Antioxidant Screening Research Articles

In vitro antioxidant activities and screening of phytochemicals from methanolic and ethyl acetate extracts of Calligonum comosum L’Her

Calligonum comosum L’Her (Family: Polygonaceae) are perennial shrub plants growing in the United Arab Emirates, and are being used in traditional medicinal system of UAE. The aim of the proposed study was to evaluate the phytochemicals and in vitro antioxidant activities of the aerial parts of C. comosum. Further, the plant extract was tested for the free radical scavenging activity such as 2, 2′-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS●+) radical decolorization, DPPH (2, 2-diphenyl, 2-picryl hydrazyl), hydroxyl and nitric oxide radical. The obtained results from phytochemical screening of the plant extracts showed the presence of flavonoid, tannin, carbohydrates, alkaloid, protein, steroids, terpenoids, saponin, phenols and phlobatannin. The plant leaves did not contain cardiacglycoside, anthraquinines and volatile oils. Furthermore, total phenolics content of C. comosum methanolic extract (CCME) and C. comosum Ethyl acetate extract (CCEAE) was 8.15, 4.53 mg/g of extract calculated as quercetin equivalent and the flavonoid was 2.13, 1.67 mg/g of extract calculated as gallic acid equivalent, respectively. The results exhibited a positive linear correlation between these phytochemicals and the free radical scavenging activities. Our findings provide evidence that the CCME and CCEAE posses a potential antioxidants and this justifies its use in folkloric medicines. Thus, a scientific validation of traditional knowledge been achieved in a preliminary level. The plant revealed promising antioxidant activity, and require further studies to throw light on their chemical composition.

GC-MS profile of antimicrobial and antioxidant fractions from Cordia rothii roots

Context: An ethnobotanical survey of Cordia rothii Roem. & Schult. (Boraginaceae) reveals it as a medicinal plant.Objective: Antimicrobial and antioxidant potential evaluation and identification of chemical constituents via GC-MS of C. rothii roots fractions. To the best of our knowledge, this is the first systematic investigation of the roots exploiting GC-MS.Materials and methods: Extraction and fractionation of C. rothii roots furnished various fractions using solvents of varying polarity, i.e., n-hexane, chloroform, ethyl acetate, acetone and methanol. In vitro antimicrobial and antioxidant screening was performed using disk diffusion and DPPH methods, respectively. MIC of active fractions was also determined using disk diffusion method. GC-MS was used to identify constituents which may be responsible for these activities.Results: Among various fractions from C. rothii roots, fraction KA-C showed strong antibacterial activity against 17 microorganisms tested, with MIC ranging from 250–31.25 μg/mL. Fractions KA-A, KM and KM-A exhibited significant antioxidant potential with EC50 46.875 μg/mL, while fractions KEA-PE, KM-PE and KM-M were good with EC50 93.750 μg/mL. Forty-five phytochemicals were identified in GC-MS studies including eight hydrocarbons, six free fatty acids, 11 fatty acids esters, two phenylpropanoids, four aromatics, four terpenoid quinones/hydroquinones, three triterpenes, four phytosterols, two hexose metabolites and a DNA base. Of these, 32 constituents have been reported for the first time from C. rothii, 24 from genus Cordia and 15 from Boraginaceae.Discussion and conclusion: Strong antibacterial and antioxidant potential of C. rothii roots may be due to the contribution of phytoconstituents identified through GC-MS studies.

Antioxidant Activity of Phenolic Compounds from Fava Bean Sprouts.

Fava beans are eaten all over the world and recently, marketing for their sprouts began in Japan. Fava bean sprouts contain more polyphenols and l-3,4-dihydroxyphenylalanine (l-DOPA) than the bean itself. Our antioxidant screening program has shown that fava bean sprouts also possess a higher antioxidant activity than other commercially available sprouts and mature beans. However, the individual constituents of fava bean sprouts are not entirely known. In the present study, we investigated the phenolic compounds of fava bean sprouts and their antioxidant activity. Air-dried fava bean sprouts were treated with 80% methanol and the extract was partitioned in water with chloroform and ethyl acetate. HPLC analysis had shown that the ethyl acetate-soluble parts contained phenolic compounds, separated by preparative HPLC to yield 5 compounds (1-5). Structural analysis using NMR and MS revealed that the compounds isolated were kaempferol glycosides. All isolated compounds had an α-rhamnose at the C-7 position with different sugars attached at the C-3 position. Compounds 1-5 had β-galactose, β-glucose, α-rhamnose, 6-acetyl-β-galactose and 6-acetyl-β-glucose, respectively, at the C-3 position. The amount of l-DOPA in fava bean sprouts was determined by the quantitative (1) H NMR technique. The l-DOPA content was 550.45 mg ± 11.34 /100 g of the raw sprouts. The antioxidant activities of compounds 2-5 and l-DOPA were evaluated using the 2,2-diphenyl-1-picrylhydrazyl scavenging assay. l-DOPA showed high antioxidant activity, but the isolated kaempferol glycosides showed weak activity. Therefore, it can be suggested that l-DOPA contributed to the antioxidant activity of fava bean sprouts.

In vitro photosafety and efficacy screening of apigenin, chrysin and beta-carotene for UVA and VIS protection

Currently most of sunscreens provide effective protection in the full UV range but lack VIS protection. The addition of effective antioxidants to sunscreens might afford suitable UV–VIS protection. Apigenin (API), chrysin (CRI) and beta-carotene (BTC) have shown potential for UV–VIS protection. This paper reports a photosafety and efficacy screening of such antioxidants through evaluation of the photostability, photoreactivity and phototoxicity as well as UVA/UVB ratio and critical wavelength. The assessment of the photostability, photoreactivity and phototoxicity of API, CRI and BTC, isolated and combined (CMB) was performed by HPLC, ROS assay and 3T3 NRU phototoxicity test, respectively. The phototoxicity test was also performed for CMB plus bemotrizinol (BMZ). The in vitro evaluation of the UVA protection was assessed by the determination of the UVA/UVB ratio and the critical wavelength. The antioxidants API, CRI, BTC and CMB were stable under UVA/VIS and VIS light. However weak photoreactivity after UVA/VIS irradiation was observed for API, CRI and CMB in the ROS assay. In the 3T3 NRU phototoxicity test, phototoxic potential was observed for CRI, BTC, CMB and CMB+BMZ after UVA/VIS exposure, and for BTC and CMB after VIS exposure. BMZ reduced the phototoxic potential of CMB in the VIS range. In the in vitro evaluation of UVA protection API, CRI, BTC, CMB and CMB+BMZ presented ultra UVA protection (UVA/UVB ratio>0.9) and exhibited critical wavelength close to or above 370nm. In conclusion, the use of API, CRI, BTC and their CMB aiming skin photoprotection could be considered safer in the VIS range. Furthermore, API presented the best performance in the photosafety screening among the studied antioxidants, since it was photostable and non-phototoxic in UVA/VIS and photostable, non-photoreactive and non-phototoxic in VIS range.

Antimicrobial and antioxidant screening of curcumin and pyrocatechol in the prevention of biodiesel degradation: oxidative stability

ABSTRACTOwing to its hygroscopicity biodiesel may accumulate water during storage, which becomes favorable to the growth of microorganisms. In order to control microbial contamination, use of various chemical biocides has been studied. However, the addition of a natural substance simultaneously with antioxidant and microbial growth inhibition could prove advantageous in the prevention of biodiesel oxidation and microbial contamination. Curcumin and pyrocatechol are antioxidant agents, which also exhibit microbial growth inhibition abilities. This research effort aimed at evaluating the addition of curcumin and pyrocatechol to biodiesel produced from various vegetable sources (waste frying oil, soybean oil, cottonseed oil, sesame oil, macaúba almond oil and microalgae oil). The combined addition of 1% (w/w) water and curcumin (viz. 0.2% (w/w) for biodiesel from spent frying oil, 0.5% (w/w) for biodiesel from soybean oil, 0.1% (w/w) for biodiesel from cotton seed oil, 0.5% (w/w) for biodiesel from sesame seed oil, 0.2% (w/w) for biodiesel from macaúba almond oil, and 0.2% (w/w) for biodiesel from microalgae oil) were those processing variables that promoted the best fungistatic and antioxidant effects, allowing maintenance of an unfavorable environment for microbial growth in biodiesel inoculated with the ubiquitous filamentous mold Paecilomyces variotii Bainier.

Screening of dietary antioxidants against mitochondria-mediated oxidative stress by visualization of intracellular redox state.

Mitochondrial impairment and the resulting generation of reactive oxygen species (ROS) have been associated with aging and its related pathological conditions. Recently, dietary antioxidants have gained significant attention as potential preventive and therapeutic agents against ROS-generated aging and pathological conditions. We previously demonstrated that food-derived antioxidants prevented intracellular oxidative stress under proteasome inhibition conditions, which was attributed to mitochondrial dysfunction and ROS generation, followed by cell death. Here, we further screened dietary antioxidants for their activity as redox modulators by visualization of the redox state using Redoxfluor, a fluorescent protein redox probe. Direct alleviation of ROS by antioxidants, but not induction of antioxidative enzymes, prevented mitochondria-mediated intracellular oxidation. The effective antioxidants scavenged mitochondrial ROS and suppressed cell death. Our study indicates that redox visualization under mitochondria-mediated oxidative stress is useful for screening potential antioxidants to counteract mitochondrial dysfunction, which has been implicated in aging and the pathogenesis of aging-related diseases.

TLC Screening and Evaluation of Antioxidant, Antibacterial Activity of Onopordon Macrocephalum by Bioautography Method

TLC screening and Evaluation of antioxidant, antibacterial activity of Onopordon macrocephalum by bioautography methodOnopordon known as scotch thistle is a medicinal plant of the Asteraceae family that is widely distributed in Europe and Asia, also it has many valuable medicinal properties as hypotensive and antitumor. Thin layer chromatography (TLC) is wildly used in natural product extract analysis as a finger print which can be used for identification and quality control of medicinal preparations. Performing Thin-layer chromatography TLC tests on the plant show the presence of flavonoids, coumarins and bitter principles. Planar chromatographic analysis hyphenated with the biological detection method is known as bioautography which is an effective and inexpensive technique for the phytochemical analysis of plant extracts. Thin-layer chromatography-direct bioautography links separation on the adsorbent layer with biological tests performed directly on it in order to identify antimicrobial and antioxidant activities. Bioautography revealed that Staphylococcus aureus was inhibited by most of the flavonoids separated on the TLC plates. Similarly, growth of the Bacillus cereus was also inhibited by one flavonoid band on TLC. Antioxidant bioautography shows the strong antioxidant activity of one flavonoid band, whereas no activity detected of bitter principles. Bioautography showed that the antimicrobial and antioxidant activity was probably due to flavonoids.

The in-capillary DPPH-capillary electrophoresis-the diode array detector combined with reversed-electrode polarity stacking mode for screening and quantifying major antioxidants in Cuscuta chinensis Lam.

An in-capillary 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-CE-the DAD (in-capillary DPPH-CE-DAD) combined with reversed-electrode polarity stacking mode has been developed to screen and quantify the active antioxidant components of Cuscuta chinensis Lam. The operation parameters were optimized with regard to the pH and concentration of buffer solution, SDS, β-CDs, organic modifier, as well as separation voltage and temperature. Six antioxidants including chlorogenic acid, p-coumaric acid, rutin, hyperin, isoquercitrin, and astragalin were screened and the total antioxidant activity of the complex matrix was successfully evaluated based on the decreased peak area of DPPH by the established DPPH-CE-DAD method. Sensitivity was enhanced under reversed-electrode polarity stacking mode and 10- to 31-fold of magnitude improvement in detection sensitivity for each analyte was attained. The results demonstrated that the newly established in-capillary DPPH-CE-DAD method combined with reversed-electrode polarity stacking mode could integrate sample concentration, the oxidizing reaction, separation, and detection into one capillary to fully automate the system. It was considered a suitable technique for the separation, screening, and determination of trace antioxidants in natural products.

Rapid screening and identification of phenolic antioxidants in Hydrocotyle sibthorpioides Lam. by UPLC–ESI-MS/MS

The aim of the study was to identify the phenolic compounds present in Hydrocotyle sibthorpioides (HS), Centella asiatica (CA) and Amaranthus viridis (AV) extracts and investigate their respective antioxidant activities. Herein, an ultra-high pressure liquid chromatography–mass spectrometer (UPLC–MS/MS) analytical method has been developed for the separation, and systematic characterization of the phenolic compounds in HS, CA and AV extracts and was compared along with ten standard phenolic compounds. Additionally, in vitro antioxidant activity of the phenolic compounds was also determined. The HS extract revealed excellent antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (IC50=19.7±1.2μg/mL), total reduction capability (0.169±0.003 at 100μg/mL), nitric oxide radical scavenging activity (IC50=39.33±3.2μg/mL), metal chelating activity (IC50=56.51±3.6μg/mL) and inhibition of lipid peroxidation (IC50=12.34±2.3μg/mL) as compared to CA and AV extracts. Furthermore, catechin, epicatechin, quercetin and chlorogenic acid were found to be the major components responsible for the antioxidant activity of the HS extract as evidenced from UPLC–MS/MS. Taken together, this study demonstrates the promising antioxidant properties of the HS extract, which can further be utilized in various pharmaceutical, food, and agricultural applications.

Screening of Antioxidant, Antibacterial and Antileishmanial Activities of Salvia officinalis L. Extracts from Morocco

Screening of Antioxidant, Antibacterial and Antileishmanial Activities of Salvia officinalis L. Extracts from Morocco

Phytochemical Screening and Evaluation of Antioxidant and Proximate Properties of Morinda lucida Ethanolic Extract

Phytochemical Screening and Evaluation of Antioxidant and Proximate Properties of Morinda lucida Ethanolic Extract

Phytochemical content and antioxidant potential of Clerodendrum inerme and its different parts-A comparative study

Medicinal plants are excellent sources for phytochemicals, mostly polyphenols, flavonoids which exhibit high antioxidant activity. The therapeutic efficacy of these antioxidants for specific pharmacological actions has also been established by experimental and clinical studies. The aim of this study was to investigate the phytochemical and antioxidant properties of different parts of Clerodendrum inerme in a series of in vitro assays in order to find possible sources of antioxidants in food and pharmaceutical formulations. The whole plant of C. inerme and its different parts were extracted by cold and hot extraction methods with 95% ethanol and subsequently evaluated for phytochemical and in vitro antioxidant screening. The total antioxidant capacity of leaf extracts was found to be 10.41±0.321 mg AAE/g dw and the ferric reducing power was found to be 45.39±3.563 mg AAE/g dw. The IC50 values for free radicals scavenging were found to be lowest in case of leaf extracts compared to other extracts; for DPPH (30.93±0.6569 μg/ml), H2O2 (37.37±1.107 μg/ml), Super oxide (44.10±1.177 μg/ml) and lipid peroxidation (29.32±1.106 μg/ml). The data from present results revealed that C. inerme act as an antioxidant agent due to its free radical scavenging activity and can be utilised as an effective and safe source of functional food materials such as natural antioxidants.

Rapid screening and evaluation of antioxidants in alkaloid natural products by capillary electrophoresis with chemiluminescence detection

A capillary electrophoresis (CE) incorporating chemiluminescence (CL) detection method was applied to on-line screening and evaluation of antioxidants in alkaloid natural products.

Screening and isolation of natural antioxidants from Ziziphora clinopodioides Lam. with high performance liquid chromatography coupled to a post-column Ce(iv) reduction capacity assay

A novel on-line screening method for natural antioxidants was developed with a post-column cerium(iv) reduction reaction after high performance liquid chromatography (HPLC) separation.

Evaluation of Phytochemical, Chemical Composition, Antioxidant and Antimicrobial Screening Parameters of Rhamnus prinoides (Gesho) Available in the Market of Mekelle, Tigray, Ethiopia

The objective of this study was the evaluation of phytochemical, chemical composition, antioxidant and antimicrobial screening parameters in leaf of Rhamnus prinoides which are used to impart bitterness to local alcoholic beverages in Ethiopia and as traditional medicine in some African countries. The phytochemical screening of aqueous and methanol/water plant extracts was performed using standard phytochemical techniques for the determination of the presence of alkaloids, steroids, triterpines, tannins, flavanoids, flavones, phenols, glycosides, anthraquinones, proteins and resins. The nutritional value of samples were analyzed for their chemical composition (moisture, proteins, fat, carbohydrates and ash) using AOAC (Association of Analytical chemists procedures. The antimicrobial activities of the plant extracts against Neisseria gonorrhea, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeroginosa, and Streptococcus fecalis using broth dilution technique were determined. These were compared with those of benzyl penicillin, oxytetracycline and streptomycin as positive controls in the experiment the extract of Rhamnus prinoides was positive for tannins, triterpenoids, cardiac glycosides, phenolics compounds, saponins and resins. Alkaloids were present in the methanolic/water extract only. The methanolic/water extract of Rhamnus prinoides also shows a broad spectrum of activity against all microorganisms tested except for Neisseria gonorrheae. This shows it has a high content of protein and fiber and is low in fat. The qualities demonstrate that it is this good alternative to other food stuffs and these results serve as the basis of further scientific study into various ways of enhancing the livelihood of particular areas of northern Mekelle through increased Rhamnus prinoides domestication as well as assessing the possible bioactivity of rhamnus against certain human diseases.

Avaliação Fitoquímica e Screening da Capacidade Antioxidante de Resíduos de Umbu

The umbuzeiro is a native fruit of the caatinga of northeastern Brazil. This fruit has contributed as an alternative source of income in periods of drought. The aim of this study was to evaluate and phytochemical screening of the antioxidant capacity of the waste from the municipality of umbu Ibiassuce-Bahia. The contents of total phenolics, total flavonoids, condensed tannins (butane-acid method) and hydrolyzed, carotenoids were quantified. The screening of antioxidant

Part XXIII. Synthesis and characterization of platinum(IV) complexes with O,O′-dialkyl esters of (S,S)-ethylenediamine-N,N′-di-2-(3-methyl)butanoic acid and bromido ligands. Antimicrobial, antibiofilm and antioxidant screening

Four new platinum(IV) complexes C1–C4 of general formula [PtBr4(R2-S,S-eddv)], (R=ethyl, propyl, butyl and pentyl; S,S-eddv=(S,S)--ethylenediamine-N,N′-di-2-(3-methyl)butanoate) have been synthesized and characterized by microanalysis, infrared, 1H and 13C NMR spectroscopy. In vitro antimicrobial activity for these and [PtBr4(R2-S,S-eddp)] complexes (S,S-eddp=(S,S)-ethylenediamine-N,N′-di-2-propanoate) has been investigated. The antibacterial activity was tested against 16 strains of bacteria determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) using microdilution method. In general, platinum(IV) complexes manifested moderate activity against the Gram positive bacteria and low activity against the Gram negative bacteria. The complexes showed weak antioxidative properties tested by two methods (DPPH and reducing power assay).

English

Active ingredients of medicinal plants have been used to cure several human diseases. Azadirachta indica is one of the most versatile medicinal plants having a wide spectrum of biological activity due to the presence of large number of bioactive compounds. The present study was conducted to evaluate antimicrobial and antioxidant efficiency and phytochemical screening of A. indica leaf extract using methanol as a solvent. A qualitative phytochemical screening was performed for the detection of various phytochemicals. Then, the quantitative determination of total phenols, flavonoids and proanthocyanidins was done and expressed in terms of gallic acid and rutin equivalent. Total phenolic, flavonoid and proanthocyanidin content were found to be 85.9±4.0, 104.9±5.5 and 65.4±13.9 mg/g of plant extract, respectively. Also, the antibacterial activity was performed using six different bacterial strains: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Salmonella typhi (ATCC 14028), Klebsiella pneumoniae (ATCC 700603), Pseudomonas aeruginosa (ATCC 27853) and Proteus vulgaris (ATCC 35659). It was found that the maximum zone of inhibition of 22±3 mm was shown against S. aureus using 700 µg plant extract. Similarly, the antioxidant activity of the methanolic extract of plant was also determined and it was found that maximum inhibition obtained was 71.23% when 500 µg plants extract was used.   Key words: Azadirachta indica, methanol, antibacterial, antioxidant.

On-Line HPLC with Biochemical Detection for Screening Bioactive Compounds in Complex Matrixes

On-line high-performance liquid chromatography (HPLC) coupled with biochemical detection (BCD) has been developed to screen compounds showing antioxidant action, enzyme inhibition and receptor affinity in complex matrixes. This review summarizes HPLC methods combining different post-column detection methods, such as diode-array detection (DAD), mass spectrometry (MS), chemiluminescence (CL) and nuclear magnetic resonance, for antioxidant screening. The methods based on a single relatively stable reagent such as DPPH• and ABTS•+ were the most popular. Oxygen free radical scavengers mainly depended on post-column CL detection. The on-line hyphenated HPLC–BCD systems based on post-column UV/DAD fluorescence and MS detection were also widely applied to screen enzyme- and receptor-active compounds. These strategies provide a convenient tool for quick identification and quantification of active compounds in complex matrixes.

Novel (E)-1-aryl-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-pyrazol-1-yl)ethanones: solvent-free synthesis and antimicrobial, antioxidant and UV-mediated DNA damage protective activity studies

In search of new biologically active compounds, some novel (E)-1-aryl-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-pyrazol-1-yl)ethanones 3a–u have been synthesized via solvent-free greener approach. All compounds were characterized on the basis of a combined use of IR, NMR (1H, 13C), mass spectrometry and elemental analyses. In order to establish the position of methyl groups in the compound 3b, 2D NMR (COSY, HSQC and HMBC) spectroscopic technique has also been used. To explore the biological potential, compounds were evaluated for their antimicrobial, antioxidant and UV-mediated DNA damage protective activity. Among the series, six compounds 3b, 3i, 3k, 3l, 3m and 3t were found to exhibit a very good level of antibacterial activity and four compounds 3g, 3o, 3p and 3t were emerged as an efficient class of antifungal agents in reference to the standard drugs, viz ciprofloxacin and amphotericin B, respectively. In studying the UV-mediated DNA damage protective activity, all compounds 3a–u (except 3d) protected the plasmid DNA from the UV damaging effect in which 3e was found to be the most potent DNA-protecting agent which avoids the transformation of the native supercoiled form into an open circular and linear form. In addition, the compounds 3f, 3m and 3t were found to be active in antioxidant screening using DPPH assay.