scholarly journals Extraction and Characterization of Rice Bran Polysaccharides and Their Derivative Preparation and Antioxidant Activity

2020 ◽  
Author(s):  
Gangliang Huang
Keyword(s):  
Antioxidant Activity ◽  
Rice Bran ◽  
Concentration Ratio ◽  
Reaction Conditions ◽  
Original Activity ◽  
Reducing Ability ◽  
Crude Polysaccharide ◽  
Polysaccharide Derivatives ◽  
Solid Liquid

AbstractThe crude polysaccharide of rice bran polysaccharide was extracted with water from defatted rice bran, and the optimal reaction conditions of the experiment were determined. The reaction temperature is 100°C, the reaction time is 5h, the solid-liquid ratio is 1:10; the concentration ratio of polysaccharide to Sevag reagent is 2:1, and rice polysaccharide is precipitated by ethanol insoluble property and ethanol. The ethanol concentration ratio is 3:1. Using the methods and conditions of this experiment, the maximum polysaccharide yield is 2.18%. Then the chemical structure of rice bran polysaccharide was analyzed by IR, UV and 13CNMR methods. Three rice bran polysaccharide derivatives were prepared and characterized: carboxymethylated rice bran polysaccharide, phosphorylated rice bran polysaccharide and acetylated rice bran polysaccharide. Also studied the antioxidant activity of rice bran polysaccharide and its derivatives (hydroxy radical ion scavenging ability, superoxide anion scavenging ability, anti-lipid peroxidation ability, reducing ability), and found that phosphorylated rice bran polysaccharide has good activity. The acetylated rice bran polysaccharide may weaken the original activity.

scholarly journals Synthesis and structural characterization of novel O-substituted phenolic and chalcone derivatives with antioxidant activity

2020 ◽  
pp. 174751982093278
Author(s):  
Bathélémy Ngameni ◽  
Musa Erdoğan ◽  
Victor Kuete ◽  
Erdin Dalkılıç ◽  
Bonaventure T Ngadjui ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Click Reaction ◽  
Radical Scavenging ◽  
Aromatic Aldehydes ◽  
Schmidt Method ◽  
Reaction Conditions ◽  
Aromatic Azide ◽  
Work Up ◽  
Radical Scavenging Assay

A series of novel 4- O-alkyltriazolylphenolic derivatives is first synthesized with good to excellent yields via the click reaction of 3-methoxy-4- O-propargylbenzaldehyde or 3-allyl-4- O-propargylacetophenone and aromatic azide derivatives. Next, the chalcones are prepared via the Claisen-Schmidt method from 4- O-alkylphenylketone derivatives in the presence of the corresponding (hetero)aromatic aldehydes as electrophiles. The structures of the newly synthesized compounds are confirmed from their infrared, nuclear magnetic resonance spectral data, and by elemental analysis. The main advantages of this procedure are the simplicity of the reaction conditions, easily available starting materials, and simple work-up. The antioxidant activity of several of the products is determined using the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical scavenging assay. 4- O-propargylvanillin (IC50 = 14.54 µg/mL) had moderate antioxidant activity.

Evaluation of antioxidant and Anthelmintic activity of methanolic flower extract of Nyctanthes arbor-tristis

2018 ◽  
Vol 9 (1) ◽  
pp. 78
Author(s):  
Vijaya Jyothi M ◽  
Bhargav E ◽  
Pavan Kumar K ◽  
Praneeth Gowd K ◽  
Ram Pavan S
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging Activity ◽  
Iridoid Glycosides ◽  
Radical Scavenging ◽  
Anthelmintic Activity ◽  
Total Phenolic ◽  
Standard Drug ◽  
Flower Extract ◽  
Reducing Ability ◽  
Total Flavonoids Content

Nyctanthes arbour-tristis is a shrub belongs to the family Oleaceae. The flowers of this plant are fragrant since the presence of flavonol glycosides. It has also been reported for the presence of β-sitosterol, iridoid glycosides, tannins etc., and known to have immunostimulant, hepatoprotective, antiviral and antifungal activities. In the present study an attempt is made to identify antioxidant capacity and anthelminthic potential of methanolic flower extract of Nyctanthes arbour-tristis. Antioxidant activity was evaluated by total phenolic content assay, total flavonoids content assay, free radical scavenging activity and reducing ability methods. Anthelmintic activity was evaluated on Perithima posthuma using Piperazine citrate as standard drug. The results obtained for the above activities reveals that Nyctanthes arbour-tristis shows considerable antioxidant activity for all the methods and anthelminthic potential at 300 mg/ml. Keywords: arbour-tristis; antioxidant activity; anthelminthic activity; Perithima posthuma; Piperazine citrate.

scholarly journals Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 178
Author(s):  
Souhail Maazioui ◽  
Abderrahim Maazouz ◽  
Fayssal Benkhaldoun ◽  
Driss Ouazar ◽  
Khalid Lamnawar
Keyword(s):  
Flow Behavior ◽  
Continuous Phase ◽  
Raw Material ◽  
Rheological Characterization ◽  
Phosphate Ore ◽  
Insoluble Particles ◽  
Experimental Protocols ◽  
Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

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