Water-soluble Phenolic Compounds Research Articles

Green biosynthesis of gold nanoparticles by onion peel extract: Synthesis, characterization and biological activities

Nanoparticles of various noble metals have been studied owing to their eminent outstanding physical and chemical properties, viz. controllable size, surface morphology and surface chemistry. Herein, utilization of the food waste material (aqueous extract of dried onion peels (OP)) to synthesize gold nanoparticles (OP-AuNPs) was investigated along with study of its biological potentials. The synthesized OP-AuNPs were characterized by UV–vis spectroscopy, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) analysis, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and differential thermo gravimetric analysis (DT-TGA) analysis. Surface plasmon resonance spectra were obtained at 535 nm with an average particle size of 45.42 nm. The results of FT-IR confirmed the involvement of various water soluble phenolic compounds and cysteine derivatives in the reduction and stabilization of OP-AuNPs. OP-AuNPs displayed strong synergistic antibacterial and anticandidal activity along with antioxidant and strong proteasome inhibitory potential. The results of the present study will facilitate easy green synthesis of gold nanoparticles using food waste materials and their effective applications in biomedical fields as antibacterial dressings, antibacterial and anticandidal drugs, cancer treatments, proteasome inhibitors, cosmetic industries as sunscreen lotion and anti-aging creams, food sector as antibacterial coatings, and pharmaceutical sectors as medicines and drug formulations.

Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands

Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions due to osmotic stress, and changing temperature regimes. Using four European peatlands reflecting different frequencies of frost events, we show that peatland testate amoeba communities diverge among sites with different winter climates, and that this is reflected through contrasting functions. We found that exposure to harder soil frost promoted species β-diversity (species turnover) thus shifting the community composition of testate amoebae. In particular, we found that harder soil frost, and lower water-soluble phenolic compounds, induced functional turnover through the decrease of large species (−68%, >80μm) and the increase of small-bodied mixotrophic species (i.e. Archerella flavum; +79%). These results suggest that increased exposure to soil frost could be highly limiting for large species while smaller species are more resistant. Furthermore, we found that β-glucosidase enzymatic activity, in addition to soil temperature, strongly depended of the functional diversity of testate amoebae (R2=0.95, ANOVA). Changing winter conditions can therefore strongly impact peatland decomposition process, though it remains unclear if these changes are carried-over to the growing season.

Facile synthesis of multifunctional silver nanoparticles using mangrove plant Excoecaria agallocha L. for its antibacterial, antioxidant and cytotoxic effects.

The current study describes a simple, rapid and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) using Excoecaria agallocha (E. agallocha) leaf extract as stabilizer, bioreductant and capping agent. Synthesized AgNPs were characterized by UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). Generation of AgNPs was initially confirmed with the color change from yellow to dark brown which produces intense absorbance spectra at 440nm in UV-Vis spectroscopy without any shifting of peaks. Further, XRD pattern confirms that the synthesized AgNPs was face centered cubic (fcc) crystalline in structure with an average size of 20nm. On the other hand, FTIR spectrum reveals that the active metabolites like water soluble phenolic compounds, flavonoids, methylene groups, amides and carboxylate groups. These active biocompounds plays a vital role in the reduction of Ag+ into their nanoscale values, it also acts as a stabilizing and surface functionalization agent. FESEM micrographs of synthesized AgNPs shows spherical and hexagonal shaped well dispersed particles in the dimension ranging between 23 and 42nm. EDAX confirms the presence of silver (Ag) as the major constituent element without any impurities; also substantiate the stability of generated AgNPs. The biomedical insights of nanoparticles (NPs) were assessed through radical scavenging and antibacterial properties. Additionally, synthesized AgNPs was also exhibits an excellent cytotoxic effect against human breast carcinoma cell lines (MCF-7). This study proves that synthesized AgNPs can be developed as a potential nano-drug formulation to combat pathogenic disease and also for the expansion of breast cancer therapy.

Calcium-alginate beads loaded with gallic acid: Preparation and characterization

Abstract Electrospray technique was used to prepare alginate beads with controllable size from about 200 μm to 1.3 mm by adjusting the working voltage. The encapsulation ability of alginate beads for gallic acid, a model hydrophilic phenolic compound, was investigated. Loading amount of gallic acid varied from 7 g/100 g–12 g/100 g among alginate beads samples. Fourier-transform infrared and differential scanning calorimetry result confirmed the inclusion of gallic acid. Moreover, no autoxidation of gallic acid was observed in the formulated alginate beads. Release profile result indicated that in simulated intestinal fluid the release was faster than that in gastric fluid. The release pattern was influenced by both loading amount of gallic acid and size of alginate beads. Our results suggest that alginate beads fabricated by electrospray method is a promising delivery system for water soluble phenolic compound like gallic acid.

Cannonball fruit (Couroupita guianensis, Aubl.) extract mediated synthesis of gold nanoparticles and evaluation of its antioxidant activity

Nanostructures of noble metals were immensely studied owing to their eminent salient features like morphology, controllable size dispersity and surface chemistry. Herein, we report a facile and eco-friendly route to synthesize gold nanoparticles (CGAuNPs) within a shorter period of time using the aqueous fruit extract of Couroupita guianensis Aubl. (CGFE) as a potential bioreductant to reduce Au3+ ions into their nanoscale counterparts. Growth of CGAuNPs generates a shift in the color of reaction medium due to the excitation of surface plasmon resonance (SPR) which produces an intense absorbance peak at 530nm in UV–Visible spectroscopy. Fourier transform infrared spectroscopy (FTIR) confirms the active role of water soluble phenolic compounds in achieving the reduction and stabilization of CGAuNPs. Additionally, transmission electron microscope (TEM) and X-ray diffraction (XRD) studies revealed that the synthesized CGAuNPs were anisotropic face centered cubic crystalline in nature, having an average size of 26±11nm. Dynamic light scattering (DLS) and Energy dispersive spectroscopic (EDAX) results were proved that the synthesized CGAuNPs were free from contaminants and they were stable, possessing negative electric charge without aggregation. On the other hand, in vitro antioxidant assays demonstrate that the aqueous CGFE and formulated CGAuNPs possess extraordinary antioxidant properties. Hemocompatibility assay depicts the safe nature of synthesized CGAuNPs for biomedical applications. Thus, the results of present study will be useful to synthesize AuNPs instantly via green chemistry route for its valuable applications in nanomedicine.

The Mixture of Salvianolic Acids from Salvia miltiorrhiza and Total Flavonoids from Anemarrhena asphodeloides Attenuate Sulfur Mustard-Induced Injury.

Sulfur mustard (SM) is a vesicating chemical warfare agent used in numerous military conflicts and remains a potential chemical threat to the present day. Exposure to SM causes the depletion of cellular antioxidant thiols, mainly glutathione (GSH), which may lead to a series of SM-associated toxic responses. MSTF is the mixture of salvianolic acids (SA) of Salvia miltiorrhiza and total flavonoids (TFA) of Anemarrhena asphodeloides. SA is the main water-soluble phenolic compound in Salvia miltiorrhiza. TFA mainly includes mangiferin, isomangiferin and neomangiferin. SA and TFA possess diverse activities, including antioxidant and anti-inflammation activities. In this study, we mainly investigated the therapeutic effects of MSTF on SM toxicity in Sprague Dawley rats. Treatment with MSTF 1 h after subcutaneous injection with 3.5 mg/kg (equivalent to 0.7 LD50) SM significantly increased the survival levels of rats and attenuated the SM-induced morphological changes in the testis, small intestine and liver tissues. Treatment with MSTF at doses of 60 and 120 mg/kg caused a significant (p < 0.05) reversal in SM-induced GSH depletion. Gene expression profiles revealed that treatment with MSTF had a dramatic effect on gene expression changes caused by SM. Treatment with MSTF prevented SM-induced differential expression of 93.8% (973 genes) of 1037 genes. Pathway enrichment analysis indicated that these genes were mainly involved in a total of 36 pathways, such as the MAPK signaling pathway, pathways in cancer, antigen processing and presentation. These data suggest that MSTF attenuates SM-induced injury by increasing GSH and targeting multiple pathways, including the MAPK signaling pathway, as well as antigen processing and presentation. These results suggest that MSTF has the potential to be used as a potential therapeutic agent against SM injuries.

Effects of baking conditions and dough formulations on phenolic compound stability, antioxidant capacity and color of cookies made from anthocyanin-rich corn flour

In this study, the effect of baking conditions and dough formulations on phenolic compounds, antioxidant capacity and color of cookies made from anthocyanin-rich corn flour were investigated. The control cookies were prepared from dark-red popping corn, blue popping corn and blue-standard corn flour according AACC method 10–54 and baked at 200 °C for 7 and 10 min. In control corn cookies, the content of total flavonoids and anthocyanins, as free water-soluble phenolic compounds, was reduced by applied baking conditions. Our results show that citric acid significantly increased the total flavonoids and anthocyanins content in the cookies prepared from blue popping corn and blue-standard corn. Compared with the control cookies baked at 200 °C for 7 min, the cookies prepared with 0.5 g/100 g added citric acid and baked at 150 °C for 12 min had higher contents of total flavonoids and anthocyanins by 60 and 70%, respectively. However, as a result of Maillard reaction inhibition at low pH, antioxidant capacity of anthocyanins-rich blue popping corn and blue standard corn cookies with 0.5 and 1 g/100 g citric acid was lower by 56 and 39%, respectively, compared to antioxidant capacity of their control cookies baked at 200 °C for 10 min.

PRELIMINARY RESULTS OF SOIL BIOLOGICAL AND CHEMICAL PROPERTIES AFTER LAND SPREADING ALPERUJO IN INTENSIVELY-MANAGED OLIVE ORCHARDS IN SAN JUAN, ARGENTINA

Utilization of olive oil mill wastes as olive groves soil amendment represents a simple option to recycle the residues and restore organic matter to soils. This practice has been widely evaluated in Mediterranean countries, however, there is still little consensus about the effects that it may produce on soil quality indicators. Substantial differences on climatic, soil, irrigation and management conditions as well as in the type of olive waste applied and the application method prevent to formulate wide-ranging conclusions and force to evaluate each single situation. The aim of this work was to evaluate under local conditions the use of alperujo (semi-solid by-product of two-phase olive oil mills) as soil amendment on high-density drip-irrigated olive groves. A surface layer of alperujo was applied in soils under olive trees at doses of 40 t/ha without subsequent land incorporation and soil biological and chemical parameters were evaluated after one year of the application. The results showed that alperujo amendment increased soil nitrogen (N) and available potassium (K) without affecting the levels of available phosphorous (P), water-soluble phenolic compounds (PC), C/N ratio and soil pH. Electrical conductivity (EC) was significantly increased but presenting values insufficient to adversely affect the normal growth of most crops. Regarding to biological indicators, no differences were observed in the total number of culturable soil microorganisms neither on the activity of organic matter degrading enzymes nor on the germination index of Medicago sativa seeds. Together the results indicate that soil application of alperujo under local conditions may constitute an interesting alternative to reuse this residue and supply essential nutrients to soil. Undoubtedly special attention must be taken on the increase on EC levels, therefore further long term assays must be performed.

Protection of salvianolate against atherosclerosis via regulating the inflammation in rats.

Inflammation plays an essential role in the pathophysiology of atherosclerosis. Our study was aimed to investigate whether salvianolate, a novel water-soluble phenolic compound of Danshen, alleviates atherosclerosis via regulating the inflammation in rats. High fat diet feeding plus vitamin D3 injection was used to induce atherosclerosis in rats. Salvianolate (60, 120 or 240 mg/kg) or placebo was given to atherosclerotic rats. The plasma lipids, interleukin 6 (IL-6) and C reactive protein (CRP) were measured by ELISA. CD4+CD25+Foxp3+ cells were determined by flow cytometry. Histological changes were examined by hematoxylin and eosin staining. The results showed that the levels of plasma IL-6 and CRP were elevated in the rats fed on high fat diet, and the histological analysis demonstrated the successful establishment of atherosclerosis models. Treatment with salvianolate alleviated the atherosclerotic process and decreased the levels of plasma IL-6 and CRP. Also the number of CD4+CD25+Foxp3+ cells was increased in salvianolate-treated rats. It was concluded that salvianolate could treat atherosclerosis via modulating the inflammation at cytokine and cell levels.

Bioconversion of tea polyphenols to bioactive theabrownins by Aspergillus fumigatus.

Theabrownins (TB) are water-soluble phenolic compounds associated with the various health benefits of Pu-erh tea, a post-fermented Chinese dark tea. This work reports on the production of theabrownins from infusions of sun-dried green tea leaves using a pure culture of Aspergillus fumigatus isolated from a solid-state Pu-erh tea fermentation. A theabrownins yield of 158gkg(-1) sun-dried green tea leaves was obtained in 6days at 45°C in an aerobic fermentation. In a 2l fermenter, the yield of theabrownins was 151gkg(-1) sun-dried green tea leaves in 48h of aerobic culture (45°C, 1 vvm aeration rate, 250rpm agitation speed). Extracellular polyphenol oxidase and peroxidase of A. fumigatus contributed to this bioconversion. Repeated batch fermentation process was used for producing theabrownins but was less productive than the batch process.

Optimization of reaction conditions to fabricate nano-silver using Couroupita guianensis Aubl. (leaf & fruit) and its enhanced larvicidal effect

Currently bioactive principles of plants and their nanoproducts have been extensively studied in agriculture and medicine. In this study Couroupita guianensis Aubl. leaf and fruit extracts were selected for rapid and cost-effective synthesis of silver nanoparticles (leaf-LAgNPs and fruit-FAgNPs). Various physiological conditions such as temperature, pH, concentration of metal ions, stoichiometric proportion of reaction mixture and reaction time showed influence on the size, dispersity and synthesis rate of AgNPs. Generation of AgNPs was initially confirmed with the surface plasmon vibrations at 420nm in UV–visible spectrophotometer. The results recorded from X-ray diffractometer (XRD) and Transmission electron microscope (TEM) supports the biosynthesis of cubic crystalline LAgNPs & FAgNPs with the size ranges between 10–45nm and 5–15nm respectively. Surface chemistry of synthesized AgNPs was studied with Fourier transform infrared spectroscopy (FTIR), it reveals that water soluble phenolic compounds present in the extracts act as reducing and stabilizing agent. Leaf, fruit extracts and synthesized AgNPs were evaluated against IV instar larvae of Aedes aegypti (Diptera; Culicidae). Furthermore, different extracts and synthesized AgNPs showed dose dependent larvicidal effect against A. aegypti after 24h of treatment. Compare to all extracts such as ethyl acetate (leaf; LC50 – 44.55ppm and LC90 – 318.39ppm & fruit; LC50 – 49.96ppm and LC90 – 568.84ppm respectively) and Methanol (leaf; LC50 – 85.75ppm and LC90 – 598.63ppm & fruit; LC50 – 67.78ppm and LC90 – 714.45ppm respectively) synthesized AgNPs showed extensive mortality rate (LAgNPs; LC50 – 2.1ppm and LC90 – 5.59ppm & FAgNPs; LC50 – 2.09ppm and LC90 – 5.7ppm). Hence, this study proves that C. guianensis is a potential bioresource for stable, reproducible nanoparticle synthesis (AgNPs) and also can be used as an efficient mosquito control agent.

Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies

Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i.e. pistil and leaf tannins protect against insect herbivores and root tannins against soil pathogens.

Response of soil organic layer characteristics to logging residues in three Scots pine thinning stands

The aim of this study was to determine how logging residues, consisting of tree tops and branches with needles, affect soil microbial processes in C and N cycling in Scots pine stands, and how these processes are related to the composition of terpenes and phenolic compounds, two major groups of plant secondary compounds. Samples were taken from the humus layer (Ofh) of three field experiments in Finland. The first was a single-tree experiment in a young pine stand where thinning was performed 4 years before this study and four doses of fresh logging residue were distributed on a circle around a tree, corresponding to 0, 10, 20 and 30 Mg ha−1 of dry matter. The other two field experiments had been thinned twice, one 29 and 4 years ago and the other 23 and 13 years ago; the treatments were whole-tree harvest, where logging residues had been harvested, and stem-only harvest, where logging residues were left on the plot. In the single-tree experiment, with increasing amount of residues, C/N ratio of organic matter decreased, C mineralization (CO2 production) and glucose-induced respiration increased, but C and N in the microbial biomass both remained on a similar level, regardless of the amount of logging residues. Due to high variation, it was not possible to observe any statistically significant effects of logging residues on net N mineralization, but with increasing amount of residues the trend was increasing. Amount of logging residues did not affect the concentrations of total water-soluble phenolic compounds, or the concentrations of mono-, sesqui- or diterpenes in the humus layer, whereas with increasing amount of residues the concentrations of condensed tannins and triterpenes tended to increase. Amount of logging residues did not affect monoterpene concentrations in the soil atmosphere. In the two other field experiments, logging residues had little effect on soil C and N transformations or groups of organic compounds, although some significant differences were observed in the experiment sampled 4 years after harvest of logging residue. Both C and net N mineralization correlated positively with the concentrations of water-soluble low-molecular-weight phenolic compounds and sesqui-, di- and triterpenes in the humus layer. In conclusion, the response of soil characteristics in Scots pine stands to harvest of logging residue in thinning seems to depend on the amount of residues and on the time elapsed since thinning, but the response may vary on different sites. In cases where an effect was observed, however, it pointed to a stimulative effect of residues on C and N cycling processes. Terpenes and phenolic compounds, abundant in the residue, may affect soil microbial population, e.g. by providing a long-term source of carbon.

Water-soluble phenolic compounds in lichens

The quantity and the qualitative composition (for some species) of phenolic compounds (PC) washed out of the intact thalli of lichens of the orders Peltigerales (the genera Peltigera, Solorina, and Nephroma) and Lecanorales (the genera Cladonia, Alectoria, and Cetraria) were studied. It was shown that the quantity of leachable PCs in Peltigerales was on average 2–3 times higher than in Lecanorales. At the same time, the extractability of PC from intact thalli by water was higher in Lecanorales than in Peltigerales: 48–88% and 34–70%, respectively, of the PC content in ethanol extracts from crushed thalli (i.e., of the total content of soluble PC). Water-soluble PC in the lichens Peltigera aphthosa, Solorina crocea, Cetraria islandica, Flavocetraria nivalis, Cladonia uncialis, and Cladonia arbuscula were represented by 7–12 phenolic compounds with similar qualitative composition in the species of the same order. The most part of water soluble PC were phenylpropanoids. All of the studied species showed the presence of p-hydroxybenzoic acid derivatives; vanillic and protocatechuic acid derivatives were found in Cetraria and Cladonia species, respectively.

Fruit skin color and the role of anthocyanin

Fruit skin coloration is a unique phase in the life cycle of fruiting plants and is mainly attributed to anthocyanin pigments. Anthocyanins are the largest and most diverse group of plant pigments derived from the phenyl propanoid pathway. They are water-soluble phenolic compounds that form part of a large and common group of plant flavonoids. Coloration encompasses several physiological and biochemical changes that happen through differential expression of various developmentally regulated genes. Due to research importance and economic value, Arabidopsis thaliana (chromosome no. = 5) and Vitis vinifera (chromosome no. = 19) have been used for investigations of the structural genes involved in anthocyanin biosynthesis. Thus for this review, V. vinifera is used as a model crop. In anthocyanin biosynthesis, a wide range of constructive genes including phenylalanine ammonia lyase, chalcone synthase and anthocyanidin synthase that are regulated by MYB transcription factors are involved. These genes are coordinately expressed and their levels of expression are positively related to the anthocyanin concentrations. Expression or suppression of the constructive genes contributes to a variety of changes that make fruits visually attractive and edible. Transgenic approaches also have discovered a strong relationship between phenyl propanoid/flavonoid gene expressions for fruit skin coloration. In this study, various developments that have taken place in the last decade with respect to identifying and altering the function of color-related genes are described.

Antioxidant activity of the stem bark of Shorea roxburghii and its silver reducing power

A detailed study has been performed on the antioxidant activity of the acetone and methanol extracts of the stem bark of the plant, Shorea roxburghii. The total phenolic content and antioxidant activity of the extracts were determined by DPPH, radical scavenging, ferric ion reducing power, hydroxyl radical, ABTS. radical scavenging and hydrogen peroxide scavenging activities. Reducing efficiency of the S. roxburghii towards silver nanoparticles has been evaluated using surface plasmon resonance and transmission electron microscope. Spherical shapes of particles with 4–50 nm have been reported. Formation of silver nanoparticles ascertains the role of the water soluble phenolic compounds present in S. roxburghii. Both acetone and methanol extracts of S. roxburghii stem bark was found to be a potent antioxidant. This work provides a scientific support for the high antioxidant activity of this plant and thus it may find potential applications in the treatment of the diseases caused by free radical. The extract of this plant could be used as a green reducing agent for the synthesis of Ag nanoparticles.

Distribution, antioxidant and characterisation of phenolic compounds in soybeans, flaxseed and olives

The distribution of free and bound phenolic compounds present in soybean, flaxseed and olive were investigated. The phenolic compounds were fractionated on the basis on their solubility characteristics in water, alcohol, dilute base and dilute acid. Reversed phase high pressure liquid chromatography (RP-HPLC) and mass spectrometry (MS) were used for identification of individual components of phenolic compounds. Antioxidant activity (AA%) of free and bound phenolic compounds was measured using the linoleic acid/β-carotene assay. The water-soluble phenolic compound fractions represented 68–81%, 50–72% and 46–56% of the total phenolic compounds measured in full-fat soybean, olive and flaxseed, respectively. Methanolic extraction of free phenolic compounds without heat, solubilised 21–56%, 42–62% and 34–51% of the total phenolic compounds measured in soybean, olive and flaxseed, respectively; methanol extraction of free phenolic compounds with heat solubilised a further 24–34%, 31–37% and 36–37% of phenolic compounds from soybean, olive and flaxseed, respectively. Further dilute alkali and dilute acid solubilised the remaining 10–40%, 1–21% and 12–29% of the total phenolic compounds from soybean, olive and flaxseed, respectively. Results indicated that the full-fat meals of soybean, flaxseed and olive showed higher antioxidant activity compared to defatted meals. RP-HPLC and LC–MS/MS profil1 for soybean, flaxseed and olive indicate two classes of phenolic compounds designated as free and bound phenolic compounds.

Degradation of Tannic Acid Powered by TiO&lt;sub&gt;2&lt;/sub&gt; Nanoparticles

The wastewater from the coir, pharmaceutical, leather, paper and pulp industries is contaminated with water-soluble poly phenolic compounds (tannins). Among various tannins, tannic acid is a typical hydrolysable tannin prevalent in wastewater. The degradation of tannic acid using TiO2 nanoparticles as photocatalyst was investigated. The effect of catalyst concentration, pH of aqueous suspension and also electron acceptors such as hydrogen peroxide (H2O2) and ozone (O3) on the degradation of tannic acid was studied. The degradation of tannic acid was found to be more efficient and complete in the presence of UV/TiO2/O3 compared to UV/TiO2/H2O2. The kinetics of degradation was observed to follow first order rate equation which indicates that the mineralization process is diffusion controlled.

Effects of Fat and Protein Levels on Foraging Preferences of Tannin in Scatter-Hoarding Rodents

Both as consumers and dispersers of seeds, scatter-hoarding rodents often play an important role in the reproductive ecology of many plant species. However, the seeds of many plant species contain tannins, which are a diverse group of water-soluble phenolic compounds that have a high affinity for proteins. The amount of tannins in seeds is expected to affect rodent foraging preferences because of their major impact on rodent physiology and survival. However, variable results have been obtained in studies that evaluated the effects of tannin on rodent foraging behavior. Hence, in this study, we aimed to explain these inconsistent results and proposed that a combination of seed traits might be important in rodent foraging behavior, because it is difficult to distinguish between the effects of individual traits on rodent foraging behavior and the interactions among them. By using a novel artificial seed system, we manipulated seed tannin and fat/protein levels to examine directly the univariate effects of each component on the seed preferences of free-ranging forest rats (Apodemus latronum and Apodemus chevrieri) during the behavioral process of scatter hoarding. Our results showed that both tannin and fat/protein had significant effects on rodent foraging behavior. Although only a few interactive effects of tannin and fat/protein were recorded, higher concentrations of both fat and protein could attenuate the exclusion of seeds with higher tannin concentrations by rodents, thus influencing seed fate. Furthermore, aside from the concentrations of tannin, fat, and protein, numerous other traits of plant seeds may also influence rodent foraging behavior. We suggest that by clarifying rodent foraging preferences, a better understanding of the evolution of plant seed traits may be obtained because of their strong potential for selective pressure.

Observation of the location and form of anthocyanin in purple potato using time-resolved fluorescence

Abstract Anthocyanins are water soluble phenolic compounds present in fruit and vegetables which are responsible for the bright red, blue and purple colours of these food products. They are also responsible for the characteristic autumn leaf colouration in some trees. These are versatile compounds, as well as having application in the food industry, they have also found usage to sensitise titanium dioxide in research related to dye sensitised solar cells. This has prompted investigation into their photophysical properties in order to elucidate their charge transfer mediation behaviour. Recently anthocyanins are becoming of high interest both from a health point of view and because of their potential usage as food colouring agents. However, anthocyanins are very unstable compounds and their stability can be affected by several factors such as temperature, pH, oxygen and light. Here we show the effect of the microwave process (which is a promising method for anthocyanin extraction) on the location and form of anthocyanin in Purple Majesty potato (novel variety of purple potato rich in anthocyanins, the major one of which is petanin), when compared with the raw potato using time-resolved fluorescence techniques, both on extracted anthocyanin and in-situ on potato slices using fluorescence lifetime imaging. Industrial relevance Anthocyanins can be extracted from plant based food and have potential application in Food Industry because of their anti-microbial and anti-oxidant properties. This group of compounds also present strong (principally) red and purple colourations in plant matter, which make them interesting to use as food colorants by the Food Industry. However, anthocyanins can have different structures (forms) which are dependent of the environmental conditions (mainly pH/complexation/concentration) which can affect their properties. Considering that these compounds can be extracted from plants it is important to easily observe their location in the cell and to elucidate their properties. Because of this requirement we show, in this paper, that it is possible to use time-resolved fluorescence, using microscopy and time-resolved emission spectra, which we believe add novelty to obtain pertinent information from extracted (unpurified) anthocyanin and in-situ within the potato tuber cells. This shows the potential of these techniques in elucidating data in this study and with future application in food industry.