ABTS Radical Cation Research Articles

Laccase/Mediator Systems: Their Reactivity toward Phenolic Lignin Structures.

Laccase-mediator systems (LMS) have been widely studied for their capacity to oxidize the nonphenolic subunits of lignin (70–90% of the polymer). The phenolic subunits (10–30% of the polymer), which can also be oxidized without mediators, have received considerably less attention. Consequently, it remains unclear to what extent the presence of a mediator influences the reactions of the phenolic subunits of lignin. To get more insight in this, UHPLC-MS was used to study the reactions of a phenolic lignin dimer (GBG), initiated by a laccase from Trametes versicolor, alone or in combination with the mediators HBT and ABTS. The role of HBT was negligible, as its oxidation by laccase occurred slowly in comparison to that of GBG. Laccase and laccase/HBT oxidized GBG at a comparable rate, resulting in extensive polymerization of GBG. In contrast, laccase/ABTS converted GBG at a higher rate, as GBG was oxidized both directly by laccase but also by ABTS radical cations, which were rapidly formed by laccase. The laccase/ABTS system resulted in Cα oxidation of GBG and coupling of ABTS to GBG, rather than polymerization of GBG. Based on these results, we propose reaction pathways of phenolic lignin model compounds with laccase/HBT and laccase/ABTS.

Antioxidant and antibacterial evaluation of polysaccharides sequentially extracted from onion (Allium cepa L.)

We investigated the antioxidant and antimicrobial potential of sequentially extracted onion polysaccharide fractions namely HBSS, CHSS, DASS and CASS. The different antioxidant assays indicated that ACLPs exhibited potentially appreciable antioxidant activity in a dose-dependent manner. Among all the fractions, CHSS rendered the highest antioxidant action towards ABTS radical cations (97.52%), Fe2+ chelating (98.94%) and superoxide anion radical scavenging (76.27%). Whereas, HBSS possessed the highest potential for DPPH radicals (93.68%), hydroxyl radicals (65.12%) as well as for reducing power (0.559). CASS exhibited the highest lipid peroxidation inhibition (86.43%), while, DASS showed the best β-carotene bleaching inhibition (92.26%). Furthermore, regardless of the bacterial strain, DASS represented the strongest antibacterial activity on the basis of largest inhibition zone, the lowest minimal inhibitory concentration and maximum inhibition of bacterial growth in liquid medium. Overall results indicated that ACLPs hold a promise as potential natural antioxidant additives and antimicrobial agents for formulating the functional foods with potential applications in the medical and food industries.

Assessment of Antioxidant and Antibacterial Properties on Meat Homogenates of Essential Oils Obtained from Four Thymus Species Achieved from Organic Growth.

In the organic food industry, no chemical additives can be used to prevent microbial spoilage. As a consequence, the essential oils (EOs) obtained from organic aromatic herbs and spices are gaining interest for their potential as preservatives. The organic Thymus zygis, Thymus mastichina, Thymus capitatus and Thymus vulgaris EOs, which are common in Spain and widely used in the meat industry, could be used as antibacterial agents in food preservation. The aims of this study were to determine (i) the antibacterial activity using, as culture medium, extracts from meat homogenates (minced beef, cooked ham or dry-cured sausage); and (ii) the antioxidant properties of organic EOs obtained from T. zygis, T. mastichina, T. capitatus and T. vulgaris. The antioxidant activity was determined using different methodologies, such as Ferrous ion-chelating ability assay, Ferric reducing antioxidant power, ABTS radical cation (ABTS•+) scavenging activity assay and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method; while the antibacterial activity was determined against 10 bacteria using the agar diffusion method in different meat model media. All EOs analyzed, at all concentrations, showed antioxidant activity. T. capitatus and T. zygis EOs were the most active. The IC50 values, for DPPH, ABTS and FIC assays were 0.60, 1.41 and 4.44 mg/mL, respectively, for T. capitatus whilst for T. zygis were 0.90, 2.07 and 4.95 mg/mL, respectively. Regarding antibacterial activity, T. zygis and T. capitatus EOs, in all culture media, had the highest inhibition halos against all tested bacteria. In general terms, the antibacterial activity of all EOs assayed was higher in the medium made with minced beef than with the medium elaborated with cooked ham or dry-cured sausage.

Synthesis of Bioactive Chlorogenic Acid-Silica Hybrid Materials via the Sol-Gel Route and Evaluation of Their Biocompatibility.

Natural phenol compounds are gaining a great deal of attention because of their potential use as prophylactic and therapeutic agents in many diseases, as well as in applied science for their preventing role in oxidation deterioration. With the aim to synthetize new phenol-based materials, the sol–gel method was used to embed different content of the phenolic antioxidant chlorogenic acid (CGA) within silica matrices to obtain organic-inorganic hybrid materials. Fourier transform infrared (FTIR) measurements were used to characterize the prepared materials. The new materials were screened for their bioactivity and antioxidant potential. To this latter purpose, direct DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) methods were applied: radical scavenging capability appeared strongly dependent on the phenol amount in investigated hybrids, and became pronounced, mainly toward the ABTS radical cation, when materials with CGA content equal to 15 wt% and 20 wt% were analyzed. The in vitro biocompatibility of the synthetized materials was estimated by using the MTT assay towards fibroblast NIH 3T3 cells, human keratinocyte HaCaT cells, and the neuroblastoma SH-SY5Y cell line. As cell viability and morphology of tested cell lines seemed to be unaffected by new materials, the attenuated total reflectance (ATR)-FTIR method was applied to deeply measure the effects of the hybrids in the three different cell lines.

Phenolic acids and flavonoids of peanut by-products: Antioxidant capacity and antimicrobial effects

Peanut skin (PS) and meal from dry-blanched peanuts (MDBP) were evaluated as sources of phenolic compounds. PS rendered the highest total phenolic content, antioxidant capacity towards ABTS radical cation, DPPH and hydroxyl radicals as well as reducing power. Phenolic acids were present in PS and MDBP whereas proanthocyanidins and monomeric flavonoids were found only in PS as identified by HPLC-DAD-ESI-MSn. Procyanidin-rich extracts prevented oxidation in non-irradiated and gamma-irradiated fish model system. Both extracts inhibited the growth of gram-positive (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Geobacillus stearothermophilus) and gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli). Regardless of the strain, phenolic acid-rich extracts showed the lowest minimum inhibitory capacity (MIC); therefore presenting higher antibacterial effect. The MIC of phenolic acid-rich extracts (24–49μgphenolics/mL) was higher but comparable to Ampicillin (10μg/mL). Thus, phenolics in PS and MDBP may serve as antioxidants and antimicrobial compounds.

Investigations on Antioxidant, Antiproliferative and COX-2 Inhibitory Potential of Alkaloids from Anthocephalus cadamba (Roxb.) Miq. Leaves.

In the present study, an ayurvedic medicinal plant, Anthocephalus cadamba (Roxb.) Miq. commonly known as 'Kadamb' was explored for its potential against oxidative stress and cancer. The fractions namely AC-4 and ACALK (alkaloid rich fraction) were isolated from A.cadamba leaves by employing two different isolation methods and evaluated for their invitro antioxidant and antiproliferative activity. The structure of the isolated AC-4 was characterized tentatively as dihydrocadambine by using various spectroscopic techniques such as ESI-QTOF-MS, 1 H- and 13 C-NMR, DEPT, COSY, HMQC, and HMBC. Results of various antioxidant assays viz. 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS cation radical, superoxide anion radical scavenging, and plasmid nicking assay demonstrated that both the fractions viz. AC-4 and ACALK possess ability to scavenge DPPH, ABTS radicals and effectively protected plasmid pBR322 DNA from damage caused by hydroxyl radicals. Further, when both fractions were evaluated for their potential to suppress growth of HeLa and COLO 205 cells, only ACALK fraction showed antiproliferative effects. ACALK exhibited GI50 of 205.98 and 99.54μg/ml in HeLa and COLO 205 cell lines, respectively. Results of Hoechst staining in cervical carcinoma (HeLa) cells confirmed that ACALK induced cell death in HeLa cells via apoptotic mode. Both the fractions also inhibited COX-2 enzyme activity.

Construction of a Cordyceps sinensis exopolysaccharide-conjugated selenium nanoparticles and enhancement of their antioxidant activities

A Cordyceps sinensis exopolysaccharide (EPS)-conjugated selenium nanoparticles (SeNPs) were successfully constructed through the reduction of SeO32−. The EPS-SeNPs were characterized in terms of formation, morphology, size, Se distribution and phase by UV–vis, FT-IR, transmission electron microscopy (TEM), dynamic light scattering (DLS), energy dispersive X-ray (EDX) and wide angle X-ray diffraction (WAXD) measurements. Results revealed that the SeNPs conjugated to EPS were amorphous and could be well dispersed at a size range of 80–125nm. The interactions between the OH groups of EPS and SeNPs substituted for intermolecular interaction in native EPS to form new CO⋯Se bonds, resulting in good dispersion of SeNPs in the EPS matrix. Besides, the EPS-SeNPs at different Se/P ratios exhibited significant scavenging ability on superoxide anion radical (O2−) and ABTS radical cation (ABTS+) when compared to pure EPS, indicating that the conjugated SeNPs reinforced antioxidant effect of EPS. This work not only provides a simple and efficient way to construct well-dispersed SeNPs in aqueous system, and demonstrates the vital role of the EPS as a biopolymer template for dispersion, stabilization and size control of SeNPs, but also finds the EPS-SeNPs can potentially serve as a good antioxidant towards O2− and ABTS+.

Structure-Antioxidative and Anti-Inflammatory Activity Relationships of Purpurin and Related Anthraquinones in Chemical and Cell Assays.

Anthraquinone (9,10-anthraquinone) and several hydroxy derivatives, including purpurin (1,2,4-trihydroxyanthraquinone), anthrarufin (1,5-dihydroxyanthraquinone), and chrysazin (1,8-dihydroxyanthraquinone), were evaluated for antioxidative and anti-inflammatory activities in chemical assays and mammalian cells (murine macrophage RAW 264.7 cells). Several tests were used to assess their activities: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical; ABTS radical cation; hydrogen peroxide scavenging; reduction of potassium ferricyanide; chelation of ferrous ions; inhibition of lipid peroxidation; inhibition of nitric oxide generation; scavenging of the intracellular hydroxyl radical; expression of NLRP3 polypeptide for inflammasome assembly; and quantitation of proinflammatory cytokine interleukin 1β (IL-1β) for inflammasome activation. The results show that purpurin, from the root of the madder plant (Rubia tinctorum L.), exhibited the highest antioxidative activity in both chemical and cultured cell antioxidant assays. The antioxidative activities of the other three anthraquinones were lower than that of purpurin. In addition, purpurin could down-regulate NLRP3 inflammasome assembly and activation, suggesting that it might protect foods against oxidative damage and prevent in vivo oxidative stress and inflammation. Structure-activity relationships and the significance of the results for food quality and human health are discussed.

Chemical composition and inhibitory effects of water extract of Henna leaves on reactive oxygen species, DNA scission and proliferation of cancer cells.

From the centuries, Lawsonia inermis L. (Henna) is utilized in traditional health care system as a medicinal and cosmetic agent. The present study was intended to assess antiradical, DNA protective and antiproliferative activity of water extract of Lawsonia inermis L. leaves (W-LI). Antioxidant activity was estimated using various in vitro assays such as DPPH, ABTS, superoxide anion radical scavenging, FRAP, deoxyribose degradation and DNA protection assay. Growth inhibitory effects of W-LI were assessed using MTT assay against different cancer cell lines viz. HeLa, MCF-7, A549, C6 and COLO-205. From the results of antioxidant assays, it was found that W-LI quenched DPPH and ABTS cation radicals with IC50 value of 352.77 µg/ml and 380.87 µg/ml respectively. It demonstrated hydroxyl radical scavenging potential of 59.75 % at highest test dose of 1000 µg/ml in deoxyribose degradation assay. The results of FRAP assay showed that W-LI also possesses significant reducing activity. Extract inhibited hydroxyl radical induced pBR322 plasmid DNA strand scission, thus conferring DNA protection. Growth inhibition of various cancer cell lines was achieved to the varying extent on treatment with W-LI. Further, it was observed that activity was quite promising against colon cancer COLO-205 cells (GI50 121.03 µg/ml). HPLC profiling of W-LI revealed the presence of different polyphenolic compounds such as ellagic acid, catechin, quercetin, kaempferol etc. which might be contributing towards antioxidant and cytotoxic activity. The present study demonstrated that polyphenols rich W-LI extract from leaves of L. inermis possesses ability to inhibit oxidative radicals and cancer cells proliferation.

A comparative evaluation: phytochemical composition and antioxidant capacity of three roselle (Hibiscus sabdariffaL.) accessions

An increased consumption and demand in international trade suggests a need for quality assurance of roselle (Hibiscus sabdariffa) products. A liquid chromatography-mass spectrometry method was developed for the determination of anthocyanin profiles of the calyces, phenolic acids and flavonoids of the leaves of Jamaica, Senegal and Malaysia accessions. Delphinidin-sambubioside, delphinidin-glucoside, cyanidin-sambubioside, cyanidin-glucoside and delphinidin were identified from the calyces of these accessions. Chlorogenic acid and its isomers, glycosylated derivatives of quercetin and kaempferol, and 5-(hydroxymethyl) furfural were identified from the leaves of these accessions. No significant differences in anthocyanins among accessions were found, except the accession from Malaysia, which contained significantly (P<0.05) higher amounts of delphinidin-glucoside and delphinidin. The total phenols determined by Folin-Ciocalteu's assay were 15.92+1.12, 17.63+0.7, and 19.25+1.10 mg g-1 for the calyces of Jamaica, Malaysia and Senegal, respectively, and 23.76+2.16, 22.28+1.77 and 20.62+1.61 mg g-1 for the leaves of Malaysia, Senegal and Jamaica, respectively, calculated as gallic acid equivalents. The Senegal accession contained a higher (P<0.05) amount of total phenols in calyces than the Jamaica accession. The antioxidant activities determined by the ABTS radical cation decolorization assay were 64.38+1.56, 60.36+3.34 and 62.49+2.69 mg g-1 for the calyces and 111.43+7.17, 121.84+12.55 and 110.68+10.27 mg g-1 for the leaves of Malaysia, Senegal and Jamaica, respectively, as Trolox equivalents. Macro- and micro-nutrient elements varied significantly (P<0.05) among accessions. This study reveals variability in phenolic, antioxidant and elemental nutrient contents and suggests that the selection of roselle accessions can influence the quality of developed products.

Evaluation of Antioxidant Activity of Aqueous and Ethanolic Extracts of Stem Bark of Xylopia villosa Chipp (Annonaceae)

This study aims to evaluate antioxidant activity of aqueous and ethanolic extracts of Xylopia villosa stem bark. The quantitative study of polyphenols showed that ethanolic extract (75.00 ± 3.82 g/L EqAG) contains more than the aqueous extract (55.83 ± 1.67 g/L EqAG). It is the same for the quantitative analysis of total flavonoids where ethanolic extract (135.00 ± 1.44 g/L EqQ) contains more than the aqueous extract (115.00 ± 6.61 g/L EqQ). The antioxidant activity in vitro showed that the extracts neutralize DPPH and ABTS + ° with enhanced activity of the ethanolic extract. The ethanolic and aqueous extracts of Xylopia villosa causing 50% inhibition (IC50) of the DPPH radical gave concentrations of 10.50 ± 0.24 and 24.50 ± 0.18 mcg / ml respectively for ethanol extract and aqueous extract. On the reduction of radical ABTS + °, aqueous extract caused a reduction of the radical cation ABTS + 7.82 ± 0.17 micromol TE / L while the ethanol extract reduced by 10.52 ± 0.27 micromol TE / L. Evaluation of antioxidant activity in vivo of xylopia villosa revealed that this is the ethanol extract (9.17 ± 0.48 mmol / L TBA-MDA) which offset the concentration of TBA-MDA adduct more than the aqueous extract (22.67 ± 0.33 mmol / L TBA-MDA). Concerning the total antioxidant activity, ethanolic extract reduced iron III to Iron II more than aqueous extract. After this study, it appears that the ethanolic extract has better antioxidant activity in vitro and in vivo that the aqueous extract.

Potential anthelmintic effect of Capparis spinosa (Capparidaceae) as related to its polyphenolic content and antioxidant activity

Capparis spinosa is cultivated for several proprieties and the different parts of the plant (flower buds, fruits, leaf and seeds) have been employed in drugs, foods and cosmetics. This study aimed to explore the antioxidant potential effect and to assess the anthelmintic efficacy of an aqueous extract of Capparis spinosa. In vitro antioxidant activity of aqueous extracts from the fresh leaves and flower buds of C. spinosa was measured by determining free radical-scavenging activity against DPPH and ABTS radical cations. In vitro anthelmintic activities against eggs and adult worms of Haemonchus contortus from sheep were investigated in comparison to albendazole. DPPH and ABTS activities of both aqueous extracts increased in a dose dependent manner. The IC50 values of aqueous extracts from fresh leaves, flowers buds and ascorbic acid in the DPPH radical scavenging assay were 101.40; 70.40 and 57.56 μg/ml, respectively. The IC50 values of aqueous extracts fresh leaves, flowers buds and ascorbic acid in the ABTS radical scavenging assay were 110; 87.89 and 58.17 μg/ml, respectively. Both plant extracts showed ovicidal activity at all tested concentrations. The aqueous extract from flower buds (IC50 = 2.76 mg/ml) showed higher inhibitory effects (P < 0.05) than aqueous extract from leaves (IC50 = 8.54 mg/ml) in the egg hatching assay. The aqueous extract from flower buds inhibited more worms than the aqueous extract from leaves at all tested concentrations. After 6 h of exposure, the highest tested concentrations of aqueous extracts from flower buds and leaves induced 100 and 41.66% inhibition of motility, respectively. These results show for the first time that C. spinosa possesses in vitro anthelmintic properties which may be related to its high content of phenolic compounds such as flavonoids and tannins.

Microwave-assisted synthesis of new sulfonyl hydrazones, screening of biological activities and investigation of structure–activity relationship

Sulfonyl hydrazone scaffold and the piperidine rings have important role in medicinal chemistry. This study shows the synthesis of two novel series of sulfonyl hydrazone having piperidine derivatives by condensing benzene sulfonyl hydrazides with ethyl 4-oxopiperidine-1-carboxylate and 2,6-diphenylpiperidin-4-one. Physical and chemical properties of compounds have been characterized and reported by utilizing their melting point, elemental analysis, IR, 1H-NMR, 13C NMR, 2D NMR and mass spectra results. Synthesized compounds were evaluated for antioxidant capacity and anticholinesterase activity. The antioxidant capacity of the compounds were screened through four complementary test, i.e., β-carotene–linoleic acid for lipid peroxidation, DPPH free radical (DPPH·), ABTS cation radical (ABTS+·) and CUPRAC assays. Assay results showed that N′-(2,6-diphenylpiperidin-4-ylidene)-4-bromobenzenesulfonohydrazide (11) has the highest lipid peroxidation inhibitory activity. Within the assay series, N′-(2,6-diphenylpiperidin-4-ylidene)-4-bromobenzenesulfonohydrazide (11) exhibited better activity than standard BHT in DPPH· scavenging, while N′-(2,6-diphenylpiperidin-4-ylidene)benzenesulfonohydrazide (10) showed the best ABTS+· scavenging assay. The CUPRAC assay revealed that ethyl 4-(2-(4-methoxyphenylsulfonyl)hydrazono)piperidine-1-carboxylate (5) indicated the best activity with A 0.50 value among the tested compounds than the antioxidant standard α-tocopherol. According to AChE assay, N′-(2,6-diphenylpiperidin-4-ylidene)-4-chlorobenzenesulfonohydrazide (12) had the best activity, while in BChE assay the highest activity was found for compound N′-(2,6-diphenylpiperidin-4-ylidene)-4-methylbenzenesulfonohydrazide (16). Electronic and structural characteristics and density functional studies of the all newly synthesized compounds have been reported for better understanding in molecular-level. NMR, molecular electrostatic potential (MEP), ΔE HOMO–LUMO band gap and the dipole moments of the molecules have been also analyzed and reported.

Phytochemical analysis, antioxidant, antimicrobial, anticholinesterase and DNA protective effects of Hypericum capitatum var. capitatum extracts

This is the first study on phytochemical analysis and biological evaluation of Hypericum capitatum Choisy var. capitatum (HCC) endemic to Turkey with exception of essential oil analysis. Hyperoside and isoquercetin (25.7±0.02 and 17.8±0.02μg/mg extract, respectively) were determined as the main compounds of the methanol extract. The major compounds of essential oil of HCC were found to be spathulenol and iso-longifolene (12.9% and 11.2%, respectively), and linoleic and palmitic acids (26.8% and 18.3%, respectively) were the main fatty acids. The methanol extract whose antioxidant activities studied for the first time was found to have moderate activity in β-carotene bleaching method (IC50:41.69±1.29μg/mL) and was found to be the most active extract in scavenging of DPPH free radical (IC50:16.82±0.58μg/mL) and ABTS cation radical (IC50:9.24±0.28μg/mL) and CUPRAC assays. Among the prepared four extracts of HCC, the methanol extract showed highest activity against Escherichia coli with an MIC value of 10μg/mL, and the methanol extract was also found to have high DNA damage protective activity. The methanol extract exhibited high butyrylcholinesterase inhibitory activity (70.74%). Thus, H. capitatum var. capitatum can be regarded as a potential natural antioxidant, antimicrobial, anticholinesterase source and DNA damage inhibitor.

ANTIOXIDANT CAPACITY AND TOTAL PHENOL CONTENT OF HYPTIS SPP., P. HEPTAPHYLLUM, T. PANAMENSIS, T. RHOIFOLIA, AND OCOTEA SP.

&lt;p&gt;In this work, the possible correlation between the antioxidant activities and the Total Phenolic Content (TPC) and chemical composition of Lamiaceae (&lt;em&gt;H. conferta, H. dilatata, H. mutabilis, H. suaveolens&lt;/em&gt;), Burseraceae (&lt;em&gt;P. heptaphyllum, T. rhoifoila, T. panamensis&lt;/em&gt;),&lt;em&gt; &lt;/em&gt;and Lauraceae (&lt;em&gt;Ocotea &lt;/em&gt;sp.) were evaluated. The Trolox Equivalent Antioxidant Capacity or the Total Antioxidant Activity (TAA) was determined by using a colorimetric assay with the ABTS radical cation, Effective Concentration (EC&lt;sub&gt;50&lt;/sub&gt;) was evaluated with the DPPH radical, and the TPC was established by the Folin-Ciocalteu method, for ethanolic extracts obtained by cold maceration and evaporation to dryness. Both the TAA and the EC&lt;sub&gt;50&lt;/sub&gt; were highly correlated with the TPC. The barks of &lt;em&gt;T. rhoifolia&lt;/em&gt; and&lt;em&gt; T. panamensis&lt;/em&gt; demonstrated the highest antioxidant capacities. The Burseraceae spp. exhibited the highest TPC, and the Lamiaceae (&lt;em&gt;Hyptis&lt;/em&gt; spp.) demonstrated the lowest TPC.&lt;/p&gt;

Abstract 173: A Novel Dual Function Molecule for the Treatment of Acute Ischemic Stroke

Rapid restoration of blood flow to ischemic brain is essential to prevent irreversible tissue injury and minimize neuronal function impairment after acute ischemic stroke. However, intracerebral hemorrhage, reperfusion injury and the oxidative stress provoked by returned blood supply remain the major concerns for the use of effective thrombolytic agent; such as, recombinant tissue plasminogen activator (rt-PA). DC009 is a novel small molecule designed to have both thrombolytic and free radical scavenging activities, which were characterized in various in vitro and in vivo models. The thrombolytic effect of DC009 was demonstrated in vitro using whole blood clot lysis assay and euglobulin clot lysis assay. In comparison to rt-PA (1mg/ml), DC009 (11.11 mg/ml) exerts comparable (p value = 0.40) in vitro thrombolytic activity to rt-PA. Further investigation showed that DC009 induced endogenous t-PA protein secretion from endothelial vesicles, and it enhanced endothelial t-PA mRNA expression through cAMP pathway. Ability of DC009 in ABTS radical cation scavenging (2, 2-azinobis-(3-ethylbenzthiazoline-6-sulfonate) was measured and found to be dose dependent with an EC50 of 49 μM. Using a focal cerebral ischemia induced by arterial thrombosis model in aged mice (12-15 months old), DC009 showed a steady thrombolytic action and superior safety profile compared to vessel recanalization induced by rt-PA. We further investigated DC009’s effect on normal hemostasis and maximal tolerable dose (MTD) level in rodents in order to assess its therapeutic potential. At their comparable pharmacological dose, the tail amputation bleeding assay in mice showed that DC009 (up to 30mg/kg) did not cause bleeding prolongation; vs. rt-PA (10mg/kg) prolonged the bleeding to &gt;10 folds of normal bleeding time. According to the MTD determined in preliminary toxicity dose range finding studies, greater 50 folds of safety margin was identified in both mouse and rat. In conclusion, DC009 appears to both thrombolytic and free radical scavenging with minimal risk of bleeding. As a safe and dual functional small molecule, it is a drug candidate of great potential for the treatment of ischemic stroke.

Synthesis and Antioxidant Activity of Some New Thiazolyl–Pyrazolone Derivatives

3‐Methyl‐1‐thiocarbamoyl‐2‐pyrazolin‐5‐one has been utilized as a core for the synthesis of some 1‐(thiazol‐2‐yl)‐pyrazolin‐5‐one derivatives through diazo‐coupling reaction and/or Knoevenagel condensation followed by heterocyclization with some α‐halogenated reagents such as bromoacetone, phenacyl bromide, and ethyl bromoacetate. Base prompted addition of the core compound to an equimolar amount of phenyl isothiocyanate furnished 3‐methyl‐4‐phenylthiocarbamoyl‐1‐thiocarbamoyl‐2‐pyrazolin‐5‐one which undergoes heterocyclization with α‐halogenated reagents at the more reactive phenylthiocarbamoyl moiety to afford the corresponding 4‐(thiazol‐2‐yl)‐1‐thiocarbamoyl‐2‐pyrazolin‐5‐ones. The new synthesized thiazolyl–pyrazolone compounds were evaluated for their potential antioxidant activity by using (ABTS Radical Cation Decolorization Assay).

Quinones and coumarins from Ajania salicifolia and their radical scavenging and cytotoxic activity

1,4-Naphthoquinone (1) and a new coumarin (3) were isolated from Ajania salicifolia, together with two known compounds (2, 4). The structures and stereochemistry of new compounds were elucidated using spectroscopic methods. Two compounds exhibited potent ABTS cation radical scavenging activities with IC50 values ranging 7.97–8.44 μM. Two quinones (1, 2) exhibited moderate cytotoxic activity against the human cancer cell lines (Hela, HepG2, and K562) with IC50 values of 11.24–35.15 μM in vitro. This is the first report of naphthoquinone in the genus Ajania.

Biological activity and phytochemistry of firethorn (Pyracantha coccinea M.J. Roemer)

The phytochemical composition, antioxidant and enzyme inhibitory activities of the ethanol and water extracts of Pyracantha coccinea were evaluated. Ethanol extract was found rich in phenolics, flavonoids, condensed tannins and saponins. Additionally, all the phytochemicals were found in higher amounts in ethanol extract except gallic, protocatechuic and trans-cinnamic acids. Ethanol extract had higher scavenging potential on DPPH radical, ABTS radical cation, superoxide anion and nitric oxide than the water extract. Ethanol extracts also exhibited higher activity in iron (III) to iron (II) reduction, cupric ion reducing, ferric reducing antioxidant power (FRAP) and phosphomolybdenum assays. On the other hand, activity of water extract was determined as 2.15 mg ethylenediaminetetraacetic acid equivalents (EDTAEs)/g fresh fruit in the chelating effect assay. Inhibitory activities of the extracts on acetylcholinesterase, butyrylcholinesterase, α-amylase, α-glucosidase and tyrosinase were also analysed. In parallel to its phytochemical composition, ethanol extract showed better inhibitory activity on all enzymes tested.

Antioxidant activity of ginger extract and identification of its active components

Abstract The object of presented study was the evaluation of antioxidant activity of extract from Zingiber officinale. A method for the preparation of the extract was chosen, which enabled to isolate mostly phenolic compounds. According to the measurements with Folin-Ciocalteu reagent, obtained extract comprised total polyphenols (181.41 mgGAE/g of extract) from which flavonoids contributed to 7.8 % (14.15 mgquercetin/g of extract). Nuclear magnetic resonance (NMR) analysis showed that the phenolic ketones were predominant in the extracts of whole phenolic compounds. According to results of two spectrophotometric methods (ABTS and DPPH test), ginger extract showed stronger ability to scavenge DPPH radical than ABTS cation radical.