Dediazoniation of p-hydroxy and p-nitrobenzenediazonium ions in an aqueous medium: Interference by the chelating agent diethylenetriaminepentaacetic acid

2003 ◽  
Vol 81 (7) ◽  
pp. 832-839 ◽  
Author(s):  
B Quintero ◽  
M C Cabeza ◽  
M I Martínez ◽  
P Gutiérrez ◽  
P J Martínez
Keyword(s):  
Experimental Data ◽  
Aqueous Medium ◽  
Radical Scavenging ◽  
Chelating Agent ◽  
Diethylenetriaminepentaacetic Acid ◽  
Oh Groups ◽  
Metal Chelator ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Neutral Aqueous Medium

We have made a comparative study of the dediazoniation of p-hydroxy and p-nitrobenzenediazonium ions. The electron-withdrawing and donating properties of the -NO2 and -OH groups strongly determine the reactivity of both compounds, thus exerting different influences upon the dediazoniation reaction. We describe here how the decomposition of p-hydroxy and p-nitrobenzenediazonium ions in a neutral aqueous medium follows a different pattern in the presence of the metal-chelator diethylenetriaminepentaacetic acid (DTPA). The decomposition rate of p-hydroxybenzene diazonium decreases whilst the decomposition of the p-nitrobenzenediazonium ion is enhanced. The experimental data are discussed with reference to a common scheme of interference for both benzenediazonium ions in the light of the radical-scavenging capacity of DTPA.Key words: p-hydroxybenzenediazonium ion, p-nitrobenzenediazonium ion, di-ethylenetriaminepentaacetic acid, dediazoniation, radical scavenging, artifacts.

scholarly journals Microwave heating effect on total phenolics and antioxidant activity of green and mature coconut water

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Abraham Jesús Arzeta-Ríos ◽  
Diana Guerra-Ramírez ◽  
Benito Reyes-Trejo ◽  
Ma. Carmen Ybarra-Moncada ◽  
Holber Zuleta-Prada
Keyword(s):  
Antioxidant Activity ◽  
Heating Temperature ◽  
Cocos Nucifera ◽  
Radical Scavenging ◽  
Coconut Water ◽  
Total Phenolic ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Maximum Temperatures ◽  
Increasing Temperature

AbstractCoconut water (Cocos nucifera L.) from fruits of two ripening stages (green and mature) was used to perform microwave heat treatments. Three different heating conditions with maximum temperatures of 70, 80 and 90 °C were tested in three holding times (0, 2 and 4 min). The Total Phenolic Content (TPC) using the Folin-Ciocalteu method and ABTS radical scavenging capacity were evaluated for each combination of coconut fruit age, heating temperature and holding time. It was observed that green coconut water exhibited significant differences (p < 0.05) compared to mature coconuts in terms of TPC (46.03 and 69.16 mg GAE/L, respectively) and ABTS radical scavenging capacity (422.31 and 549.1 μmol TE/L, respectively). An increase in TPC (up to 23%) and antioxidant activity (up to 19%) was also observed with increasing temperature in the range of 70–90 °C. Green coconut water showed the largest increase in both TPC and antioxidant activity.

scholarly journals A simple new method for aged seed utilization based on melatonin-mediated germination and antioxidant nutrient production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Song Yu ◽  
Xuetian Zhu ◽  
Helin Yang ◽  
Lihe Yu ◽  
Yifei Zhang
Keyword(s):  
Total Phenolics ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Dpph Radical ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Aged Seed ◽  
Phenolics Content ◽  
Dpph Radical Scavenging ◽  
Aged Seeds

AbstractSeed deterioration, coupled with a decrease in nutrients, is unavoidable following long-term storage, and these seeds are therefore used as livestock fodder. Here, we developed a simple, rapid and efficient method of producing high amounts of antioxidants from deteriorated seeds via melatonin-induced germination. Legume seeds were subjected to high humidity at 55 °C for 12–36 h to obtain aged seeds with a 40% germination rate and severely reduced antioxidant nutrition (total phenolics content, ferric reducing power and 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging capacity). Aged seeds were then treated with 0.1 mM melatonin, resulting in the production of sprouts with a higher total phenolics content (fivefold), greater ferric reducing power (sevenfold) and greater DPPH radical scavenging capacity (twofold) compared to the aged seeds. These findings suggest that melatonin treatment efficiently converted aged seed reserve residues into antioxidant nutrients, providing an alternative use for deteriorated seeds in food production.

scholarly journals Quality and Antioxidant Properties of Cold-Pressed Oil from Blanched and Microwave-Pretreated Pomegranate Seed

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 712
Author(s):  
Tafadzwa Kaseke ◽  
Umezuruike Linus Opara ◽  
Olaniyi Amos Fawole
Keyword(s):  
Radical Scavenging ◽  
Total Phenolic ◽  
Yellowness Index ◽  
Cold Pressing ◽  
Microwave Pretreatment ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Pomegranate Seed ◽  
Cold Pressed

The present research studied the influence of blanching and microwave pretreatment of seeds on the quality of pomegranate seed oil (PSO) extracted by cold pressing. Pomegranate seeds (cv. Acco) were independently blanched (95 ± 2 °C/3 min) and microwave heated (261 W/102 s) before cold pressing. The quality of the extracted oil was evaluated with respect to oxidation indices, refractive index, yellowness index, total carotenoids content, total phenolic content, flavor compounds, fatty acid composition, and 2.2-diphenyl-1-picryl hydrazyl (DPPH) and 2.2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity. Blanching and microwave pretreatments of seeds before pressing enhanced oil yield, total phenolic content, flavor compounds, and DPPH and ABTS radical scavenging capacity. Although the levels of oxidation indices, including the peroxide value, free fatty acids, acid value, ρ-anisidine value, and total oxidation value, also increased, and the oil quality conformed to the requirements of the Codex Alimentarius Commission (CODEX STAN 19-1981) standard for cold-pressed vegetable oils. On the other hand, blanching and microwave heating of seeds decreased the pomegranate seed oil’s yellowness index, whilst the refractive index was not significantly (p > 0.05) affected. Even though both blanching and microwave pretreatment of seeds added value to the cold-pressed PSO, the oil extracted from blanched seeds exhibited lower oxidation indices. Regarding fatty acids, microwave pretreatment of seeds before cold pressing significantly increased palmitic acid, oleic acid, and linoleic acid, whilst it decreased the level of punicic acid. On the contrary, blanching of seeds did not significantly affect the fatty acid composition of PSO, indicating that the nutritional quality of the oil was not significantly affected. Therefore, blanching of seeds is an appropriate and valuable step that could be incorporated into the mechanical processing of PSO.

Effect of 1-MCP on Bioavailability of Lingwu Long Jujube In Vitro Digestion

2012 ◽  
Vol 554-556 ◽  
pp. 1357-1360
Author(s):  
Zhong Li Jiang ◽  
Ai Li Wang ◽  
Xi Hong Li ◽  
Min Peng Zhu ◽  
Jun Wei Wang
Keyword(s):  
Free Radical ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Total Phenolic ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Control Samples

The present study investigated the effect of 1-MCP on bioavailability of Lingwu long jujube stored at 0 °C for 60 days. At the end of the storage, compared with the control samples, Lingwu long jujube treated with 1-MCP exhibited higher Vc bioaccessibility, total phenolic content and free radical scavenging capacity, which demonstrated that 1-MCP treatment could provide a better effect on maintaining the bioavailability of Lingwu long jujube.

scholarly journals Effects of Fruit Maturity on Physicochemical Properties, Sugar Accumulation and Antioxidant Capacity of Wild Harvested Kakadu Plum (Terminalia ferdinandiana)

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 48
Author(s):  
Anh Dao Thi Phan ◽  
Maral Seidi Damyeh ◽  
Saleha Akter ◽  
Mridusmita Chaliha ◽  
Michael E. Netzel ◽  
...  
Keyword(s):  
Free Radical ◽  
Antioxidant Capacity ◽  
Soluble Sugars ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Maturity Stages ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Kakadu Plum ◽  
Terminalia Ferdinandiana

Terminalia ferdinandiana (Kakadu plum), belonging to the family Combretaceae, is endemic to Australia and has a long history of traditional medicinal applications and food cuisine by the Australian Indigenous people. This study investigated the effects of maturity stages on the morphology, physicochemical parameters (total soluble solids (TSS), total acid content (TAC), and pH), soluble sugar profile and antioxidant capacity of Kakadu plum (KP) fruits that were wild harvested from different trees and classified into four different maturity stages (immature to mature). TSS and TAC were determined by standard assays/procedures, main sugars by UHPLC–MS/MS and antioxidant capacity (total phenolic content (TPC) and DPPH free radical scavenging capacity) by spectrophotometry. The results showed that soluble sugars (glucose, sucrose and fructose) ranging from 1.3 to 17.7% dry weight (DW), TSS (17.0–52.7% DW) and TAC (1.3–6.7% DW) increased with maturity. However, antioxidant capacity (TPC in the range of 7.4–21.9% DW and DPPH free radical scavenging capacity from 22 to 76% inhibition at the extract concentration of 20 g·L−1) did not follow the same trend as the one observed for soluble sugars, TSS and TAC. These differences were associated with the tree-to-tree variability as a consequence of the wild harvest condition. This study provides important information to both the KP industry and Indigenous enterprises regarding the selection of the appropriate maturity stage to harvest KP fruit to target for different markets (e.g., low-sugar vs. high-sugar fruit).

Antioxidative properties of Sambacus nigra extracts

2015 ◽  
Vol 69 (9) ◽  
Author(s):  
Dominika Topoľská ◽  
Katarína Valachová ◽  
Peter Rapta ◽  
Stanislav Šilhár ◽  
Elena Panghyová ◽  
...  
Keyword(s):  
Acute Inflammation ◽  
Radical Scavenging ◽  
Oxidative Degradation ◽  
Protective Effects ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Diammonium Salt ◽  
Dose Dependent ◽  
Oxidative System

AbstractPotential protective effects of elderberry (Sambucus nigra) extracts against oxidative degradation of hyaluronan (HA) were detected in vitro. To induce free-radical-mediated HA degradation, Weissberger’s biogenic oxidative system, which mimics the situation of acute inflammation, was applied. Time- and dose-dependent changes of dynamic viscosity of the HA solutions in the presence and absence of two elderberry extracts produced in 2006 and 2012 were recorded by rotational viscometry (RV). Radical scavenging capacity of both extracts was investigated by the spectrocolorimetric ABTS [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] assay and the “inverted” ABTS assay. Oxygen consumption of the system oxidizing HA either in the absence or presence of the elderberry extracts was determined. The results of RV revealed that an addition of the newer extract (2012) promoted the inhibition of HA degradation more markedly compared to the older extract (2006). The same effect of both extracts on ABTS

scholarly journals Age-Induced Diminution of Free Radical Scavenging Capacity in Bee Pollens and the Contribution of Constituent Flavonoids

2003 ◽  
Vol 51 (3) ◽  
pp. 742-745 ◽  
Author(s):  
Maria G. Campos ◽  
Rosemary F. Webby ◽  
Kenneth R. Markham ◽  
Kevin A. Mitchell ◽  
Antonio P. da Cunha
Keyword(s):  
Free Radical ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity

scholarly journals Free Radical-Scavenging Capacities, Phenolics and Capsaicinoids in Wild Piquin Chili (Capsicum annuum var. Glabriusculum)

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2655 ◽  
Author(s):  
Yolanda Moreno-Ramírez ◽  
Guillermo Martínez-Ávila ◽  
Víctor González-Hernández ◽  
Cecilia Castro-López ◽  
Jorge Torres-Castillo
Keyword(s):  
Free Radical ◽  
Phenolic Compounds ◽  
Radical Scavenging ◽  
Natural Populations ◽  
Free Radical Scavenging ◽  
Chemical Diversity ◽  
Total Phenolic ◽  
Total Phenolic Compounds ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity

The total phenolic compounds content, free radical-scavenging capacity and capsaicinoid content in populations of wild Piquin chili (C. annuum) were studied. Aqueous and hydroalcoholic extracts from nine ecotypes were evaluated. High contents of phenolic compounds and free radical-scavenging capacities were observed for both extracts; however, the values that were found for the hydroalcoholic phase were substantially higher. LC-MS analysis allowed for the detection of 32 compounds, where apigenin-8-C-glucoside followed by vanillic acid 1-O-β-o-glucopyranosylester (Isomer I or II) and 7-ethoxy-4-methylcoumarin were the most widely distributed; they were found in more than 89% of the ecotypes. The diversity of identified phenolic compounds was different among ecotypes, allowing them to be distinguished by chemical diversity, free radical-scavenging capacities and heat Scoville units. The total capsaicinoid content was higher in Population I (23.5 mg/g DW) than in Populations II and III, which had contents of 15.3 and 10.7 mg/g DW, respectively. This variability could lead to phytochemical exploitation and the conservation of the natural populations of wild chili.

scholarly journals Synthesis of antioxidative anthraquinones as potential anticancer agents

BIBECHANA ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 143-153
Author(s):  
Richa K. Gupta ◽  
Ganesh M. S. Thakuri ◽  
Gan B Bajracharya ◽  
Ram Narayan Jha
Keyword(s):  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Anticancer Agents ◽  
Radical Scavenging ◽  
Antibacterial Activities ◽  
Dpph Radical ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Dpph Radical Scavenging

Antioxidant and antibacterial activities of natural anthraquinones namely chrysophanol (1) and emodin (2), and synthesized anthraquinones viz. 2-methylanthraquinone (3), anthraquinone (4), 2-bromoanthraquinone (5), rubiadin (6), chrysophanol diacetate (7), rubiadin diacetate (8) and 1,8-dimethoxy-3-methylanthraquinone (9) were investigated. Anthraquinones 9, 3, 6, 5 and 2 exhibited a high DPPH• radical scavenging capacity (IC50 = <500 μg/mL) showing their therapeutic potentiality for the treatment of cancers. These anthraquinones 1-9 have also displayed a weak to moderate antibacterial activity against Bacillus subtilis. Chrysophanol diacetate (7) including emodin (2) have been appeared as the valuable antibacterials. BIBECHANA 18 (2) (2021) 143-153

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