Superoxide Radical Scavenging Activity Research Articles

Antioxidant, anti-inflammatory, and α-amylase inhibitory activities of Ulva lactuca extract

In this study, an extract of Ulva lactuca was investigated for its in vitro antioxidant activities (2,2-diphenyl1-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical scavenging activity, and reducing power) and enzyme inhibitory activities (α-amylase and α-glucosidase). The anti-inflammatory effect of U. lactuca extract was evaluated in lipopolysaccharide-stimulated RAW 264.7 cells, a widely used macrophage cell line. We observed that U. lactuca extract contained a relatively high total phenolic content (7.72 mg of gallic acid equivalents/g of extract) and exhibited multiple antioxidant activities including the scavenging of 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl, and superoxide anion radicals as well as reducing power. Simultaneously, we found that U. lactuca extract exhibited anti-inflammatory activity as evidenced by the reduction of nitric oxide in the U. lactuca extract-treated RAW 264.7 cells. Moreover, U. lactuca extract had a moderate inhibitory effect on α-amylase, although it showed no obvious inhibitory effect on α-glucosidase at the concentration tested. Collectively, our results demonstrated that the phenolic-enriched U. lactuca extract exhibited antioxidant and anti-inflammatory activities, and inhibited enzyme (α-amylase) relevant to hyperglycemia. Further research is required to determine the potential of developing the U. lactuca extract as a nutraceutical or pharmaceutical ingredient.

PHYTOCHEMICAL PROFILING, FREE-RADICAL SCAVENGING AND ANTI-INFLAMMATORY ACTIVITIES OF MELIOSMA SIMPLICIFOLIA (L.)

Objective: In the current research, to determine the stem extract of Meliosma simplicifolia (L.) for total phenol, tannin, total flavonoid, antioxidant activity, anti-inflammatory and identify the phytoconstituents utilizing GC-MS and FT-IR.
 Methods: The ability of the plant extract to act as hydrogen/electrons donor or scavenger of radicals was determined by in vitro antioxidant assays using 2,2-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, reducing power assay, superoxide radical (O2•) scavenging activity. The anti-inflammatory activity was evaluated using carrageenan and formalin-induced paw edema models using Wistar albino rats. The GC-MS and FT-IR analysis of the methanolic stem extract of M. simplicifolia was revealed the presence of phytochemicals.
 Results: Quantitative studies of estimated phenol, flavonoid and tannin, as for the methanol extract of stem showed the highest content of phenolic compounds (39.83±3.62GAE mg/100). Antioxidant activities were concluded the estimation M. simplicifolia stem for as followed the studies. In stem the methanol extract showed the highest DPPH scavenging activity (124.3µg/ml). The anti-inflammatory activity has shown in high doses of methanolic extract 250 mg/kg of significant value (p<0.05) inhibition of paw edema, on 6th hour, respectively. The FT-IR analysis has confirmed their characteristic peak values and functional groups.
 Conclusion: M. simplicifolia has an effective of anti-inflammatory activity and constitutes a potential source for the development of new treatments.

In Vitro Toxicity, Antioxidant, Anti-Inflammatory, and Antidiabetic Potential of Sphaerostephanos unitus (L.) Holttum.

Pteridophytes have been widely used in several systems of medicine. Several reports have increasingly assessed their bioactive effects, but for Sphaerostephanos unitus (L.) Holttum, only its antibacterial potential has been assessed. In this sense, the present study was carried out to reveal the phytochemical profile and to determine the toxicity, antioxidant, antidiabetic, and anti-inflammatory potential of S. unitus. Brine shrimp lethality, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, phosphomolybdenum assay, superoxide radical scavenging activity, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay (ABTS), and in vitro α-amylase inhibitory and membrane stabilization assays were applied. S. unitus extract toxicity showed variable mortality percentages, with LC50 values ranging from 4 to 30 mg/mL. DPPH radical scavenging effects of S. unitus extracts were as follows: methanol > acetone > petroleum ether > chloroform. S. unitus acetone extract displayed the strongest phosphomolybdenum reduction (10 ± 2 mg Ascorbic Acid Equivalent/g). The studied extracts also revealed efficient, superoxide scavenging effects in a dose-dependent manner. In S. unitus, the highest ABTS radical scavenging rate was observed in the chloroform extract (3000 ± 40 µmol/g). The S. unitus anti-inflammatory effect was as follows: petroleum ether > chloroform > methanol > acetone. In S. unitus extract, the highest percentage of α-amylase activity (80%) was observed for the petroleum ether extract (25 µg/mL). Faced with these findings, further studies should be performed to isolate and identify the S. unitus compounds responsible for their antioxidant, antidiabetic and anti-inflammatory effects.

Preparation of glycosylated hydrolysate by liquid fermentation with Cordyceps militaris and characterization of its functional properties

This study aimed to investigate the potential of a novel preparation strategy for glycosylated hydrolysate by liquid fermentation in order to provide a high-quality glycosylated hydrolysate. Protein solubility, surface hydrophobicity and antioxidant activity were evaluated. The results of Fourier transform infrared spectra demonstrated the occurrence of glycosylation reaction. The results of Fluorescence emission spectroscope revealed the decrease of tertiary conformation stability. Circular dichroism spectra revealed significant decrease in α-helix and increase in β-sheet and random coil by glycosylation reaction. In comparison with zein hydrolysate, glycosylated hydrolysate had lower surface hydrophobicity but higher in solubility and in vitro digestibility due to glycosylation. Glycosylated hydrolysate presented higher ABTS (2,2'-Azinobis [3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt) and superoxide radicals scavenging activities as well as Cu2+ chelating capacity. It is concluded that the glycosylation confer an open structure and modified properties of zein, and glycosylated hydrolysate is a potential ingredient with better hydration and antioxidant activities than zein hydrolysate.

Antioxidant potential and free radical scavenging activity of Parkia roxburghii, G. Don, a lesser known leguminous tree from North East India

Total phenolics in extracts of different parts of Parkia roxburghii varied from 80.1 (flowers) to 311.6 mg/ g GAE (Pods) with moderate amounts of flavonoids and high antioxidant activity (50.1–92.4%). The pods of Parkia roxburghii were found to be potent DPPH radical scavengers followed by leaves, seeds and then flowers as evident by their low IC50, EC50 values and reasonably high ARP values (34.5–230.4). The pod and seed extracts exhibited good reducing power expressed as ascorbic acid equivalents (ASE/ ml) and significant protection against DNA damage caused by free radicals too. The extracts of Tree bean studied showed appreciable free radical scavenging activities through inhibition of lipid per oxidation (LPO) measured by ammonium thiocyanate assay, inhibition of hydroxyl radical observed in non-site specific and site specific assays, metal chelating capacity and superoxide radical scavenging activity. In most of the assays, the pod extracts showed higher potency in scavenging of free radicals than quercetin which was used as a standard. The specific phenolic composition of Parkia roxburghii extracts performed through HPLC and LC-MS/MS showed presence of gallic acid, caffeic acid, chlorogenic acid, ellagic acid ferulic acid. Low amounts of flavonoids like kaempferol, quercetin, diadzein and genestein were also observed in some parts of the plant. Such scientific evidences in the present investigation on the functional attributes of Parkia roxburghii, a traditional food plant would hold significant importance in genetic diversity studies and also for disease prevention and management through diets.

Effects of Some Heavy Metals (Cd, Cu, Pb, and Zn) Concentration on Qualitative Traits of Dill (Anethum graveolens L.) and Basil (Ocimum basilicum L.)

Soil pollution is a global concern from past to recent. Toxic and high resistance nature of chemical pollutants, such as heavy metals show their important as environmental risk and a serious problem for human health, because they can introduce to the food chain from contaminated environments. Experiments were conducted to evaluate the effect of Cd, Cu, Pb, and Zn on qualitative parameters of dill (Anethum graveolens L.), and basil (Ocimum basilicum L.) grown in polluted soil environment. Heavy metals concentration, total phenol and flavonoid, essential oil percentage, DPPH radical scavenging activity, super and nitric oxide radical scavenging activity in leave and stem parts of the plants were analysed in this study according to standard methods. According to results, Cu was the dominant heavy metal in leave and stem of both studied plants, followed by Pb, Zn, and Cd. The concentration of various heavy metals in dill was more than two times higher than basil. Total phenol and flavonoids showed significant differences in leave and stem in both plants. DPPH, super oxide and nitric oxide radical scavenging activity showed significant higher values in leave than stem in both plants.

Quality Characteristics and Antioxidant Activity of Yogurt Salad Dressing Added with Lingonberry Powder

This study evaluated the quality characteristics and antioxidant activity of yogurt salad dressing, prepared with lingonberry (Vaccinium vitis-idaea L.) powder (0, 1, 3, and 5%). The pH of the yogurt decreased with increasing amounts of lingonberry powder. Moreover, titratable acidity, sugar content, and viscosity increased as the amount of lingonberry powder increased. The lightness (L) value decreased, whereas the redness (a) value increased with increasing amounts of lingonberry powder. The consumer acceptance test revealed no significant difference between the control group and the groups containing 1 and 3% lingonberry powder in terms of color, smell, and overall acceptability. The total polyphenol and total anthocyanin content ranged from 3.99∼26.69 mg gallic acid equivalent/100 g and 0.02∼7.90 mg/100 g, respectively, which increased as the amount of lingonberry powder increased. The antioxidant activity, which was measured by the DPPH radical scavenging assay, superoxide anion radical scavenging activity, and reducing power increased as the amount of lingonberry powder increased. Taken together, addition of up to 3% of lingonberry powder can improve the antioxidant properties of yogurt salad dressing without affecting its sensory qualities.

Impact of Genotype, Environment, and Malting Conditions on the Antioxidant Activity and Phenolic Content in US Malting Barley

The phenolic content and antioxidant potential of malting barley are important in brewing. The objective of our study was to investigate the effects of barley genotype, growing environment, and malting conditions on the total phenolic content and antioxidant activities of malting barley grown in North America. Eight barley cultivars grown at three locations over three years were used. For the malting study, a single barley cultivar, separated into different kernel size fractions, was germinated for various periods of time and then processed by kilning or freeze-drying. Total phenolic content (TPC) and some of the antioxidant activities, including DPPH, ABTS, and superoxide anion radical scavenging activities, reducing power, and iron (II) chelating activity, were significantly impacted by the barley genotype, growth environment, and their interactions. The TPC and most antioxidant activities were also influenced by malting conditions and were generally higher in the malted barleys of the thin kernel size fraction, four-day germination, and in samples processed by kilning, when compared to the plumper kernel size fractions, one and two days of germination, and freeze-dried samples, respectively. There were interactions between malting parameters, and stepwise regression analysis was used to suggest the contribution of each parameter to the TPC and antioxidant activities.

Green synthesis of silver nanoparticles using Indian Belladonna extract and their potential antioxidant, anti-inflammatory, anticancer and larvicidal activities.

Atropa acuminata aqueous leaf extract biosynthesized silver nanoparticles showed strong antioxidant, anticancerous (HeLa cells) and anti-inflammatory activities. Besides, this bio syn-AgNP also proved effective against mosquito vectors causing malaria, dengue and filariasis. Present study highlights eco-friendly and sustainable approach for the synthesis of silver nanoparticles (AgNP) using aqueous leaf extract of A. acuminata, a critically endangered medicinal herb. The addition of 1mM silver nitrate to aqueous leaf extract resulted in the synthesis of AgNP when solution was heated at 60°C for 30min at pH 7. Absorption band at 428nm, as shown by UV-Vis spectroscopy confirmed the synthesis of AgNP. XRD patterns revealed the crystalline nature of AgNP and TEM analysis showed that most of the nanoparticles were spherical in shape. Zeta potential of AgNP was found to be -33.5mV which confirmed their high stability. FT-IR investigations confirmed the presence of different functional groups involved in the reduction and capping of AgNP. The synthesized AgNP showed effective DPPH (IC50-16.08µg/mL), H2O2 (IC50-25.40µg/mL), and superoxide (IC50-21.12µg/mL) radical scavenging activities. These plant-AgNP showed significant inhibition of albumin denaturation (IC50-12.98µg/mL) and antiproteinase activity (IC50-18.401µg/mL). Besides, biosynthesized AgNP were found to have strong inhibitory effect against a cervical cancer (HeLa) cell line (IC50-5.418µg/mL) as well as larvicidal activity against 3rd instar larvae of Anopheles stephensi (LC50-18.9ppm, LC90-40.18ppm), Aedes aegypti (LC50-12.395ppm, LC90-36.34ppm) and Culex quinquefasciatus (LC50-17.76ppm, LC90-30.82ppm) and were found to be non-toxic against normal cell line (HEK 293), and a non-target organism (Mesocyclops thermocyclopoides). This is the first report on the synthesis of AgNP using aqueous leaf extract of A. acuminata, validating their strong therapeutic potential.

Extraction of flavonoids from Cyclocarya paliurus (Juglandaceae) leaves using ethanol/salt aqueous two‐phase system coupled with ultrasonic

An aqueous two phase system (ATPS) coupled with ultrasonic was employed to extract flavonoids from Cyclocarya paliurus (Batalin) Iljinskaja leaves first time. The optimal conditions were determined by Response Surface Methodology(RSM) of ethanol concentration 33%; salt concentration 15%; extraction time 52 min; liquid-solid ratio 33:1, while the flavonoids extraction yield obtained the maximum of 3.00 ± 0.1%. The antioxidant activity of flavonoids was evaluated by vitro antioxidant assays under the optimal conditions, which indicated that the extract has strong DPPH, ABTS + and superoxide anion radical-scavenging activity (IC50 value of 0.0013 mg/ml, 0.0296 mg/ml and 0.126 mg/ml) which were close to and even better than Vc (extremely close to 0, 0.0291 mg/ml and 0.433 mg/ml). The study showed that the ATPS-ultrasonic was a commendable approach for the extraction of flavonoids from C. paliurus and the flavonoids may serve as new natural antioxidant for functional food ingredients and additives. Practical applications In this study, ethanol and inorganic salt are selected as the extraction and separation solvent, which is simpler than the traditional method, environmental friendly, while reducing the process cost, and has great application value. Furthermore, through the analysis of the extraction components of the edible plant Cyclocarya paliurus, it was found that the flavonoids contained in C paliurus had antioxidant activity close to vitamin C. Combined with the above research, C. paliurus has the potential to develop into functional food and additives with antioxidant function.

Probiotic Potential of Bacillus Strains Isolated from an Acidic Fermented Food Idli.

Present study is intended to assess the probiotic properties of Bacillus spp. isolated from idli batter, a traditional fermented food of Southern India and Sri Lanka. A total of 32 isolates were screened for potential pathogenic behaviour through haemolysis assay, DNase activity and antibiotics sensitivity. Two of the isolates were found to be potentially safe and identified as Bacillus spp. These strains were characterized for in vitro probiotic attributes and antioxidant activity. Both the strains showed strong acid and bile tolerance, transit tolerance, lysozyme tolerance, cell surface hydrophobicity, auto-aggregation, co-aggregation, biofilm formation potential and adhesion to human colon adenocarcinoma (HT 29) cell line demonstrating potential probiotic ability. These strains also exhibited considerable cholesterol binding, thermostability, β-galactosidase production, proteolytic, amylolytic and lipolytic activity. Cell-free supernatant inhibited the biofilm formation by Pseudomonas aeruginosa (KT266804) to 90%. Intact cells showed significant DPPH (41%), hydroxyl (31%), radical scavenging activity and lipid peroxidation inhibition (20.38%), while cell-free extracts exhibited significant superoxide anion radical scavenging activity (16.25%). Results revealed that isolates could be potential probiotic candidate after further assessment of in vivo probiotic properties and safety evaluation and could be utilised as starter cultures in functional foods.

Assessment of chemical, biological and immunological properties of “Damiana de California” Turnera diffusa Willd extracts in Longfin yellowtail (Seriola rivoliana) leukocytes

In Mexican herbal medicines or natural remedies, Turnera diffusa (Turneraceae) known as “Damiana de California”, has ethnopharmacological relevance, including aphrodisiac, diuretic, and antimicrobial activities. To explore the immunological effect of infusion and methanolic extracts from Damiana de California, this study investigated its chemical, biological, antimicrobial and immunological properties in Longfin yellowtail Seriola rivoliana leukocytes. The analysis of chemical compounds revealed a considerable level of total phenolic and flavonoid contents in the infusion compared with methanolic extract. Furthermore, the antioxidant activity showed high hydroxyl radical scavenging activity in infusion extract compared with BHT positive control. Superoxide radical scavenging activity and ion chelation were higher in methanolic extract followed by infusion treatment. Interestingly, notable antimicrobial activity was observed in both extracts of T. diffusa against Vibrio parahaemolyticus. An in vitro study was performed using leukocytes of S. rivoliana treated with infusion or methanolic extracts at 12.5, 25 and 50 μg/mL for 24 h. Remarkably, infusion extract induced proliferation at any concentration but not the methanolic extract, which was diminished in a dose-dependent fashion. The immunostimulation study demonstrated that the phagocytosis activity increased in those leukocytes stimulated with methanolic extract but diminished the respiratory burst activity, in contrast to the activity observed in those leukocytes stimulated with infusion treatment. Finally, leukocytes incubated with the extracts and confronted with V.parahaemolyticus up-regulated the transcription of proinflammatory cytokine IL-1β gene in a dose response relationship. These findings suggest that the infusion treatment has potential therapeutic properties, promoting the antioxidant capacity and enhancing immune parameters in Longfin yellowtail S. rivoliana.

Integrated HPLC fingerprinting and multivariate analysis differentiates between wild and cultivated Hedyotis diffusa Willd

Hedyotis diffusa Willd (HDW) is widely used to treat various diseases and as a health supplement. The high demand for wild HDW has resulted in the emergence of numerous cultivated HDW. However, there is a little information about the chemical and pharmacological differences between wild and cultivated HDW. In the present study, 20 wild and cultivated HDW samples were collected from different regions in China. An integrated method of high performance liquid chromatography (HPLC) fingerprinting and multivariate analysis, including similarity analysis (SA), hierarchical cluster analysis (HCA), principal components analysis (PCA), and orthogonal partial least square method-discriminant analysis (OPLS-DA), was developed to characterize the differences in chemical compositions between wild and cultivated HDW. The anti-oxidant activity of wild and cultivated HDW was compared using the 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS), the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), and the superoxide radical scavenging activity (SRS) assays. In total, 23 common peaks from fingerprinting chromatograms were included in the multivariate analysis. SA showed obvious differences in similarity values (0.685 - 0.929). Twenty samples were accurately distinguished between wild and cultivated HDW using OPLS-DA, but not HCA and PCA. High performance liquid chromatography (HPLC) coupled with electrospray ionization-quadrupole-time of flight-mass spectrometry (HPLC-ESI-TOF/MS) identified nine major chemical compounds that discriminated between wild and cultivated HDW. The anti-oxidant activity of wild HDW was significantly higher compared with the cultivated HDW. This study provides a suitable method for germplasm discrimination and quality evaluation of HDW and a chemical and pharmacological method to determine a replacement possibility for cultivated HDW.

New benzimidazole-aldehyde hybrids as neuroprotectors with hypochlorite and superoxide radical-scavenging activity.

Many neurodegenerative disorders include oxidative stress-mediated pathology. Melatonin and its metabolites act as endogenous reactive oxygen species (ROS) scavengers and antioxidants. N,N'-Disubstituted benzimidazole-2-thiones with extended side chains could exert antioxidant and neuroprotective properties due to structural similarities to melatonin. The toxicological potential of the compounds was evaluated by monitoring the synaptosomal viability and the levels of reduced glutathione (GSH) in isolated rat brain synaptosomes. The neuroprotective effects were assessed in vitro in a model of 6-hydroxydopamine (6-OHDA)-induced neurotoxicity. The capability to decrease superoxide anion radical and hypochlorite was evaluated by luminol-dependent chemiluminescent assays. Compounds 5-7 containing residues of veratraldehyde, vanillin, and syringaldehyde at concentration 250μM, preserved at the highest degree the synaptosomal viability and GSH levels. Further screening of compounds 5-7 at lower concentrations of 100μM, 10μM, and 1μM, respectively, demonstrated that 6 and 7 do not show any toxicity within this concentration range. In the model of 6-OHDA-induced oxidative stress, 6 revealed concentration-dependent, neuroprotective, and antioxidant activities similar to melatonin. All the three compounds demonstrated ability to decrease the chemiluminescent scavenging index (CL-SI) in the hypochlorite containing system. In the superoxide system, the hydrazones exhibited different effects on the signal. Our studies suggest that the benzimidazole-aldehyde hybrids act as direct ROS scavengers and membranes' stabilizers against free radicals. Thus, they play a role in the antioxidative defense system and have a promising potential as therapeutic neuroprotective agents for the treatment of neurodegenerative disorders.

Ultrasonic pretreatment improved the antioxidant potential of enzymatic protein hydrolysates from highland barley brewer's spent grain (BSG).

Highland barley brewer's spent grain (BSG), being China's brewing industry's major by-product is the focus of current research. The aim of the present study was to scrutinize the effects of ultrasound and heat pretreatments on enzymatic hydrolysis of highland barley BSG protein hydrolysates (HBSGPH) and evaluate the effect of enzymatic hydrolysis time on the antioxidant activity of hydrolysates by Alcalase. Different ultrasonic waves (40 and 50kHz) and heat pretreatment temperatures (50 and 100 °C) were chosen and the pretreatment time was 15, 30, and 60min. The obtained results revealed that the ultrasound pretreatment of highland barley BSG protein at 40 and 50kHz has significantly (P <0.05)enhanced about 57 and 67% of oxygen radical absorption capacity of obtained hydrolysate over the untreated substrate. The 1,1-diphenyl-2-picrylhdrazl (DPPH) radical scavenging activity (DRSA) 28%, metal chelating activity (MCA) 54%, superoxide radical scavenging activity (SRSA) 18%, and hydroxyl radical scavenging activity (HRSA) 25% of HBSGPH at 50kHz were also improved (P <0.05)significantly. HBSGPH from heat treatment at 100 °C showed no SRSA and HRSA scavenging activities but improved significantly (P <0.05)about 27% ferric reducing antioxidant power (FRAP) assay values. In the present work, the resultant HBSGPH had stronger antioxidant properties with ultrasound pretreatment at 50kHz and the enzymatic hydrolysis after 4hr was facilitating the enzymatic release of antioxidant peptides from HBSGPH. PRACTICAL APPLICATION: Highland barley BSG is attracting toward natural food products due to its potent natural antioxidants to overcome the risk of diseases and are beneficial for human health.

Bioactive compounds and in vitro antioxidant activity assessment of GM Bt eggplant-III (Noyantara) and stability upon boiling

To control the fruit-and-shoot borer infestation and meet the demand of booming consumer, genetically modified GM Bt eggplant-III (Noyantara) was introduced in India, Bangladesh, and the Philippines in 2013. This genetic modification could lead to changes in metabolic pathways and may result in the variation of the molecular pattern, with particular attention to antioxidant compounds. With this purview, this study was carried out to investigate the status of bioactive compounds and antioxidant activity of GM Bt eggplant-III and their changes upon common processing methods likely boiling. To investigate the effect of boiling, the Bt eggplant-III was boiled at 100 °C for 1, 5, 10, and 20 min, respectively. From the physicochemical analysis, it was found that the pH and water solubility index increased with increasing the boiling time, whereas ash content decreased. The present study revealed that Bt eggplant-III contains an appreciable amount of polyphenols, flavonoids, anthocyanin, and carotenoids. However, processing by boiling caused the loss of these valuable compounds except for carotenoids. The present study evaluated the antioxidant activities of Bt eggplant-III in terms of different in vitro methods such as DPPH, metal chelating activity, and superoxide radical scavenging activity. Results showed that the ethanolic extract of Bt eggplant-III could effectively scavenge reactive oxygen species. For prolonged boiling, the IC50 values were increased which thereby indicating a decreased in antioxidant activity of Bt eggplant-III.

Quercetin-grafted chitosan prepared by free radical grafting: characterization and evaluation of antioxidant and antibacterial properties.

Chitosan (CS) is considered a versatile biopolymer with promising applications. However, it is not a good chain-breaking antioxidant due to the lack of H-atom donors. In this work, CS was combined with quercetin (Q), a natural antioxidant, via a free radical-mediated procedure to strengthen the antioxidant capacity. The successful formation of Q-grafted CS (Q-CS) was confirmed by ultraviolet-visible absorbance and Fourier transform infrared spectroscopy. After combination, the obtained Q-CS had a phenolic content of 13.9mg QE/g Q-CS and showed a lower crystallinity and thermal stability than the native CS. The 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), superoxide, and hydroxyl radical scavenging activities of Q-CS were higher than those of CS, illustrating that grafting with Q is an available way to improve the antioxidant capacity of CS. In addition, Q-CS showed higher minimal inhibitory concentrations against tested bacteria than CS, suggesting that combining with Q has a negative effect on the antibacterial activity of CS. Our results indicate that Q-CS may have great potential for applications in the fields of food and healthcare.

Quantification of Total Phenolics, Flavonoids and Evaluation of in vitro Free Radical Scavenging Activities in Psidium guajava L.

The present study was undertaken to quantify total phenolics and flavonoids and investigate in vitro free radical scavenging activities of leaf extracts of two varieties of Psidium guajava L. viz., Lalit and Allahabad safeda. Leaf extracts of Lalit and Allahabad safeda were prepared by Soxhlet extraction and ethanol extracts were used for in vitro assays. Total phenolic and flavonoid contents, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, nitric oxide and super oxide free radical scavenging activities were determined at 100, 200, 300, 400, 500, 600 and 700 µg/ml concentrations of Lalit and Allahabad safeda leaf extracts. Results indicated the presence of higher phenolic and flavonoid contents in the leaf extract of Lalit compared to that of Allahabad safeda. The leaf extracts of Lalit and Allahabad safeda showed dose-dependent increase in 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl and nitric oxide radical scavenging activities and a decrease in super oxide radical scavenging activities. However, Lalit showed higher free radical scavenging activity compared to that of Allahabad safeda. Further, the IC50 values of Lalit for DPPH, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), nitric oxide and super oxide free radicals were 229.56, 503.07, 430.40, 07 and 377.96 µg/ml, respectively. In addition, the IC50 values of Allahabad safeda for 2,2-diphenyl-1-picrylhydrazyl, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), nitric oxide and super oxide free radicals were, 270.24, 543.63, 469.99 and 515.50 µg/ml, respectively. This study clearly demonstrated antioxidant activity in both the extracts of Lalit and Allahabad safeda. The better antioxidant activity of Lalit extract could be due to the presence of higher phenolic content compared to Allahabad safeda.

Preparation, characteristics, and antioxidant activity of the selenium nanoparticles stabilized by polysaccharides isolated from Grateloupia filicina

Background: Selenium is an essential trace element which is of fundamental importance to human health. Compared to organic and inorganic selenium, selenium nanoparticles (SeNPs) display unique biological and physicochemical properties. Objectives: In this study, we aimed to optimize the extraction parameters of polysaccharides of Grateloupia filicina (GFPs) and investigate the antioxidant activity of SeNPs stabilized by GFPs. Materials and Methods: GFPs were extracted using hot water. The extraction parameters were optimized by performing an orthogonal experiment. SeNPs were prepared under mild conditions using GFP as the modifier and the stabilizer. A scanning electron microscope (SEM) was used to characterize the prepared GFPs-SeNPs. The antioxidant activities of GFPs, SeNPs, and GFPs-SeNPs were compared by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radical scavenging activity, superoxide anion radical scavenging activity, and via reducing power assay. Results: The optimal conditions for the extraction were determined as follows: extraction time 5 h, extraction temperature 90°C, and the ratio of water to raw material 100 mL/g. Under these conditions, the yield of GFPs was 50.34% ±0.27%. GFP-decorated SeNPs with an average diameter of 100 nm were synthesized. GFPs-SeNPs showed a higher antioxidant activity compared to GFPs and SeNPs alone. Conclusion: Hot water extraction was found to be efficient in the process of extraction of polysaccharides of G. filicina. GFPs can significantly enhance the antioxidant activity of SeNPs as modifier and stabilizer. GFPs-SeNPs is an efficient radical scavenger and may be explored as a novel antioxidant agent for use in the fields of foodstuff and medicine.

Antioxidant Activity of Ruthenium(Ii) Complexes Containing Tridentate Triamines and Their Capability to Inhibit Xanthine Oxidase

Biological activities of organoruthenium complexes [chloro [N,N′-[(2,6-pyridinediyl-κN) diethylidyne] bis-[benzenamine-κN]] [N-[(2-pyridinyl-κN) methylene] benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 1), [chloro [2,2′-(2,6-pyridinediyl-κN) bis [1H-benzimidazole-κN3]][N-[(2-pyridinyl-κN) methylene] benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 2), and [chloro[2,6-di(1H-pyrazol-3-yl-κN2) pyridine-κN] [N-[(2-pyridinyl-κN) methylene] [benzenesulfonamide-κN] ruthenium(II)] chloride (Cmplx 3) have been studies. The compounds were tested for in vitro biological activity on test models including 2,2-diphenyl-1-picryl-hydrazyl (DPPH) reducing power, superoxide anion radical-scavenging activity, and lipid peroxidation activity by ferric thiocyanate. It is established that Cmplx 2 with benzimidazole ligand displays significant xanthine oxidase inhibitory activity (IC50 = 53.80 ± 2.69 μM), DPPH free radical scavenging activity (79.49 ± 1.59), and superoxide anion radical scavenging activity (75.73 ± 2.85%). The coordination of benzenamine and benzenesulfanoamine ligands reduces lipid peroxidation as observed in the case of Cmplx 1 (87.17 ± 3.88%) and the higher reducing power of Cmplx 1 obtained at all concentrations. It was concluded from the test results that organoruthenium complexes showed much better antioxidant activity than expected.