The Specific Rates of Solvolysis of t-Butyl Chloride in Aqueous Methanol, Aqueous Acetone and Aqueous Dioxane and of t-Butyl Bromide in Aqueous Acetone1

1954 ◽  
Vol 76 (24) ◽  
pp. 6248-6253 ◽  
Author(s):  
W. H. Cropper ◽  
Frances Spieth ◽  
A. R. Olson
Keyword(s):  
Aqueous Acetone ◽  
Aqueous Dioxane ◽  
Butyl Chloride ◽  
Aqueous Methanol ◽  
Butyl Bromide

scholarly journals Drying Temperature Effect on Total Phenols and Flavonoids Content, and Antioxidant Activity of Borassus aethiopum Mart Ripe Fruits’ Pulp

2017 ◽  
Vol 6 (2) ◽  
pp. 50 ◽  
Author(s):  
Tagouelbe Tiho ◽  
Jean Claude N'guessan Yao ◽  
Casimir Yao Brou ◽  
Augustin Amissa Adima
Keyword(s):  
Antioxidant Activity ◽  
Aqueous Acetone ◽  
Total Flavonoids ◽  
Distilled Water ◽  
Total Phenols ◽  
Aqueous Methanol ◽  
Drying Temperature ◽  
Total Flavonoids Content ◽  
Main Effects ◽  
Borassus Aethiopum

We assessed the total phenols content (TPC) by Folin-Ciocalteux method, total flavonoids content (TFC), and antioxidant activity (AOA) using ABTS radical cation of Borassus aethiopum Mart ripe fruits; uniquely its pulp was considered. Fresh and dried at 40, 50, 60, 70 and 80oC pulps were analyzed, through maceration and decoction, and distilled water (DW), aqueous acetone (DW+Aceto, DW/acetone, 30/70, v/v) and aqueous methanol (DW+Meth) prepared in the same way were used. Though 80oC product extracted through decoction delivered the highest extracts of TPC with DW, DW+Aceto and DW+Meth, 654.434, 780.066 and 729.934 mg GAE/g respectively; we could not retain it as the best. Very likely, the sugars were caramelizing and the derived product had an intense brown color. Whereas, at 70oC, TPCs were 447.866, 337.334 and 327.066 mg GAE/g, respectively, by decoction and in the same above solvents order. The best extract obtained with DW was statistically different from that of DW + Aceto and DW + Meth, which were not significantly different from each other, with Duncan least squares means comparison test in a confidence interval of 99%. The corresponding TFCs and AOAs were (59.34, 68.34, and 51.66 mg QE/g) and (0.4404, 0.52088, and 0.6524 µmol TE/g). The flour has a nice chocolate color. Except 60oC, an increase of the drying temperature leaded to a rising amount of TPC. Taking each factor, the extraction mode and drying temperature were main effects for extracts (p< 0.0001). The overall regression analysis showed significant correlation coefficient between TPC and AOA, with R2=0.8394.

scholarly journals Estimation of Total Phenolic and Flavonoid Contents in Some Medicinal Plants and Their Antioxidant Activities

2015 ◽  
Vol 15 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Bedraj Pandey ◽  
Meena Rajbhandari
Keyword(s):  
Free Radical ◽  
Methanol Extract ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Aqueous Acetone ◽  
Total Phenolic ◽  
Aqueous Methanol ◽  
Acetone Extracts ◽  
Phenolic And Flavonoid

Quercetin was isolated from ethyl acetate fraction of a methanol extract of the outer scale of onion by repeated sephadex LH-20 column chromatography. Methanol, 50% aqueous methanol and 70% aqueous acetone extracts of different parts of four medicinal plants, Ficus benghalensis, Elaeocarpus sphaericus, Ipomea carnea and Azeratum conyzoides were prepared and screened for total phenolic and flavonoid contents and free radical scavenging activity. The total phenolics contents were measured spectrophotometrically by using Folin-Ciocalteu reagent and total flavonoids content by using aluminum chloride colorimetric method. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay. All the investigated medicinal plant extracts contained high amount of phenolics. The highest amount was detected in 70% aqueous acetone extract of E. sphaericus (298.8±9.03 mg GAE/g extract) and lowest amount in 50% aqueous methanol extract of F. benghalensis (6.7±0.73 mg GAE/g extract). The highest amount of flavonoid was found in methanol extract (78.2±2.72 mg quercetin/g extract) and the lowest amount was detected in 50% aqueous methanol extract (2.1±0.25 mg quercetin/g extract) of F. benghalensis. DPPH free radical scavenging assay was carried out only in 70% acetone extracts. The highest IC50 value was observed for E. sphaericus (34.0 μg/ml). A strong linear correlation between total phenolic content and antioxidant activity was found indicating that the major antioxidants are phenolics.DOI: http://dx.doi.org/10.3126/njst.v15i1.12010  Nepal Journal of Science and Technology Vol. 15, No.1 (2014) 53-60

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