Repellent,toxic, and food protectant effects of pithraj,Aphanamixis polystachya extracts against pulse beetle,Callosobruchus chinensis in storage

Ground leaves, bark, seeds, and four seed extracts of pithraj,Aphanamixis polystachya (family Meliaceae), a locally grown plant in Bangladesh, were evaluated for their repellency, contact toxicity, and food protectant efficacy against adult pulse beetle (Callosobruchus chinensis L.). The seed extracts showed poor repellent effects, but high contact toxicity to adults at 72 hr after application. The ground leaves, bark, and seeds provided good protection for mung beans against pulse beetles, and the seed powder greatly reduced the F1 progeny and seed damage rates.     

Chemical Analysis of Polyphenols with Antioxidant Capacity from Pinus durangensis Bark

The most active phenolics in Pinus durangensis residual bark were identified and evaluated following a chromatographic fractionation. Bark powder was defatted with hexane, and a crude extract (CE) was obtained by extraction with aqueous acetone (67%). A liquid partition with ethyl acetate was performed to produce an organic extract (OE), which was subsequently purified by column chromatography (Toyopearl HW-40F, methanol), resulting in ten fractions (MF1 to MF10) and an oligomeric fraction eluted with acetone 67% (OLF). Subfraction MF6-1 was obtained by a second chromatographic purification of MF6. Extraction yields, total phenolics, flavonoids, and flavanols contents were determined in CE and OE. The antioxidant activity of bark extracts was measured by DPPH and ABTS assays at 100 µg/mL, expressed in percentage, median effective concentration (IC₅₀), and TEAC (mM). Also the low density lipoprotein inhibition was evaluated. Identification of major phenolics was carried out by HPLCESI–MS and HPLC–DAD instruments. Bioactive taxifolin (dihydroquercetin), dihydromyricetin, myricetin, quercetin, pinomyricetin (myricetin-methoxy), pinoquercetin (quercetin-methoxy), trimeric, and tetrameric procyanidins were detected and identified in P. durangensis bark extracts. Polyphenols found are similar to those contained in Pycnogenol and other Pinus species.     

Thermal Degradation of Condensed Tannins from Radiata Pine Bark

Abstract

In order to understand the influence of the inherent chemistry on the relative thermal stability of condensed tannins, the thermal degradation behaviors of various radiata pine bark extracts have been investigated using thermogravimetric analysis (TGA). Generally, results suggest pine bark extract fractions may be readily processed at temperatures below 200°C if co-extracted polysaccharides contents are minimized. Those extracts possessing greater carbohydrate content and lower tannin purity tend to have decreased thermal stability. The initial onset temperature for degradation of relatively crude extracts with high proportions of carbohydrate contents were relatively low (ca. 150°C), whereas extract purification to < 5% carbohydrate content gave increases in thermal stability of at least 50°C. The complicity of the carbohydrate content in the degradation of the tannin samples was also supported by calculated Ozawa activation energies and modulated TGA experiments. While no increase in the thermal stability was gained by acetylating the pendant hydroxyl groups of the pine bark tannin extract, chemical variations such as sulfonation have a large effect on thermal degradation, promoting lower degradation temperatures.     

Toxicity of Phenolic Compounds Extracted from Bark Residues of Different Ages

In Quebec, Canada, industrial bark wastelands cover several hundred hectares of land. Bark residue that has piled up for decades tends to remain free of vegetation for years. To assess the revegetation potential of such sites, we sought to determine those factors responsible for poor plant growth. Phenolic compounds from fresh to 20-year-old bark residues were extracted with four solvents and quantified by high-performance liquid chromatography (HPLC). We simulated solutions (mixtures of standard phenolic compounds) to evaluate the potential toxic effects of phenolic compounds on the rhizobial growth, germination index, plant growth, nodule number, and nitrogen fixation activity of two legume species under laboratory conditions. The concentration of individual phenolic compounds varied from none detected to 350 μg/g bark residue. The extracted phenolic compounds differed among solvents and bark residues. The highest concentration of total phenolic compounds was from fresh bark; most of these were soluble in water or 0.1 M NaOH. For older bark residues, the total phenolic content depended on solvent strength, generally in the order of 2.0 M NaOH > 0.1 M NaOH = hot water > cold water. The biological activity of the simulated bark extracts was not established with the rhizobial growth inhibition test but with the germination index and rhizobium–legume symbiosis tests. With these, the toxicity of the simulated phenolic extracts decreased from fresh to the older bark residues. Plant dry weight, nodule number, and nitrogen fixation activity of vetch (Vicia sativa L.) were less negatively affected by high concentrations of phenolics than birdsfoot trefoil (Lotus corniculatus L.), although birdsfoot trefoil grew at lower concentrations. The rhizobium–legume symbiosis has potential for revegetating bark wastelands with less than 1 year old and older bark residues.     

Extraction of polyphenolic substances from bark as natural colorants for wool dyeing

In Europe, considerable amounts of bark are available from wood‐processing industries such as forestry and timber production. Polyphenolic components can be collected by hot water extraction. The extracted compounds can then be applied as colorants in textile dyeing operations. In this study, a comparative assessment of four different tree species with regard to their colouristic potential for wool dyeing was performed. Aqueous extracts from alder, ash tree, spruce and oak bark were prepared and analysed for their total phenolic content and ultraviolet (UV) absorption at 360–370 nm. The extracts were used for meta‐mordant dyeing by adding iron sulphate mordant (FeSO₄ × 7H₂O). For comparison, iron salt‐based dye lakes were prepared and used in dyeing experiments. For each tree species, a specific correlation between the total phenolic content of the dyebath and the colour depth in terms of K/S and CIELab coordinates was observed, both for the aqueous extracts and the dye lakes. Based on this relationship, standardisation and quality control of raw materials and dye lakes can be installed as important stages in the industrialisation of natural colorants from bark. The preparation of concentrated dye lakes permits formation of a concentrated colorant as dye product, which then can be standardised and delivered to textile dyehouses, similar to synthetic dyes. The preparation of dye lakes offers a relevant route towards achieving the commercialisation of bark extracts as natural colorants.     

Allelochemical Potential of Metopium brownei

Metopium brownei is a tree that grows in coastal tropical forests along the Gulf of Mexico and in the Yucatan Peninsula. This medicinal species produces a strongly irritant exudate, and sometimes forms pure populations favored by fire. The bioactivity of the aqueous leachates, organic extracts (leaves, bark, and wood), and mixtures of urushiols and flavonoids from M. brownei were evaluated on the growth of two plants: Amaranthus hypochondriacus and Echinochloa crusgalli, and four phytopathogenic fungi: Fusarium oxysporum, Helminthosporium sp., Alternaria sp., and Pythium sp. Alkylcatechols (urushiols) were isolated from an acetone extract of the bark. Dihydroquercetin and eriodictyol were isolated from the chloroform–methanol extract of the wood. In addition, masticadienoic acid was isolated from the leaves. The aqueous leachates, organic extracts, and the mixtures of flavonoids and urushiols were inhibitory to the growth of test plants and phytopathogenic fungi. The allelochemical role of the bioactive compounds from M. brownei is discussed in relation with other results reported in some studies on Anacardiaceae family and M. brownei.     

Localization of Phenolics in Phloem Parenchyma Cells of Norway Spruce (Picea abies)

Norway spruce (Picea abies) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle Ips typographus and its microbial associate, the blue stain fungus Ceratocystis polonica. These cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. Laser microdissection of spruce bark sections combined with cryogenic NMR spectroscopy demonstrated significantly higher concentrations of the stilbene glucoside astringin in phloem parenchyma cells than in adjacent sieve cells. After infection by C. polonica, the flavonoid (+)‐catechin also appeared in phloem parenchyma cells and there was a decrease in astringin content compared to cells from uninfected trees. Analysis of whole‐bark extracts confirmed the results obtained from the cell extracts and revealed a significant increase in dimeric stilbene glucosides, both astringin and isorhapontin derivatives (piceasides A to H), in fungus‐infected versus uninfected bark that might explain the reduction in stilbene monomers. Phloem parenchyma cells thus appear to be a principal site of phenolic accumulation in spruce bark.     

Enrichment of antibacterial compound from the stem bark of Stereospermum fimbriatum using supercritical carbon dioxide extraction

ABSTRACT

Supercritical carbon dioxide (sc-CO₂) extraction was carried out on Stereospermum fimbriatum’s stem bark in order to obtain an enriched extract containing the targeted active compound. The recovery of its active compound, C1, was compared with the most active Soxhlet’s extract of dichloromethane. A minimum inhibitory concentration (MIC) assay was done to examine the antibacterial activity of extracts against methicillin-resistant Staphylococcus aureus. The optimum condition for an enriched extract of sc-CO₂ to have a maximum recovery of C1 at MIC value of 400 µg/mL was suggested to be operated at 40°C and pressure at 30 MPa, with addition of 6% co-solvent.     

Bioactive compounds from the bark of Broussonetia papyrifera after solid fermentation with a white rot fungus Perenniporia tephropora

Abstract

In this study, potential bioactive compounds in the products of the solid fermentation of the paper mulberry tree bark (Broussonetia papyrifera) with a white rot fungus (Perenniporia tephropora) were investigated. Fractionation of methanolic extracts from the fermented products of the bark led to the isolation of 10 known compounds, namely broussonin B (1), broussonin A (2), 7,4'-dihydroxy-3'-prenylflavan (3), cathayanon H (4), broussoflavonol B (5), isoliquiritigenin (6), broussochalcone B (7), glyasperin A (8), marmesin (9), and vomifoliol (10). Their structures were determined by spectroscopic analysis (including considerations of MS, ¹H, ¹³C NMR, COSY, HMQC, and HMBC spectra) and compared with structures that had been published in the literature. Of these compounds identified, cathayanon H (4) and glyasperin A (8) were isolated for the first time from the paper mulberry tree. Vomifoliol (10) was produced from the bark only after fermentation with white rot fungi. It was observed that concentrations of marmesin (9) and vomifoliol (10) generally increased with an increase in fermentation time, whereas concentration of compounds 1?8 in the fermented products decreased during the same period. Biological tests showed that the tyrosinase inhibitory activity of marmesin (9) (IC₅₀ = 168.0?μM) was similar to that of arbutin, a well-known tyrosinase inhibitor, whereas vomifoliol (10) exhibited no tyrosinase inhibition activity at any concentration higher than 2?mM. Accordingly, both solids and the liquid broth left after fermentation of the paper mulberry tree bark with the aforementioned white rot fungus could be developed for potential use in industrial applications.     

Evidence of an oviposition stimulant for peachtree borer

Peachtree borer (PTB) cocoons, peach tree bark, and a mixture of frass and gum obtained arount PTB wounds were extracted with organic solvents of increasing polarity. Female PTB moths,Synanthedon exitiosa (Say), laid the greatest number of eggs on filter paper substrates treated with acetone extracts of PTB cocoons, ethyl acetate extracts of peach tree bark and acetone extracts of frass and gum mixtures. The extracts of cocoons or frass and gum mixture were separated by liquid chromatography and thin layer chromatography.Synanthedon exitiosa (Say).Mention of a commercial or proprietory product does not constitute an endorsement of this product by the USDA.     

Characterization and antioxidative properties of condensed tannins from the mangrove plant Aegiceras corniculatum

Freeze‐dried leaf, stem bark, and root bark powders of Aegiceras corniculatum were extracted with three different types of polar solvents: methanol, ethyl acetate, and water. The methanol extracts had the highest concentrations in total phenolics and extractable condensed tannins, followed by water and ethyl acetate extracts. Analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) suggested that condensed tannins from leaf, stem bark, and root bark contained prodelphinidins and procyanidins, with the predominance of prodelphinidins and high level of galloylation. Acid‐catalyzed degradation in the presence of benzyl mercaptan indicated that gallocatechin, epigallocatechin, epigallocatechin‐3‐O‐gallate, and epicatechin‐3‐O‐gallate occurred as the terminal units and (epi)gallocatechin, (epi)gallocatechin‐3‐O‐gallate, (epi)catechin, and (epi)catechin‐3‐O‐gallate occurred as the extension units. The mean degrees of polymerization (mDP) of condensed tannins from leaf, stem bark, and root bark were 13.5, 7.4, and 12.3, respectively. The condensed tannins from leaf and stem bark exhibited a higher DPPH radical scavenging activity and ferric reducing/antioxidant power compared to that of synthetic antioxidant butylated hydroxyanisole (BHA). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of birch (Betula pendula) bark and food protein level on root voles (Microtus oeconomus): I. food consumption,growth, and mortality

The effect of protein and birch bark powder (BBP) content of forage on food consumption and growth of root voles (Microtus oeconomus) was studied by feeding young voles with eight different diets for two weeks. Voles ate more when the protein content of forage was moderate (6%) or low (3%), and when BBP was added to the diets, as compared to a high (12%) protein diet without BBP addition. On high and moderate protein diets voles gained weight, whereas on low protein diets they lost weight. Addition of BBP caused reduced growth or weight loss. Consuming a diet with moderate (6%) protein and high BBP (20%) resulted in high mortality (9 of 10 died). These results show that root voles need at least 6% protein for growth and that the effect of birch bark depends on the protein content of the forage.     

Lignin Degradation by Flavodon flavus (Klotzsch.) Ryv. and Schizophyllum commune Fr. on Mangifera indica and Syzygium cumini Woods

Abstract

The lignin degradation by Flavodon flavus (Klotzsch) Ryv. and Schizophyllum commune Fr. on Mangifera indica and Syzygium cumini wood, changes in the chemical composition of the degraded wood, and production of extra-cellular lignocellulolytic enzymes were analyzed. White rot fungi F. flavus and S. commune selectively degraded the lignin of S. cumini rather than the holocellulose component, whereas simultaneous degradation of lignin occurred in the case of M. indica. After 90 days of pretreatment with F. flavus, total weight loss was 29% and loss in lignin content was 25.7% in M. indica wood. However, 8% loss of holocellulose was caused by S. commune in S. cumini wood. Extracellular enzymes from F. flavus such as ligninase and cellulase showed higher activity in degradation of M. indica wood than in S. cumini wood. Weight loss and changes in chemical composition of M. indica and S. cumini woods showed good correlation with enzyme activity in lignocellulose degradation. Woods of S. cumini showed resistance to the white rot fungi could be due to the presence of polyphenols.     

Identification of Δ<Superscript>7</Superscript> phytosterols and phytosteryl glucosides in the wood and bark of several <Emphasis Type="Italic">Acacia</Emphasis> speciesphytosterols and phytosteryl glucosides in the wood and bark of several <Emphasis Type="Italic">Acacia</Emphasis> species

The wood and bark of four Acacia species growing in Portugal, namely, A. longifolia, A. dealbata, A. melanoxylon, and A. retinodes, were investigated for their sterol content. The lipids fractions of the different wood and bark samples were isolated, and the sterols were identified and quantified by GC-MS. Two Δ⁷ sterols, specifically, spinasterol and dihydrospinasterol, were the main sterols found in considerable amounts, particularly in wood tissues (more than 0.5 g/kg of dry wood in the case of A. melanoxylon and A. retinodes). The corresponding unusual steryl glucosides were also identified in significant amounts in the wood and bark extracts.     

Revisiting the Mechanism of β-O-4 Bond Cleavage during Acidolysis of Lignin. Part 2: Detailed Reaction Mechanism of a Non-Phenolic C6-C2 Type Model Compound

Abstract

The detailed reaction mechanism of a C₆-C₂ dimeric non-phenolic β-O-4 type lignin model compound, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)ethanol (V′G), was examined under acidolysis conditions (mainly 0.2 mol/l HBr in 82% aqueous 1,4-dioxane at 85°C), and was suggested to be as follows. The initial elementary reaction step is protonation of the α-hydroxyl group, followed by the release of water to afford a benzyl cation intermediate (BC′). The latter step is relatively slow but reversible. The β-proton abstraction from BC′ by the solvents affords an enol ether compound, 1-(2-methoxyphenoxy)-2-(3,4-dimethoxyphenyl)ethene (EE′). This step is practically irreversible, and is the rate-determining step in the disappearance of V′G. The stereoisomers of EE′ are rapidly converted into each other, accompanied by protonation of the double bond. Complete protonation affords a β-oxymethylene cation intermediate (OMC′), which is also formed via hydride transfer from the β- to α-position of BC′ as a minor route. OMC′ preferentially undergoes the addition of water at the β-position, and the consequent β-O-4 bond cleavage affords 2-methoxyphenol and a Hibbert's monomer, 3,4-dimethoxyphenylacetaldehyde.     

Effects of molecular weight and arm number on properties of star‐shape styrene–butadiene–styrene triblock copolymer

A star‐shape styrene–butadiene–styrene triblock copolymer SBS (802) was synthesized and fractionated into four fractions coded as 802‐F1 (four arms), 802‐F2 (two arms), 802‐F3 (one arm), and 802‐F4 by repeating fractional precipitation. Their weight‐average molecular weight (M_w) was measured by size‐exclusion chromatography combined with laser light scattering to be 16.0 × 10⁴, 8.2 × 10⁴, 4.3 × 10⁴, and 1.19 × 10⁴, respectively. The samples were, respectively, compression‐molded and solution‐cast to obtain the sheets coded as 802C, 802‐F1C, 802‐F2C, and 802S, 802‐F1S, 802‐F2S. The structures and mechanical properties of the sheets were characterized by ¹H‐NMR, scanning electron microscope, wide‐angle X‐ray diffractometer, tensile testing, and dynamic mechanical thermal analysis. The results indicated that the compression‐molded 802‐F1C exhibited the higher tensile strength (σ_b, 28.4 MPa) and elongation at break (ε_b, 1610%), and its optical transmittance is much higher than those of 802C and 802‐F2C. This work revealed that the star‐shape SBS with four arms could be helpful in the enhancement of the properties as a result of good miscibility of the compression‐molded SBS sheets. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 832–840, 2005     

Evaluation of the effect of inner and outer bark extracts of sugar maple (Acer saccharum var. saccharum) in combination with citric acid against the growth of three common molds

The bark of trees is an abundant material for chemical by-products. The combination effects of different concentrations of Acer saccharum var. saccharum inner (IB) and outer (OB) bark acetone extracts with citric acid (CA) applied to Leucaena leucocephala wood were evaluated against the growth of three common molds (Trichoderma viride, Fusarium subglutinans, and Aspergillus niger). IB, OB, and CA solutions were prepared at 0.25% and 0.5% and their combinations were formulated in equal amounts. Acetone extracts of IB and OB were analyzed for their chemicals composition and phenolic compounds using GC/MS and PHLC, respectively. The IB acetone extract contained 4-hydroxy-4-methyl-2-pentanone (31.67%), palmitic acid (15.52%), and linoleic acid (11.14%), while the OB acetone extract contained 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (9.34%), (Z,E)-9,12-tetradecadien-1-ol (8.86%), and cis-tetrahydro-6-methoxy-2H-pyran-3-ol (5.72%). The HPLC analysis indicated the presence of 14 phenolic compounds in IB extract with major constituents caffeine (362.88?µg/g extract), and p-hydroxy benzoic acid (358.06?µg/g extract), while OB contained 12 compounds with major constituents p-hydroxy benzoic acid (8950.5?µg/g extract), gallic acid (5261?µg/g extract) and salicylic acid (572.38?µg/g extract). High total phenolic content in OB (292.67?mg GAE/g) was associated with high antioxidant activity with an IC₅₀ values of 1.77 and 4.14?μg/mL, as measured by DPPH and β-Carotene-linoleic acid, respectively. The combination treatment of IB0.25%+ OB0.25%+CA0.25% produced the highest antifungal effects against growth of T. viride with an inhibition percentage (IP) of 10.37%, IB0.5%+CA0.5% (IP 16.66%) with F. subglutinans, while CA0.5% and OB0.25%, showed IP of 27.77% and 23.70% with A. niger, respectively. The combination effects of IB, OB and CA could be used as biocide agents for preventing mold growth on wood.     

Antifeedants and Feeding Stimulants in Bark Extracts of Ten Woody Non-host Species of the Pine Weevil, Hylobius abietis

Bark of ten woody species, known to be rejected as a food source by the pine weevil, Hylobius abietis, were sequentially extracted by a Soxhlet apparatus with pentane followed by methanol. Species were alder (Alnus glutinosa), aspen (Populus tremula), beech (Fagus sylvatica), guelder rose (Viburnum opulus), holly (Ilex aquifolium), horse chestnut (Aesculus hippocastanum), lilac (Syringa vulgaris), spindle tree (Evonymus europaeus), walnut (Juglans regia), and yew (Taxus baccata). Bark of each species was collected in southern Scandinavia during the summer. Resulting extracts were tested for antifeedant activity against the pine weevil by a micro-feeding choice assay. At a dose corresponding to that in the bark, methanol extracts from Aesculus, Taxus, Ilex, and Populus were antifeedant active, while pentane extracts of Aesculus, Fagus, Syringa, and Viburnum were stimulatory. Four known antifeedants against H. abietis, the straight-chained carboxylic acids, hexanoic and nonanoic acid (C6 and C9), carvone, and carvacrol were identified by gas chromatography (GC)–mass spectrometry (MS) in several extracts. The major constituents were identified and tested for feeding deterrence. The aromatic compounds benzyl alcohol and 2-phenylethanol are new non-host plant-derived feeding deterrents for the pine weevil. Additionally, two feeding stimulants, β-sitosterol and 5-(hydroxymethyl)-2-furaldehyde, were identified. One active methanol extract of Aesculus bark was sequentially fractionated by liquid chromatography, and major compounds were tentatively identified as branched alcohols and esters of hexanoic acid. Five commercially available hexanoate esters and two commercially available branched alcohols were identified as new active antifeedants. Both stimulatory and inhibiting compounds were found in the same extracts and co-eluted in the same or adjacent fractions. The mix of semiochemicals of opposite activity in each extract or fraction could explain the stimulatory-, inhibitory-, or sometimes neutral activity. Generally, such co-occurrence confounds the isolation of antifeedants.     

The correspondence between loss of H-NMR signal intensity and mesophase growth during the thermal maturation of a petroleum pitch

Samples of petroleum pitch, Ashland 240, were heated isothermally at 380, 400, 430 and 450°C and the hydrocarbon evolution and mesophase growth monitored simultaneously by the use of high temperature ¹H-nuclear magnetic resonance (NMR) analysis. For all four temperatures the NMR signal indicated no mesophase formation until the signal intensity had dropped by 30%, which corresponded to 20% weight loss from the pitch. The correlation between the onset and increase in mesophase formation with signal intensity loss was found to be independent of temperature. This temperature independence for the petroleum pitch agrees with the work presented previously by Honda et al. (Carbon 1970, 8, 181). who compared weight loss with the growth of quinoline-insoluble material for a coal-derived pitch. Given the correlation between signal loss and mesophase formation, it is suggested that a relative measure of NMR signal intensity could be used to estimate mesophase content of petroleum pitch, during maturation.     

ANTIOXIDANT AND ANTI-LIPASE COMPOUNDS ISOLATED FROM HEARTWOOD OF YAKUSHIMA NATIVE CEDAR (Cryptomeria japonica)

This article describes the biological activities of heartwood extracts from Yakushima native cedar (Cryptomeria japonica) and identifies their main active compounds. Black heartwood and red heartwood were each divided into two parts from the center (the pith) to outer heartwood (the cambium). The methanol extracts of those parts were screened for antioxidant and anti-lipase activities. The extract from the pith of the red heartwood showed the highest ORAC activity among the samples. Regarding anti-lipase activity, all the extracts showed relatively high activity (the IC₅₀ value were 9.71–37.24?μg mL^?1). In addition, four compounds were isolated and identified from the pith of red heartwood by NMR and MS analyses. Agatharesinol (3) and sequirin C (4) were thought to be the main active compounds responsible for the antioxidant and anti-lipase activities.