Butein imparts free radical scavenging, anti-oxidative and proapoptotic properties in the flower extracts of Butea monosperma

The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference molecules.The levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured.The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes.Interestingly,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin.The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death.Both extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase activity.Lactate dehydrogenase leakage and cell death were also prevented.However,only butein revived the catalase activity.Thus,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells.

Study on the Free Radical Scavenging Activity of Sea Cucumber (Paracaudina chinens var.) Gelatin Hydrolysate

Gelatin from the sea cucumber(Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff(MWCO). The portion(less than 5 kDa) was further separated by Sephadex G-25. The active peak was col-lected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals(O2·-) and hydroxyl radi-cals(·OH) of the fraction with the highest activity were 29.02% and 75.41%,respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.

Preparation of (±)-5,6,7-Trioxygenated Dihydroflavonols and Evaluation of their Superoxide Radical Scavenging Activity

The synthesis of （±）-5, 6, 7-trioxygenated dihydroflavonols was carried out. All synthetic compounds were passed through superoxide radical scavenging activity in vitro. Compounds 1 e and 1 g exhibited significant bioactivity with the inhibitory rates of 68.1% and 80.9% at 40 μg/mL, respectively.

Why Static O-H Bond Parameters Cannot Characterize the Free Radical Scavenging Activity of Phenolic Antioxidants: ab initio Study

The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE.

STUDIES ON FREE RADICAL SCAVENGING ACTIVITY IN CHINESE SEAWEEDS PART I. SCREENING RESULTS

Antioxidants have attracted the attention of researchers due to their beneficial effects as free radical scavengers. Application of a stable free radical named 1,1 diphenyl 2 picrylhydrazyl(DPPH) to screen the free radical scavenging activity in 27 species of Chinese seaweed showed that 15 of them had significant activity in at least one of the organic solvent extracts. The most interesting seaweed species were Gelidium amansii, Gloiosiphonia capillaris, Polysiphonia urceolata, Sargassum kjellmanianum, Desmarestia viridis, and Rhodomela teres.

Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts

Objective:To study the phytochemical screening of different extracts from Citrullus colocynthis(C.colocynthis)seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.Methods:Phytochemical screening,total content of polyphenols and flavonoids of C.colocynthis seeds extracts,including a crude aqueous extract(E1),a defatted aqueous extract(E2),a hydromethanolic extract(HM),an ethyl acetate extract(EA)and a n-butanol extract(n-B)was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant.Results:None of these extracts contained detectable amount of alkaloid,quinone,antraquinone,or reducing sugar.Catechic tannins and flavonoids were abundant in E1,MM and EA,whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM.Coumarins were found in E2,EA and n-B.Polyphenols,expressed as gallic acid equivalent,amounted,per 100 g plant matter,to 329,1002 and 150 mg in EA,HM an E1 respectively.Flavonoids,expressed as catechin equivalent,amounted.per 100 g plant matter to 620,241 and 94 mg in EA,HM and E1 respectively.Comparable values were found in n-B and E1,with lower values in E2.Quercetin,myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography,The antioxidative effect of these extracts yielded,when tested at a concentration of 2000μg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay,a reducing percentage of 88.8%with EA,74.5%with HM and 66.2%with E1,and corresponding IC_(50)of 350,580and 500μg/mL as compared to 1.1μg/mL for ascorbic acid.Conclusions:These qualitative and quantitative analytical data document the presence in C.colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity,as well as other biological activities of this plant.

Antioxidant activity and free radical scavenging activities of Streptomyces sp.strain MJM 10778

Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were determined.Results:The 16 S rDNA sequencing analysis revealed that Streptomyces sp.strain MJM 10778.which was isolated from Hambak Mountain.Korea,has 99.9% similarity to Streptomyces misionensis(S.misionenis) NBRC 13063.The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC.13063.The entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging activity.The IC_(50) values of the strain MJM 10778 extract on DPPH,.NO.and ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,respectively.The ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability assay.Conclusions:The results obtained suggesl that the ethyl acetate extract of Streptomyces sp.strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.

Constituents from Aerial Parts of Bidens ceruna L. and Their DPPH Radical Scavenging Activity

A new chalcone glycoside, butein-4-methoxyl-4′-O-（6＂-O-acetyl）-β-D-glucopyranoside（2）, along with seven known compounds, namely, quercitrin（1）, luteolin-7-O-β-D-glucopyranoside（3）, butein-4＇-O-β-D-glucopyranoside（4）, butein-4-methoxyl-4＇-O-β-D-glucopyranoside（5）, butin-7-O-β-D-glucopyranoside（6）, isoquercitrin（7）, and sulfurein（8） was isolated from aerial parts of Bidens ceruna L. Their structures were elucidated on the basis of spectroscopic studies. Compounds 1-8 were tested for their DPPH radical scavenging activity and, except compounds 2 and 5, other compounds showed scavenging activitv.

Evaluation of free radical scavenging activity of various extracts of leaves from Kedrostis foetidissima(Jacq.)Cogn

The present study was aimed to investigate the in vitro free radical scavenging activity of various leaf extracts(aqueous,methanol,acetone chloroform and petroleum ether)of Kedrostis foetidissima.In vitro free radical scavenging activities of the extracts were assessed against DPPH and hydroxyl radicals.The metal chelating activity and reducing power ability of the extracts were also determined.The free radical scavenging activity was found to be high in methanolic extract for DPPH and hydroxyl radicals in a concentration dependent manner followed by chloroform,aqueous,acetone and petroleum ether extracts.The metal chelating activity and reducing power ability was also found to be high in methanolic extract.The difference in scavenging potential of the extracts may be due to variation in the percentage of phytoconstituents extracted in various solvents.Thus the result suggests that the methanolic leaf extract of K.foetidissima could serve as a potential source of antioxidants and can be explored as a therapeutic agent in free radical induced diseases.©2015 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Physicochemical and radical scavenging activities of honey samples from Malaysia

The physical properties, total phenols, total flavonoid content and free radical scavenging activities of honey samples from Malaysia were investigated. The physical properties of Tualang, Gelam and Acacia honey samples, in terms of pH, color, moisture, electrical conductivity and total soluble solid were significantly different (p = 0.000). Gelam honey was reported to have the highest total phenols (606.17 mg GAE/kg honey) and flavonoid content (183.43 mg RE/kg honey). Tualang honey was reported to have the highest free radical scavenging activity with the IC50, 72.75 g/L compared to Gelam (77.41 g/L) and Acacia (90.83 g/L). There is no significant difference has been revealed among honey samples for radical scavenging activity (p = 0.827). Nevertheless, strong correlation was obtained between pH, color, electrical conductivity and total soluble solid with the scavenging activity of all honey samples with the correlative coefficient, r = 0.979, 0.902, 0.917 and 0.957, respectively. The establishment of the statistical correlation could be useful for honey related industry.

Evaluation of Hydroxyl Radical and Alkyl-oxy Radical Scavenging Activity of Coffee by ESR Spin Trapping Method

We evaluated the hydroxyl and alkyl-oxy radical scavenging activity of instant coffee using an electron spin resonance （ESR） spin-trapping method, which was based the spin-trapping reagent 5-（2,2-dimethy-l,3-propoxycyclophosphoryl）-5-methyl-l-pyrroline N-oxide （CYPMPO）. In this method, very pure hydroxyl and alkyl-oxy radicals were generated by illuminating a phosphate buffer solution containing hydrogen peroxide and 2,2＇-azobis （2-amidinopropane） dihydrochloride with a Hg-Xe arc lamp. The ESR adduct signal was sensitive and very stable. We concluded that instant coffee has high hydroxyl radical and alkyl-oxy radical scavenging activity.

Evaluation of lipid peroxidation inhibition and free radical scavenging abilities of 5,6,7-trimethoxy dihydroflavonols

Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols （3-6） and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols （7-8） were designed and synthesized. Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2^＊- free radicals, as well as by measuring their inhibitory ability against LPO. Both the 2,3-trans and the 2,3- cis conformers exhibited certain quenching abilities to DPPH and O2^＊- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO.

Enhanced Free Radical Scavenging and Inhibition of DPP-4 and ACE Activities by Compounds from Salmon Tissues Digested in Vitro with Gastrointestinal Proteases

Research on marine bioactive peptides has mainly focused on characterization of peptides in hydrolysates prepared with commercial industrial enzymes and the usefulness of such hydrolysates in health and functional foods. However, a relevant question is whether digestion of fish proteins with gastrointestinal proteases per se generates peptides that also can have health promoting properties and can reduce, e.g., diabetes 2, inflammation and hypertension either in relation to gastrointestinal digestion or as alternative to industrial proteases. The aim of the study was to investigate hydrolysates obtained from in vitro sequential digestion of salmon muscle and skin with gastrointestinal proteases including pepsin, pancreatic and pancreatic ＋ mucosal proteases for their ability to scavenge ABTS^＋ radicals and inhibit activity of angiotensin I-converting enzyme （ACE） and dipeptidyl peptidase 4 （DPP-4）. Furthermore, it was the aim to study the inhibitory mechanism and stability towards ACE and DPP-4 activity. Analysis of〈 10 kDa hydrolysates showed that gastrointestinal proteases generated peptides with clear radical scavenging activity and DPP-4 and ACE inhibiting activity as well. Hydrolysates from pepsin digestion exhibited the lowest ECso values for radical scavenging activity and ACE inhibition, whereas ECso increased in hydrolysates after subsequent digestion with pancreatic and mucosal proteases. Interestingly, ECso values for the DPP-4 inhibition were hardly affected by sequential digestion. Inhibition modes for the muscle hydrolysates were both competitive and non-competitive, but prolonged incubation showed that the inhibitory properties were unstable and therefore they were probably digested as competitive substrates by gastrointestinal proteases.

Hypoglycemic activities of flowers of Xanthoceras sorbifolia and identification of anti-oxidant components by off-line UPLC-QTOF-MS/MS-free radical scavenging detection

Objective: To identify phytochemical constituents present in the extract of flowers of Xanthoceras sorbifolia and evaluate their anti-oxidant and anti-hyperglycemic capacities.Methods: The AlCl3colorimetric method and Prussian Blue assay were used to determine the contents of total flavonoids and total phenolic acids in extraction layers, and the bioactive layers was screened through anti-oxidative activity in vitro. The Waters ACQUITY UPLC system and a Waters ACQUITY UPLC BEH C18column(2.0 mm × 150 mm, 5 μm) were used to identify the ingredients. And anti-oxidative ingredients were screened by off-line UPLC-QTOF-MS/MS-free radical scavenging. The ameliorative role of it was further evaluated in a high-fat, streptozotocin-induced type 2 diabetic rat model and the study was carried out on NADPH oxidase(PDB ID: 2CDU) by molecular docking.Results: Combined with the results of activity screening in vitro, the anti-oxidative part was identified as the ethyl acetate layer. A total of 24 chemical constituents were identified by liquid chromatographymass spectrometry in the ethyl acetate layer and 13 main anti-oxidative active constituents were preliminarily screened out through off-line UPLC-QTOF-MS/MS-free radical scavenging. In vivo experiments showed that flowers of X. sorbifolia could significantly reduce the blood glucose level of diabetic mice and alleviate liver cell damage. Based on the results of docking analysis related to the identified phytocompounds and oxidase which involved in type 2 diabetes, quercetin 3-O-rutinoside, kaempferol-3-O-rhamnoside, isorhamnetin-3-O-glucoside, and isoquercitrin showed a better inhibitory profile.Conclusion: The ethyl acetate layer was rich in flavonoids and phenolic acids and had significant anti-oxidant activity, which could prevent hyperglycemia. This observed activity profile suggested X. sorbifolia flowers as a promising new source of tea to develop alternative natural anti-diabetic products with a high safety margin.

Extraction Storage and Qualitative Analysis of Free Radicals Scavenging Substances from Sweet Potato Leaves

[ Objective ] The research aimed to provide reference for the application of extracts from sweet potato leaves in anti-aging cosmetics. [ Method ] The extraction and storage conditions for free radicals scavenging substances from sweet potato leaves were optimized by orthogonal test and the bioactive components in extracts were investigated by correlation analysis. [ Result] Sweet potato leaves contain the bioactive substances scavenging DPPH free radical and hydroxyl free radical. Extracting solvent species is the most important factor that influencing extraction yield. The optimal extraction and storage conditions are as following： water as solvent, pH 8.0 of extracting liquid, storage at 25 ℃. There is a good positive linear relationship between the content of total phenols in sweet potato leaves and corresponding scavenging rates against both the DPPH free radical and hydroxyl free radical. For the content of total flavones in sweet potato leaves, just a correlation with scavenging rate against hydroxyl free radical shown in test. [ Conclusion] The phenols in ex- tracts could effectively scavenge both the DPPH free radical and hydroxyl free radical, whereas the flavones in extracts can only function on the hydroxyl free radical.

Free radical scavenging activity of Eagle tea and their flavonoids

In this study,an online HPLC-DAD-MS coupled with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)diammonium salt(A BTS)assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components.Twenty-three chromatographic peaks were detected,and nineteen components had free radical scavenging activity.Among them,eight compounds were identified as flavonoids(hyperin,isoquercitrin,quercitrin,quercetin,kaempferol),catechins,chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.

Studies on kinetics of reactions between phycobiliproteins and hydroxyl radicals by a pulse radiolytic technique

Scavenging of hydroxyl radical (·OH) by phycobiliproteins (C-phycocyanin, Allophyco- cyanin and R-phycoerythrin) was studied by competitive kinetics methods. Hydroxyl radicals were generated from pulse radiolysis of aqueous systems saturated with nitrous oxide (N2O). The experimental results indicated that the three types of phycobiliproteins are all strong scavengers of· OH, the rate constants are around (2.8-5.6)×109 L·2 mol1 · s 1.

SUPEROXIDE RADICAL SCAVENGING AND CYTOTOXIC EFFECTS OF DIFFERENT MARINE SPECIES FROM TURKEY'S COASTS

In this study,acetone extracts of thirteen different species distributed in Turkey Coasts including tunicates,sea anemones,sponges and corals were investigated for their superoxide(SO)radical scavenging and cytotoxic activities.VWhile SO radical scavenging activity was tested using alkaline DMSO method,cytotoxic activity was tested by MTT assay against Hep-2 cancer cell line.As a result of bioactivity studies,Paramuricea clavata extract showed

MOLECULAR UNDERSTANDING OF NATURAL POLYPHENOLS: FREE RADICAL SCAVENGING AND INTERACTION WITH BIOMEMBRANES

Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic parameters(mainly bond dissociation enthalpies(BDE)of the O-H phenolic bond)allowed an accurate prediction of the antioxidant capacities of