A Review on Sources,Extractions and Analysis Methods of a Sustainable Biomaterial:Tannins

Condensed and hydrolysable tannins are non-toxic natural polyphenols that are a commercial commodity industrialized for tanning hides to obtain leather and for a growing number of other industrial applications mainly to substitute petroleum-based products.They are a definite class of sustainable materials of the forestry industry.They have been in operation for hundreds of years to manufacture leather and now for a growing number of applications in a variety of other industries,such as wood adhesives,metal coating,pharmaceutical/medical applications and several others.This review presents the main sources,either already or potentially commercial of this forestry by-materials,their industrial and laboratory extraction systems,their systems of analysis with their advantages and drawbacks,be these methods so simple to even appear primitive but nonetheless of proven effectiveness,or very modern and instrumental.It constitutes a basic but essential summary of what is necessary to know of these sustainable materials.In doing so,the review highlights some of the main challenges that remain to be addressed to deliver the quality and economics of tannin supply necessary to fulfill the industrial production requirements for some materials-based uses.

Biochemistry and transcriptome analysis reveal condensed tannins alleviate liver injury induced by regulating cholesterol metabolism pathway

Free cholesterol has been considered to be a critical risk factor of nonalcoholic fatty liver disease(NAFLD).It remains unknown whether dietary intake of condensed tannins(CTs)have distinguishable effects to alleviate liver damage caused by a high cholesterol diet.Male C57BL/6 mice were fed a high cholesterol diet for 6 weeks,and given CTs treatment at a dosage of 200 mg/(kg·day)at the same time.The results indicated that compared with mice fed a normal diet,a high cholesterol diet group resulted in significant weight loss,dysregulation of lipid metabolism in blood and liver,and oxidative stress in the liver,but CTs treatment dramatically reversed these negative effects.Hematoxylin and eosin(H&E)staining and frozen section observation manifested that CTs treatment could effectively reduce the deposition of liver cholesterol and tissue necrosis caused by high cholesterol intake.CTs alleviated liver injury mainly by regulating the expression of related genes in cholesterol metabolism pathway and AMPK phosphorylation.Our results confirmed that CTs have remarkable cholesterol lowering and anti-liver injury effects in vivo.

Structural Elucidation of the Polymeric Condensed Tannins of Acacia nilotica Subspecies by ^(13)C NMR, MALDI-TOF and TMA as Sources of Bioadhesives

Tannin was extracted from different subspecies of Acacia nilotica,Acacia nilotica nilotica(Ann),Acacia nilotica tomentosa(Ant)and Acacia nilotica adansonii(Ana).The aim was to elucidate their structure and evaluate their reactivity as bioadhesives in the wood industry.The extracts were prepared by hot water extraction(90°C tem-perature).Their gel time with paraformaldehyde was used atfirst to compare their reactivity.The tannin contents and the percentage of total polyphenolic materials in different solutions of the extracts spray dried powder were determined by the hide powder method.Concentrated solutions(47%)were tested by both MALDI ToF,13CNMR.The thermomechanical analysis(TMA)was performed to evaluate their modulus of elasticity(MOE)at different pHs.The gel times of all the three tannin extracts showed that their reactivity and it was com-parable to other known procyanidin/prodelphinidin tannin extract types.Ana,Ann and Ant showed highest per-cent of total polyphenolic materials at 70%,64%,and 57%,respectively.The 13CNMR spectra showed that the three subspecies of condensed tannins were mainly constituted of procyanidins(PC)and prodelphinidins(PD)in slightly different ratios.Ann(56.5%PC and 43.4%PD),Ant(57%PC and 43%PD)and Ana(58%PC and 42%PD).MALDI–TOF spectra showed the presence offlavonoid monomers,and oligomers some of which linked to short carbohydrates monomers or dimers.TMA revealed that the three types of tannins had high MOE at their initial pH(5).

Shear Resistance of Siltous Sands Improved with Bridelia Tannins

The ruin of several civil engineering works occurs due to shear rupture of the ground. When the stress is greater than the shear resistance, the internal friction angle and the cohesion of the soil loosen and rupture occurs. Cement and lime are often used to stabilize soils and improve soil strength. The costs and environmental problems of these technologies raise concerns and challenge researchers to innovate with clean, inexpensive materials, accessible to the most disadvantaged social classes. The question that this study seeks to answer is whether the binders derived from plant tannins, which also stabilize soils, improve the shear resistance of these soils. To do this, we determined for silty sand the shear parameters, notably the cohesion and the angle of internal friction in the non-stabilized state and when they are stabilized with the powder of the bark of the Bridelia under different water states. The results show that the addition of Bridelia powder to silty sand increases the cohesion of the soil by nearly 70.71% and the friction angle by 4.31%. But in unfavourable water conditions, the cohesion and internal friction angle of the silty sand material improved with Bridelia bark powder drops drastically by nearly 81.56%. but does not dissolve completely as for the same material. When it is not stabilized. This information is an invaluable contribution in the search for solutions to increase the durability of earthen constructions by improving the water-repellent properties of soils.

Composite Panels from the Combination of Rice Husk and Wood Chips with a Natural Resin Based on Tannins Reinforced with Sugar Cane Molasses Intended for Building Insulation: Physico-Mechanical and Thermal Properties

The objective of this work is to develop new biosourced insulating composites from rice husks and wood chips that can be used in the building sector. It appears from the properties of the precursors that rice chips and husks are materials which can have good thermal conductivity and therefore the combination of these precursors could make it possible to obtain panels with good insulating properties. With regard to environmental and climatic constraints, the composite panels formulated at various rates were tested and the physico-mechanical and thermal properties showed that it was essential to add a crosslinker in order to increase certain solicitation. an incorporation rate of 12% to 30% made it possible to obtain panels with low thermal conductivity, a low surface water absorption capacity and which gives the composite good thermal insulation and will find many applications in the construction and real estate sector. Finally, new solutions to improve the fire reaction of the insulation panels are tested which allows to identify suitable solutions for the developed composites. In view of the flame tests, the panels obtained are good and can effectively combat fire safety in public buildings.

Tannins from Acacia mangium Bark as Natural Dyes for Textiles:Characteristics and Applications

Tannins are capable of producing natural dyes with antioxidant and antibacterial propertis,while synthetic dyes are commonly used in the textile industry,causing environmental issues like water pollution.This research aims to utilize waste tannins as natural dyes as an alternative to synthetic dyes.This study examined the effect of the extraction method on tannin properties such as phenolic content,antioxidants,and antibacterial activity.In addition,Pyrolysis Gas Chromatography‒Mass Spectrometry(Py-GCMS)analysis was used to identify the effect of extraction temperature on the chemical elucidation of tannin.The effect of tannin concentration was evaluated against four bacteria that are usually found on human skin:Staphylococcus epidermidis,Bacillus subtilis,Propionibacterium acnes,and Staphylococcus aureus.Extraction temperature significantly influences the chemical composition of tannin,which leads to different antioxidant properties.The maximum antibacterial properties of tannin were obtained at 90℃with the inhibition zone in the range of 0.9–1.0 mm against four bacteria,tannin yield of 26.59%,Gallic Acid Equivalents or total phenolic content(GAE)of 40.30 mg/g,and Radical Scavenging Activity or antioxidant activity(RSA)of 89.88%.Moreover,the concentration of tannin was significantly linear with its antibacterial properties.Tannin was successfully applied to the textile by using alum as a mordanting agent to create an antibacterial textile.The textile’s bacterial structure damage was analyzed under Field Emission Scanning Electron Microscopy(FESEM).After 50 washings,tannin-textiles with alum-modified properties remained stable compared to those without alum,with S.aureus and S.epidermidis being the most vulnerable bacteria,as confirmed by FESEM images.Hence,tannin is a feasible alternative to harmful and nondegradable synthetic dyes and antibacterial agents.

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

Chemistry and ecological significance of tannins

This paper summarized of the chemistry characteristics of tannins and their various adverse effects onmammalian herbivore, including the chemical nature of hydrolyzable and condensed tannins, their analysis mathods, and the tannins antifeedant mechanisms.

Biochemical changes in phenols,flavonoids,tannins,vitamin E,β-carotene and antioxidant activity during soaking of three white sorghum varieties

Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum varieties.Methods: The changes in total phenols,total ilavonoids,tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity during soaking of sorghum grains were determined.Results:Total phenols,total flavonoids,tannins,vitamin E,P-carotene and antioxidant activity in raw sorghum were ranged from 109.21 to 116.70,45.91 to 54.69,1.39 to 21.79 mg/100 g,1.74 to 5.25,0.54 to 1.19 mg/kg and 21.72%to 27.69%and 25.29%to 31.97%,respectively. The above measured compounds were significantly decreased after soaking.p-Hydroxybenzoic acid,vanillic acid,syringic acid and cinnamic acid represent the major phenolic acids in Dorado variety.While ferulic acid,p-coumaric acid,gallic acid and caffeic acid represent the major phenolic acids in Shandaweel-6.On the other hand,protocatechuic acid represents the major phenolic acids in Giza-15.Regarding flavonoids components,Dorado was the highest variety in kampferol and naringenin while Shandaweel-6 was the highest variety in luteolin, apigenin,hypersoid,quercelin and christen.Finally,Giza-15 was the highest variety in catechin. Phenolic acids,flavonoid compounds and antioxidant activities were decreased after soaking. Conclusions:Sorghum varieties have moderate quantities from total phenols,total flavonoids, tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity which decreased after soaking.

Tannins from Canarium album with potent antioxidant activity

The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS） and nuclear magnetic resonance （NMR） analyses The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using l,l-diphenyl-2-picrylhydrazyl （DPPH） and ferric reducing/antioxidant power （FRAP） model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.

Protective effect of tannins from Ficus racemosa in hypercholesterolemia and diabetes induced vascular tissue damage in rats

Objective:To evaluate the protective effect of tannins from Ficus racemosa(F.racemosa) on the lipid profile and antioxidant parameters in high fat meal and streptozotocin induced hypercholestremia associated diabetes model in rats.Methods:The crude tannin fraction was separated from the acetone(70%v/v) bark extract of F.racemosa.Oral administratipn of tannin fraction(TF)(100 & 200 mg/kg body weight) to rats fed with high fat meal for 30 days (4%cholesterol,1%cholic acid,0.5%egg albumin) and injected with streptozotocin(35 mg/ kg i.p.in citrate buffer on 14th day).Results:The administration of TF significantly reverse the increased blood glucose,total cholesterol,triglycerides,low density lipoprotein and also significandy restored the insulin and high density lipoprotein in the serum.In addition tannins significantly restored the activity of antioxidant enzymes such as superoxide dismutase,catalase and decreased the,glutathione peroxidase,and glutathione,thereby restoring the antioxidant status of the organs to almost normal levels.Conclutions:The results of this study show that two different doses of tannin supplementation had a favorable effect on plasma glucose and lipid profile concentrations.It also had an influence on attenuating oxidative stress in diabetic tats.

Antioxidant, antimicrobial and cytotoxic potential of condensed tannins from Leucaena leucocephala hybrid-Rendang

Condensed tannins(CTs)are one of the promising compounds due to their potentially health-promoting qualities.In this study,CTs were extracted from a Leucaena leucocephala hybrid-Rendang and subjected to various biological studies including antioxidant(using Ferric reducing antioxidant power(FRAP),DPPH and ABTS radical scavenging assay),anti-microbial(against different pathogens)and cytotoxic activities(toward human breast adenocarcinoma(MCF-7),human colon carcinoma(HT29),human cervical carcinoma(HeLa)and human liver carcinoma(HepG2)cell lines)in cancer cells through in vitro experiments.The structural characteristics and purity of CTs extract were determined using 13C NMR.The results showed that CTs exhibited higher in vitro antioxidant activities(2257.12±80.55 mg TEAC/g extract,605.3±1.82 mg TEAC/g extract and 1014.03±1.20 mg TEAC/g extract in FRAP,ABTS and DPPH assay,respectively)and demonstrated anti-microbial activities toward selected Gram’s positive and Gram’s negative bacteria tested with MIC and MBC value at 6.25–50 mg/mL.Furthermore,among other selected cancer cells,CTs also demonstrated cytotoxic activity toward human breast cancer cells(MCF-7)(IC50=38.33±2.08mg/mL).Characteristic of apoptosis such as cell shrinkage,nuclear condensation and apoptotic bodies were shown in MCF-7.These preliminary investigations have provided scientific rationale to use CTs as an alternative therapy for various oxidative and inflammatory associated diseases.©2016 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

The effects of tannins-containing ground pine bark diet upon nutrient digestion,nitrogen balance,and mineral retention in meat goats

Background： Pine bark is a rich source of phytochemical compounds including tannins, phenolic acids, anthocyanins, and fatty acids. These phytochemicals have potential to significantly impact on animal health and animal production. The goal of this work is to measure the effects of tannins in ground pine bark as a partial feed replacement on feed intake, dietary apparent digestibility, nitrogen balance, and mineral retention in meat goats. Results： Eighteen Kiko cross goats （initial BW = 31.8 ± 1.49 kg） were randomly assigned to three treatment groups （n = 6）. Dietary treatments were tested： control （0 % pine bark powder （PB） and 30 % wheat straw （WS））; ] 5 % PB and 15 % WS, and 30 % PB and 0 % WS. Although dry matter （DM） intake and digestibility were not affected （P〉 0.10） by feeding PB, neutral detergent fiber （linear; P= 0.01）, acid detergent fiber （linear; P= 0.001） and lignin digestibility （linear; P= 0.01） decreased, and crude protein （CP） digestibility tended to decrease （P=0.09） as PB increased in the diet, apparent retention of Ca （P= 0.09）, P （P=0.03）, Mg （P= 0.01）, Mn （P= 0.01）, Zn （P= 0.01） and Fe （P= 0.09） also increased linearly. Nitrogen intake and fecal N excretion were not affected （P〉 0.05） by addition of PB in the diet, but N balance in the body was quadratically increased （P〈 0.01） in the 15 % PB diet compared to other diets. This may be due to more rumen escape protein and less excreted N in the urine with the 15 % PB diet. The study showed that a moderate level of tannin-containing pine bark supplementation could improve gastrointestinal nitrogen balance with the aim of improving animal performance. Conclusion： These results suggest that tannin-containing PB has negative impact on fiber, lignin, and protein digestibility, but positively impacted on N-balance.

Self-Blowing Non-Isocyanate Polyurethane Foams Based on Hydrolysable Tannins

ABSTRACT Non-isocyanate polyurethane(NIPU)foams using a hydrolysable tannin,also vulgarly called tannic acid,namely here commercial chestnut wood tannin extract was prepared.Compression strength did not appear to depend on the foam apparent density while the formulation composition of the NIPU foams has been shown to be more determinant.These NIPU foams appeared to be self-extinguishing once the high temperature flame is removed.The ignition time gave encouraging results but for improved fire resistance the foams may need some fire-retardant addition.FTIR spectrometry showed the formation of non-isocyanate urethane linkages.Thermogravimetric analysis indicated a good thermal resistance of these foams,with thermal degradation following four phases.First in the interval 25℃–120℃ range,mainly evaporation of water occurs with a maximal loss of 10%weight.In the 150℃–450℃ temperature range foams mass loss is of almost 70%.In particular in the 125℃–275℃ range occurs the degradation of some small molecular weight substances.In the 500℃–790℃ temperature range the foams do not present any further large degradation.

Corrosion Inhibition of Mild Steel in Hydrochloric Acid by Tannins Rom Rhizophora Racemosa

Studies on the corrosion behaviour of mild steel electrodes in inhibited hydrochloric acid are described. Conventional weight loss measurements show that a maximum concentration of 140 ppm of tannin from Rhizophora racemosa is required to achieve 72% corrosion inhibition. Similar concentration of tannin: H3PO4 in ratio 1:1 gave 61% inhibition efficiency, whereas efficiency obtained for phosphoric acid as inhibitor in the same environment was 55%. Corrosion rates obtained over six hours of exposure in 1M HCl solution at inhibitor concentrations of 140 ppm are 2 mA/cm2, 2.4 mA/cm2, 2.6 mA/cm2 and 6 mA/cm2 for tannin, tannin/H3PO4 and H3PO4-inhibited and uninhibited specimens respectively. Natural atmospheric exposure studies revealed that specimens treated in H3PO4 resisted corrosion for three weeks, while tannin treated specimens suffered corrosion attack after one week of exposure tests.

On the Role of Chloroplasts in the Polymerization of Tannins in Tracheophyta: A Monograph

Proanthocyanidins are formed in the chlorophyllous organs of Tracheophyta from a redifferentiation of chloroplasts involving the thylakoidal membrane and lumen. With the purpose to help researchers of concerned disciplines to identify such chloroplasts, we described herein the morphologies of functional and redifferentiating chloroplasts in various members of Tracheophyta. The most obvious sign of redifferentiation is a tremendous swelling of the chloroplast which turns obese. De novo genesis of osmiophilic materials is also characteristic, either as single dots attached to the inner face of the swollen thylakoidal membrane which will yield the tannosomes, or as pearl necklace-shaped structures protruding into the lumen;this last formation can be viewed as a giant tannosome forming finally stromal chlorotannic accretions. Whatever their mode of formation is, tannosomes are expulsed from the chloroplast as shuttles.

Effects of Quebracho Tannins on Growth Performance and Blood Routine of Simmental Fattening Cattle

[Objectives]The effects of condensed quebracho tannins on the production performance and blood routine indices of Simmental fattening cattle were investigated experimentally.[Methods]Twenty four Simmental fattening cattle were selected and randomly divided into two treatment groups according to their body weight,with 12 animals in each group.The diet of the control group consisted of beef cattle concentrate supplement+silage+hay,and the diet of the experimental group consisted of beef cattle concentrate supplement+silage+hay+tannins,and the experimental period was 30 d.[Results]Compared with the control group,the addition of tannins[30 g/(cattle·d)]to the diet of beef cattle increased the daily weight gain of Simmental beef cattle by 24.68%(P<0.01),while the feed conversion ratio decreased by 2.57%(P>0.05).The gross profit per cattle increased by 973.63 yuan,and the economic benefit increased by 114.78%.Platelets were higher in the experimental group than in the control group(P<0.01);hemoglobin was lower in the experimental group than in the control group(P<0.01);leukocytes,neutrophils,monocytes and lymphocytes were lower in the experimental group than in the control group(P<0.01);and erythrocytes were lower in the experimental group than in the control group(P<0.05).[Conclusions]This study provides a theoretical basis for the rational utilization of quebracho tannins.

Quantification of Tannins in Four Species of Genus Mucna Seeds

In order to make Mucuna seeds consumable, seeds are treated according to the following procedures: boiling, soaking followed by boiling in the presence of 0.5% KOH and finally soaking for a long time followed by boiling in the presence of 0.5% KOH, so that tannins can be removed. Preliminary studies done on the raw seeds of four Mucuna species revealed the presence of tannins. The results showed that the crushed seeds contained all high tannin with the content of 0.370 g GAE/100g DM, 0.336 g GAE/100g DM;0.266 g GAE/100g DM and 0.203 g GAE/100g DM for Mucuna deerigiana, Mucuna nagaland, Mucuna cochinchinensis and Mucuna rajada respectively. The different methods of seed treatment significantly reduced the tannin content in Mucuna seeds. The method of soaking the seeds for 12 hours and then scalding in the presence of 0.5% KOH reduced tannins in Mucuna deerigiana, Mucuna nagaland, Mucuna cochinchinensis, and Mucuna rajada seeds by 47.29%;48.21%;66.16%;and 15.76% respectively. This method gave the highest tannin reduction rate.

Oxidation of HDPE in the Presence of PVC Grafted with Natural Polyphenols (Tannins) as Antioxidant

In the current research study, an attempt is made to modification of polyvinyl chloride (PVC) by grafting with biologically based phenolic resin, namely, tannins. The reaction was carried out at 110&#176;C in DMF solution. FTIR spectra show the presence of phenolic hydroxylic groups and other functional groups of tannins into the PVC-tannins derivative. Evaluation of the new PVC derivative as polymeric antioxidant for high density polyethylene (HDPE) was the main purpose of this study. Samples of HDPE containing (0.0, 0.5 and 2.0) %W/W from PVC-tannins and pure HDPE were exposed to thermal program by differential scanning calorimetry (DSC) by temperature sweep from 100&#176;C to 350&#176;C. DSC scans of the thermal oxidation process of pure HDPE as well as HDPE with PVC derivative show oxidation exothermic stage started at 195&#176;C and continues to 285&#176;C. The samples of polyethylene contain the PVC-tannins show more resistance to oxidation reactions until 215&#176;C for HDPE sample stabilized with 0.5% and 221&#176;C for HDPE stabilized with 2.0%. Faster initiation of degradation rate was observed when HDPE contained PVC-tannins. According to the DSC analysis, the PVC derivative can participate in stabilization mechanism of HDPE but at limited performance.

Effects of Condensed Tannins from Quebracho Extract on the Kinetic of in vitro Gas Production on Trifofium repens, Lotus corniculatus and Lofium perenne

The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens （0.81 equivalents of tannic acid） and in L .corniculatus （1.07 equivalents of tannic acid） but not in L .perenne （0 equivalents of tannic acid）. The concentration of condensed tannins in the 3 species was： 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction （P 〈 0.05） of gas production happened for doses of 5% of CT in comparison with the other two concentrations： 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.