Wood Resin Research Articles

Inducing Aquilaria sinensis (Lour.) Spreng “Qinan” Agarwood Formation with Chemical Reagents

Agarwood is a highly sought-after resinous wood for use in medicine, incense, and perfume production. However, the process of agarwood formation is slow. In this study, the induction of agarwood formation in three-year-old Aquilaria sinensis “Qinan” trees through treatment with ethephon, hydrogen peroxide, sodium chloride, distilled water, and wounding was investigated. The results showed that the starch content significantly decreased and that the soluble sugar content significantly increased during the process of agarwood formation, with no significant difference between the different treatment groups. The net photosynthetic rate significantly decreased. Except for the sodium chloride treatment, the total antioxidant capacity and the contents of flavonoids and phenols significantly increased during the process of agarwood formation. The essential oil yield of the ethephon and hydrogen peroxide treatment groups was significantly higher than that of the other treatment groups, with the highest essential oil yield in the ethephon treatment group. Compared to the control group, salt treatment produced the lowest essential oil yield of agarwood. The results indicate that appropriate concentrations of ethephon and hydrogen peroxide can promote the formation of agarwood in A. sinensis “Qinan”.

Various handcrafted artificial vessels: Evaluation of practicality and feasibility for supermicrosurgery training

BackgroundSupermicrosurgery demands more refined skills compared to traditional microsurgery, necessitating comprehensive training prior to clinical implementation. Despite the existence of various training models, they often fall short in terms of cost, ethical considerations, and infection risk. Our objective was to develop and evaluate novel training models for supermicrosurgery that are cost-effective, ethical, and risk-free. MethodsWe fabricated tubes using polyvinyl alcohol (PVA) liquid glue, polyvinyl acetate resin (PAR) wood glue, and hydrocolloid dressing (HCD), aiming to identify suitable, low-cost candidates for a supermicrosurgery training model. These tubes were anastomosed under a microscope using 10-0 or 11-0 nylon sutures. We assessed the time and cost involved in tube creation, their diameters, and the overall feasibility of the models. ResultsThe average time and cost to fabricate a 15-mm-long luminal tube were 33.5minutes and $0.02 USD for the PVA group, 23minutes and $0.02 USD for the PAR group, and 63seconds and $0.40 USD for the HCD group, respectively. The average diameter of the tubes was 0.49mm in the PVA group, 0.58mm in the PAR group, and 1.55mm in the HCD group. The PVA and PAR tubes, with their transparent and thin walls, facilitated easier evaluation of anastomosis patency compared to the HCD tubes. ConclusionWe have successfully developed new supermicrosurgery training models using non-living materials, characterized by their low cost, absence of ethical concerns, and elimination of infection risk. The PAR and PVA tubes, in particular, are suitable for residents' training in supermicrosurgery.

A formaldehyde-free amino resin alternative to urea-formaldehyde adhesives: A bio-based oxidized glucose – urea resin

Urea-formaldehyde resins (UF) are the most commonly used wood-based panels adhesive in industry. These adhesives are more than 80 % by volume of the wood adhesives market. However, due to formaldehyde toxicicity and extreme volatility UF resins yield panels with formaldehyde emission problem both during wood panels preparation and their in-service use. In order to address this problem, to find an environment friendly replacement for formaldehyde to manufacture novel and safe aminoresins is essential research for wood adhesives. In this article, a bio-based amino resin wood adhesive (OGU) is developed by using oxidized glucose reacted with urea. The research work presented here tests the impact on the adhesive properties of a number of oxidation treatment parameters and of the glucose to urea molar ratio. The molecular structure and thermal properties of the OGU adhesive were studied by different analytical techniques. The results indicate that the bioaldehydes are obtained by glucose under mild oxidation conditions. The bioaldehydes obtained can then be reacted with urea to form a novel oxidized glucose-urea amino resin, suitable to manufacture plywood. Under the specified process conditions at pH 4 and at a urea-to-glucose molar ratio of 1, the OGU adhesive yielded plywood with a dry strength of 0.99 MPa, 24 h cold water soaking wet strength of 0.77 MPa, and 3 h hot water (63°C) soaking wet strength of 0.76 MPa. These results satisfy the requirements of the GB/T 9846–2015 standard. The OGU resin adhesive prepared has then a good market potential to replace the current UF resins used in the industrial production of wood-based panels and as a novel biomass amino resin adhesive.

Enhancement of thermal conductivity and abrasion resistance of woody carbon fiber composites via boride catalysis

In order to investigate the effect of boron element on liquefied wood carbon fibers and their composites, boric acid and boron carbide were utilized to modify liquefied wood resin through copolymerization and blending methods respectively. Then boric acid-modified liquefied wood carbon fiber (BA-WCF) and boron carbide-modified liquefied wood carbon fiber (BC-WCF) were produced via melt spinning, curing, and carbonization treatments. As expected, this modification approach effectively prevents the formation of skin-core structures and accelerates the evolution of a graphite microcrystalline structure, thereby enhancing the mechanical properties of the carbon fibers. Particularly, the tensile strength and elongation at break of BA-WCF increased to 331.57 MPa and 7.57 % respectively, representing increments of 117 % and 86 % compared to the conventional fibers. Furthermore, the as-fabricated carbon fiber/resin composites (CFPRs), composing of BA-WCF or BC-WCF as fillers and liquefied wood resin as matrix, exhibited excellent interlaminar shear strength, outstanding abrasion resistance, and well thermal conductivity, as well as electrical performance, significantly outperforming the conventional carbon fiber/phenolic resin composites. The friction rate of BC-WP/BA-WCF/CF was 2.37 %, while its thermal conductivity could reach 1.927 W/(m·K). These promising attributes lay the groundwork for the development of high-performance carbon fiber-based materials, fostering their widespread utilization across various industries.

Biosystematic Studies, Distribution and Conservation Status of Guaiacum officinale L. in Karnataka State

Guaiacum L. is an evergreen tree indigenous to South America, West Indies and USA. It was introduced during British period. The stem is hard, abundant resin wood, ash- grey-green bark and paripinnate leaves. The flowers are blue-purple in colour and occur in axillary clusters. The fruit is a capsule. Anomocytic, Paracytic and tertacytic types of stomata present only on abaxial surface of the leaf, trichomes absent on both surface. Pollen monad, radialy sysmmetric, tricolporate. The secondary veins are joined to form a loop at the margin. Phenolic test, alkaloid test etc. gave positive results. This plant is having commercial as well as medicinal value. In Karnataka state this plant found only in two places, one in Lalbagh, Bangalore and another in Karnataka College, Dharwad. Silviculture experiments were conducted but not succeeded. In both the places flowers are many, but fruit setting is negligible. It inhibits the spreading of the species in Karnataka.

Development of urea-glyoxal resin wood adhesives with multiple crosslinking network structures using epoxy resin

To mitigate the potential risks posed to human health and the environment by formaldehyde emissions originating from formaldehyde-based adhesives, adopting low-toxicity and biodegradable glyoxal as an alternative to formaldehyde in the synthesis of amino resin adhesives represents a direct, convenient, and promising strategy. Urea-glyoxal (UG) resins represent the most minimalist category within the family of glyoxal-based wood adhesives. However, their widespread application is limited due to inferior adhesive properties and inadequate water resistance. In this study, we enhanced the bonding properties of urea-formaldehyde (UG) by formulating EPn-UG wood adhesive, which integrates UG resin with epoxy resin (EP). Structural characterization revealed successful incorporation of the epoxy backbone into the low molecular chain of the UG resin via ring-opening reactions between the epoxy groups and amino groups on the UG resin. Additionally, the EPn-UG adhesive exhibits a lower curing temperature and higher storage modulus. At an EP addition level of 5 %, the dry and wet strength of EP5-UG bonded plywood, measured after immersion in water at room temperature for 24 hours, were recorded as 1.65 and 1.02 MPa, respectively. This demonstrates a significant improvement of 34 % and 149 % compared to UG resin. Notably, the bonding strength exhibited a remarkable breakthrough from 0 to 0.61 MPa after immersion in water at 63°C for 3 hours. These findings suggest that the introduction of EP enhances the formation of a denser crosslinked network, effectively boosting both the bonding strength and water resistance of UG adhesives. This study presents a novel approach for investigating formaldehyde-free adhesives, further facilitating the industrial implementation of UG resin.

Synthesis of lignin-based resin and fabrication of sustainable transparent wood based on bio-recycling concept

Transparent wood (TW) has attracted much attention in the field of energy saving building structural materials because of its high light transmittance, good thermal insulation performance and good toughness. However, the polymeric resins used in the present study to impregnate lignin-based wood templates are usually derived from petroleum-based chemical resources, which pose a fatal threat to human beings both in terms of consuming large amounts of resources and causing environmental pollution problems. It is therefore important to develop alternatives to petroleum-derived chemicals in renewable natural resources. Here, we report a green and sustainable TW production process based on the bio-recycling concept. Lignin-based sustainable resin (LSR) was prepared from waste lignin produced during delignification by polymerization of guaiacol. At the same time, according to FT-IR and NMR data analysis combined with previous studies, the synthesis mechanism of LSR was proposed, and this result provided a reference for bio-based resins made from biomass materials. The prepared lignin-based sustainable transparent wood (LSTW) has good light transmittance and good dimensional stability. In addition, the LSTW also shows good thermal insulation and indoor temperature regulation capabilities compared with the common glass.

Development of Agarwood Oil Research and Benefit: Bibliometric Analysis


 
 
 
 Agarwood oil, derived from the fragrant resinous wood of the Aquilaria and Gyrinops trees, has attracted great attention due to its diverse pharmacological properties and commercial value. The complex chemical composition of agarwood oil, consisting of more than 150 chemical compounds, has been linked to its therapeutic potential in treating chronic inflammatory diseases, anxiety, depression, and insomnia. This research uses exploratory, descriptive research. The research used in this research is the literature study method regarding the development of agarwood oil research and its benefits. Documents from the Scopus website are saved in the following form: RIS-type files. Analysis was conducted using VOSviewer 1.6.18 for Windows software. The research results show that there has been a decline in the trend of research on agarwood oil over the last 10 years; most research on agarwood oil has been carried out by Malaysia and China and followed by Japan. Research has revealed numerous benefits of agarwood oil, indicating its potential for development into derivative goods, particularly in the health and fragrance industries.
 
 
 

Structural, defense enzyme activity and chemical composition changes in the xylem of Aquilaria sinensis during fungus induction

Agarwood is a dark resinous wood, of high quality and in a short period, can be formed after inoculation with the efficient fungus in Aquilaria sinensis. However, the action site and mechanism of the fungus inducing the agarwood formation remain unclear. In this work, the efficient fungal infection was used to induce agarwood formation on A. sinensis, and samples were collected according to inoculation time. Subsequently, the xylem structure, histochemistry, defense enzyme activities, and the accumulation and in-situ distribution of chemical composition were investigated. The transition layer (TL) was the critical layer for the continuous accumulation of agarwood, and began to appear in the injection of fungal inducers for 15 days (15D). The parenchyma cells of the xylem rays and interxylary phloem were the main action site of fungus in the formation and accumulation of agarwood. The sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) were mainly accumulated in the agarwood layer (AL) and decay layer (DL), while their relative contents were highest in the injection of fungal inducers for 30 days and 180 days (30D and 180D), respectively. Among them, PECs appeared earlier than sesquiterpenes, and both were flindersia-type PECs. They were mainly concentrated in the cell corners and intercellular layer of the cell wall. In addition, Redundancy analysis (RDA) and Mantel test revealed that the different layer percentage (DLP), phenylalanine ammonia lyase (PAL), and starch grains (SG) were the drivers of PECs, and catalase (CAT) was the driver of sesquiterpenes. Therefore, this study will provide a theoretical foundation for revealing the mechanism of fungus-induced agarwood formation and inducing high-quality and high-yielding agarwood in the future.

Recent Advancement in Agarwood Induction Technology: A Comprehensive Review for the Transformation of Artificial Agar Resin Induction Methods

Agarwood is a high valued resinous wood containing aromatic constituents of sesquiterpenes and phenyl-ethylchromones. They are typically found in the wood tissue of Thymalaeaceae family trees such as Aquilaria and Gyrinops species once they have been physically or chemically damaged or diseased by microbial pathogens. However, the natural occurrence based agarwood production is inadequate to fulfill the worldwide market demand as it never reach to the potential yield. As a result, recent advancements in artificial agarwood induction technology have led to the efficient production of agarwood resin, surpassing conventional methods. These technologies include mechanical, biological, and chemical methods, as well as combinations of these techniques such as fungal inoculation, nailing, drilling, partly trunk pruning, aeration method, agar-wit, C-A kits, Agar-sit, Bottle dipping, ChemJet, Pinhole infusion, Automated transfusion, Agar-Bit and Bamboo stick method. While interdisciplinary approaches have pros and cons, chemical inducers have shown rapid invasion inside particular tree species trunks to produce superior agarwood resin at consistent rate. Therefore, diverse forms of inducers can be utilized to develop this finest fragrance resinous wood in cultivated trees within a short period of time compared to the natural approach and almost similar in the quality compared to the natural agarwood formations. The objective of this review paper was to presents a comprehensive collection of agarwood resin inducing methods and their potential to enhance the total production and the quality of agarwood in the final harvest. The application of these techniques has significant implications to the agarwood industry as it seeks to meet the growing global demand for this highly sought-after and valuable product leading to a high profitable business. Therefore, this review article serves as a valuable collection of resource for the researchers and industry professionals who are ambitious to develop their agarwood industry to a new level.

Tandem mass spectrometry (MS/MS) molecular networking guided profiling of small molecules from Aquilaria sinensis (Lour.) Gilg leaves and their bioactivity evaluation.

Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported. To conduct a rapid untargeted liquid chromatography-mass spectrometry (LC-MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value. A MN-assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α-glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application. Five main chemical groups including phenol C-glycosides, organic acids, 2-(2-phenylethyl) chromones, benzophenone O-glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty-one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C-glycosides and benzophenone C-glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α-glucosidase inhibitory fraction, respectively. Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high-quality development of agarwood industry.

Development of a pyrolytic aqueous phase derived from resinous wood and having a biostimulant action for plant growth

Development of a pyrolytic aqueous phase derived from resinous wood and having a biostimulant action for plant growth

Combining Near-Infrared (NIR) Analysis and Modelling as a Fast and Reliable Method to Determine the Authenticity of Agarwood (Aquilaria spp.)

The resinous wood produced by the Aquilaria and Gyrinops species—agarwood—is both rare and highly valuable. It is used in products from perfumes to medicines and has an estimated global market value of $32 billion. As a result, the adulteration and illegal purchasing of agarwood is widespread and of specific concern to enforcement agencies globally. Therefore, it is of interest to have a fast, reliable, and user-friendly method to confirm the authenticity of a sample of agarwood. We investigated the use of near infrared (NIR) data to develop a method that rapidly distinguished between authentic and non-authentic agarwood samples, based upon a soft independent model of class analogy (SIMCA), using software specific to the application of infrared data to material authentication. The model showed a clear distinction between the authentic and non-authentic samples. However, the small values involved led to poor automatic validation results.

Effectiveness of Natural-Based Coatings on Sweet Oranges Post-Harvest Life and Antioxidant Capacity of Obtained By-Products

The use of natural-based coatings is an eco-friendly approach that can be applied in citrus postharvest to preserve fruit quality and to prolong shelf life. Additionally, the study of antioxidant capacity of obtained by-products from fruits is of great value to mitigate better practices to manage the residues left from the juice processing industry. Under this context, the aim of this study was to investigate the use of carnauba wax/wood resin-based coating and cold storage on postharvest life of Valencia Late and Natal IAC sweet oranges, as well as the physicochemical quality and antioxidant capacity of its by-products. Mature fruits were harvested in 2019 and 2020 seasons. Initially, fruits were assessed for physicochemical quality and antioxidant capacity. Then, fruits were treated with carnauba wax and wood resin mixture and stored for 0, 15, 30, 45 and 60 days in a cold chamber. Fruit color index, weight loss, physicochemical quality and sensory profile of the fruits were monitored at harvest and during each cold storage period. Evaluations were performed in triplicates of 10-fruit. Valencia Late and Natal IAC fruits had proper quality in both years, attending the requirements of the fresh market and processing industry. Flavedo and albedo section displayed the highest concentration of bioactive compounds such as phenolics, flavonoids and antioxidant activity. The coating treatment associated with cold storage was efficient to preserve fruit color and to retard weight loss for both varieties up to 60 days. The sensory profile and quality of the carnauba wax/wood resin treated fruits were preserved all over the cold storage period, while uncoated fruits ranked low for most of the sensory attributes. Together, Valencia Late and Natal IAC fruits contain a high level of healthy beneficial compounds, which may be exploited as a natural source of low-cost antioxidants. Further, carnauba wax/wood resin coating associated with cold storage effectively reduce weight loss and color progression in sweet orange fruits, in addition to preserving overall physicochemical and sensory quality.

Chemical and Mechanical Properties for Rosin-based Hybrid Resins

The increasing concern for the protection of the environment, through the use of renewable natural resources, has led in the last decades to the realization of a number of natural polymers or hybrids to be able to replace petroleum-based polymeric materials. Rosin is a low-cost wood resin extracted from conifers. In this paper, based on FTIR and Raman analyses, the spectra of natural Rosin resin and some hybrid resins with volume proportions of 45, 55 and 65% Rosin were studied. Some mechanical properties such as modulus of elasticity, elongation at break, tensile strength were determined from stress-strain diagrams obtained from tensile stress. Increasing the volume proportion of Rosin leads to a decrease in stiffness and strength properties and obtaining a visco-elastic behavior.

Evaluation of the resistance of adhesive joints of carpentry to atmospheric fluctuations

Wood and wooden glued products are widely used as building structures in various construction industries that operate within a wide range of atmospheric factors and require stability and durability. Therefore, the goal was to conduct experimental studies to determine the stability of the adhesive bond of a window element made of wood under the influence of temperature and moisture static fluctuations. In this regard, a comprehensive approach was applied to experimentally establish the effectiveness of the glued wood layer by investigating the resistance of the adhesive layer to destruction when changing temperature and humidity fields within a wide range. According to the experimental values of the adhesive layer boundary after exposure to temperature and humidity fields such as glued wood, it was established that the best result of the tensile strength (0.29 N/mm2) was obtained for polyurethane adhesive. For rubber glue and PVA, the tensile strength was 0.17 N/mm2, which provides adhesion quite well due to its properties. This is due to the fact that the adhesive composition must have sufficient elasticity to allow the wood to expand and dry out under the influence of temperature. In turn, the glued layer based on bustilate and liquid glass, has the tensile strength set at a preasure of 0.07 N/mm2 and 0.12 N/mm2 accordingly. A decrease in the adhesive capacity for bustilate is due to the fact that at a low-temperature level, it loses its properties. The liquid glass-based adhesive has an alkaline environment and interacts with the components of wood resin acids, reducing adhesion. The results obtained allow selecting effective adhesives for the production of composite materials from wood, depending on the operating conditions, and provide for the properties of glued wood

Genome-wide investigation of Cytochrome P450 superfamily of Aquilaria agallocha: Association with terpenoids and phenylpropanoids biosynthesis

Agarwood is a dark resinous wood, produced when Aquilaria tree responds to wounding and microbial infection resulting in the accumulation of fragrant metabolites. Sesquiterpenoids and 2-(2-phenylethyl) chromones are the major phytochemicals in agarwood and Cytochrome P450s (CYPs) are one of the important enzymes in the biosynthesis of these fragrant chemicals. Thus, understanding the repertoire of CYP superfamily in Aquilaria can not only give insights into the fundamentals of agarwood formation, but can also provide a tool for the overproduction of the aroma chemicals. Therefore, current study was designed to investigate CYPs of an agarwood producing plant, Aquilaria agallocha. We identified 136 CYP genes from A. agallocha genome (AaCYPs) and classified them into 8 clans and 38 families. The promoter regions had stress and hormone-related cis-regulatory elements which indicate their participation in the stress response. Duplication and synteny analysis revealed segmental and tandem duplicated and evolutionary related CYP members in other plants. Potential members involved in the biosynthesis of sesquiterpenoids and phenylpropanoids were identified and found to be upregulated in methyl jasmonate-induced callus and infected Aquilaria trees by real-time quantitative PCR analyses. This study highlights the possible involvement of AaCYPs in agarwood resin development and their complex regulation during stress exposure.

Physicochemical and aging characterisation of bio-binders from pine wood resin for paving applications

This study characterised two bio-binders (named Bio A and Bio B) derived from pine wood resins and designed for full replacement of asphalt binder. Bio A and Bio B were compared to a petroleum-based asphalt binder (AC 30/45). Elemental analysis, Fourier-Transform Infrared Spectroscopy, Gas Chromatography-Mass Spectrometry, Thermogravimetric analysis, and Linear Viscoelastic characterisation were applied to evaluate the materials studied. The susceptibility to aging was evaluated by comparing unaged and short-term aged samples of the three binders. Bio A showed a penetration grade of 29 (0.1 mm) and softening point of 55.2°C, while Bio B showed 21 (0.1 mm) and 57°C, respectively. AC 30/45 showed a penetration grade of 30 (0.1 mm) and softening point of 55°C. Bio B was found as more prone to aging than Bio A and AC30/45. This result might be related to the higher presence of saturated fatty acid methyl esters in Bio B.

Gastroprotective 2-(2-phenylethyl)chromone-sesquiterpene hybrids from the resinous wood of Aquilaria sinensis (Lour.) Gilg

Six previously unprecedented 2-(2-phenylethyl)chromone-sesquiterpene hybrids, aquisinenins A–F (1 – 6), were isolated from the resinous wood of Aquilaria sinensis by a LC-MS-guided fractionation procedure. Their structures were determined by extensive spectroscopic analysis (1D and 2D NMR, UV, IR, and HRMS) and experimental and computed ECD data. Compounds 1 – 6 were rare dimeric 2-(2-phenylethyl)chromone-sesquiterpene derivatives featuring 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone hybridized with different sesquiterpene (eudesmane/guaiane type) moieties via ester bond. Furthermore, all the isolated compounds were evaluated for their protective effects on taurocholic acid (TCA)-induced GES-1 cell injury. The most effective aquisinenin F (6) was used to elucidate the involved mechanism on protection against TCA-induced gastric mucosal damage. Our results indicated that 6 protected against gastric mucosal cell insult by downregulation of the ER stress triggered by TCA.

Effectiveness of three Gabonese tree resin fractions combined with tebuconazole as wood preservative formulations

Wood treatments based on oleoresins from Aucoumea Klaineana, Canarium schweinfurthii and Dacryodes edulis have shown interesting anti-termites properties but poor resistance to fungi and leaching. Oleoresins were combined with tebuconazole to produce both antifungal and anti-termite wood preservatives formulations with an expected better fixation of chemicals mixtures in the wood. Beech and Scots pine wood block samples were impregnated by these different formulations and exposed to white and brown rot, respectively, as well as to European termite (Reticulitermes flavipes). The use of aqueous formulations of each oleoresin of combined to tebuconazole improved the wood resistance against termites and mainly brown rot. In addition, the best formulation was found by using the raw resin from Aucoumea Klaineana. These results are mainly due to the antifungal activity of tebuconazole. In addition, the presence of antioxidant chemicals in the wood resins inhibits the wood decay fungi growth and acts as enzyme and metabolism inhibitors disturbing the treated wood digestion process by termites. For the future, the promising protection obtained should be formulated to be resistant to leaching.