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Concept: Aquilaria


Agarwood is the fragrant resin-infused wood derived from the wounded trees of Aquilaria species. It is a valuable non-timber forest product used in fragrances and as medicine. Reforestation for Aquilaria trees in combination with artificial agarwood-inducing methods serves as a way to supply agarwood and conserve of wild Aquilaria stock. However, the existing agarwood-inducing methods produce poor-quality agarwood at low yield. Our study evaluated a novel technique for producing agarwood in cultivated Aquilaria trees, called the whole-tree agarwood-inducing technique (Agar-Wit). Ten different agarwood inducers were used for comparison of Agar-Wit with three existing agarwood-inducing methods. For Aquilaria trees treated with these ten inducers, agarwood formed and spread throughout the entire tree from the transfusion point in the trunk to the roots and branches of the whole tree. Agarwood yield per tree reached 2,444.83 to 5,860.74 g, which is 4 to 28 times higher than that by the existing agarwood-inducing methods. Furthermore, this agarwood derived from Agar-Wit induction was found to have a higher quality compared with the existing methods, and similar to that of wild agarwood. This indicates Agar-Wit may have commercial potential. Induction of cultivated agarwood using this method could satisfy the significant demand for agarwood, while conserving and protecting the remaining wild Aquilaria trees.

Concepts: Forestry, Tree, Wood, Branch, Trunk, Agarwood, Aquilaria, Aquilaria sinensis


Agarwood is the resinous material harvested from threatened Aquilaria species. We investigated how many protonated 2-(2-phenylethyl)chromone ions were sufficient to make an accurate identification of agarwood. Analysis of 125 reference samples was carried out by direct analysis in real time time-of-flight mass spectrometry (DART-TOFMS). The identification criteria developed were applied to commercial samples.

Concepts: Mass spectrometry, Calculus, Ion source, Time-of-flight, Agarwood, Aquilaria, Aquilaria malaccensis


Agarwood is a resinous material formed in wounded Aquilaria sinensis in China, which is widely used as an effective traditional Chinese medicine (TCM). This study is aimed to use gas chromatography-mass spectrometry combined with chemometric methods to create reliable criteria for accurate identification of natural agarwood and artificial agarwood, as well as for quality evaluation of artificial agarwood. Natural agarwood and artificial agarwood (stimulated by formic acid or formic acid plus fungal inoculation) were used as standards and controls for the gas chromatography-mass spectrometry (GC-MS) and multivariate analysis. The identification criteria developed were applied to commercial agarwood. A reliable criteria including correlation coefficient of GC-MS fingerprint of natural agarwood and 22 markers of metabolism in natural and artificial agarwood was constructed. Compared with chemically stimulated agarwood (formic acid) and in terms of the 22 markers, artificial agarwood obtained by formic acid stimulation and fungal inoculation were much closer to natural agarwood. The study demonstrates that the chemical components of artificial agarwood obtained by comprehensive stimulated method (formic acid plus fungal inoculation) are much closer to the natural agarwood than those obtained by chemically stimulated method (formic acid), as times goes by. A reliable criteria containing correlation coefficient of GC-MS fingerprint of natural agarwood and 22 metabolism markers can be used to evaluate the quality of the agarwood. As an application case, three samples were identified as natural agarwood from the 25 commercial agarwood by using the evaluation method.

Concepts: Oxygen, Mass spectrometry, Evaluation, Chromatography, Chemical compound, Agarwood, Aquilaria, Aquilaria sinensis


Phytochemical analysis of the high quality Chinese agarwood ‘Qi-Nan’ originating from Aquilaria sinensis (Lour.) Glig led to the isolation of a new 2-(2-phenylethyl)chromone derivative, qinanones G (1), and four known 2-(2-phenylethyl)chromones (2-5). Their structures were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR) and MS analyses. The NMR data of chromones 1-3 were first reported, and chromones 2 and 3 showed weak inhibitory activity against acetylcholinesterase.

Concepts: Infrared, Aquilaria


As widely recognized, agarwood formation in Aquilaria trees is induced by external wounding. Because agarwood usually harbors specific microbes, the function of microbes in agarwood formation has been debated for almost a century. In this study, two wounding methods, the burning-chisel-drilling method (BCD) and the whole-tree agarwood-inducing method (Agar-Wit), were used under the non-contamination of environmental microorganisms. After pyrosequencing the small rRNA subunits of the wounds induced by the BCD and Agar-Wit, no substantial variation was observed either in fungal and bacterial enrichment and diversity or in the relative abundances of taxa. By contrast, significant variations in fungal and bacterial communities were detected following the partial tree pruning (PTP)-wounding. The wound-induced sesquiterpene biosynthesis and vessel-occlusion formation, however, were found to be similar in all types of wounded trunks. We thus infer that wounding in the absence of variations in microbial communities may induce agarwood formation. This result does not support the long-standing notion that agarwood formation depends on microbes.

Concepts: Archaea, Bacteria, Microbiology, Eukaryote, Biotechnology, Microorganism, Agarwood, Aquilaria


Aquilaria crassna has been used in traditional Asian medicine to treat vomiting, rheumatism, asthma, and cough. Furthermore, earlier studies from our laboratory have revealed that the essential oil extract from agarwood inhibited colorectal carcinoma cells. Despite of the wide range of ethno-pharmacological uses of agarwood, its toxicity has not been previously evaluated through systematic toxicological studies. Therefore, the potential safety of essential oil extract and its in vivo anti-tumor activity had been investigated.

Concepts: Cancer, Poison, Traditional Chinese medicine, Essential oil, Oil, Oils, Agarwood, Aquilaria


Aquilaria crassna Pierre ex Lecomte has been traditionally used in Thailand for treatment of infectious diseases such as diarrhoea and skin diseases for a long time. The main objectives of this study were to examine antibacterial activity of the Aquilaria crassna leaf extract against Staphylococcus epidermidis and its underlying mechanism. The antioxidant activity and acute toxicity were studied as well.

Concepts: Infectious disease, Bacteria, Infection, Staphylococcus, Toxicology, Staphylococcus epidermidis, Aquilaria, Aquilaria crassna


2-(2-Phenylethyl)chromones are the main compounds responsible for the quality of agarwood, which is widely used in traditional medicines, incenses and perfumes. H2O2and NADPH oxidases (also known as respiratory burst oxidase homologs, Rbohs) mediate diverse physiological and biochemical processes in environmental stress responses. However, little is known about the function of H2O2and NADPH oxidases in 2-(2-phenylethyl)chromones accumulation. In this study, we found that salt stress induced a transient increase in content of H2O2and 2-(2-phenylethyl)chromones accumulation in Aquilaria sinensis calli. Exogenous H2O2remarkably decreased the production of 2-(2-phenylethyl)chromones, while dimethylthiourea (DMTU), a scavenger of H2O2, significantly increased 2-(2-phenylethyl)chromones accumulation in salt treated calli. Three new H2O2-generating genes, named AsRbohA-C, were isolated and characterized from A. sinensis. Salt stress also induced a transient increase in AsRbohA-C expression and NADPH oxidase activity. Furthermore, exogenous H2O2increased AsRbohA-C expression and NADPH oxidase activity, while DMTU inhibited AsRbohA-C expression and NADPH oxidase activity under salt stress. Moreover, diphenylene iodonium (DPI), the inhibitor of NADPH oxidases, reduced AsRbohA-C expression and NADPH oxidase activity, but significantly induced 2-(2-phenylethyl)chromones accumulation during salt stress. These results clearly demonstrated the central role of H2O2and NADPH oxidases in regulation of salt-induced 2-(2-phenylethyl)chromones accumulation in A. sinensis calli.

Concepts: DNA, Redox, NADPH oxidase, Oxidase, Stress, Agarwood, Aquilaria, Aquilaria sinensis


A novel sequential three-dimensional gas chromatography - high resolution time-of-flight mass spectrometry (3D GC-accTOFMS) approach for profiling secondary metabolites in complex plant extracts is described. This integrated system incorporates a non-polar first-dimension (1Dnp) separation step, prior to microfluidic heart-cut (H/C) of a targeted region(s) to a cryogenic trapping device, directly followed by rapid re-injection of trapped solute into a polar second-dimension (2DPEG) column for multidimensional separation (GCnp-GCPEG). For additional separation, effluent from2DPEGcan then be modulated according to a comprehensive 2D GC process (GC×GC), using an ionic liquid phase as third-dimension (3DIL) column, to produce a sequential GCnp-GCPEG×GCILseparation. Thus unresolved or poorly resolved components, or regions that require further separation, can be precisely selected and rapidly transferred for additional separation on2D or3D columns, based on the greater separation realized by these steps. The described integrated system can be used in a number of modes, but one useful approach is to target specific classes of compounds for improved resolution. This is demonstrated through the separation and detection of oxygenated sesquiterpenes in hop ( Humulus lupulus L.) essential oil and agarwood ( Aquilaria malaccensis) oleoresin. Improved resolution and peak capacity was illustrated through the progressive comparison of tentatively identified components for GCnp-GCPEGand GCnp-GCPEG×GCILmethods. Relative standard deviations of intraday retentions (1tR,2tR, and3tR) and peak areas of ≤ 0.01%, 0.07%, 0.71% and 7.5%, respectively, were achieved. This analytical approach comprising three GC column selectivities, hyphenated with high resolution TOFMS detection should be a valuable adjunct for improved characterization of complex plant samples, particularly in the area of plant metabolomics.

Concepts: Mass spectrometry, Gas chromatography, Resolution, Metabolomics, Time-of-flight, Essential oil, Humulus lupulus, Aquilaria


Agarwood (jinkoh in Japanese) is a resinous wood from Aquilaria species of the family Thymelaeaceae and has been used as incense and in traditional medicines. Characteristic chromone derivatives such as agarotetrol have been isolated from agarwood. In previous study, we isolated two new 2-(2-phenylethyl)chromones together with six known compounds from MeOH extract of agarwood. Further chemical investigation of the MeOH extract led to isolation of eighteen 2-(2-phenylethyl)chromones, including three new 5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromones with stereochemistry enantiomeric to agarotetrol-type, viz. (5R,6S,7S,8R)-2-[2-(3'-hydroxy-4'-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (2), (5R,6S,7S,8R)-2-[2-(4'-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (6), and (5R,6S,7S,8R)-2-[2-(4'-hydroxy-3'- methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (13). The absolute configurations of the new compounds were determined by exciton chirality method. All isolated compounds were tested for their phosphodiesterase (PDE) 3A inhibitory activity by fluorescence polarization method. Compounds 8, 12-15, 21-24 showed moderate PDE 3A inhibitory activity.

Concepts: Absolute, Stereochemistry, Enantiomer, Chirality, Essential oil, Incense, Agarwood, Aquilaria