Akiko Nakagawa-izumi

High-molecular-weight polyphenols from oolong tea and black tea : Purification, some properties, and role in increasing mitochondrial membrane potential

High-molecular-weight polyphenols from oolong and black teas increased mitochondrial membrane potential, as measured by a method using ciliated protozoan Tetrahymena and rhodamine 123. These polyphenols, referred to as mitochondrial activation factors (MAFs), were purified from oolong and black teas by solvent extraction and Toyopearl column chromatography. The number-average molecular weights of the MAFs were 9,000 to 18,000, and the weight-average molecular weights were 15,000 to 25,000. The MAFs increased the mitochondrial membrane potential more than catechins did. Treatment of the MAFs with tannase indicated that they contained galloyl residues. When the MAFs were hydrolyzed with HCl-n-BuOH, cyanidin and delphinidin were detected. The partial structure of the MAFs was analyzed by pyrolysis-gas chromatography-mass spectrometry, and nine compounds were identified. These results suggest that MAFs are heterogeneous polymers of flavan-3-ols and flavan-3-ol gallates with intermonomeric linkages of B-ring to B-ring and C-ring to A-ring.

Composition of intake sugars and emission of gases from paper sludges by Coptotermes formosanus Shiraki.

Paper sludge is a by-product of the pulping process and is landfilled or incinerated for disposal. In this study, we evaluated ingestion and digestibility of carbohydrates, by the termite Coptotermes formosanus, in two kinds of sludges: sludge C from the chemical pulp mill and sludge M from the mechanical pulp mill. The no-choice tests using the termite for three weeks showed that the mass loss of sludge C was significantly higher than that of the control samples: a bleached pulp and red pine wood. It is considered that the higher inorganic content of sludge C resulted in the higher mass loss when the same amount of carbohydrates was taken by the pulp- or wood-fed termite. Although the inorganic content of sludge M was almost the same as that of sludge C, the higher lignin content in sludge M is thought to have resulted in the lower mass loss. Analysis of sugar composition in the faecal materials of the termite showed that about 73% of glucose and 81% of xylose in sludge C were digested. It was concluded that the digestibility of these sugars in sludge C was the same as that of the control samples despite containing high amounts of inorganic compounds. However, the hydrogen conversion rate by the termites that were fed sludge was lower than that of the termites that were fed pulp in the no-choice test for three days: one mole of glucose from the sludge and pulp was converted to 0.51 and 0.80 moles of hydrogen, respectively.

Differential behavior between acacia and Japanese larch woods in the formation and decomposition of hexenuronic acid during alkaline cooking

The effects of anthraquinone (AQ) and polysulfide (PS) on the hexenuronic acid (HexA) content of pulp during kraft cooking were studied using Acacia mearnsii (acacia) and Larix leptolepis (Japanese larch) sapwood. In contrast to the results of cooking Japanese larch at an H-factor of 1200, the HexA contents of acacia pulp with a kappa number of 20 at an H-factor of 291 did not differ greatly between the kraft, kraft-AQ, and PS-AQ cooking methods, although the hydroxide ion concentration in the acacia cooking liquor decreased on the addition of AQ or sulfur. To explain this difference, we studied the behavior of the formation and degradation of HexA during alkaline cooking of glucuronoxylan from cotton linter, which was cooked with 1.0 and 2.0 mol/l NaOH. The relationship between HexA content and H-factor during alkaline cooking of glucuronoxylan was clarified. The amount of HexA and its rate of decomposition were higher in the 2.0 mol/l solution than in the 1.0 mol/l solution. At a low H-factor similar to that for hardwood cooking, HexA content increased to a maximum level and then started to decrease at high hydroxide ion concentrations such as 2.0 mol/l, whereas it slowly decreased at low hydroxide concentrations such as 1.0 mol/l. At an H-factor of around 450, the HexA formation/degradation curve for 1.0 mol/l of hydroxide crossed the decomposition curve for 2.0 mol/l of hydroxide. Therefore, it was shown that at a low H-factor, a decrease in hydroxide ion concentration during acacia wood cooking had little effect on the HexA content of pulp.

Evidence of Subterranean Termite Feeding Deterrent Produced by Brown Rot Fungus Fibroporia radiculosa (Peck) Parmasto 1968 (Polyporales, Fomitopsidaceae).

We found that decayed wood stakes with no termite damage collected from a termite-infested field exhibited a deterrent effect against the termite Reticulitermes speratus, Kolbe, 1885. The effect was observed to be lost or reduced by drying. After identification, it was found that the decayed stakes were infected by brown rot fungus Fibroporia radiculosa (Peck) Parmasto, 1968. In a no-choice feeding test, wood blocks decayed by this fungus under laboratory condition deterred R. speratus feeding and n-hexane extract from the decayed stake and blocks induced termite mortality. These data provided an insight into the interaction between wood-rot fungi and wood-feeding termites.

Structural elucidation of condensed tannin from the bark waste of Acacia crassicarpa plantation wood in Indonesia

Recently, Acacia crassicarpa has been planted in peatland areas with acidic soil in Indonesia for use in pulp and paper materials. Its bark is not suitable to produce bleached pulp; hence, it is discarded as waste. Meanwhile, in South Africa and other countries, Acacia mearnsii has been planted for a long time, and its bark extracts have been used as a leather tanning agent. First, the structure of condensed tannin from the bark waste of A. crassicarpa is characterized. The yield of the extracts obtained from A. crassicarpa using a 70% acetone aqueous solution (7% based on bark weight) is less than that obtained from A. mearnsii (34%). A novel flavan dimer from the condensed tannin, specific to A. crassicarpa, is isolated from the bark extracts. To the best of our knowledge, this dimer is a new compound as evidenced from pyrolysis–gas chromatography–mass spectrometry and nuclear magnetic resonance analyses; it corresponds to a gallocatechin–catechin flavan dimer with the absence of one oxygen atom at the 3C of the pyran ring. In addition, 2,4,6-trimethoxybenzoic acid methyl ester is identified as a novel pyrolysis product obtained from the cleavage of the pyran ring.

Feeding Deterrence to Reticulitermes speratus (Kolbe) by Fibroporia radiculosa (Peck) Parmasto 1968

Brown rot fungus Fibroporia radiculosa (Peck) Parmasto grown in decayed wood and non-wood material, potato dextrose agar (PDA) media, deterred Reticulitermes speratus (Kolbe) feeding. Decayed wood and PDA media were extracted and tests were performed to assess termite feeding behavior towards the extracts. We found that the extract from PDA media also suppressed termite feeding, although it did not induce mortality. Using gas chromatography and mass spectrometry analysis, two bioactive compounds were detected from the decayed wood extract, and one was detected from the PDA extract. Based on National Institute of Science and Technology (USA) Mass Spectral library match and compound fragmentation, both of the compounds belong to the sesquiterpenes family.

Toxicity and Feeding Deterrent Effect of 2-Methylanthraquinone from the Wood Extractives of Tectona grandis on the Subterranean Termites Coptotermes formosanus and Reticulitermes speratus

No-choice feeding tests using ethanol, chloroform, and acetone extractives of teak (Tectona grandis) heartwood clearly showed feeding deterrent activity and toxicity to the subterranean termite Reticulitermes speratus. The amount of 2-methylanthraquinone (MAQ) in teak wood extractives was not related to the feeding deterrents or toxicity, as shown by the no-choice feeding tests conducted using crude extractives containing various amounts of MAQ, MAQ alone, and fractions of crude extractives. As a native pest, the subterranean termite Coptotermes formosanus was more tolerant to the fractions of crude extractives than Reticulitermes speratus, and the mortality observed in C. formosanus was not due to the presence of MAQ.

Quality evaluation of dissolving pulp fabricated from banana plant stem and its potential for biorefinery

The study was conducted to evaluate the quality of dissolving pulp of Musa sapientum L. (banana) plant stem and its potential for biorefinery. Introduction of pre-hydrolysis prior to any alkaline pulping process helps to reduce the content of hemicellulose and consequently produce acceptably high content of cellulose pulp. Water pre-hydrolysis was done at 150°C for 90min. The amount of lignin, xylan and glucan in the extracted pre-hydrolysis liquor (PHL) was 1.6, 4.9 and 1.6%, respectively. Pulping of pre-extracted chips was done following soda-AQ, alkaline sulfite and kraft process. The ratio of chip to liquor was 1:7 for both pre-hydrolysis and pulping. The kraft pulping process with 20% active alkali and 25% sulfidity at 150°C for 90min showed the best result. The lowest kappa number was 26.2 with a considerable pulp yield of 32.7%. The pulp was bleached by acidic NaClO2 and the consistency was 10% based on air-dried pulp. The lowest amount of 7% NaClO2 was used for the bleaching sequence of D0ED1ED2. After D0ED1ED2 bleaching, the pulp showed that α-cellulose, brightness and ash were 91.9, 77.9 and 1.6% respectively. The viscosity was 19.9cP. Hence, there is a possibility to use banana plant stem as a raw material for dissolving grade pulp and other bioproducts.

Influences of saltwater immersion on properties of wood-cellulosic paper

The saltwater immersion method was developed to inhibit mould growth on flood- or tsunami-damaged paper. Commercially available fine paper used for printing and writing showed decreased tensile indices after saltwater immersion. The salt remaining in the paper tended to increase the moisture content because of the salt deliquescence and moisture in the air. The tensile index was restored by removing salt from the paper. Crystallization and distribution of salt in interfibre pores were also considered to influence interfibre rebonding. The difference in the fibre responses to saltwater depended on the relationship between nano-scaled pores in the fibre walls, osmotic pressure, and the degree of sizing, which resulted in low water retention values. More of the starch applied as a surface sizing agent was dissolved or dispersed during distilled water immersion than saltwater immersion. This loosened the fibre network, which was a factor that decreased the sizing degree of the paper.