New Accelerators for Vulcanization of Rubber—Part III: Synthesis, Characterization, and Evaluation of Some 2-Mercaptobenzimidazole Derivatives

1985 ◽  
Vol 58 (4) ◽  
pp. 713-727 ◽  
Author(s):  
D. Pal ◽  
A. Khamrai ◽  
B. Adhikari ◽  
T. Dutta ◽  
Mrinal M. Maiti ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Antioxidant Properties ◽  
Antioxidant Compounds ◽  
Dual Function ◽  
Cure Characteristics ◽  
Aging Resistance ◽  
Rubber Part ◽  
Derivatives Of ◽  
Better Than

Abstract Five derivatives of 2-mercaptobenzimidazole containing S—N bonds have been synthesized and evaluated for their action as accelerator-antioxidant in NR gum stocks. All these compounds exhibit varying degree of accelerating efficiency; some of them, viz. MBSTP, MBSPT, and MBDSPT, offer excellent cure characteristics and vulcanizate properties comparable to some of the best commercially available curatives such as CPTD. Substitution at the N or S atom of the MB molecule does not affect adversely its antioxidant properties; rather, an improvement in aging resistance has been achieved. The degree and nature of substitution play an important role in the antioxidation properties of these MB derivatives. Thus, disubstitution offers better antioxidation characteristics than monosubstitution, and the latter, in turn, is better than unsubstituted MB. Some discussion on correlation of reactivities of these MB derivatives and their cure synergism with CPTD have been reported. It was observed that these new accelerator—antioxidant compounds show very little cure synergism with CPTD but do show promise as dual-function curatives for natural rubber.

scholarly journals Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 100
Author(s):  
Minerva C. García-Vargas ◽  
María del Mar Contreras ◽  
Irene Gómez-Cruz ◽  
Juan Miguel Romero-García ◽  
Eulogio Castro
Keyword(s):  
Chemical Composition ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Nutritional Properties ◽  
Aqueous Fraction ◽  
Extraction Solvent ◽  
Main Components ◽  
A Minor ◽  
Derivatives Of

Avocado has become fashionable due to its great organoleptic and nutritional properties. It is consumed as a fresh product and it is also processed to obtain salad oil and guacamole. In all cases, the only usable portion is the pulp. Therefore, to be a more sustainable and profitable agribusiness, it is important to recognize which compounds from the peel and the stone waste can be converted into valuable bio-products. Therefore, their chemical composition was determined according to the National Renewable Energy Laboratory, the total phenolic content by the Folin-Ciocalteu method and the antioxidant properties by the FRAP and TEAC assays. The main components of the peel and stone were acid-insoluble lignin (35.0% and 15.3%, respectively), polymeric sugars (23.6% and 43.9%, respectively), and the aqueous extractives (15.5% and 16.9%, respectively). Both biomasses contain lipids and protein, but a minor proportion (<6%). The valorization of lignin and sugars is of interest given the high content; stones are a rich source of glucose (93.2% of the polymeric fraction), which could be used to obtain biofuels or derivatives of interest. The extractive fraction of the peel contained the highest number of phenolic compounds (4.7 g/100 g biomass), mainly concentrated in the aqueous fraction (i.e., 87%) compared to the ethanol one, which was subsequently extracted. It correlated with major antioxidant activity and, therefore, the peel can be applied to obtain antioxidants and water can be used as an environmentally friendly extraction solvent.

scholarly journals Sustainable Biosynthesis of Antioxidants from Koji Rice Fermented with Aspergillus flavus Using Microwave-Assisted Extraction

2021 ◽  
Vol 11 (1) ◽  
pp. 430
Author(s):  
Hassan Hadi Mehdi Al Rubaiy ◽  
Ammar Altemimi ◽  
Ali Khudair Jaber Al Rikabi ◽  
Naoufal Lakhssassi ◽  
Anubhav Pratap-Singh
Keyword(s):  
Ethyl Acetate ◽  
Aspergillus Flavus ◽  
Bioactive Compounds ◽  
Ethylenediaminetetraacetic Acid ◽  
Ethyl Acetate Extract ◽  
Antioxidant Properties ◽  
Antioxidant Compounds ◽  
Microwave Assisted Extraction ◽  
Microwave Assisted ◽  
Assisted Extraction

The present study proposes microwave-assisted extraction as a sustainable technique for the biosynthesis of bioactive compounds from rice fermented with Aspergillus flavus (koji). First, fermentation conditions (i.e., pH from 3–12, five temperatures from 20–40 °C, and four culture-fermentation media viz. wheat, wheat bran, malt and rice) were optimized for producing microbial bioactive compounds. Microwave extraction was performed at 2450 MHz and 500 W for 20, 30, and 40 s with seven solvents (distilled water, ethyl acetate, hexane, ethanol, chloroform, diethyl ether, and methanol). The obtained results revealed that ethyl acetate is the most appropriate solvent for extraction. Effects of this ethyl acetate extract were compared with a commercial synthetic antioxidant. Antioxidant properties were enhanced by preventing the oxidation of the linoleic acid (C18H32O2) with an inhibition rate (antioxidant efficacy) of 73.13%. Notably, the ferrous ion binding ability was marginally lower when compared to the disodium salt of ethylenediaminetetraacetic acid (EDTA). Additionally, the obtained total content of phenolic compounds in the ethyl acetate extract of fermented rice (koji) by Aspergillus flavus was 232.11 mg based on gallic acid/mL. Antioxidant compounds in the ethyl acetate extract of fermented rice showed stability under neutral conditions, as well as at high temperatures reaching 185 °C during 2 h, but were unstable under acidic and alkaline conditions. The results demonstrate the efficacy of novel microwave-assisted extraction technique for accelerating antioxidant production during rice fermentation.

scholarly journals Preliminary Study on Pasta Samples Characterized in Antioxidant Compounds and Their Biological Activity on Kidney Cells

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1131 ◽  
Author(s):  
Federico Di Marco ◽  
Francesco Trevisani ◽  
Pamela Vignolini ◽  
Silvia Urciuoli ◽  
Andrea Salonia ◽  
...  
Keyword(s):  
Indoleacetic Acid ◽  
Antioxidant Properties ◽  
Antioxidant Compounds ◽  
Kidney Cells ◽  
Hek 293 ◽  
293 Cells ◽  
High Concentrations ◽  
Β Carotene ◽  
Egg Pasta

Pasta is one of the basic foods of the Mediterranean diet and for this reason it was chosen for this study to evaluate its antioxidant properties. Three types of pasta were selected: buckwheat, rye and egg pasta. Qualitative–quantitative characterization analyses were carried out by HPLC-DAD to identify antioxidant compounds. The data showed the presence of carotenoids such as lutein and polyphenols such as indoleacetic acid, (carotenoids from 0.08 to 0.16 mg/100 g, polyphenols from 3.7 to 7.4 mg/100 g). To assess the effect of the detected metabolites, in vitro experimentation was carried out on kidney cells models: HEK-293 and MDCK. Standards of β-carotene, indoleacetic acid and caffeic acid, hydroalcoholic and carotenoid-enriched extracts from samples of pasta were tested in presence of antioxidant agent to determine viability variations. β-carotene and indoleacetic acid standards exerted a protective effect on HEK-293 cells while no effect was detected on MDCK. The concentrations tested are likely in the range of those reached in body after the consumption of a standard pasta meal. Carotenoid-enriched extracts and hydroalcoholic extracts showed different effects, observing rescues for rye pasta hydroalcoholic extract and buckwheat pasta carotenoid-enriched extract, while egg pasta showed milder dose depending effects assuming pro-oxidant behavior at high concentrations. The preliminary results suggest behaviors to be traced back to the whole phytocomplexes respect to single molecules and need further investigations.

scholarly journals Extraction of Antioxidant Compounds from Blueberry Fruit Waste and Evaluation of Their In Vitro Biological Activity in Human Keratinocytes (HaCaT)

2021 ◽  
Author(s):  
Tomasz Piechowiak ◽  
Bartosz Skóra ◽  
Katarzyna Grzelak-Błaszczyk ◽  
Michał Sójka
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Properties ◽  
Waste Material ◽  
Lower Amount ◽  
Process Time ◽  
Antioxidant Compounds ◽  
Mass Unit ◽  
Diet Supplements ◽  
Study Results

AbstractThe purpose of this study was to investigate the biological properties of an extract obtained from the waste of blueberry fruit. The study covered the optimization of extraction of antioxidants from blueberry pomace and the determination of antioxidant properties of the extract using HaCaT as the model organism. Research showed that the yield of antioxidants extraction from blueberry waste was dependent on the applied extraction conditions. Based on the mathematical models, the optimal conditions of extraction process in which the maximum quantity of antioxidant compounds is achieved from the waste mass unit, i.e., the relation of the waste mass to the volume of ethanol equal to 1:17.36, and process time equal to 1000 s. The obtained extract was characterized by high antioxidant activity, which was shaped by high content of polyphenols, mainly anthocyanins. Moreover, the extract showed a high ability to protect HaCaT cells from the occurrence of oxidative stress induced by H2O2. Cells treated with the extract and H2O2 generated a lower amount of ROS than cells treated with H2O2 only. The obtained results will be base of further studies on applying the extract in production of diet supplements and functional foods with increased antioxidant activity. Moreover, the main research material is blueberry pomace which is a troublesome waste material for juice producers. Consequently, according to a sustainable development idea, the study results will provide an opportunity to increase interest in the problem of rational use of the waste material to a certain extent.

A Mathematical Principle and Application on Design of Planar Six-Bar Mechanism with unto Three-Ordered Intermission at Limit Position(s)

2010 ◽  
Vol 37-38 ◽  
pp. 9-13
Author(s):  
Hong Xin Wang ◽  
Ning Dai
Keyword(s):  
Design Method ◽  
Optimization Method ◽  
Basic Function ◽  
Mathematical Principle ◽  
Transmission Characteristics ◽  
Basic Functions ◽  
Combined Mechanism ◽  
Limit Position ◽  
Derivatives Of ◽  
Better Than

A non-iterative design method about high order intermittent mechanisms is presented. The mathematical principle is that a compound function produced by two basic functions, and then one to three order derivatives of the compound function are all zeroes when one order derivative of each basic function is zero at the same moment. The design method is that a combined mechanism is constructed by six bars; the displacement functions of the front four-bar and back four-bar mechanisms are separately built, let one order derivatives of two displacement functions separately be zero at the same moment, and then get geometrical relationships and solution on the intermittent mechanism. A design example shows that this method is simpler and transmission characteristics are better than optimization method.

scholarly journals Studies on drying characteristic, nutritional composition, and antioxidant properties of Stevia rebaudiana (Bertoni) leaves

2015 ◽  
Vol 29 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Yolanda B. Moguel-Ordóñez ◽  
Diana L. Cabrera-Amaro ◽  
Maira R. Segura-Campos ◽  
Jorge C. Ruiz-Ruiz
Keyword(s):  
Antioxidant Properties ◽  
Reducing Power ◽  
Stevia Rebaudiana ◽  
Biological Properties ◽  
Nutritional Composition ◽  
Antioxidant Compounds ◽  
Drying Methods ◽  
Stevia Rebaudiana Bertoni ◽  
Trolox Equivalent ◽  
Drying Treatment

Abstract Drying characteristics of Stevia rebaudiana (Bertoni) leaves using radiation drying, convection drying, sun drying, and shade drying treatments were investigated in a convective type. Results for all treatments indicated that drying took place in the falling rate period. The chroma of the dried samples ranged between 29.66 and 23.85. Convection and shade drying samples were found better in colour and had the highest content of total pigments. The proximate and fibre composition were affected by the drying treatments. Extracts obtained from convection drying and shade drying leaves exhibited higher values of Trolox equivalent antioxidant capacities 416.89-423.64 mM mg−1 and ferric reducing power 85.19-87.97%. These extracts also showed ion chelating capacity 59.05-60.21% for Cu+2 and 55.05-59.11% for Fe+2. The results indicate that it is possible to select the drying treatment to obtain the best nutritional and biological properties. Convection drying and shade drying were the least aggressive treatments and leaf powders obtained by these drying methods could be used as sources of nutrients, fibre, and antioxidant compounds.

Mechanochemical devulcanization of natural rubber vulcanizate by dual function disulfide chemicals

2016 ◽  
Vol 129 ◽  
pp. 34-46 ◽  
Author(s):  
Soumyajit Ghorai ◽  
Satyaban Bhunia ◽  
Madhusudan Roy ◽  
Debapriya De
Keyword(s):  
Natural Rubber ◽  
Dual Function ◽  
Rubber Vulcanizate

Comparative Evaluation of Onion Germplasm (Allium Cepa L.) Of Bangladesh for Physical And Antioxidant Properties

2021 ◽  
Vol 19 (1) ◽  
pp. 113-123
Author(s):  
PK Dash ◽  
S Das ◽  
MA Mannan ◽  
M Jahan
Keyword(s):  
Free Radicals ◽  
Antioxidant Properties ◽  
Biological Properties ◽  
Physicochemical Analysis ◽  
The Other ◽  
Antioxidant Compounds ◽  
Visual Methods ◽  
Ic50 Value ◽  
Onion Germplasm

Determination of antioxidant activity is one of the key elements for understanding the biological properties of a widely used spice onion (A. cepa). In contrast, physical properties help understand the textural quality of onion necessary for postharvest operations of sorting and grading in particular. Considering the physicochemical importance of onion, the present study focused on the determination of physical attributes and antioxidant content of the onion germplasm in Bangladesh using visual methods and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The five-onion germplasms (BARI Piaz-2, BARI Piaz-3, BARI Piaz-4, BARI Piaz-5, Faridpuri Vati) collected from selected onion growers of the Department of Agricultural Extension (DAE) of the southwestern part of Bangladesh were used as treatments for physicochemical analysis at the Horticulture laboratory of the Agrotechnology Discipline, Khulna University, Khulna, Bangladesh during the period from February to August 2019. The laboratory study was laid out in Completely Randomized Design (CRD) with three replications. Most of the physical characteristics of onion were highest in germplasm-1 than those of the other germplasm tested. The results showed that the DPPH free radicals were scavenged by all onion germplasm extracts in a concentration-dependent pattern. The highest IC50 value (238.10 ppm) was noticed in germplasm-3 and the lowest in germplasm-5 (161.29 ppm) with no statistical difference from germplasm-4 (172.41 ppm). The lower IC50 value indicating that onion germplasms-5 and -4 extracts were more potent in scavenging free radicals than the other onion germplasms. Thus, the low IC50 value facilitated the germplasm-5 and -4 to be enriched with antioxidant compounds significantly in higher amounts than the others. SAARC J. Agric., 19(1): 113-123 (2021)

Cure Characteristics and Mechanical Properties of Natural Rubber/Organoclay Nanocomposites

2003 ◽  
Vol 39 (1) ◽  
Author(s):  
P. L. Teh ◽  
Z. A. Mohd Ishak ◽  
U. S. Ishiaku ◽  
J. Karger–Kocsis
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Cure Characteristics
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