Antioxidant Properties of Select Radiation Mitigators Based on Semicarbazone and Pyrazole Derivatives of Curcumin

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Proceedings ◽

10.3390/foods_2020-07750 ◽

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.

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ChemInform Abstract: HETEROCYCLIC STEROIDAL, (16,15-C)PYRAZOLE DERIVATIVES OF ESTRADIOL AND ESTRONE

Chemischer Informationsdienst ◽

10.1002/chin.197546444 ◽

1975 ◽

Vol 6 (46) ◽

pp. no-no

Author(s):

P. DE RUGGIERI ◽

M. FAZIO ◽

G. MONOTORO ◽

O. SIGHINOLFI

Keyword(s):

Pyrazole Derivatives ◽

Derivatives Of

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ChemInform Abstract: NMR SPECTRA OF PYRAZOLE DERIVATIVES OF BORON

Chemischer Informationsdienst ◽

10.1002/chin.198323044 ◽

1983 ◽

Vol 14 (23) ◽

Author(s):

W. J. LAYTON ◽

K. NIEDENZU ◽

S. L. SMITH

Keyword(s):

Nmr Spectra ◽

Pyrazole Derivatives ◽

Derivatives Of

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Semisynthesis and acaricidal activities of isoxazole and pyrazole derivatives of a natural product bisdemethoxycurcumin

Journal of Pesticide Science ◽

10.1584/jpestics.d13-027 ◽

2013 ◽

Vol 38 (4) ◽

pp. 214-219 ◽

Cited By ~ 6

Author(s):

Jinxiang Luo ◽

Wei Ding ◽

Yongqiang Zhang ◽

Zhenguo Yang ◽

Yang Li ◽

...

Keyword(s):

Natural Product ◽

Pyrazole Derivatives ◽

Derivatives Of

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Suppression of Methane Generation during Methanogenesis by Chemically Modified Humic Compounds

Antioxidants ◽

10.3390/antiox9111140 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1140

Author(s):

Elena Efremenko ◽

Olga Senko ◽

Nikolay Stepanov ◽

Nikita Mareev ◽

Alexander Volikov ◽

...

Keyword(s):

Antioxidant Properties ◽

Nutrient Media ◽

Potassium Humate ◽

Methane Generation ◽

Chemically Modified ◽

Humic Compounds ◽

Negative Effect ◽

The Media ◽

First Time ◽

Derivatives Of

The introduction of various concentrations of chemically modified humic compounds (HC) with different redox characteristics into the media with free and immobilized anaerobic consortia accumulating landfill gases was studied as approach to their functioning management. For this purpose, quinone (hydroquinone, naphthoquinone or methylhydroquinone) derivatives of HC were synthesized, which made it possible to vary the redox and antioxidant properties of HC as terminal electron acceptors in methanogenic systems. The highest acceptor properties were obtained with potassium humate modified by naphthoquinone. To control possible negative effect of HC on the cells of natural methanogenic consortia, different bioluminescent analytical methods were used. The addition of HC derivatives, enriched with quinonones, to nutrient media at concentrations above 1 g/L decreased the energetic status of cells and the efficiency of the methanogenesis. For the first time, the significant decrease in accumulation of biogas was reached as effect of synthetic HC derivatives, whereas both notable change of biogas composition towards increase in the CO2 content and decrease in CH4 were revealed. Thus, modification with quinones makes it possible to obtain low-potential HC derivatives with strongly pronounced acceptor properties, promising for inhibition of biogas synthesis by methanogenic communities.

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