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 ◽  
...  

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.

2011 ◽  
Vol 66 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Milan Čačić ◽  
Maja Molnar

In our effort to obtain biologically active compounds, new 3,5-disubstituted 1,3-thiazolidine-2,4- diones (5a - r) were synthesized. A series of 5-arylmethylidene-1,3-thiazolidine-2,4-diones (3a - r) were prepared by Knoevenagel reaction from 1,3-thiazolidine-2,4-dione (2) and appropriate aromatic aldehydes. Condensation of 3a - r with 7-hydroxy-4-bromomethyl-2-oxo-2H-chromene (1) afforded novel 3-(7-hydroxy-2-oxo-2H-chromen-4-ylmethyl)-5-arylidene-1,3-thiazolidine-2,4-diones 5a - r. Compounds 3a - r and 5a - r were evaluated for their antioxidant activity (DPPH free radical scavenging activity).


Author(s):  
Shaista Amin ◽  
Amrita Parle

Objective: To synthesize benzothiazole derivatives, characterize them by 1HNMR and ATIR techniques and evaluate for their antioxidant activity.Methods: In the present study 12 benzothiazole derivatives were synthesized by reacting 2-chloronitro benzene as the primary reactant with different aromatic aldehydes and benzoic acids. Reactions were monitored using thin layer chromatography technique, and the newly synthesized derivatives were characterized by ATIR and 1HNMR techniques. The antioxidant assay was performed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS method and 2,2-diphenyl-1-picrylhydrazyl or DPPH method.Results: The antioxidant activity was found to be better in ABTS assay than DPPH assay. The compounds showed comparable activity to ascorbic acid at 100µg/ml.Conclusion: It was found that the synthesized benzothiazole derivatives showed significant radical scavenging potential.


2020 ◽  
Vol 8 (2) ◽  
pp. 35-44
Author(s):  
Vineet Kumar Singh ◽  
Amrita Parle

Objective: To synthesize benzimidazole derivatives, characterize them by 1HNMR and ATIR techniques and evaluate their antioxidant activity. Methods: In the present study 19 benzimidazole derivatives were synthesized by reacting O-phenylenediamine as the primary reactant with different aromatic aldehydes and benzoic acids. Reactions were monitored using thin layer chromatography technique, and the newly synthesized derivatives were characterized by ATIR and 1HNMR techniques. The antioxidant assay was performed using ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] method and DPPH [2,2-diphenyl-1-picrylhydrazyl] method. Results: Compounds BNZ-1, BNZ-2, BNZ-3, BNZ-9, and BNZ-10 showed comparable antioxidant activity to ascorbic acid at higher dose. Conclusion: The synthesized benzimidazole derivatives have significant radical scavenging potential.    


Author(s):  
Pranabendu Mitra ◽  
Venkatesh Meda ◽  
Rick Green

The main objective of this research was to compare the retention of antioxidant activity and total anthocyanin content of Saskatoon berries dried by freeze drying, microwave-vacuum drying, thin layer hot air drying and vacuum drying. Antioxidant activity of berry samples was determined by DPPH radical scavenging and ABTS radical scavenging, and the pH differential method was used to determine total anthocyanin content of the berry samples. The results showed that the freeze dried Saskatoon berries exhibited the highest retention of anthocyanin and antioxidant activity among the dried samples, followed by microwave-vacuum dried berries, thin layer hot air dried berries and vacuum dried berries. There were significant differences between the berry samples at P<0.05.  DPPH radical scavenging and ABTS radical scavenging were correlated linearly with an R2 value of 0.99 at P<0.05 showing their effectiveness for the determination of the antioxidant activity of the Saskatoon berries. However, the DPPH radical scavenging assay was more effective than the ABTS radical scavenging assay. The results also showed that antioxidant activity of the berries was highly correlated with the total anthocyanin content of the fruit. The reduction of anthocyanin in dried berry samples was linearly correlated with the reduction of DPPH radical scavenging with an R2 value of 0.97 at P<0.05 and, also, linearly correlated with the reduction of ABTS radical scavenging with an R2 value of 0.88 at P<0.05.


2013 ◽  
Vol 2 (2) ◽  
Author(s):  
Pranabendu Mitra ◽  
Venkatesh Meda ◽  
Rick Green

The main objective of this research was to compare the retention of antioxidant activity and total anthocyanin content of Saskatoon berries dried by freeze drying, microwave-vacuum drying, thin layer hot air drying and vacuum drying. Antioxidant activity of berry samples was determined by DPPH radical scavenging and ABTS radical scavenging, and the pH differential method was used to determine total anthocyanin content of the berry samples. The results showed that the freeze dried Saskatoon berries exhibited the highest retention of anthocyanin and antioxidant activity among the dried samples, followed by microwave-vacuum dried berries, thin layer hot air dried berries and vacuum dried berries. There were significant differences between the berry samples at P<0.05.  DPPH radical scavenging and ABTS radical scavenging were correlated linearly with an R2 value of 0.99 at P<0.05 showing their effectiveness for the determination of the antioxidant activity of the Saskatoon berries. However, the DPPH radical scavenging assay was more effective than the ABTS radical scavenging assay. The results also showed that antioxidant activity of the berries was highly correlated with the total anthocyanin content of the fruit. The reduction of anthocyanin in dried berry samples was linearly correlated with the reduction of DPPH radical scavenging with an R2 value of 0.97 at P<0.05 and, also, linearly correlated with the reduction of ABTS radical scavenging with an R2 value of 0.88 at P<0.05.


2015 ◽  
Vol 748 ◽  
pp. 183-186
Author(s):  
Zhi Cheng Sun ◽  
Shu Ying Chen ◽  
Zhi Peng Guo ◽  
Mei Juan Cao ◽  
Lu Hai Li

A novel one-pot method for the synthesis of substituted μ-oxo-bis [tetraphenyl porphyrinatoiron] compounds ([TRPPFe]2O) from pyrrole and aromatic aldehydes was proposed and investigated in this paper. Four kinds of [TRPPFe]2O were designed and synthesized by one-pot reaction and characterized by elemental analysis, infrared spectra and ultraviolet-visible spectroscopy. Moreover, the [TRPPFe]2O yields of 18.7~22.4% could be obtained with this novel method under the optimum reaction conditions.


Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2176
Author(s):  
Meriam Missaoui ◽  
Isabella D’Antuono ◽  
Massimiliano D’Imperio ◽  
Vito Linsalata ◽  
Sadok Boukhchina ◽  
...  

The Opuntia ficus indica (L.) (OFI) is used as a nutritional and pharmaceutical agent in various dietary and value added products. This study underlines the possible use of native prickly pear cladode powder as a functional ingredient for health-promoting food production. To summarise, chemical characterization of polyphenols, minerals and soluble dietary fibre was performed; furthermore, the antioxidant activity and bioaccessibility of polyphenols and minerals were assessed. Eleven compounds between phenolic acids and flavonoids were identified, with piscidic acid and isorhamnetin derivatives being the most abundant. Opuntia’s dietary fibre was mainly constituted of mucilage and pectin, and was composed of arabinose, galactose, glucose, mannose, rhamnose, and xylose sugars. The polyphenols’ bioaccessibility was very high: piscidic acid at 200%, eucomic and ferulic acids >110% and flavonoids from 89% to 100%. The prickly pear cladode powder is also a source of minerals, as cations (calcium, sodium, potassium and magnesium) and anions (sulphate and chloride), with high magnesium bioaccessibilty (93%). OFI powder showed good capacity of radical scavenging measured by DPPH and ABTS methods, with 740 and 775 μmol Trolox/100 g OFI, respectively. Finally, the presented results allow the consideration of this natural product as a source of several essential nutrients, with a possible use in the food industry as a functional ingredient.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Yuliang Zhang ◽  
Zhongqiang Zhou

A simple and efficient synthesis of 5-arylidene-2,4-thiazolidinediones by the Knoevenagel condensation of aromatic aldehydes with 2,4-thiazolidinedione catalyzed by ethylenediamine diacetate under solvent-free conditions is described. The major advantages of this method are simple experimental and work-up procedures, solvent-free reaction conditions, small amount of catalyst, short reaction time, high yields, and utilization of an inexpensive and reusable catalyst.


2005 ◽  
Vol 2005 (9) ◽  
pp. 600-602 ◽  
Author(s):  
Yu-Ling Li ◽  
Mei-Mei Zhang ◽  
Xiang-Shan Wang ◽  
Da-Qing Shi ◽  
Shu-Jiang Tu ◽  
...  

In this paper the preparation of 3,3,6,6-tetramethyl-9-aryl-1,2,3,4,5,6,7,8,9,10- decahydroacridin-1,8-dione derivatives from aromatic aldehydes, 5,5-dimethyl-1,3- cyclohexanedione and ammonium acetate in ionic liquids [bmim+][BF4-] is described. This new method has the advantages of easier work-up, milder reaction conditions, high yields and an environmentally benign procedure compared with other methods.


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