Isolation and Characterization of Novel Benzoates, Cinnamates, Flavonoids, and Lignans from Riesling Wine and Screening for Antioxidant Activity

2001 ◽  
Vol 49 (6) ◽  
pp. 2788-2798 ◽  
Author(s):  
Beate Baderschneider ◽  
Peter Winterhalter
2012 ◽  
Vol 7 (12) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Rafaela Ferreira Oliveira ◽  
Celso Amorim Camara ◽  
Maria de Fátima Agra ◽  
Tania Maria Sarmento Silva

Investigation of the green fruits of Clusia paralicola (Clusiaceae) led to the isolation and characterization of two 3,8″-biflavonoids, 2R, 3S, 2″R, 3″R-GB1-7″- O-β-glucoside (1) and 2R, 3S, 2″R, 3,8″-binaringenin-7″-O-β-glucoside (2), together with four known compounds: β-sitosterol, stigmasterol, β-amyrin, and epicatechin. The structures were established from the IR, LC-ESI-MS and NMR spectral data, including 2D-NMR experiments. The absolute configurations of 1 and 2 were determined by CD spectra. The total extract and the biflavonoids demonstrated significant antioxidant activity in DPPH, ABTS, and β-carotene/linoleic acid tests.


2020 ◽  
Vol 10 ◽  
Author(s):  
Yakubu Rufai ◽  
Norazah Basar ◽  
Aliyu Sani

Background: Deinbollia pinnata belonging to Sapindaceae family are known as medicinal plants for the treatment of human diseases. Because of human over-exploitation, the choice of phytochemicals re-search and screening was basically made to add to the available compounds and ethno-medicinal records. Objective: To investigate phytochemicals and their antioxidant activities. Method: Antioxidant assays (DPPH, ABTS, FRAP) activities; phytochemical contents (Folin Ciocalteaus’s (FC) and aluminum chloride) methods; and phytochemical analysis were employed. Successful characterization of isolates using spectroscopic methods (1H NMR, 13C NMR, FTIR and GC-MS analysis). Results: Alkaloid, simple sugar, phenolics, tannins and steriods were present in all the parts. Saponin, terpenes and flavonoids were found in both leaves and root bark, while root bark and heartwood possessed quinones. The methanol extracts demonstrated total phenolic content at 75. 9 ± 2.05 GAE (mg GAE/g dw) and total flavonoid content at 88.41 ± 0.56 QUE (mg QUE/g dw). The plant extracts showed good DPPH scavenging activity with percentage inhibition more than 70% at 125 ppm. The methanol extracts showed excellent antioxidant activity towards ABTS assay with the IC50 value of 13.68 µg/mL. The extracts also exhibited the most potent ferric ion reducer at 3.45 ± 1.30 mM FRAP equivalent. Methyl gallate (2) displayed the highest antioxidant radical scavenging activity towards DPPH assay with the IC50 value of 0.19 µg/mL and pyrogallol (4) showed the highest ABTS activity with the SC50 value of 7.44 µg/mL. While, 3,4-dihydroxybenzoic acid (1) also showed the potential as ferric ion reducer ranging from 0.67± 0.01 to 3.63±0.12 mM FRAP equivalent respectively. Conclusion: Based on the antioxidant activity, methanolic extracts and its isolated constituents can be used as antioxidant sources for the management of oxidative causative diseases. Being the first report of these phytochemicals from genius Deinbollia and specie pinnata.


2021 ◽  
Vol 11 (4) ◽  
pp. 4105-4113

In this study, chitin nanofibers are isolated from Calocybe indica (Milky White Mushroom), and they are further characterized using various analytical techniques such as UV-VIS, FTIR, TGA, Fe - SEM, and XRD. Antioxidant activity of the chitin nanofibers was studied by performing various assays such as DPPH, ABTS, H2O5 Scavenging Activity, Hydroxyl Radical Activity, Superoxide Assay, and Reduced Glutathione Activity. Isolated Chitin nanofibers were then chemically treated to form hydrogels. The hydrogels formed were further characterized.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Silvana Alves de Souza ◽  
Celso Amorim Camara ◽  
Eva Monica Sarmento da Silva ◽  
Tania Maria Sarmento Silva

An investigation of the geopropolis collected byMelipona subnitida(jandaíra) stingless bee led to the isolation and characterization of two phenylpropanoids, 6-O-p-coumaroyl-D-galactopyranose (1) and 6-O-cinnamoyl-1-O-p-coumaroyl-β-D-glucopyranose (2), and seven flavonoids, 7-O-methyl-naringenin (3), 7-O-methyl aromadendrin (4), 7,4′-di-O-methyl aromadendrin (5), 4′-O-methyl kaempferol (6), 3-O-methyl quercetin (7), 5-O-methyl aromadendrin (8), and 5-O-methyl kaempferol (9). The structure of the new phenylpropanoid (1) was established from IR, LC-ESI-MS, and NMR spectral data, including 2D NMR experiments. The extract and fractions demonstrated significant antioxidant activity in DPPH, ABTS, andβ-carotene/linoleic acid tests.


Sign in / Sign up

Export Citation Format

Share Document