Concentrations Of Pyrogallol Research Articles

Reproductive and endocrine-disrupting toxicity of pyrogallol in catfish (Clariasgariepinus)

Endocrine disruptors are synthetic or natural chemicals that can agonize/antagonize hormone receptors or can interfere with the production and secretion of hormones, leading to altered tissue histology and physiology. Pyrogallol is a contaminant widely distributed in aquatic environments that presents health risks to both humans and animals. However, the potential for endocrine disruption by pyrogallol, particularly in fish, are lacking. The purpose of this study was to shed light on how pyrogallol may affect hormone signalling, histopathology, and reproductive outcomes in African catfish Clarias gariepinus. To investigate this, African catfish were exposed to one sublethal concentration of pyrogallol at either 0, 1, 5 or 10 mg/L for 15 days. We then assessed the effects of pyrogallol on the thyroid gland as well as the reproductive system by measuring sex hormone, seminal quality, gonadal histopathology, and histochemistry. Thyroid stimulating hormone and thyroxine showed notable decreases in catfish, and triiodothyronine was decreased with 10 mg/L pyrogallol. Unlike luteinizing hormone, follicle-stimulating hormone was significantly reduced in fish following exposure to pyrogallol relative to controls. Testosterone was also decreased in fish following pyrogallol exposure, whereas 17β-estradiol increased in catfish exposed to pyrogallol. Additionally, in response to pyrogallol toxicity, sperm quality indices, including count, spermatocrit, motility, and sperm viability were adversely affected in a concentration-dependent manner. Pyrogallol exposure also induced several changes in the gonad following exposure to 1, 5, or 10 mg/L. Deformed tubular structures, vacuolation, thickening of the basement membrane, hypertrophy of the seminiferous tubules, intense melanomacrophage localization, spermatozoa loss, and necrosis were all observed in the testes. In the ovary, atretic follicles, deteriorated mature oocytes, degenerated yolk globules, and an increase in perinucleolar oocytes were observed in catfish exposed to pyrogallol. These findings suggest that pyrogallol may act as endocrine disrupting substance in aquatic environments. Further research on the mechanisms by which pyrogallol impairs endocrine systems, particularly in fish, is recommended.

Phytochemical Profiling of Aqueous Methanol Extract of Terminalia bellirica from Bokaro District of Jharkhand, India

Plants are a vital source of medicine for human being from ancient times. Various plant parts are highly medicinal due to the presence of different bioactive compounds and secondary metabolites. Many of these compounds present in medicinal plants are unknown to the scientific community. T. bellirica is distributed in tropical parts of the world and is a known ethnomedicinal plant that is the reservoir of various bioactive compounds. The present investigated the bioactive and secondary metabolite present in the fruits of T. bellirica collected from the Bokaro district and has been analysed using Gas chromatography-Mass spectrometry analysis. The investigation found 55 compounds from the methanol extract of the fruit sample of T. bellirica. Among the recorded compounds, Pyrogallol is the major constituent with 85% area in the chromatogram, followed by 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)with 5% area, and the rest of the compounds are altogether 10% of the total. In conclusion, the present study recorded and highlighted a total of 55 bioactive compounds from the dry fruits and pericarp, which is more than a double of the compounds earlier known from the plant species. Further, among the recorded biochemical compounds, the concentration of Pyrogallol was alone more than 85% of the total compounds found from the methanol extract of the fruit sample of T. bellirica.

Pyrogallol Detection Based on the Cobalt Metal–Organic Framework of Nanomaterial-Enhanced Chemiluminescence

The cobalt metal–organic framework (Co-MOF) is a kind of crystalline porous material within a periodic network structure, which is formed via the self-assembly of a Co metal center and a bridged organic ligand. In this paper, a Co-MOF was facilely synthesized via an ultrasonic method and applied to enhance the chemiluminescence (CL) emission of the NaIO4-H2O2 system. The synthesized Co-MOF was nanosheet-like in nature and stacked in 2–3-micrometer flower shapes. Compared to the NaIO4-H2O2 system without a Co-MOF, the CL intensity of the Co-MOF-NaIO4-H2O2 system was enhanced about 70 times. This CL mechanism was determined to be a result of the synergistic effects of chemiluminescence resonance energy transfer (CRET) and electron–hole annihilation (EHA). The Co-MOF not only acted as a catalyst to accelerate the generation of reactive oxygen species in the CL reaction, but also worked as an emitter to further enhance the CL. Based on the Co-MOF-NaIO4-H2O2 system, a highly sensitive CL analysis method was established for pyrogallol (PG) detection. Addition of PG into the CL system generated 1O2*, which could transfer energy to the Co-MOF and further enhance the CL response. The enhanced CL was linear with the PG concentration. The CL analysis method exhibited a linear range of 1 × 10−4 M to 1 × 10−7 M, as well as having a linear correlation coefficient of 0.9995 and a limit of detection of (S/N = 3) of 34 nM.

Sensitive voltammetry method for analysis of the antioxidant pyrogallol using a carbon paste electrode with CdS nanoparticle

A voltammetry method for the determination of pyrogallol (PY) was developed employing a carbon paste electrode (CPE) modified with CdS nanoparticle that was synthesized by microwave. The effect of different parameters i.e. time and irradiation power on the morphology and the sample’s particle size have been investigated. The synthesized nanostructures were characterized by X-ray diffraction and scanning electron microscopy. The optimized condition for time and power consumption to prepare CdS nanoparticles was obtained 4 min and 360 W. Cyclic voltammetry study of the modified electrode indicated that the oxidation potential shifted towards a lower potential by approximately 106 mV and the peak current was enhanced by 2 fold in comparison to the bare CPE. The effect of pH and interferences from some inorganic salts and organic compounds were studied. The usability of this method for the quantification of pyrogallol was investigated with differential pulse voltammetry (DPV). Under the optimal conditions, the peak current was proportional to pyrogallol concentration in the range of 7.0 ×10-7 to 3.0 × 10-4 mol L-1 with a LOD of 4.8 × 10-7 mol L-1. These values are satisfactory for application to real samples. Finally, the developed method was successfully used for the analysis of samples.

A polyphenol, pyrogallol changes the acidic pH of the digestive vacuole of Plasmodium falciparum

Pyrogallol has a capability of generating free radicals like other antimalarial drugs such as artemisinin, which is thought to inhibit the proton pump located in the membrane of the Plasmodium falciparum digestive vacuole, thus alkalinising this acidic organelle. This study aimed to determine pH changes of the malaria parasite’s digestive vacuole following treatment with pyrogallol. The antimalarial activity of this compound was evaluated by a malarial SYBR Green 1 fluorescence-based assay to determine the 50% inhibitory concentration (IC50). Based on the IC50 value, different concentrations of pyrogallol were selected to ensure changes of the digestive vacuole pH were not due to parasite death. This was measured by flow cytometry after 4-hour pyrogallol treatment on the fluorescein isothiocyanate-dextran-accumulated digestive vacuole of the mid-trophozoite stage parasites. Pyrogallol showed a moderate antimalarial activity with the IC50 of 2.84 ± 9.40 µM. The treatment of 1.42, 2.84 and 5.67 µM pyrogallol increased 2.9, 3.0 and 3.1 units of the digestive vacuole pH, respectively as compared with the untreated parasite (pH 5.6 ± 0.78). The proton pump, V-type H+-ATPase might be inhibited by pyrogallol, hence causing the digestive vacuole pH alteration, which is similar with the result shown by a standard V-type H+-ATPase inhibitor, concanamycin A. This study provides a fundamental understanding on the antimalarial activity and mechanism of action of pyrogallol that has a potential to be the antimalarial drug candidate.

Targeting Salmonella Typhimurium Invasion and Intracellular Survival Using Pyrogallol.

Salmonella enterica serovar Typhimurium, an intracellular pathogen, evades the host immune response mechanisms to cause gastroenteritis in animals and humans. After invading the host cells, the bacteria proliferate in Salmonella-containing vacuole (SCV) and escapes from antimicrobial therapy. Moreover, Salmonella Typhimurium develops resistance to various antimicrobials including, fluoroquinolones. Treating intracellular bacteria and combating drug resistance is essential to limit the infection rate. One way of overcoming these challenges is through combination therapy. In this study, Pyrogallol (PG), a polyphenol, is combined with marbofloxacin (MAR) to investigate its effect on Salmonella Typhimurium invasion and intracellular survival inhibition. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PG against Salmonella Typhimurium were 128 and 256 μg/mL, respectively. The lowest fractional inhibitory concentration (FIC) index for a combination of PG and MAR was 0.5. The gentamycin protection assay revealed that PG (30 μg/mL) alone and in combination with sub-MIC of MAR inhibited 72.75 and 76.18% of the invading bacteria in Caco-2 cells, respectively. Besides, the intracellular survival of Salmonella Typhimurium was reduced by 7.69 and 74.36% in treatment with PG alone and combined with sub-MIC of MAR, respectively, which was visualized by the confocal microscopy. PG has also shown to increase the intracellular accumulation of fluoroquinolone by 15.2 and 34.9% at 30 and 100 μg/mL concentration, respectively. Quantitative real-time PCR demonstrated PG suppressed the genetic expression of hilA, invF, sipB, and acrA by 14.6, 15.4, 13.6, and 36%, respectively. However, the downregulation of hilA, invF, sipB, and acrA increased to 80, 74.6, 78, and 70.1%, in combination with sub-MIC of MAR, respectively. Similarly, PG combined with MAR inhibited the expression of sdiA, srgE, and rck genes by 78.6, 62.8, and 61.8%, respectively. In conclusion, PG has shown antimicrobial activity against Salmonella Typhimurium alone and in combination with MAR. It also inhibited invasion and intracellular survival of the bacteria through downregulation of quorum sensing, invading virulence, and efflux pump genes. Hence, PG could be a potential antimicrobial candidate which could limit the intracellular survival and replication of Salmonella Typhimurium.

Colorimetric and fluorimetric (dual-mode) nanoprobe for the determination of pyrogallol based on the complexation with copper(II)- and nitrogen-doped carbon dots.

Carbon dots doped with copper(II) and nitrogen (Cu,N@C-dots) were prepared and are shown to be viable fluorescent nanoprobe for pyrogallol (PGL) was developed for the first time. The reaction is based on (a) the complexation reaction between Cu,N@C-dots and catechol moiety, and (b) the generation of a quinone-like structure. Thus, the co-ordination complex formed between Cu(II) in C-dots and PGL results in quenching of the fluorescence of C-dots. In addition, the formation of a yellow color due to complex formation between the nanoprobe and Cu(II) allowed the colorimetric determination of PGL. The nanoprobe was prepared by thermal synthesis, using ethylenediaminetetraacetic acid salt and copper(II) chloride as sources for carbon, nitrogen and copper, respectively. The carbon dots were characterized by UV-VIS spectroscopy, Fouriertransform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy) and dynamic light scattering. Fluorescence drops linearly in the 0.15 to 70μM PGL concentration range with a detection limit of 39nM and a relative standard deviation of 1.8%.The optimal excitation and emission wavelengths are 370nm and 428nm, respectively. The colorimetric assay has a linear response at 325nm absorption wavelengths in the 6 to 140μM PGL concentration range with a detection limit of 1.8μM and a 2.3% relative standard deviation. Graphical abstractDual mode colorimetric and fluorimetric nanoprobe was designated for pyrolgallol determination based on complexation with copper(II)- and nitrogen-doped carbon dots.

Antioxidant Effects of Pyrogallol in Neural Cells and Mice Brain

Polyphenols can easily react with reactive oxygen species (ROS) resulting in powerful antioxidant activity. Pyrogallol is a polyphenol found in a variety of fruits and vegetables. Therefore, plants containing pyrogallol can be used for their antioxidant, anti-bacterial, anti-fungal, anti-allergic, and anti-inflammatory properties. However, its effectiveness as an antioxidant is still a matter of debate because pyrogallol is also a superoxide anion generator and induces superoxide anion-mediated death of several types of cells. In this study, we tried to confirm the antioxidant effects and mechanisms of pyrogallol in mouse neuroblastoma (N2A), human neural stem cells (F3), and mouse brain. Treatments with various concentrations of pyrogallol significantly increased the free radical scavenging ability and reduced lipid peroxidation in N2A and F3 cells in a concentration-dependent manner. In the cytotoxicity test, low concentrations of pyrogallol (0–10 µg/mL) did not significantly influence cell viability, while high concentrations (125-1000 µg/mL) induced death in N2a and F3 cells. Furthermore, treatment with pyrogallol(1.0, 3.2, and 10.0 µg/mL) up-regulated the mRNA expression of superoxide dismutases 1, 2, and 3, glutathione peroxidase (GPx)1, and phospholipid hydroperoxide GPx in N2A and F3 cells, in the brains of mice that were orally administered pyrogallol (1.0, 3.2, and 10.0 mg/kg/day) for 7 days. The mice did not exhibit any toxic effects due to this treatment. Taken together, although pyrogallol induced cell death at high concentrations, it might be a good candidate antioxidant for neurodegenerative disease at low concentrations.

Antimicrobial and improved barrier properties of natural phenolic compound-coated polymeric films for active packaging applications

Functional antimicrobial low-density polyethylene (LDPE) films with coatings containing different amounts of pyrogallol (PGL), a natural phenolic substance, and polyurethane were prepared. To examine the applicability of the prepared LDPE/PGL films in packaging, the films were characterized by scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis, and X-ray diffraction. The role of the coating, the barrier and color properties, and the antimicrobial activity of the films were evaluated. The thermal stability of the LDPE/PGL films was affected by the PGL concentration. Coatings with pyrogallol caused the barrier properties for water, and oxygen was increased from 0.78–0.32 to 470 ± 23.2–273 ± 57.1 (g mm)/(m2 h kPa), respectively. These findings indicate that the barrier properties of the LDPE/PGL films were highly improved compared to those of neat LDPE. Moreover, the LDPE/PGL films exhibited acceptable antimicrobial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), especially for S. aureus. Further studies are necessary to increase the thermal stability of the pyrogallol coatings with the LDPE substrate in order to improve their performance and extend their packaging applications.

Novel imidazole fluorescent poly(ionic liquid) nanoparticles for selective and sensitive determination of pyrogallol

This paper reports novel imidazole fluorescent poly(ionic liquid) nanoparticles (FPILNs) of poly(1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide (poly([MVI]Br) for selective and sensitive determination of pyrogallol. An imidazole ionic liquid of 1-[(4-methyphenyl)methyl]-3-vinyl-imidazolium bromide ([MVI]Br) was synthesized and used as the only monomer to obtain poly([MVI]Br) possessing phenyl fluorophores using a radical polymerization technique. The obtained poly([MVI]Br) can form nanoparticles in water. Scanning electron microscopy and dynamic light scattering results revealed majority of poly([MVI]Br) FPILNs with diameters ranging from 40 to 400nm. Although [MVI]Br showed weak fluorescence intensity, poly([MVI]Br) FPILNs exhibited strong fluorescence intensity with a quantum yield of 0.192, which is attributed to the presence of significant number of phenyl fluorophores and rigid construction. The selective and sensitive determination of pyrogallol was achieved through fluorescence quenching of poly([MVI]Br) FPILNs, and the quenching was attributed to the oxidation of poly([MVI]Br) FPILNs by O2˙¯ produced by pyrogallol autoxidation. The poly([MVI]Br) FPILNs-based sensor demonstrated a good linear relationship between the extent of fluorescence quenching and the concentration of pyrogallol in a range of 0.05 – 10.0μM, achieving a detection limit of 0.01μM. Furthermore, the poly([MVI]Br) FPILNs-based assay detected pyrogallol in environmental water samples, suggesting its potential to be applied for practical purposes.

Sensitive voltammetric method for the fast analysis of the antioxidant pyrogallol using a boron-doped diamond electrode in biofuels

A sensitive voltammetric method for the determination of pyrogallol (PY) was developed employing a boron-doped diamond electrode (BDDE). The composition of the supporting electrolyte was investigated during the development of the methodology. Linear sweep voltammetry (LSV) under the optimized experimental conditions was applied for PY determination with a limit of detection and limit of quantification of 0.85 and 2.82 μmol L−1, respectively. These values are satisfactory for application to real samples. The usability of this method for the quantification of pyrogallol was in range from 2.82 to 296.00 μmol L−1. Finally, the developed method was successfully used for the analysis of real samples of biodiesel produced from rapeseed oil and its blend with diesel fuel. Samples of biodiesel and biodiesel blends were analyzed directly in an electrochemical cell, while samples with very low concentrations of PY in biodiesel were extracted with water using the proposed simple and fast process.

Modular material system for the microfabrication of biocompatible hydrogels based on thiol-ene-modified poly(vinyl alcohol)

Novel modifications of the synthetic polymer poly(vinyl alcohol) (PVA) were developed for application in the field of biomedical engineering. PVA was modified with allyl succinic anhydride, norbornene anhydride as well as with γ-thiobutyrolactone to produce macromers with reactive ene and thiol groups, respectively. Cytotoxicity studies have shown that the material exhibits almost no cell-toxicity, when used in concentrations of 1 and 0.1 wt % for 24 h. The obtained macromers were photocrosslinked via thiol–ene chemistry. Storage stability of the macromer mixtures with different concentrations of pyrogallol as stabilizer were investigated. Photorheometry was employed to optimize mixtures concerning reactivity based on their thiol-to-ene ratio, photoinitiator concentration, and macromer content. The crosslinked hydrogels were studied concerning their swellability. To form hydrogels with cellular structure two-photon-polymerization (2PP) was employed. Processing windows for 2PP of selected mixtures were determined. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2060–2070

Pyrogallol, an absorbable microbial gallotannins-metabolite and mango polyphenols (Mangifera Indica L.) suppress breast cancer ductal carcinoma in situ proliferation in vitro

Mango is rich in bioactive absorbable polyphenols, but also contains considerable amounts of unabsorbable gallotannins at varying degrees of polymerization. Gallotannins are not absorbable upon consumption and have rarely been considered in the discussion of health benefits of polyphenols. Therefore, the objective of this study was to investigate the anti-proliferative activities of the major microbial metabolite of gallotannins, pyrogallol (PG) and a low molecular weight fraction of mango (Mangifera Indica L.) polyphenols (ML) and involved pathways including the AKT/mTOR signaling axis in an in situ breast cancer cell line, MCF10DCIS.COM. Fluorouracil (5-FU), a widely used genotoxic cancer therapeutic, was used a positive control and in combination with ML and PG to assess potential interactions. Concentrations that were non-cytotoxic in non-cancer cells were identified in non-cancer mammary fibroblasts (MCF-12F) and only non-cytotoxic dietarily relevant concentrations were selected for the investigation in MCF10DCIS.COM cancer cells. In addition to proliferation and viability, mRNA and expression of total and phosphorylated protein were investigated. Results show that both, ML and PG significantly reduced proliferation in MCF10DCIS.COM, but did not significantly reduce viability following a 48 h exposure. ML significantly reduced mRNA expression of mTOR and HIF-1α, while PG significantly reduced mRNA of IGF-1R, AKT, mTOR and HIF-1α. ML and PG reduced total protein expression of IGF-1R, IR, AKT, mTOR, and P70S6K. In addition, PG reduced IRS protein. Both treatments also had an effect on phosphorylated protein levels, with PG significantly reducing IGF-1R, AKT, and P70S6K levels. ML had a similar effect and significantly decreased IR, AKT, and P70S6K phosphorylation levels. Within the low concentration-range, ML and PG did not interact with the cytotoxic activities of 5-FU. Overall, the AKT/mTOR signaling axis appears to be implicated as causal in decreased proliferation induced by diet-relevant concentrations of ML and PG.

New insights of superoxide dismutase inhibition of pyrogallol autoxidation.

Autoxidation of pyrogallol in alkaline medium is characterized by increases in oxygen consumption, absorbance at 440 nm, and absorbance at 600 nm. The primary products are H2O2 by reduction of O2 and pyrogallol-ortho-quinone by oxidation of pyrogallol. About 20 % of the consumed oxygen was used for ring opening leading to the bicyclic product, purpurogallin-quinone (PPQ). The absorbance peak at 440 nm representing the quinone end-products increased throughout at a constant rate. Prolonged incubation of pyrogallol in alkali yielded a product with ESR signal. In contrast the absorbance peak at 600 nm increased to a maximum and then declined after oxygen consumption ceased. This represents quinhydrone charge-transfer complexes as similar peak instantly appeared on mixing pyrogallol with benzoquinones, and these were ESR-silent. Superoxide dismutase inhibition of pyrogallol autoxidation spared the substrates, pyrogallol, and oxygen, indicating that an early step is the target. The SOD concentration-dependent extent of decrease in the autoxidation rate remained the same regardless of higher control rates at pyrogallol concentrations above 0.2 mM. This gave the clue that SOD is catalyzing a reaction that annuls the forward electron transfer step that produces superoxide and pyrogallol-semiquinone, both oxygen radicals. By dismutating these oxygen radicals, an action it is known for, SOD can reverse autoxidation, echoing the reported proposal of superoxide:semiquinone oxidoreductase activity for SOD. The following insights emerged out of these studies. The end-product of pyrogallol autoxidation is PPQ, and not purpurogallin. The quinone products instantly form quinhydrone complexes. These decompose into undefined humic acid-like complexes as late products after cessation of oxygen consumption. SOD catalyzes reversal of autoxidation manifesting as its inhibition. SOD saves catechols from autoxidation and extends their bioavailability.

An efficient nonisocyanate route to polyurethanes via thiol‐ene self‐addition

ABSTRACTA novel and efficient strategy for the synthesis of nonisocyanate polyurethanes has been developed via thiol–ene self‐photopolymerization. An aliphatic thiol–ene carbamate monomer (allyl(2‐mercaptoethyl)carbamate, AMC) was synthesized by a one‐step synthesis procedure, from cysteamine and allyl chloroformate. The urethane group was therefore incorporated directly into the monomer precursor, avoiding the problems associated to toxic isocyanates. AMC was successfully stabilized with the radical inhibitor pyrogallol (1% wt). In addition, the use of phenyl phosphonic acid as coadditive allowed its stabilization for lower concentrations of pyrogallol (0.1% wt). AMC was directly transformed into thermoplastic polyurethane (TPU) through thiol–ene photopolymerization by UV‐irradiation at 365 nm. The obtained TPU presented semi‐crystalline nature and very high thermal stability (T5% ∼325 °C). It was found that high concentrations of pyrogallol decreased the reaction rate and final conversion of photopolymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3017–3025

Perturbation of the EphA2–EphrinA1 System in Human Prostate Cancer Cells by Colonic (Poly)phenol Catabolites

The Eph tyrosine kinase receptors and their ephrin ligands play a central role in human cancer as their deregulated expression induces tumorigenesis with aggressive phenotypes. To evaluate their potential contribution to EphA2-ephrinA1 modulation, several colonic catabolites of dietary (poly)phenolics, known to be generated in vivo, were screened using an ELISA-based binding assay. Some of the catabolites inhibited the binding in a dose-dependent manner (IC(50) values from 0.26 to 43 μM). Functional studies on prostate adenocarcinoma cells revealed that pyrogallol and protocatechuic acid specifically antagonized ephrinA1-Fc-induced EphA2 phosphorylation at concentrations that were not cytotoxic. The active concentrations of pyrogallol appear to be close to what can be reached in vivo under physiological conditions. Finally, because of the roles played by the Eph-ephrin system not only in cancer development but also in neurodegeneration and diabetes, pyrogallol and protocatechuic acid are candidates for more detailed functional studies to elucidate their role in these pathophysiological processes.

Studies on the effect of antioxidants on the long-term storage and oxidation stability of Pongamia pinnata (L.) Pierre biodiesel

This study investigates the impact of various synthetic phenolic antioxidants on the oxidation stability and storage stability of Pongamia (karanja) biodiesel (PBD). The results of Rancimat experiments show that the induction point (IP) increased substantially on adding certain antioxidants to the Pongamia biodiesel. The study reveals pyrogallol (PY) to be the best antioxidant to show the best improvement in the oxidative stability of PBD, the induction time being enhanced to 34.35h at a PY concentration of 3000ppm at 110°C. The storage stability studies were carried out according to the ASTM standard procedures 1) ASTM D4625 at 30°C/50weeks and 2) ASTM D4625 at 43°C/12weeks by adding different antioxidants like BHT, BHA, PY, GA and TBHQ. The effectiveness of these five antioxidants on PBD was examined at varying loading levels during the storage period.

Oxidation, Thermal, and Storage Stability Studies of Jatropha Curcas Biodiesel

The present work reports the results of the study of the effect of metal contaminants on the oxidation, thermal, and storage stability of Jatropha curcas biodiesel (JCB) with and without antioxidants. Taking Pyrogallol (PY) as the most effective antioxidant based on the earlier work of the authors, JCB was mixed with different transition metals—Fe, Ni, Mn, Co, and Cu in different concentrations. Induction period (IP) was measured using Rancimat method (EN 14112). The ASTM D6468 and thermogravimetric analysis (TGA) methods are used for evaluating the thermal behavior of JCB. Based on results, several correlations are developed for assessing the oxidation, thermal, and storage stability. For the purpose of optimization, response surface methodology (RSM) is used. A comparison between the experimental values and those predicted by the correlation shows that all the data points lie within ±10% deviation lines of the experimental results. The optimized concentration of PY for 2 ppm metal-contaminated biodiesel to have an IP of 6 hr is 326.96, 361.64, 386.15, 417.24, and 600 ppm for Fe, Ni, Mn, Co, and Cu, respectively. From the experiments it is found that if metal concentration is 0, then, 200 ppm of PY is sufficient to make biodiesel stable for 6 months. If metal (Fe) concentration is 2 ppm or more, then 800 ppm PY is sufficient to make biodiesel stable for 5.5 months. This is the first study of its kind being reported in the literature in which RSM is used for design of experiment for developing the correlation for oxidation, thermal, and storage stability. The models developed by RSM will be highly useful for predicting the optimum antioxidant concentration to impart maximum fuel stability in JCB.

Study on Synthesis and Characterization of a Fluorescence Probe and its Application for Determination of Superoxide Anion Radical

A novel Schiff base, 2-(Salicylideneamino)pyridine (2-SAP) synthesized by 2-aminopyridine and salicylaldehyde was used as a fluorescence probe to determine superoxide anion radical (O2•-) in this study. The synthetic product was characterized by IR, 1H-NMR and GC-MS methods. A fluorescence quenching reaction occurs between 2-SAP and O2•-, and the fluorescence intensity decreased significantly. The effect of pyrogallol concentration (2.0×10-5 M to1.0×10-3 M) was discussed in this study. In the range from 2.0×10-5 M to 1.0×10-4 M, relative fluorescence intensity (y) and pyrogallol concentration (x) shown a good linear relationship, y=37.801x+76.854, r=0.993. Based on this phenomenon, the O2•- generated by pyrogallol autoxidation could be determined simply with high sensitivity.

Property modification of jatropha oil biodiesel by blending with other biodiesels or adding antioxidants

The feasibility of biodiesel production from jatropha ( Jatropha curcas) oil was investigated with respect to the biodiesel blending properties and its oxidation stability with antioxidants. The JME (jatropha oil methyl esters) had the cetane number of 54, cold filter plugging point of −2 °C, density of 881 kg/m 3 at 15 °C, ester content of 99.4 wt.%, iodine value of 96.55 g I 2/100 g, kinematic viscosity of 4.33 mm 2/s at 40 °C, and oxidation stability of 3.86 h. Furthermore, the JME was blended with palm oil biodiesel and soybean oil biodiesel at various weight ratios and evaluated for fuel properties as compared to the relevant specifications. In addition, several antioxidants at concentrations between 100 and 1000 ppm were studied for their potential to improve the oxidation stability of the JME. The relationship between the IP (induction period) in the measurement of the oxidation stability associated with the antioxidant consumption in the JME was described by first-order reaction rate kinetics. Moreover, the ln IP (natural logarithm of the IP) at various concentrations of pyrogallol showed a linear relationship with the test temperature. The oxidation stability at ambient temperatures was predicted on the basis of an extrapolation of the temperature-dependent relationship.