A series of heterocyclic compounds bearing the well-known free radical scavenging 3,4,5-trimethoxybenzyloxy group, was synthesized. The key compound 4-(3,4,5-trimethoxybenzyl-oxy)benzohydrazide was converted into thiosemicarbazide derivatives, which were subsequently cyclized with NaOH to provide 1,2,4-triazole derivatives. Alternative treatment of the acid hydrazide with carbon disulfide in th...

Total polyphenol content, catechins content, and antioxidant capacities of green, dark, oolong, and black teas made from Camellia sinensis in China were evaluated. The total polyphenol content of 20 samples of tea was in the range of 7.82-32.36%. Total catechins content was in the range of 4.34-24.27%. The antioxidant capacity of tea extract was determined by the oxygen radical absorbance capac...

The radical-scavenging activities of the synthetic antioxidants 2-allyl-4-X-phenol (X = NO2, Cl, Br, OCH3, COCH3, CH3, t-(CH3)3, C6H5) and 2,4-dimethoxyphenol, and the natural antioxidants eugenol and isoeugenol, were investigated using differential scanning calorimetry (DSC) by measuring their anti-1,1-diphenyl-2-picrylhydrazyl (DPPH) radical activity and the induction period for polymerizatio...

BACKGROUND Bitter cumin (Centratherum anthelminticum (L.) Kuntze), is a medicinally important plant. Earlier, we have reported phenolic compounds, antioxidant, and anti-hyperglycemic, antimicrobial activity of bitter cumin. In this study we have further characterized the antioxidative activity of bitter cumin extracts in various in vitro models. METHODS Bitter cumin seeds were extracted with ...

The paper presents the antioxidant activity evaluation of Silybum marianum L. extract in comparison with the commercial silymarin standard solution (2 mg/mL) and the time-dependent antioxidant capacity by calculating the free radical 2,2-diphenyl-1-pycryl-hydrazyl (DPPH) reaction rate in the presence of these biosystems. The best result was obtained in the case of S. marianum L. extract, with a...

Curcumin metabolites namely curcumin monoglucuronide and curcumin diglucuronide were synthesized using an alternative synthetic approach. The anti-oxidant potential of these curcumin glucuronides was compared with that of curcumin using DPPH scavenging method and Oxygen Radical Absorbance Capacity (ORAC) assay. The results show that curcumin monoglucuronide exhibits 10 fold less anti-oxidant ac...

A series of 3,4-dihydroisoquinoline-3-carboxylic acid derivatives were synthesised and tested for their free-radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+), superoxide anion radical (O2·-) and nitric oxide radical (·NO) assays. We also studied d-amino acid oxidase (DAAO), acetylcholinestera...

plants are rich source of phenolic compounds (phenolic acids, flavonoids and tannins) that are most important natural antioxidants. in the present study two ultrasonic methods including probe and bath were used for the extraction of phenolic and flavonoid compounds from celtis australis. the effects of different extraction time including 30, 60 and 90 min (bath method) and 5, 10 and 20 min (pro...

Phytochemical investigation of the aerial parts of Senecio desfontainei afforded one new benzoxepine derivative, senecioside (1) along with eleven known compounds (2-12). Their structures were assigned from H and C NMR spectra, DEPT and 2D COSY, NOE, HSQC and HMBC NMR experiments. All these compounds were tested for antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scaven...

As plants produce a huge amount of antioxidants they can represent a source of new compounds with antioxidant activities. From this point of view, the main goal of this research was to study the antioxidant activities of the Ficus carica through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicalscavenging method. Since DPPH assay has been largely used as a quick, reliable, and reproducible parame...