scholarly journals Voltammetric Behavior, Flavanol and Anthocyanin Contents, and Antioxidant Capacity of Grape Skins and Seeds during Ripening (Vitis vinifera var. Merlot, Tannat, and Syrah)

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 800 ◽  
Author(s):  
Nawel Benbouguerra ◽  
Tristan Richard ◽  
Cédric Saucier ◽  
François Garcia

Skin and seed grape extracts of three red varieties (Merlot, Tannat, and Syrah) at different stages of ripening were studied for their total phenolic content (TPC) by using the Folin-Ciocalteu assay and for their total antioxidant capacity (TAC) by using spectrophotometric and electrochemical assays. Flavanol and anthocyanin compositions were also investigated using Ultra Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Results showed that seeds had the highest phenolic content and the highest antioxidant potential compared to skins at all stages of ripening. The highest TPC and TAC values were measured in seeds at close to veraison and veraison ripening stages. In skins, the highest values were found at the green stage, it was in accordance with the flavanols content. The voltammetric measurements were carried out using disposable single walled carbon nanotubes modified screen-printed carbon electrodes (SWCNT-SPCE). Three peaks on voltammograms were obtained at different oxidation potentials. The first anodic peak that oxidized at a low potential describes the oxidation of ortho-dihydroxy phenols and gallate groups, the second peak corresponds to the malvidin anthocyanins oxidation and the second oxidation of flavonoids. The third voltammetric peak could be due to phenolic acids such as p-coumaric acid and ferulic acid or the second oxidation of malvidin anthocyanins. The high linear correlation was observed between antioxidant tests and flavanols in skins (0.86 ≤ r ≤ 0.94), while in seeds, ‘r’ was higher between electrochemical parameters and flavanols (0.64 ≤ r ≤ 0.8).

2019 ◽  
pp. 49-59
Author(s):  
Nu Linh Giang Ton ◽  
Thi Hoai Nguyen ◽  
Quoc Hung Vo

Avocado peel has been considered as a potential source of natural antioxidants in which phenolics are among the most important compounds. Therefore, this study aims to optimize the extraction process of phenolics using response surface methodology and evaluate the corresponding antioxidant activity. From the quadratic model, the optimal condition was determined including the ethanol concentration 54.55% (v/v), the solvent/solute ratio 71.82/1 (mL/g), temperature 53.03 oC and extraction time 99.09 min. The total phenolic content and the total antioxidant capacity at this condition with minor modifications were 26,74 ± 0,04 (mg GAE/g DW) and 188.06 ± 1.41 (mg AAE/g DW), respectively. The significant correlation between total phenolic content and total antioxidant capacity was also confirmed. Key words: response surface methodology, central composite rotatable design, total phenolic content, total antioxidant capacity, avocado peel


Genetika ◽  
2020 ◽  
Vol 52 (3) ◽  
pp. 825-834
Author(s):  
Emre Sevindik ◽  
Sinem Aydin ◽  
Mehmet Paksoy ◽  
Bahar Sokmen

The genus Inula belongs to family Asteraceae and it is medicinally important because it possesses cytotoxic, anticancer, hepatoprotective, antibacterial and anti-inflammatory properties. The aim of this research was to explore antioxidant and anti-urease activities of fifteen Inula taxa in Turkey. Ethanol extracts of Inula taxa were obtained by Soxhlet extraction. Antioxidant activity was determined through total antioxidant activity, total phenolic content and copper reducing antioxidant capacity (CUPRAC) analyses. The highest total phenolic content and total antioxidant capacity were found in I. orientalis (158.54?0.002 ?g GAE/mL) and I. macrocephala (189.16?0.002 ?g AAE/mL). CUPRAC activity increases with the increasing concentration of the extracts and the standard. Moreover, all the tested plants exhibited better anti-urease activity than standard thiourea except for I. anatolica and I. thapsoides subsp. thapsoides. Results obtained from this study demonstrate that Inula species might be utilized as a probable natural source in the pharmaceutical and food industries but further and more specific studies are needed to determine active antioxidative and anti-urease compounds in the extracts.


2021 ◽  
Vol 3 (1) ◽  
pp. 172-177
Author(s):  
Mohammad Shoeb ◽  

Fruits of red and green varieties of Syzygium samarangense, commonly known as Jamrul in Bangladesh, are very popular for all ages of people. Air-dried fruits of S. samarangense were successively extracted with n-hexane, dichloromethane (DCM) and methanol. The moisture and ash content of the raw fruits were determined by thermal heating at 105 and 700, respectively. Different biologically important functional groups were identified by FT-IR spectroscopy. The n-hexane, DCM and methanolic extracts were tested for cytotoxicity against HeLa and Vero cell lines. Total phenolic content, total flavonoid content and total antioxidant capacity in the three extracts of both varieties were determined. The moisture content and ash content were 92% and 90%, and 0.12% and 0.16% in red variety and green variety, respectively. UV-Vis spectrum revealed the presence of long chain conjugation or polycyclic aromatic chromophores in n-hexane, DCM and methanolic extracts of S. samarangense. The DCM extract of both varieties had highest total phenolic content, flavonoid content and antioxidant capacity compared to n-hexane and methanol extracts. The study concludes that the fruit of S. samarangense (red and green variety) grown in Bangladesh are rich source of phytochemicals which possess antioxidant activity and safe to health for their non-cytotoxic properties. The green variety contains more phenolic content and antioxidant capacity than red variety.


2019 ◽  
Vol 15 ◽  
pp. 04001 ◽  
Author(s):  
L. Castro-López ◽  
G. Castillo-Sánchez ◽  
L. Díaz-Rubio ◽  
I. Córdova-Guerrero

The evaluation of the antioxidant capacity of grape cultivars Cabernet sauvignon is important because it varies according to the production area. In this work, it was evaluated the content of phenolic compounds and the total antioxidant capacity (CAT) of grape skins and grape seed Cabernet sauvignon (Vitis vinifera L.) in three vineyards located in the Valley of Guadalupe, B.C, México. The content of total phenols was determined by the Folin-Ciocalteau method and the CAT of grape skin and seed extracts by the stabilization methods of the (ABTS•+) and DPPH• radicals. The CAT in the seed extracts was increased (P < 0.05) in the following order: vineyard 2 < vineyard 1 < vineyard 3. The highest contents of gallic acid, resveratrol and rutin were found in the extracts that presented the highest CAT, which corresponded to the cultivars of vineyard 3. The same happened in extract of skins, having vineyard 3 the contents of CAT (ABTS•+) higher. The total phenolic seed compound was presented in vineyard 2 with 1,545, followed by vineyard 1 with 1,523, vineyard 3 with 1,146 expressed as g GAE.100 g of sample. In skin, the behavior was as follows; vineyard 3 <vineyard 2 <vineyard 1. 1,062, 1,086, 1,115 expressed as g GAE.100 g sample respectively.Keywords: antioxidant, phenolics, ABTS, gallic acid.


2013 ◽  
Vol 93 (4) ◽  
pp. 725-734 ◽  
Author(s):  
Cara K. Isaak ◽  
Jay C. Petkau ◽  
O Karmin ◽  
Kim Ominski ◽  
Juan Carlos Rodriguez-Lecompte ◽  
...  

Isaak, C. K., Petkau, J. C., O, K., Ominski, K., Rodriguez-Lecompte, J. C, and Siow, Y. L. 2013. Seasonal variations in phenolic compounds and antioxidant capacity of Cornus stolonifera plant material: Applications in agriculture. Can. J. Plant Sci. 93: 725–734. The present study was carried out to establish the antioxidant capacity of plant material of Cornus stolonifera (syn. Cornus sericea, Red Osier Dogwood) grown in Manitoba, by measuring total phenolic content and oxygen radical absorbance capacity (ORAC) over a 3-yr period. The presence and concentrations of flavonoids that might account for antioxidant abilities were investigated using ultra-performance liquid chromatography and a total anthocyanins assay. Both ORAC levels and phenolic content increased during the spring, peaked during the summer months (1631.65±166.30 µmol trolox equivalents g−1DW in July 2011, 220.38±2.29 mg gallic acid equivalents g−1DW in August 2012), and then declined during the fall in all 3 yr. Analysis of individual flavonoids in 2010 samples revealed that high levels of rutin, a glycoside of quercetin, were present ranging from 7.46±0.09 (July 2010) to 18.77±0.23 mg g−1dried sample (October 2010). Anthocyanin content was high in the spring, very low in the summer months, and increased in the fall over all 3 yr. Although polyphenolic and antioxidant content in Cornus spp. plants have been largely attributed to their berries, results from this study demonstrate that other plant material may also be an abundant source of these compounds.


2015 ◽  
Vol 14 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Matthias Onyebuchi Agbo ◽  
Philip Felix Uzor ◽  
Uchenna Nneamaka Akazie Nneji ◽  
Chidozie Uzoma Eze Odurukwe ◽  
Uchenna Basilia Ogbatue ◽  
...  

Plant phenolics and flavonoids play a great role in scavenging free radicals in the body and act as antioxidants. Thus their determination is sometimes nedded. Total antioxidant capacity, total phenolic and flavonoid contents of the extracts of 10 medicinal plants (Lochnera rosea, Allamanda cathartica, Asplenium platyneuron, Euphorbia prostrate, Baphia nitida, Crotolaria retusa, Zapoteca portoricensis, Platycerium bifurcatum, Mussaenda afzelii and Craterosiphon scandens) from 7 botanical families growing in the tropical rainforest of Nigeria were included in this study. The total antioxidant capacity of the extracts was assessed by using the phosphomolybdate method. The phenolic content was determined by using Folin-Ciocalteau assay, while the total flavonoid was determined by the aluminium chloride colorimetric assay. The results obtained showed that the total antioxidant capacity for all the extracts were in the range of 0.888 ± 0.75 to 0.938 ± 0.00 mg EAA/g. The results showed that E. prostrate, P. bifurcatum and A. platyneuron were found to be the richest source of phenolic (97.77 ± 0.77, 87.62 ± 1.22 and 82.33 ± 0.30 mg GAE/g) while B. nitida and M. afzelii had the least total phenolic content (11.67 ± 0.09 and11.18 ± 0.30 mg GAE/g). The highest total flavonoid content was revealed in P. bifurcatum (648.67 ± 12.3 mg QE) while M. afzelii also had the least total flavonoid content (3.67 ± 0.00 mg QE/g). The ratio of flavonoid to the phenolic in each extract was also determined to ascertain extracts that are rich in flavonoids.Dhaka Univ. J. Pharm. Sci. 14(1): 35-41, 2015 (June)


Foods ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 107 ◽  
Author(s):  
Seydi Yıkmış

In this study, the aim is to produce non-thermal vinegar by using red Uruset apples, which have high bioavailability among apple varieties. For this purpose, Uruset apple vinegar was produced and ultrasound at different times (2, 4, 6, 8 and 10 min) and different amplitudes (40%, 50%, 60%, 70%, and 80%); in addition, a 26 kHz frequency was applied to the samples. Total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (1,1-diphenyl- 2-picrylhydrazyl (DPPH) and cupric reducing antioxidant capacity (CUPRAC)), and color values were evaluated for the optimization of process conditions. At the same time, the differences between commercial apple vinegar (CV), pasteurized Uruset apple vinegar (PV), and a control (C) of untreated apple vinegar were investigated. Ultrasound treatment of Uruset apple vinegar was more successful for the enrichment of bioactive substances than the other samples. At the end of the study, the maximal optimization values for Uruset apple vinegar were 7.4 min and 62.2 amplitude. At the end of optimization, CUPRAC (0.69 mg TEAC/mL), DPPH (0.49 mg TEAC/mL), total flavonoid content (46.95 mg CE/L), and total phenolic content (124.25 mg GAE/L) were determined. As a result, ultrasound technology was successfully used for Uruset apple vinegar production.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
C. Priyanthi ◽  
R. Sivakanesan

Background. The present study evaluates the antioxidant properties of some Sri Lankan red rice varieties using water extracts. Methods. Water extracts of rice varieties Attakkari, Bg2907, and Bg407 were used in this study. The total antioxidant capacity was measured by ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and reducing power assays. The total phenolic content (TPC), total flavonoid content (TFC), monomeric anthocyanin, and condensed tannin contents were measured by Folin-Ciocalteu, aluminium chloride, pH differential, and vanillin assays, respectively. Results. It was observed that mean FRAP, DPPH, reducing power, TPC, TFC, monomeric anthocyanin content, and condensed tannin content were in the range of 0.561 ± 0.113 to 0.695 ± 0.077   mmol / 100   g fresh weight (FW), 26.07 ± 3.08 to 53.66 ± 7.61   mg / mL   FW , 33.49 ± 4.105.14 to 40.81 ± 3.65   mg / mL , 0.676 ± 0.078 to 0.900 ± 0.057   mg tannic acid equivalent (TAE)/g, 5.36 ± 0.75 to 6.38 ± 0.82   mg   TAE / g   FW , 0.0202 ± 0.005 to 0.0292 ± 0.009   mg / g   FW , and 0.078 ± 0.015 to 0.104 ± 0.017   mg   TAE / g   FW , respectively. Significant differences were observed in DPPH, reducing power, and TPC among rice varieties ( p < 0.05 ). Rice variety Attakkari had the highest total antioxidant capacity (TAC), scavenging activity, reducing power, TPC, TFC, monomeric anthocyanin content, and condensed tannin content followed by Bg2907 and Bg406. Conclusion. Total phenolic compounds, total flavonoid, and condensed tannin are the major antioxidants in all three varieties of rice while the monomeric anthocyanin is only a minor antioxidant.


Author(s):  
Naficeh Sadeghi ◽  
Masoomeh Behzad ◽  
Behrooz Jannat ◽  
Mannan Hajimahmoodi ◽  
Mohammad Reza Oveisi ◽  
...  

Tea is the most widely consumed and popular non-alcoholic beverage in the world. Reactive oxygen spices may cause wide range of damages to biological systems. Purpose of this study was to determine the total antioxidant capacity and total phenolic of different black tea samples in Iran. The FRAP (Ferric reducing antioxidant power) assay was used for antioxidant activity. The total phenolic content was measured based on the Folin-Ciocalteu method. The results showed that all samples had substantial antioxidant activity and total phenolic content. Iranian tea samples had significantly the lowest 0.98 ± 0.15, 0.75 ± 0.17 µmoll-1 and Kenya tea samples had significantly the highest 2.67 ± 0.61, 2.10 ± 0.65 µmoll-1 amount of total antioxidant capacity and total phenolic, respectively. A linear positive relationship was observed between the antioxidant activity and total phenolic content of the black tea samples. These findings suggest that black tea can be considered as natural source of antioxidant and total phenolic compounds.


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