related to the antioxidant activity, but was highly correlated with the stigmasterol content in the sample extracts (R?=?0.95). Therefore, plant sterols present in the extracts might be responsible for a-amylase inhibitory activities in the extracts.•The developed method for quantification of a-amylase inhibitory activity provides an efficient and effective tool that can be used to screen, detect and quantify a-amylase inhibitory activity in plant extracts.•The proposed protocol is easy to run, involves minimal sample preparation, with multiple samples able to be analyzed in parallel on the same chromatographic plate, in a short time.•There were significant differences in a-amylase inhibitory activity, stigmasterol content, and total free radical scavenging activity between methanol, ethanol, dichloromethane, and ethyl acetate ant plant extracts.

Determination of free phenolic acids in plant-derived foods by high-performance thin-layer chromatography with direct 2,2′-diphenyl-1-picrylhydrazyl assay

The healthy properties of functional food are associated with the presence of a wide range of phenolic antioxidants. Thus, the aim of this study was to develop a simple, rapid, and reproducible high-performance thin-layer chromatographic (HPTLC) method combined with a direct 2,2′-diphenyl-1-picrylhydrazyl (DPPH) assay, to compare antioxidant activity in terms of free radical scavenging activity in functional food. We wanted to quantify caffeic acid, chlorogenic, and gallic acid, three natural phenolic antioxidants commonly found in functional food, and determine their contribution to the total free radical scavenging activity. Antioxidant activities of organic cacao, green coffee, chia seeds, goji berries, spirulina, and chlorella were evaluated and compared. The most potent free radical scavenger was found to be chlorogenic acid. Free radical scavenging activity in the functional foods tested was mostly affected by the presence of chlorogenic and caffeic acid, while gallic acid, although present in highe...

Study antioxidant activity in Thalassemia Iraqi patients

The aims of this study was to estimate the total antioxidant activity level in serum among the Thalassemia Iraq patients. We estimated total free radical scavenging activity in the120 serum of Thalassemic patients their age range from 2-27years. The DPPH activity of serum ranged from 0.1-3.11µmol/ml, the mean serum level of total antioxidants in Thalassemia patients was significantly lower than the control group, and no relation to age or sex. We concluded that DPPH is useful for evaluating the total antioxidant capacity.

Application of heat stress in situ demonstrates a protective role of irradiation on photosynthetic performance in alpine plants.

The impact of sublethal heat on photosynthetic performance, photosynthetic pigments and free radical scavenging activity was examined in three high mountain species, Rhododendron ferrugineum, Senecio incanus and Ranunculus glacialis using controlled in situ applications of heat stress, both in darkness and under natural solar irradiation. Heat treatments applied in the dark reversibly reduced photosynthetic performance and the maximum quantum efficiency of photosystem II (Fv/Fm), which remained impeded for several days when plants were exposed to natural light conditions subsequently to the heat treatment. In contrast, plants exposed to heat stress under natural irradiation were able to tolerate and recover from heat stress more readily. The critical temperature threshold for chlorophyll fluorescence was higher under illumination (Tc′) than in the dark (Tc). Heat stress caused a significant de-epoxidation of the xanthophyll cycle pigments both in the light and in the dark conditions. Total free radical scavenging activity was highest when heat stress was applied in the dark. This study demonstrates that, in the European Alps, heat waves can temporarily have a negative impact on photosynthesis and, importantly, that results obtained from experiments performed in darkness and/or on detached plant material may not reliably predict the impact of heat stress under field conditions.

Overexpression of CsDFR and CsANR enhanced flavonoids accumulation and antioxidant potential of roots in tobacco

Flavonoids are widespread throughout the plant kingdom and present in different parts of plants. Tea (Camellia sinensis) is well known for very high content of flavonoids especially flavan-3-ols antioxidants and is an aluminium (Al) accumulator plant. Dihydroflavonol 4-reductase (DFR) and anthocyanidin reductase (ANR) are known to be regulatory enzymes of flavonoid biosynthetic pathway. In this study, cDNA encoding DFR (CsDFR) and ANR (CsANR) from tea were overexpressed individually in tobacco to check their influence on accumulation of flavonoid contents and antioxidant potential in roots of transgenic tobacco. Root morphological features, such as total volume and the number of lateral roots were improved in CsDFR and CsANR overexpressing tobacco plants relative to control tobacco plants. Both types of transgenic showed higher content of flavonoids and proanthocyanidins and lower content of anthocyanins in the roots compared to roots of control tobacco. Among flavan-3-ols, only epigallocatechin was observed in the roots and its content was higher in CsDFR and CsANR overexpressing tobacco as compared to control tobacco. Expression of genes encoding various other enzymes of flavonoid pathway like Phenylalanine ammonia-lyase, Chalcone isomerase, Flavanol synthase and Anthocyanin synthase was increased in roots of CsDFR and CsANR overexpressing tobacco plants as compared to control tobacco. The antioxidant potential of root portion of CsDFR and CsANR transgenic tobacco plants was found to be increased as indicated by enhanced total free radical scavenging activity and tolerance against Al toxicity. Taken together, these changes in roots of CsDFR and CsANR transgenic tobacco provided tolerance to aluminum toxicity.

Sesame lignans enhance the thermal stability of edible vegetable oils

The effect of sesame lignans on the thermal and storage stability of edible vegetable oils (soybean-SBO, sunflower-SFO and ricebran-RBO) was studied by (i) determining the total free radical scavenging activity (RSA) using DPPH, (ii) % total tocol retention, (iii) lignan profile and (iv) PUFA composition. The order of RSA and retention of total tocols of oils heated up to 120 min at frying temperature (FT) were RBO = SBO > SFO and RBO > SBO > SFO, respectively. Heating SBO or SFO at FT after addition of 1.2% lignans increased RSA of SBO to a greater extent than that of SFO, and increased retention of total tocols only in SBO. However, addition of lignans did not further increase the RSA of RBO. Heating oils with added lignans, increased sesamol and decreased sesamolin while sesamin was relatively resistant to heat. These findings suggest that sesame lignans may have potential application as natural antioxidants in the edible oil and food industry.

Free radical scavenging activity in the nonenzymatic fraction of human saliva: a simple DPPH assay showing the effect of physical exercise.

Free-radicals and other reactive oxygen species (ROS) have been implicated as being major damaging species in pathology and they have been widely investigated. Using 1,1'-diphenyl-2-picrylhydrazyl (DPPH), we estimated total free radical scavenging activity in the low-molecular-weight nonenzymatic fraction (LMNEF) of human whole saliva. The activity of the whole saliva and serum were measured in terms of the rate of decrease in the absorbance at 517 nm in a 40% ethanol DPPH solution (pH 7.4) at room temperature. The DPPH activity of saliva and serum showed a significant linear relationship. The mean DPPH activities of saliva from 257 subjects aged 4-72 was found to be 0.389+/-.190 micromol/ml and bore no relation to age or sex. The activity in saliva of 86 subjects aged 4-11 was significantly different before and after exhaustive aerobic dance exercise for 1 hr. Physical exercise markedly decreased free radical scavenging activity in whole saliva of children. On the basis of the above results, we concluded that DPPH is useful for evaluating the total antioxidant capacity of LMNEF of human saliva.

Poor Glycaemic Control is Associated with Reduced Serum Free Radical Scavenging (Antioxidant) Activity in Non-Insulin-Dependent Diabetes Mellitus

The diabetic patient is at significantly increased risk of developing vascular disease. Its aetiology may involve oxidative damage by free radicals and protection against such damage can be offered by radical-scavenging antioxidants. We investigated whether there was a relationship between glycaemic control as assessed by measurement of glycated haemoglobin (HbA1c) and serum antioxidant status in a population of 118 diabetic outpatients with either insulin-dependent or non-insulin-dependent diabetes. Amongst patients with non-insulin-dependent diabetes mellitus there was a significant inverse correlation between levels of glycated haemoglobin and total free radical scavenging activity (r = -0.456, P < 0.0001). This association resulted primarily because of a similar correlation with uric acid (r = -0.421, P = 0.0003). There was also a weak inverse correlation with vitamin A but no significant association with vitamin C or vitamin E levels. There were no significant associations found amongst the patients with insulin-dependent diabetes. These results indicate that poor diabetic control is associated with reduced serum free radical scavenging (antioxidant) activity in non-insulin-dependent diabetes mellitus. By implication improved glycaemic control may preserve serum antioxidant status in diabetes.

Antioxidant activity in Brassica napus L. plants expressing lox-dependent BAR gene

Aim. The study of possible unintended biochemical peculiarities of newly obtained herbicide-resistant canola (Brassica napus L.) plants expressing the lox-dependent BAR gene was the aim. Methods. Total soluble protein content, total free radical scavenging activity, and superoxide dismutase activity have been investigated using Bradford’s, DPPH, and nitroblue tetrazolium assays, respectively. Fresh weight of plants grown on media with or without phosphinothricin was also measured. Results. The antioxidant activity of leaf extracts of untransformed plants under in vitro growth condi-tions had no significant differences in comparison with ones of phospinothricin-resistant plants in the third generation. No significant changes in parameters investigated were observed in transgenic plants cultivated on media with herbicide addition compared to ones grown on media without it. Fresh weight and total soluble protein content were similar in transgenic and untransformed canola plants under growth without phosphinothricin. Conclusions. Lox-dependent BAR gene introduction and expression resulted in no significant differences in leaf antioxidant activity in transgenic canola plants comparing to untransformed controls.Keywords: Brassica napus, antioxidant activity, DPPH, glufosinate, superoxide dismutase.