Peroxidation Of Linoleic Acid Emulsion Research Articles

Polyphenol Contents, Antioxidant and Antibacterial Activities of Aqueous Algerian Propolis Extracts

The propolis, an extremely complex resinous material, exhibits valuable pharmacological and biological properties, mainly attributed to the presence of polyphenols. The composition of propolis depends on time, vegetation, and the area of collection. Total flavonoid and polyphenol contents of aqueous extracts of propolis samples from different areas of Algeria, determined by using aluminum chloride and Folin–Ciocalteu colorimetric methods, were in the range of 3.047 ± 0.004–5.273 ± 0.013 mg/g and 96.833 ± 0.027–458.833 ± 0.0005 mg/g crude extract of propolis, respectively. This study examined the antioxidant and antimicrobial activities of propolis. Aqueous extracts of propolis were obtained in order to evaluate their antioxidant activities by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, β-carotene and electrochemical assays. All tested propolis samples had relatively strong antioxidant activities, which were also correlated with the total polyphenol and flavonoid content present. The percentage of inhibition of lipid peroxidation of linoleic acid emulsion during 24 h varied between 86.04 ± 0.42 and 90.60 ± 3.77% among the tested samples. The highest DPPH radical scavenging activity was observed by ABAL (Ain Abassa Aqueous Extract) with IC50 = 8.49 ± 5.07 10−5 μg/ml, and the lowest was observed by SAL (Setif Aqueous Extract) with IC50 of 21.16 ± 0.0001 μg/ml. The most important antibacterial activity was obtained with Ain Abassa extract; the zones of inhibition obtained for this excerpt vary from 15.22 to 15.5 mm. Followed by the Setif extract with areas of 12.33 to 12.75 mm, the Tizi-Ouzou extract with areas of 10.11 to 11.11 mm. This study will bring an innovation for further studies with regard to the antioxidant and antibacterial properties of the aqueous extracts of propolis. This study corroborates that Algerian propolis is a rich source of natural antioxidants, properties which could be used in the prevention of different diseases, both in humans and in animals.

Synthesis of Fe(III) Complexes as Antioxidants and DNA Cleavage Protectors

Synthesis of quinolines containing selenium and sulfur bioactive ligands and their Fe(III) complexes is described. Invitro antioxidant activity were evaluated against, 1,1-diphenyl-2-picryl-hydrazil (DPPH), hydrogen peroxide, superoxide anion radical, reducing power and hydroxyl radical (·HO). At different concentrations, (20-60 μg/mL) the total antioxidant activity of synthesized ligands showed 71, 75 and 83% and complexes showed 76, 85, 94% of inhibition. Where at the same concentration and experimental condition the standard antioxidant such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol exhibited 94, 95 and 63% inhibitions on peroxidation of linoleic acid emulsion. In support to antioxidants, DNA cleavage investigation of complexes leads to protective effect on DNA cleavage. Hence, this study confirms ligands and their Fe(III)-chelator as antioxidants as well as protect against DNA cleavage.

TOTAL PHENOLIC CONTENTS AND ANTIOXIDANT ACTIVITY OF SOME FRESH THAI CURRY

The objectives of this work were to study the total phenolic contents (TPC) and antioxidant activity of methanolic extracts of six fresh Thai curry. The TPC of the fresh Thai curry were found in the range of 0.989-1.1132 mg GAE/mg of extract. Among the curry, red curry present the highest amount of TPC. Antioxidant activity of the extracts was measured by DPPH-radical-scavenging assay, lipid peroxidation inhibition and metal ion chelating assay. The Thai red curry extract exhibited the highest inhibition of lipid peroxidation of linoleic acid emulsion (81.41±0.55%), radical-scavenging activity (IC50 = 0.0476 mg/mL). In addition, the fresh of Thai red curry had the highest of metal chelating activity (76.58±0.72%). However, all of fresh Thai curry showed metal chelating similar potential activity and not significant statistical differences. These results suggest that the fresh Thai curry had interesting antioxidant activities and should be propose as potential sources of safe natural antioxidants and preservatives for curry industry.

Acethylcholinesterase inhibitory potential and antioxidant properties of pyrogallol

Pyrogallol is found naturally in crops and fruits of many plants. It is also an active ingredient of many pharmaceuticals. For this reason, we employed different in vitro antioxidant assays such as cupric ion Cu2+ reducing power, Fe3+ reducing power, total antioxidant activity by ferric thiocyanate method, ABTS radical scavenging, DMPD radical scavenging, DPPH • scavenging, Fe2+ chelating, scavenging and H2O2 scavenging activities of pyrogallol. Pyrogallol inhibited 77.95% lipid peroxidation of linoleic acid emulsion at 30 μg/mL concentration. BHA, BHT, α-tocopherol and trolox exhibited inhibitions of 89.88, 89.97, 83.82 and 91.85% against peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, pyrogallol was an effective of all the scavenging and reducing power results. In this study, pyrogallol was also evaluated as potential inhibitor for acethycholinesterse enzyme. The results showed that pyrogallol exhibited potent acetylcholinesteras inhibitory activity with IC50 and Ki values 10.2 and 8.6 μM, respectively.

Antioxidant, antiradical, and anticholinergic properties of cynarin purified from the Illyrian thistle (Onopordum illyricum L.)

Cynarin is a derivative of hydroxycinnamic acid and it has biologically active functional groups constituent of some plants and food. We elucidated the antioxidant activity of cynarin by using different in vitro condition bioanalytical antioxidant assays like DMPD•+, ABTS•+, , DPPH• and H2O2 scavenging effects, the total antioxidant influence, reducing capabilities, Fe2+ chelating and anticholinergic activities. Cynarin demonstrated 87.72% inhibition of linoleic acid lipid peroxidation at 30 µg/mL concentration. Conversely, some standard antioxidants like trolox, α-tocopherol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) exhibited inhibitions of 90.32, 75.26, 97.61, 87.30%, and opponent peroxidation of linoleic acid emulsion at the identical concentration, seriatim. Also, cynarin exhibited effective DMPD•+, ABTS•+, , DPPH•, and H2O2 scavenging effects, reducing capabilities and Fe2+ chelating effects. On the contrary, IC50 and Ki parameters of cynarin for acetylcholinesterase enzyme inhibition were determined as 243.67 nM (r2: 0.9444) and 39.34 ± 13.88 nM, respectively. This study clearly showed that cynarin had marked antioxidant, anticholinergic, reducing ability, radical-scavenging, and metal-binding activities.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian asteraceae plants

ObjectiveTo study the antioxidant properties of crude extract of different Asteraceae plants. MethodsThe antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. ResultsPicris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. ConclusionsIn most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger.

Pistachio (Pistacia vera L.) Gum: a potent inhibitor of reactive oxygen species

In the present study, in order to evaluate antioxidant and radical scavenging properties of Pistachio gum (P-Gum), different bioanalytical methods such as DPPH• scavenging activity, DMPD•+ radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, reducing ability Fe3+–Fe2+ transformation, Cuprac and FRAP assays, scavenging by riboflavin-methionine-illuminate system and ferrous ions (Fe2+) chelating activities by 2,2′-bipyridyl reagent were performed separately. P-Gum inhibited 54.2% linoleic acid peroxidation at 10 µg/ml concentration. On the other hand, BHA, BHT, α-tocopherol and trolox, pure antioxidant compounds, indicated inhibition of 80.3%, 73.5%, 36.2% and 72.0% on peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, all of sample had an effective DPPH•, DMPD•+ and scavenging, Fe3+ reducing power by Fe3+–Fe2+ transformation and FRAP assay, Cu2+ reducing ability by Cuprac method and Fe2+ chelating activities.

Spectroscopic studies on the antioxidant activity of ellagic acid

Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTS+ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

Spectroscopic studies on the antioxidant activity of p-coumaric acid

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS+ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

Radical Scavenging and Antioxidant Capacity of Serotonin

Serotonin is a monoamine neurotransmitter and biochemically derived from tryptophan. The present paper examines the in vitro antioxidant and radical scavenging capacity of serotonin using different in vitro methodologies. For the determination of antioxidant activity of serotonin, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH-) scavenging, 2,2´- azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe3+-Fe2+ transformation method, superoxide anion radical scavenging by riboflavin-methionine-illuminate system, H2O2 scavenging and ferrous ions (Fe2+) chelating activities of serotonin were performed. Also, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox, a water-soluble analog of α-tocopherol, were used as the reference antioxidant radical scavenger compounds. Serotonin completely inhibited lipid peroxidation of a linoleic acid emulsion at 15 µg/mL concentration. On the other hand, the above mentioned standard antioxidants displayed inhibition of 92.2, 99.6, 84.6 and 95.6% on peroxidation of linoleic acid emulsion, respectively at the 45 µg/mL concentration. In addition, serotonin was effective in DPPH· scavenging, ABTS•+ radical scavenging, superoxide anion radical scavenging, H2O2 scavenging, ferric ions (Fe3+) reducing power and metal chelating on ferrous ions (Fe2+) activities. Also, those various antioxidant activities were compared to BHA, BHT α-tocopherol and trolox as references antioxidant compounds. Keywords: Serotonin, antioxidant activity, metal chelating, reducing power, radical scavenging.

Antioxidative and Melanogenesis‐Inhibitory Activities of Caffeoylquinic Acids and Other Compounds from Moxa

The MeOH extract of moxa, the processed leaves of Artemisia princeps PAMP. (Asteraceae), exhibited potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and melanogenesis-inhibitory activity in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 melanoma cells. Eight caffeoylquinic acids, 1 and 6-12, five flavonoids, 13-17, two benzoic acid derivatives, 18 and 19, three coumarin derivatives, 20-22, four steroids, 23-26, and six triterpenoids, 27-32, were isolated from the MeOH extract. Upon evaluation of compounds 1, 6-23, and four semisynthetic caffeoylquinic acid esters, 2-5, for their DPPH radical-scavenging activity, 15 compounds, 1-13, 17, and 19, showed potent activities (IC(50) 3.1-16.8 μM). The 15 compounds exhibited, moreover, potent inhibitory activities (51.1-92.5% inhibition) against peroxidation of linoleic acid emulsion at 10 μg/ml concentration. In addition, when 27 compounds, 1-8, 10, 12, 13, 15-18, 20-25, and 27-32, were evaluated for their inhibitory activity against melanogenesis in α-MSH-stimulated B16 melanoma cells, five caffeoylquinic acids, i.e., chlorogenic acid (1), ethyl chlorogenate (3), propyl chlorogenate (4), isopropyl chlorogenate (5), and butyl chlorogenate (6), along with homoorientin (17) and vanillic acid (18), exhibited inhibitory activities with 33-62% reduction of melanin content at 100 μM concentration with no or almost no toxicity to the cells (89-114% of cell viability at 100 μM). Western blot analysis showed that compound 6 reduced the protein levels of microphtalmia-associated transcription factor (MITF), tyrosinase, tyrosine-related protein 1 (TRP-1), and TRP-2 mostly in a concentration-dependent manner, suggesting that this compound inhibits melanogenesis on α-MSH-stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase, TRP-1, and TRP-2. Furthermore, four compounds, 13, 15, 16, and 30, exhibited cytotoxicities against HL60 human leukemia cell line (IC(50) 7.0-11.1 μM), and nine compounds, 14-16, 23, 26-28, 31, and 32, showed inhibitory effects (IC(50) 272-382 mol ratio/32 pmol 12-O-tetradecanoylphohrbol-13-acetate (TPA)) against Epstein-Barr virus early antigen (EBV-EA) activation induced by TPA in Raji cells.

Phytochemical investigation of Tunisian Salicornia herbacea L., antioxidant, antimicrobial and cytochrome P450 (CYPs) inhibitory activities of its methanol extract

The chemical composition of Salicornia herbacea L. a food plant belonging to Chenopodiaceae was investigated based on its mineral composition, proteins and carbohydrates contents. The phenolic composition analyzed by high performance liquid chromatography with diode array detection (HPLC-DAD) showed the presence of eight phenolic acids and eight flavonoids. The biological activities of the methanol extract were conducted on the antioxidant activity evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and β-carotene–linoleic acid bleaching test. The extract was an efficient radical scavenger (IC50 = 55.3 ± 2.7 μg/mL) and exhibited a moderate inhibition of lipid peroxidation of linoleic acid emulsion. Antibacterial activity determined by disc diffusion method against four Gram negative and two Gram positive bacteria, showed effects against all strains.Cytochrome P450s (CYPs) inhibitory activity studied for the first time was evaluated against three CYP isozymes namely CYP1A2, CYP3A4 and CYP2D6. The extract was a potent inhibitor against CYP2D6 (IC50 = 3.88 ± 0.02 μg/mL).

Total phenolic content, antioxidant and antibacterial activities of fruits of Eucalyptus globulus cultivated in Algeria

Crude extract from fruit of Eucalyptus globulus (E. globulus) was screened for its in vitro antioxidant and antibacterial properties. Antioxidant activity was measured by two methods, namely the reducing power and lipid peroxidation inhibition. Antibacterial activity was determined by using disc diffusion method against three bacteria (Staphylococcus aureus: ATCC 6538, Bacillus subtilis: ATCC 6633 and Klebsiella pneumoniae: E 47). The extract exhibited moderate inhibition of lipid peroxidation of linoleic acid emulsion (51.34±0.72%) and high reducing power (IC50=39.52μg/mL). It also exhibited strong antibacterial activity against B. subtilis and S. aureus with minimum inhibitory concentration (MIC) values of 30μg/mL and 80μg/mL, respectively. These results suggest that fruits of E. globulus have interesting antibacterial and antioxidant activities.

Evaluation of in-vitro Antioxidant Properties of Hydroalcoholic Solution Extracts Urtica dioica L., Malva neglecta Wallr. and Their Mixture.

The study was aimed at evaluating the antioxidant activity of hydroalcoholic solution extracts of Urtica dioica L. (UD), Malva neglecta Wallr. (MN) plants and their mixture. In this study, flower (UDF), root (UDR), seed (UDS) and leaf (UDL) parts of UD and flower (MNF) and leaf (MNL) parts of MN were used. The antioxidant properties of hydroalcoholic extracts and their mixture were evaluated using different antioxidant tests such as total antioxidant activity, reducing power, superoxide anion radical scavenging, hydrogen peroxide scavenging, free radical scavenging, and metal chelating activity for comparison. In addition, total phenolic compounds in the extracts of both plants were determined as catechin equivalent. The various antioxidant activities were compared to natural and synthetic standard antioxidants such as BHA, BHT and α-tocopherol. According to FTC method, the both extracts exhibited strong total antioxidant activity. At the concentration of 100 μg/mL, Hydroalcoholic extracts of UDS, UDR, UDF, UDL, MNF, MNL, and UD-MN showed 81.7%, 79.8%, 78.3%, 76.4%, 77.3%, 74.1%, and 80.7%, respectively. Comparable, 100 μg/mL of standard antioxidants BHA, BHT and α-tocopherol exhibited 66.2%, 70.6%, and 50.1% inhibition on peroxidation of linoleic acid emulsion, respectively. In addition, UD-MN showed strong superoxide anion radical scavenging activity comparable with UDR, UDF, UDL, MNF, and MNL. Based on the findings, plants mixture was commonly found to have synergistically higher antioxidant activity.

Radical scavenging and antioxidant activity of Hibiscus rosasinensis extract

Free radicals induce numerous diseases by lipid peroxidation, protein peroxidation and DNA damage. It has been reported that numerous plant extracts have antioxidant activities to scavenge free radicals. In the present study, the antioxidant properties of crude extract ofHibiscus rosasinensis were examined, using different in vitro analytical methodologies, such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS+ radical cation) radical cation scavenging activity and superoxide anion radical scavenging by riboflavin-methionine-illuminate system. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol were used as the reference antioxidant radical scavenger compounds. The crude extract inhibited 94.58% peroxidation of linoleic acid emulsion at 20 μg/ml concentration, while the standard antioxidants BHA, BHT and α-tocopherol indicated an inhibition of 93.75, 96.66 and 83.33% at 60 μg/ml concentration, respectively. The hydrogen peroxide radical, DPPH radical, ABTS+ radical cation(s) and superoxide anion radical scavenging activities of crude extract were also compared to BHA, BHT and α-tocopherol as references antioxidant compounds. The present study shows that the crude extract is an effective natural antioxidant component. Key words: Hibiscus rosasinensis, antioxidant activity, free radical scavenging activity.

Radical Scavenging and Antioxidant Activity of Carthamus tinctorius Extracts

ABSTRACT Free radicals induce numerous diseases by lipid peroxidation, protein peroxidation, and DNA damage. It has been reported that numerous plant extracts have antioxidant activities to scavenge free radicals. In the present study, we examines the in vitro radical scavenging and antioxidant capacity of Crude extract of Carthamus tinctorius by using different in vitro analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging by riboflavin–methionine-illuminate system. Also, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol were used as the reference antioxidant radical scavenger compounds. Extract inhibited 94.50% lipid peroxidation of linoleic acid emulsion at 20 μg/mL concentration. On the other hand, the above mentioned standard antioxidants indicated an inhibition of 93.75%, 96.66% and 83.33% on peroxidation of linoleic acid emulsion at 60 μg/mL concentration, respectively. In addition, hydrogen peroxide scavenging, DPPH scavenging, ABTS + radical scavenging and superoxide anion radical scavenging. Also, those various antioxidant activities were compared to BHA, BHT and α-tocopherol as references antioxidant compounds. The present study shows that Extract is the effective natural antioxidant component.

Caffeic acid phenethyl ester (CAPE): correlation of structure and antioxidant properties

Caffeic acid phenethyl ester (CAPE), a plant polyphenolic concentrated in honeybee propolis, has been found to be biologically active in a variety of pathways. The aim of this study was to determine the antioxidant activity of CAPE using different methods such as total antioxidant activity by the thiocyanate method, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid radicals, 1,1-diphenyl-2-picryl-hydrazyl free radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride radicals and superoxide anion radicals scavenging activities, reducing power and ferrous ions (Fe2+) chelating activities. CAPE showed 97.9% inhibition on lipid peroxidation of linoleic acid emulsion. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol and trolox indicated an inhibition of 87.3, 97.6, 75.3 and 90.3% on peroxidation in the same system, respectively.

In vitro antioxidant and radical scavenging of Guinean kinkeliba leaf (Combretum micranthum G. Don) extracts

The antioxidant properties of the water and ethanol leaf extracts of kinkeliba (Combretum micranthum) were investigated, including scavenging of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (IC50 values: 8.02 ± 0.34 for the ethanol extract [KE] and 9.1 ± 0.28 for the water extract [KW]), the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical (IC50 values: 7.4 ± 0.14 for KE and 11.8 ± 0.01 for KW) and the hydroxyl radical (58.1% for KE and 61.1% for KW). The ferric thiocyanate method, reducing power, metal chelating activity, an assay of protein oxidation and the β-carotene–linoleic bleaching assay were also used. Butylated hydroxytoluene and ascorbic acid were used as the reference antioxidant compounds. At 20 mg mL−1 concentration, KW and KE provided 36.8% and 75.1% inhibition of lipid peroxidation of linoleic acid emulsion, respectively. The IC50 values of the ethanol extract in ABTS and DPPH tests were significantly lower than those from the water extract. Furthermore, crude polyphenols were extracted from kinkeliba leaf with 90% ethanol solution using a water bath treatment and then purified by a macroporous resin, AB-8. The polyphenols from kinkeliba leaf were subjected to analyses by RP-HPLC and ESI-MS. The dominant polyphenols in kinkeliba leaf were identified as gallic acid, rutin trihydrate, (+)-catechin and benzoic acid.

Antioxidant activity of clove oil – A powerful antioxidant source

The number of methods to measure the antioxidants in botanicals, foods, nutraceuticals and other dietary supplements has increased considerably in the last decade. Clove oil is obtained by distillation of the flowers, stems and leaves of the clove tree. In the present paper, clove oil was evaluated by employing various in vitro antioxidant assay such as α,α-diphenyl-β-picryl-hydrazyl free radical (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe3+–Fe2+ transformation method, superoxide anion radical scavenging by riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe2+) chelating activities. Clove oil inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15μg/mL concentration. However, under the same conditions, the standard antioxidant compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox demonstrated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45μg/mL concentration, respectively. In addition, clove oil had an effective DPPH scavenging, ABTS+ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, these various antioxidant activities were compared to BHA, BHT, α-tocopherol and trolox as reference antioxidant compounds.

Antioxidant activities of methanolic extract of Sapium ellipticum

The stem bark extract of S. ellipticum (Hochst) Pax was investigated for its antioxidant properties in this study. The extract was evaluated for antioxidant activity in vitro in terms of its ability to inhibit lipid peroxidation and its free radical scavenging, reducing and metal chelation powers. The total amount of phenolic compounds in the extract was also determined in terms of gallic acid equivalent. The extract produced effective free radical scavenging and reducing activities in a dose dependent fashion. The extract exhibited noticeable inhibition of lipid peroxidation of linoleic acid emulsion. These activities were less than that of ascorbic acid and 2,6-Di-tert-butyl-4-methylphenol used as positive controls. The extract however demonstrated poor iron chelating ability compared to ethylene diamine tetraacetic acid. The total phenolic content of the extract was 50.61 +/- 0.08 mg g(-1) in terms of gallic acid. This study showed that the stem bark extract of S. ellipticum exhibits significant antioxidant activity and is a good source of natural antioxidants.