Poly(vinyl alcohol)-tannic Acid Cryogel Matrix as Antioxidant and Antibacterial Material

The biocompatible, viscoelastic properties of poly(vinyl alcohol) (PVA) in combination with the antimicrobial and antioxidant natural polyphenolic, tannic acid (TA), and the natural flavonoid and antioxidant curcumin (Cur), were used in the preparation of PVA:TA and PVA:TA:Cur cryogel composites using cryotropic gelation to combine the individually beneficial properties. The effect of TA content on the antioxidant and antimicrobial activities of PVA:TA cryogel composites and the antioxidant activities of PVA:TA:Cur cryogel composites was determined using Trolox equivalent antioxidant capacity (TEAC) and total phenol content (TPC) assays, and were compared. The PVA:TA:Cur cryogel composite showed the highest antioxidant activity, with a TEAC value of 2.10 ± 0.24 and a TPC value of 293 ± 12.00. The antibacterial capacity of the PVA:TA and PVA:TA:Cur 1:1:0.1 cryogel composites was examined against two different species of bacteria, E. coli and S. aureus. It was found that the minimum inhibition concentration (MIC) value of the PVA:TA:Cur 1:1:0.1 cryogel composites varied between 5 and 10 mg/mL based on the type of microorganism, and the minimum bactericidal concentration (MBC) value was 20 mg/mL irrespective of the type of microorganism. Furthermore, the hemocompatibility of the PVA:TA cryogel composites was evaluated by examining their hemolytic and coagulation behaviors. PVA:TA 1:1 cryogels with a value of 95.7% revealed the highest blood clotting index value amongst all of the synthesized cryogels, signifying the potential for blood contacting applications. The release of TA and Cur from the cryogel composites was quantified at different pH conditions, i.e., 1.0, 7.4, and 9.0, and additionally in ethanol (EtOH) and an ethanol–water (EtOH:Wat) mixture. The solution released from the PVA:TA cryogels in PBS was tested for inhibition capability against α-glucosidase (E.C. 3.2.1.20). Concentration-dependent enzyme inhibition was observed, and 70 µL of 83 µg/mL PVA:TA (1:1) cryogel in PBS inhibited α-glucosidase enzyme solution of 0.03 unit/mL in 70 µL by 81.75 ± 0.96%.

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Self-Crosslinked Ellipsoidal Poly(Tannic Acid) Particles for Bio-Medical Applications

Molecules ◽

10.3390/molecules26092429 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2429

Author(s):

Nurettin Sahiner

Keyword(s):

Tannic Acid ◽

Hydrolytic Degradation ◽

Single Step ◽

Trolox Equivalent Antioxidant Capacity ◽

Total Phenol Content ◽

Frap Assay ◽

E Coli ◽

Gram Positive Bacteria ◽

Trolox Equivalent ◽

Free Media

Self-crosslinking of Tannic acid (TA) was accomplished to obtain poly(tannic acid) (p(TA)) particles in single step, surfactant free media using sodium periodate (NaIO4) as an oxidizing agent. Almost monodisperse p(TA) particles with 981 ± 76 nm sizes and −22 ± 4 mV zeta potential value with ellipsoidal shape was obtained. Only slight degradation of p(TA) particles with 6.8 ± 0.2% was observed at pH 7.4 in PBS up to 15 days because of the irreversible covalent formation between TA units, suggesting that hydrolytic degradation is independent from the used amounts of oxidation agents. p(TA) particles were found to be non-hemolytic up to 0.5 mg/mL concentration and found not to affect blood clotting mechanism up to 2 mg/mL concentration. Antioxidant activity of p(TA) particles was investigated by total phenol content (TPC), ferric reducing antioxidant potential (FRAP), trolox equivalent antioxidant capacity (TEAC), total flavanoid content (TFC), and Fe (II) chelating activity. p(TA) particles showed strong antioxidant capability in comparison to TA molecules, except FRAP assay. The antibacterial activity of p(TA) particles was investigated by micro-dilution technique on E. coli as Gram‑negative and S. aureus as Gram-positive bacteria and found that p(TA) particles are more effective on S. aureus with over 50% inhibition at 20 mg/mL concentration attained.

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ANTIOXIDANT CAPACITY AND TOTAL PHENOL CONTENT OF HYPTIS SPP., P. HEPTAPHYLLUM, T. PANAMENSIS, T. RHOIFOLIA, AND OCOTEA SP.

Revista Colombiana de Química ◽

10.15446/rev.colomb.quim.v44n2.55217 ◽

2016 ◽

Vol 44 (2) ◽

pp. 28-33 ◽

Cited By ~ 5

Author(s):

Geovanna Tafurt García ◽

Luisa Jiménez Vidal ◽

Ana Calvo Salamanca

Keyword(s):

Antioxidant Capacity ◽

Phenolic Content ◽

Antioxidant Activities ◽

Colorimetric Assay ◽

Trolox Equivalent Antioxidant Capacity ◽

Total Phenolic ◽

Total Phenol Content ◽

Total Antioxidant ◽

Trolox Equivalent ◽

Highly Correlated

In this work, the possible correlation between the antioxidant activities and the Total Phenolic Content (TPC) and chemical composition of Lamiaceae (H. conferta, H. dilatata, H. mutabilis, H. suaveolens), Burseraceae (P. heptaphyllum, T. rhoifoila, T. panamensis), and Lauraceae (Ocotea sp.) were evaluated. The Trolox Equivalent Antioxidant Capacity or the Total Antioxidant Activity (TAA) was determined by using a colorimetric assay with the ABTS radical cation, Effective Concentration (EC50) was evaluated with the DPPH radical, and the TPC was established by the Folin-Ciocalteu method, for ethanolic extracts obtained by cold maceration and evaporation to dryness. Both the TAA and the EC50 were highly correlated with the TPC. The barks of T. rhoifolia and T. panamensis demonstrated the highest antioxidant capacities. The Burseraceae spp. exhibited the highest TPC, and the Lamiaceae (Hyptis spp.) demonstrated the lowest TPC.

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Antioxidant and Antibacterial Activity of Selected Indonesian Honey against Bacteria of Acne

Jurnal Kimia Sains dan Aplikasi ◽

10.14710/jksa.23.8.267-275 ◽

2020 ◽

Vol 23 (8) ◽

pp. 267-275

Author(s):

Shafira Ananda Djakaria ◽

Irmanida Batubara ◽

Rika Raffiudin

Keyword(s):

Antibacterial Activity ◽

Antioxidant Activities ◽

Apis Cerana ◽

Antibacterial Activities ◽

Trolox Equivalent Antioxidant Capacity ◽

Microdilution Method ◽

South Sulawesi ◽

Inhibition Concentration ◽

Trolox Equivalent ◽

Gallic Acid Equivalent

Honey has natural bacteriostatic and bactericide activities; thus, it could be active compounds as an antibacterial against Propionibacterium acnes, the main bacteria in acne forming state. Our study aims to determine phenolic and flavonoid contents (qualitative and quantitative), antioxidants, along with antibacterial activity against P. acnes of selected Indonesian honey. Honey used in this study, including honeybees and stingless bees, were collected from Sumbawa, Riau, Belitung, Sukabumi, Banyuwangi, Bogor, and South Sulawesi. In the method, the quantitative content of phenols and flavonoid were measured using a spectrophotometer. Further, DPPH (2, 2’-diphenylpicryl hydrazyl) and ABTS (2’-azino-bis (3- ethylbenzothiazoline-6-sulfonic acid) assays were used to measure the antioxidant activities, and subsequently microdilution method was applied to determine antibacterial activity. The results showed that Indonesian honey contains phenolics and flavonoids in the range of 49.5-67.3 μg Gallic Acid Equivalent (GAE)/g and 766.5-1509.5 μg Quercetin Equivalent (QE)/g, respectively. All honey samples also show antioxidant and antibacterial activities. Of note, Apis cerana honey from Banyuwangi has the highest antioxidant and antibacterial activity compared to others. It has the Inhibition Concentration (IC50), Trolox Equivalent Antioxidant Capacity, Minimum Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) values of 59.85 mg/L, 122 μg Trolox/g, 125 mg/mL, and 500 mg/mL respectively. Our study reveals that Indonesian honey can inhibit and kill P. acnes as well. Nonetheless, the phenolic content of honey is not always linear with antioxidant and antibacterial activities.

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Phenolic Profiles and Antioxidant Activities of 30 Tea Infusions from Green, Black, Oolong, White, Yellow and Dark Teas

Antioxidants ◽

10.3390/antiox8070215 ◽

2019 ◽

Vol 8 (7) ◽

pp. 215 ◽

Cited By ~ 18

Author(s):

Cai-Ning Zhao ◽

Guo-Yi Tang ◽

Shi-Yu Cao ◽

Xiao-Yu Xu ◽

Ren-You Gan ◽

...

Keyword(s):

Antioxidant Activities ◽

Dry Weight ◽

Trolox Equivalent Antioxidant Capacity ◽

Total Phenolic ◽

Antioxidant Power ◽

Phenolic Contents ◽

Tea Infusions ◽

Phenolic Profiles ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power

Tea is among the most consumed drink worldwide, and its strong antioxidant activity is considered as the main contributor to several health benefits, such as cardiovascular protection and anticancer effect. In this study, the antioxidant activities of 30 tea infusions, which were obtained by the mimic of drinking tea of the public, from green, black, oolong, white, yellow and dark teas, were evaluated using ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, ranging from 504.80 ± 17.44 to 4647.47 ± 57.87 µmol Fe2+/g dry weight (DW) and 166.29 ± 24.48 to 2532.41 ± 50.18 µmol Trolox/g DW, respectively. Moreover, their total phenolic contents (TPC) were detected by Folin-Ciocalteu assay and were in the range of 24.77 ± 2.02 to 252.65 ± 4.74 mg gallic acid equivalent (GAE)/g DW. Generally, Dianqing Tea, Lushan Yunwu Tea, and Xihu Longjing Tea showed the strongest antioxidant activities among 30 teas. Furthermore, the phenolic compounds in tea infusions were identified and quantified, with catechins most commonly detected, especially in green tea infusions, which were main contributors to their antioxidant activities. Besides tea polyphenols, considerable content of caffeine also presented in 30 tea infusions.

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Naphtho-Gamma-Pyrones Produced by Aspergillus tubingensis G131: New Source of Natural Nontoxic Antioxidants

Biomolecules ◽

10.3390/biom10010029 ◽

2019 ◽

Vol 10 (1) ◽

pp. 29 ◽

Cited By ~ 3

Author(s):

Quentin Carboué ◽

Marc Maresca ◽

Gaëtan Herbette ◽

Sevastianos Roussos ◽

Rayhane Hamrouni ◽

...

Keyword(s):

Cell Death ◽

Antioxidant Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Trolox Equivalent Antioxidant Capacity ◽

Aspergillus Tubingensis ◽

Toxigenic Strain ◽

Abts Assay ◽

Trolox Equivalent ◽

Cancerous Cells

Seven naphtho-gamma-pyrones (NγPs), including asperpyrone E, aurasperone A, dianhydroaurasperone C, fonsecin, fonsecinone A, fonsecin B, and ustilaginoidin A, were isolated from Aspergillus tubingensis G131, a non-toxigenic strain. The radical scavenging activity of these NγPs was evaluated using ABTS assay. The Trolox equivalent antioxidant capacity on the seven isolated NγPs ranged from 2.4 to 14.6 μmol L−1. The toxicity and ability of the NγPs to prevent H2O2-mediated cell death were evaluated using normal/not cancerous cells (CHO cells). This cell-based assay showed that NγPs: (1) Are not toxic or weakly toxic towards cells and (2) are able to protect cells from oxidant injuries with an IC50 on H2O2-mediated cell death ranging from 2.25 to 1800 μmol mL−1. Our data show that A. tubingensis G131 strain is able to produce various NγPs possessing strong antioxidant activities and low toxicities, making this strain a good candidate for antioxidant applications in food and cosmetic industries.

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Nanocomposite films based on chitosan–poly(vinyl alcohol) and silver nanoparticles with high antibacterial and antioxidant activities

Process Safety and Environmental Protection ◽

10.1016/j.psep.2017.06.018 ◽

2017 ◽

Vol 111 ◽

pp. 112-121 ◽

Cited By ~ 45

Author(s):

Sawssen Hajji ◽

Rabeb Ben Slama-Ben Salem ◽

Marwa Hamdi ◽

Kemel Jellouli ◽

Wajdi Ayadi ◽

...

Keyword(s):

Silver Nanoparticles ◽

Vinyl Alcohol ◽

Antioxidant Activities ◽

Nanocomposite Films ◽

Poly Vinyl Alcohol

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Antioxidants from Tropical Herbs

Natural Product Communications ◽

10.1177/1934578x1000500321 ◽

2010 ◽

Vol 5 (3) ◽

pp. 1934578X1000500 ◽

Cited By ~ 5

Author(s):

Rasyidah Razab ◽

Azlina Abdul Aziz

Keyword(s):

Free Radicals ◽

Antioxidant Capacity ◽

Strong Correlation ◽

Antioxidant Activities ◽

Polyphenolic Compounds ◽

Trolox Equivalent Antioxidant Capacity ◽

Antioxidant Power ◽

Polyphenolic Content ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power

Plants that contain high amounts of polyphenolic compounds are potential candidates for natural antioxidant sources. Studies are on going in the search for new sources of antioxidants. Not much data are available on the antioxidant capacity of tropical herbs. With this in mind, 19 commonly consumed Malaysian herbs were analyzed for their polyphenolic content and antioxidant activities. A majority of these plants have never been studied before with regards to their polyphenolic content and antioxidant activities. The shoots of Anacardium occidentale, the shoots and fruits of Barringtonia racemosa, Pithecellobium jiringa and Parkia speciosa had high polyphenolic contents (> 150 μg gallic acid equivalents/mg dried plant) and antioxidant activities when measured using the ferric reducing antioxidant power (FRAP) (>1.2 mM) and Trolox equivalent antioxidant capacity (TEAC) assays (>2.4 mM). A strong correlation was observed between the two antioxidant assays (FRAP vs TEAC) implying that the plants could both scavenge free radicals and reduce oxidants. There was also a strong correlation between the antioxidant activities and polyphenolic content suggesting the observed antioxidant activities were contributed mainly by the polyphenolics in the plants.

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Exploring the Antioxidant Features of Polyphenols by Spectroscopic and Electrochemical Methods

Antioxidants ◽

10.3390/antiox8110523 ◽

2019 ◽

Vol 8 (11) ◽

pp. 523 ◽

Cited By ~ 6

Author(s):

Berta Alcalde ◽

Mercè Granados ◽

Javier Saurina

Keyword(s):

Antioxidant Activities ◽

Reference Electrode ◽

Principal Component ◽

Trolox Equivalent Antioxidant Capacity ◽

Hydroxyl Groups ◽

Antioxidant Power ◽

Chemical Structures ◽

Trolox Equivalent ◽

Ferric Reducing Antioxidant Power ◽

Comprehensive Study

This paper evaluates the antioxidant ability of polyphenols as a function of their chemical structures. Several common food indexes including Folin-Ciocalteau (FC), ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays were applied to selected polyphenols that differ in the number and position of hydroxyl groups. Voltammetric assays with screen-printed carbon electrodes were also recorded in the range of −0.2 to 0.9 V (vs. Ag/AgCl reference electrode) to investigate the oxidation behavior of these substances. Poor correlations among assays were obtained, meaning that the behavior of each compound varies in response to the different methods. However, we undertook a comprehensive study based on principal component analysis that evidenced clear patterns relating the structures of several compounds and their antioxidant activities.

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Chemical and Cellular Antioxidant Activities of In Vitro Digesta of Tilapia Protein and Its Hydrolysates

Foods ◽

10.3390/foods9060833 ◽

2020 ◽

Vol 9 (6) ◽

pp. 833

Author(s):

Xiaogang Zhang ◽

Parinya Noisa ◽

Jirawat Yongsawatdigul

Keyword(s):

Structural Modification ◽

Physiological Condition ◽

Antioxidant Activities ◽

Protein Hydrolysate ◽

Principal Component ◽

Hydrogen Atom Transfer ◽

Trolox Equivalent Antioxidant Capacity ◽

Degree Of Hydrolysis ◽

Trolox Equivalent

Production of protein hydrolysate as nutraceuticals is typically based on the activity of the hydrolysate, which might not yield the optimal activity under physiological condition due to structural modification of peptides upon gastrointestinal (GI) digestion. This study systematically compared the chemical and cellular antioxidant activities of the in vitro digesta of tilapia protein and its hydrolysates prepared with various degree of hydrolysis (DH) by Alcalase. The enzymes used in the in vitro GI digestion analysis significantly contributed to the peptide content, Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC). Proteins and all hydrolysates were slightly digested by pepsin but hydrolyzed extensively by pancreatin. Both hydrolysate and digesta predominantly scavenged free radicals via hydrogen atom transfer (HAT). The antioxidant activities of the hydrolysates increased with the increasing DH up to 16 h of hydrolysis. However, the digesta of 10-h hydrolysate displayed the highest chemical and HepG2 cellular antioxidant activities, while the protein digesta displayed the lowest. Principal component analysis (PCA) showed that the TEAC of the digesta was positively correlated with the cellular antioxidant activity (CAA). Therefore, the production of protein hydrolysate should be optimized based on the activity of the hydrolysate digesta rather than that of hydrolysates.

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Outstanding flame retardancy for poly(vinyl alcohol) achieved using a resveratrol/tannic acid complex

RSC Advances ◽

10.1039/d1ra08000h ◽

2022 ◽

Vol 12 (1) ◽

pp. 285-296

Author(s):

Yuan Lin ◽

Jialian Chen ◽

Hongzhou Li

Keyword(s):

Molecular Structure ◽

Tannic Acid ◽

Flame Retardancy ◽

Vinyl Alcohol ◽

Poly Vinyl Alcohol ◽

Acid Complex ◽

Complete Combustion ◽

Residual Amount

The rigid molecular structure of biobased resveratrol/tannic acid (RETA) complex increases the residual amount of RETA-poly(vinyl alcohol) after complete combustion.

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