Free Radical Scavenging Activity Of Extracts Research Articles

Comparative Effects of Two Forms of Chitosan on Selected Phytochemical Properties of Plectranthus amboinicus (Lour.)

In response to stress factors, plants produce a wide range of biologically active substances, from a group of secondary metabolites, which are applied in medicine and health prophylaxis. Chitosan is a well-known elicitor affecting secondary metabolism in plants, but its effect on the phytochemical profile of Plectranthus amboinicus has not been assessed yet. In the present experiment, the effectiveness of the foliar application of two forms of chitosan (chitosan suspension or chitosan lactate) was compared in order to evaluate their potential to induce the accumulation of selected polyphenolic compounds in the aboveground parts of P. amboinicus. It was shown that chitosan lactate had substantially higher elicitation efficiency, as the use of this form exerted a beneficial effect on the analysed quality parameters of the raw material, especially the content of selected polyphenolic compounds (total content of polyphenols, flavonols, anthocyanins, and caffeic acid derivatives) and the free radical-scavenging activity of extracts from elicited plants. Concurrently, it had no phytotoxic effects. Hence, chitosan lactate-based elicitation can be an effective method for optimisation of the production of high-quality P. amboinicus raw material characterised by an increased concentration of health-promoting and antioxidant compounds.

Ascorbic Acid and Polyphenols Mediated Green Synthesis of Silver Nanoparticles from Tagetes erecta L. Aqueous Leaf Extract and Studied Their Antioxidant Properties

Silver nanoparticle synthesis of the leaf extract Tagetes erecta L. enriched with ascorbic acid and polyphenols has been investigated. The color of the golden yellow extract has changed to pinkish-brown due to the reduction of Ag+ to the colloidal solution of AgNPs and a sharp absorption peak at 420 nm under the UV-Vis spectrophotometer. In addition, the Fourier Transfer Infrared Spectroscopy (FTIR) estimation was completed in order to recognize and identify the biomolecules present in the extract acting as a reducing and capping agent for the AgNPs. The X-ray diffraction (XRD) peaks at (111), (201), (220), and (311) confirm the presence of monoclinic crystals in the solution. The morphology and size of the particles were provided by transmission electron microscopy (TEM) images of AgNPs. At a scale of 100 nm, synthesized AgNPs were predominantly spherical with a size range of 7-35 nm. In comparison to 7.39 mg/100 g in AgNPs, aqueous leaf extract was 55.14 mg/100 g higher in ascorbic acid. The phenolic and flavonoid content of extract was 52.54 ± 2.15 mg (GAE/100 g) and 15.43 ± 0.34 mg (QE/mL), and the colloidal AgNP solution was 21.45 ± 1.15 mg (GAE/100 g) and 8.05 ± 2.42 mg (QE/mL), respectively. Phenolic and flavonoid contents play a major role as a reducing agent and reduce the precursor AgNO3 into AgNPs. The DPPH scavenging assay also assessed the antioxidant properties of extract and its derived AgNPs. As compared antioxidant value to aqueous leaf extract (mg/mL), higher percentage inhibition (PI) was found in AgNPs and free-radical scavenging activity of extract and AgNPs were directly linked to their concentrations. Results of this research have discovered a higher potential for free-radical scavenging AgNPs and will help to develop new and more potent antioxidants for the treatment of different diseases caused by oxidative stress; the higher antioxidant properties bearing AgNPs might be used.

Chemometric Profile of Calotropis gigantea and its Antioxidant Activity through Bioactive Compounds from Latex, Leaves and Flower Extracts

In present study, antioxidant effect was compared among latex, leaf and flower extract of Calotropis gigantea and is first report on comparing the chemometric profiling of various parts of C. gigantea. Ethanol and chloroform extracts of C. gigantea revealed the presence of 28 different chemotypes in latex, 27 in leaves and 32 in flowers. Major phtyochemicals present were of which fatty acid ethyl esters, fatty alcohols, terpenes, coumarins and carbocycles. C. gigantea leaf extract recorded 78% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and IC50 values of 14.44, 6.74 and 21.35 μg/mL were observed for latex, leaves and flower extracts respectively. For 2,2′-azinobis-(3- ethylbenzthiazolin-6-sulfonic acid) [ABTS+] assay, IC50 values ranged between 6.74 and 21.25 μg/mL by various components of C. gigantea. The results represent free radical-scavenging activities of extracts of several parts of C. gigantea. The findings will definitely use in new directions in pharmacological and therapeutic investigations on C. gigantea latex, leaves and flowers.

Effect of Extraction and Fractionation on Antioxidant Activity of Extract and Fraction Crescentia Cujete L Leaves

Antioxidant compunds like phenols and flavonoids scavenge free radicals and thus inhibit the oxidative mechanisms that lead to control degenerative and other diseases. The aim of this study was to investigate the antioxidant activity in extracts and fractions of Crescentia cujete leaves. 1,1-difenil-2-pikrilhidrazil (DPPH) assay was performed to measure the free-radical scavenging activity of extracts. The results of the study show that leaves of C. cujete possesses significant free radical scavenging properties. All the ethanol extract, etyl acetat extract and fractions exhibited antioxidant activities, however, ethanol fractions of leaves showing the highest antioxidant activity based on the results of DPPH tests.

Evaluation of Total Polyphenol Content, Antioxidant Activity and Chemical Composition of Methanolic Extract from Allium Kharputense Freyn et. Sint. and Determination of Mineral and Trace Elements

Allium kharputense Freyn Et. Sint. ( A. kharputense ) was analyzed for total polyphenol content, antioxidant activity, chemical composition and mineral and trace element composition. Total polyphenol content was determined as 257 mg GA 100 g -1 dried weight by using Folin-Ciocalteu method. DPPH test was performed for antioxidant activity analysis. IC 50 values of gallic acid and Trolox were determined as 0.02642 mg mL -1 and 0.225 mg mL -1 , respectively. IC 50 value of A. kharputense was found as 2.186 mg mL -1 . DPPH free radical-scavenging activity of extract from 1 mg of A. kharputense was determined 0.01207 mg GAE and 0.1029 mg TrE, respectively. GC-MS was used to determine chemical composition. Dimethyl trisulfide, methyl (methylthio)methyl disulfide, 2-Pyrrolidinone, 4-vinylphenol, 2-Phenylpyrrole , norharmane , linoleic acid, palmitic acid, γ-Tocopherol and α-Tocopherol are some of 40 compounds which were detected in methanolic extracts of A. Kharputense. 20 Mineral and trace elements were determined along with their levels by ICP-MS using microwave digestion procedure for preparing acid extracts.

Radical scavenging and antimicrobial activity of essential oil and extracts of Echinophora sibthorpiana Guss. from Macedonia

This study was undertaken to determine the antioxidant and antimicrobial effect of essential oil and extracts of Echinophora sibthorpiana Guss. (fam. Apiaceae) collected in Macedonia. The chemical composition of E. sibthorpiana essential oil was characterized by the presence of methyl eugenol (60.40%), p-cymene (11.18%) and ?-phellandrene (10.23%). The free radical scavenging activity of extracts and essential oil was evaluated by DPPH and ABTS assays. The aqueous extract of aerial parts exhibited the strongest scavenging activity (IC50=1.67 mg/ml); results of the ABTS test showed that the most effective was the ethanol extract of aerial parts (1.11 mg vit. C/g). The essential oil showed stronger antioxidant activity compared to hydroxyanisole, ascorbic acid and quercetin that were used in the DPPH and ABTS tests, respectively. The total phenolic and flavonoid concentrations in the extracts ranged between 38.65-60.72 mg GA/g, and 3.15-19.00 mg Qu/g, respectively. The antimicrobial properties of the extracts and essential oil were investigated using a micro-well dilution technique against human pathogenic strains. The results were comparable with the effects of the positive controls, streptomycin and fluconazole. These findings indicate that E. sibthorpiana extracts and oil can be used in preventive treatments and as an alternative for synthetic preservatives.

Assessment of free-radical scavenging activity of Gypsophila pilulifera: assay-guided isolation of verbascoside as the main active component

Gypsophila pilulifera, Boiss & Heldr, Caryophyllaceae, is a perennial medicinal herb that grows in the southwestern region of Turkey. Except for only one report on the isolation of cytotoxic saponins from the underground parts of G. pilulifera, there are no published thorough phytochemical or bioactivity studies on this species. In the present study, the free-radical scavenging activity of extracts and fractions of the stems of G. pilulifera was evaluated, using a slightly modified and more precise version of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, reported here for the first time. The DPPH assay-guided HPLC-PDA-purification of the active solid-phase extraction fraction (50% methanol in water) of the methanolic extract exhibited verbascoside as the main free-radical scavenger present in this species. The structure of this active compound was resolved by spectroscopy, and the free-radical scavenging potential of verbascoside was determined.

Extract of Ginkgo biloba is equivalent to vitamin E in attenuating and preventing vacuous chewing movements in a rat model of tardive dyskinesia

Free radical-mediated abnormalities may contribute toward the pathogenesis of tardive dyskinesia (TD). Many studies have reported the protective antioxidant and free radical-scavenging activities of extract of Ginkgo biloba (EGb761) against free radical-induced cell damage and dysfunction. This study aimed to compare the efficacy of EGb761 with that of vitamin E for the prevention and treatment of TD in a rat model. We carried out two studies. First, rats were injected with haloperidol (2 mg/kg intraperitoneally) daily for 5 weeks. EGb761 (50 mg/kg/day) or vitamin E (20 mg/kg/day) were then administered for another 5 weeks, and their effects on vacuous chewing movements (VCMs) were compared. Second, we compared 10 weeks of haloperidol alone with 10 weeks of haloperidol plus EGb761 or vitamin E. The administration of haloperidol led to a progressive increase in VCMs, which peaked at week 5. In study one, EGb761 and vitamin E, administered by an oral gavage for 5 weeks during withdrawal from chronic haloperidol treatment, decreased VCMs significantly, showing 83.8 and 91.0% reduction, respectively, compared with the haloperidol-alone group. In study two, the concomitant administration of EGb761 and vitamin E led to significantly fewer VCMs, by 64.4 and 73.9%, respectively, compared with the haloperidol-alone group. There was no significant difference in either study between EGb761 and vitamin E treatment. EGb761 shows promise for the prevention and treatment of TD in a rat model with a magnitude that was similar to that of vitamin E.

Evaluation of Antioxidant Activities of Aqueous Extracts and Fractionation of Different Parts of Elsholtzia ciliata

The aim of this study was to investigate the antioxidant and free-radical scavenging activity of extract and fractions from various parts of Elsholtzia ciliata. The inflorescences, leaves, stems and roots of E. ciliata were extracted separately and two phenolic component enrichment methods: ethyl acetate-water liquid-liquid extraction and macroporous resin adsorption-desorption, were adopted in this study. The antioxidant activities of water extracts and fractions of E. ciliata were examined using different assay model systems in vitro. The fraction root E (purified by HPD300 macroporous resin) exhibited the highest total phenolics content (497.2 ± 24.9 mg GAE/g), accompanied with the highest antioxidant activity against various antioxidant systems in vitro compared to other fractions. On the basis of the results obtained, E. ciliata extracts can be used potentially as a ready accessible and valuable bioactive source of natural antioxidants.

The antioxidant and free-radical scavenging activities of extract and fractions from corn silk (Zea mays L.) and related flavone glycosides

This study was designed to evaluate both the antioxidant and free-radical scavenging activities of extract and fractions from corn silk. N-butanol fraction (BF) demonstrated the highest total phenolic content (164.1±9.7μg GAE/g DCS) and total flavonoids content (69.4±5.1μg RE/g DCS), accompanied with the highest antioxidant activity compared to other fractions through all antioxidant assays. Two flavone glycosides showing potent antioxidant activity were isolated from BF and identified, by comparing spectral data (UV, FAB-MS and NMR) with literature values, to be isoorientin-2″-O-α-l-rhamnoside and 3′-methoxymaysin. The two isolated flavone glycosides, particularly isoorientin-2″-O-α-l-rhamnoside, demonstrated significant total antioxidant activity, DPPH radical scavenging activity, reducing power and iron-chelating capacity, with EC50 values of 14.24±1.49, 22.69±2.33, 6.58±1.07 and 30.25±3.05μg/ml, respectively. Results obtained indicated that corn silk extracts can be used potentially as a ready accessible and valuable bioactive source of natural antioxidants.

In vitro antioxidant activity of Juglans regia L. bark extract and its protective effect on cyclophosphamide-induced urotoxicity in mice

Walnut (Juglans regia L.) bark has been claimed to possess anti-inflammatory, blood purifying, anticancer, depurative, diuretic and laxative activities. It contains several therapeutically active constituents, especially polyphenols. We studied the antioxidant potential of aqueous extract of walnut bark and its modulatory effect on cyclophosphamide (CP)-induced urotoxicity in Swiss albino male mice. Free radical-scavenging activity of extract was assessed in four in vitro assays. The phenolic and flavonolic contents of the extract were also measured. Walnut bark extract treatment (150 mg/kg p.o. × 10 days) resulted in protective restoration of decreased antioxidants in CP-treated (18 mg/kg i.p. × 10 days) animals. CP treatment caused decreases in the activities of catalase (CAT), glutathione peroxidase (GP), glutathione reductase (GR) and glutathione S-transferase (GST) and in the glutathione (GSH) content in urinary bladder and a significant concomitant increase in lipid peroxidation (LPO). Administration of extract restored all the antioxidants significantly and lowered the elevated LPO in the bladder. A correlation between radical scavenging capacities of the extract with phenolic content was observed thus justifying its antioxidant potential against oxidative stress-mediated urotoxicity in mice. Walnut is reported to possess antiproliferative activity. Its protective effect on CP-induced toxicity in bladder is a promising activity, which warrants possible clinical investigations on this medicinal plant.

Anti-genotoxic and free-radical scavenging activities of extracts from (Tunisian) Myrtus communis

The effect of extracts from leaves of Myrtus communis on the SOS reponse induced by Aflatoxin B1 (AFB1) and Nifuroxazide was investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37. Aqueous extract, the total flavonoids oligomer fraction (TOF), hexane, chloroform, ethyl acetate and methanol extracts and essential oil obtained from M. communis significantly decreased the SOS response induced by AFB1 (10 μg/assay) and Nifuroxazide (20 μg/assay). Ethyl acetate and methanol extracts showed the strongest inhibition of the induction of the SOS response by the indirectly genotoxic AFB1. The methanol and aqueous extracts exhibited the highest level of protection towards the SOS-induced response by the directly genotoxic Nifuroxazide. In addition to anti-genotoxic activity, the aqueous extract, the TOF, and the ethyl acetate and methanol extracts showed an important free-radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These results suggest the future utilization of these extracts as additives in chemoprevention studies.

Free radical-scavenging activity of Aloe vera ( Aloe barbadensis Miller) extracts by supercritical carbon dioxide extraction

The free radical-scavenging activities of extracts of Aloe vera of leaf skin by supercritical CO 2 extraction and solvent extraction were determined. An orthogonal array design matrix of L 9 (3 4) was considered to optimize supercritical carbon dioxide extraction processing at a CO 2 flow rate of 12–36 l h −1, 35–45 MPa and 32–50 °C. The optimum extracted yield of 1.47% was provided at 50 °C 36 l h −1, 35 MPa and 20% of modifier of methanol. These four factors were all demonstrated to be significantly crucial in the supercritical carbon dioxide extraction operation, as two-variable interactions. The extracts of A. vera rind by supercritical carbon dioxide extraction and solvent extracts provided significantly higher free radical-scavenging activities of 33.5% and 39.7%, respectively, than extracts of A. vera gel extracted by ethanol with a free radical-scavenging activity of 14.2%. The inhibition percentage of extracts of A. vera and reference antioxidants followed the decreasing order: Trolox (76.8%) > ethanol extracts of A. vera skin (39.7%) > BHT (35.9%) > the extract of supercritical carbon dioxide extraction (33.5%) >α-tocopherol (25.6%) > ethanol extracts of A. vera pulp (14.2%). Compared to BHT and α-tocopherol, the extracts of A. vera skin, by supercritical carbon dioxide extraction and ethanol, showed stronger antioxidant activities. Components in the rind of A. vera are responsible for the higher antioxidant activity of A. vera extracts.