Agarwood Samples Research Articles

On-Site Analysis and Rapid Authentication of Valuable Agarwood Samples by Paper Capillary Spray Miniature Mass Spectrometry

On-Site Analysis and Rapid Authentication of Valuable Agarwood Samples by Paper Capillary Spray Miniature Mass Spectrometry

Successful development of molecular diagnostic technology combining mini-barcoding and high-resolution melting for traditional Chinese medicine agarwood species based on single-nucleotide polymorphism in the chloroplast genome.

Agarwood is a valuable traditional medicine and fragrance. The production process is a typical injury-induced defense response. Currently, there are approximately 22 known species in the genus Aquilaria Lam., all of which can produce agarwood, whereas there are only two legal species of traditional Chinese medicinal agarwood, Aquilaria sinensis (Lour.) Spreng. and Aquilaria agallocha (Lour.) Roxb. The Taiwan herbal Pharmacopoeia of China stipulates that the medicinal agarwood species are A. sinensis and its relatives in the same genus. Moreover, there are five species of agarwood available for clinical medicinal use in Japan, including A. agallocha and A. sinensis, which are often confused with each other or used in a mixed way in the trade process. Therefore, accurate identification of traditional Chinese medicinal agarwood species is important to ensure the authenticity of traditional medicines and to guide the safety of clinical medication. In this study, 59 specific single-nucleotide polymorphism loci were screened and obtained from the chloroplast genomes of 12 species of the genus Aquilaria Lam. We established an identification method for traditional Chinese medicinal agarwood using mini-barcoding combined with high-resolution melting (HRM) and designed and validated 10 pairs of primers from the psbM-trnD, psbA, rps16, petN, ndhE-psaC, rps4, atpE, ycf1, rps15-trnN, and matK regions. The amplification products were all less than 200 bp, with a high success rate of amplification. The method was applied to successfully identify traditional Chinese medicinal agarwood species from commercial agarwood samples. Overall, the sensitivity of this method was sufficient to detect 1% of adulterants in medicinal agarwood products, proving that mini-barcoding HRM is a powerful and flexible tool. This method can be used as a fast and effective high-throughput method for authenticity testing of traditional Chinese medicinal agarwood and its raw materials containing agarwood-containing proprietary Chinese medicines and is recommended for industrial applications.

Utilizing metabolomics and network analysis to explore the effects of artificial production methods on the chemical composition and activity of agarwood.

Introduction: Agarwood is a traditional aromatic southern medicine. It has a long history of being used in traditional Chinese aromatherapy to treat insomnia, anxiety and depression. Due to the scarcity of wild resources, people have planted trees successfully and begun to explore various agarwood-inducing techniques. This study comparative analysis of volatile metabolites in agarwood produced by various inducing techniques and its potential sleep-promoting, anti-anxiety and anti-depressant network pharmacological activities. Methods: A total of 23 batches of two types of agarwood were collected, one of which was produced by artificial techniques, including 6 batches of TongTi (TT) agarwood produced by "Agar-Wit" and 6 batches of HuoLao (HL) agarwood produced by "burning, chisel and drilling", while the other was collected from the wild, including 6 batches of BanTou (BT) agarwood with trunks broken due to natural or man-made factors and 5 batches of ChongLou (CL) agarwood with trunks damaged by moth worms. The study employed metabolomics combined with network analysis to compare the differences in volatile metabolites of agarwood produced by four commonly used inducing techniques, and explored their potential roles and possible action targets in promoting sleep, reducing anxiety, and alleviating depression. Results: A total of 147 volatile metabolites were detected in agarwood samples, mainly including small aromatic hydrocarbons, sesquiterpenes and 2-(2-phenylethyl) chromone and their pyrolysis products. The results showed composition of metabolites was minimally influenced by the agarwood induction method. However, their concentrations exhibited significant variations, with 17 metabolites showing major differences. The two most distinct metabolites were 6-methoxy-2-(2-phenylethyl) chromone and 6,7-dimethoxy-2-(2-phenylethyl) chromone. Among the volatile metabolites, 142 showed promising potential in treating insomnia, anxiety, and depression, implicating various biological and signaling pathways, predominantly ALB and TNF targets. The top three active metabolites identified were 2-(2-phenylethyl) chromone, 1,5-diphenylpent-1-en-3-one, and 6-methoxy-2-[2-(4'-methoxyphenyl) ethyl] chromone, with their relative content in the four types of agarwood being TT>HL>CL>BT. Conclusion: The differences in the content of 2-(2-phenylethyl) chromones suggest that they may be responsible for the varying therapeutic activities observed in different types of agarwood aromatherapy. This study offers theoretical support for the selection of agarwood in aromatherapy practices.

Solid-Phase Microextraction/Gas Chromatography-Time-of-Flight Mass Spectrometry Approach Combined with Network Pharmacology Analysis to Evaluate the Quality of Agarwood from Different Regions against Anxiety Disorder.

Agarwood (Aquilaria malaccensis Lam.) is a resinous material from different geographical locations. The current evaluation of agarwood quality is usually based on its physical properties and chemical compounds, yet only a few studies have linked agarwood quality with its anxiolytic effect, as indicated by characteristic compounds. In this study, using solid-phase microextraction/gas chromatography-time-of-flight mass spectrometry (SPME/GC-TOFMS) and multivariate analysis, we found 116 significantly different compounds in agarwood samples from four locations in Southeast Asia with regard to their quality. Brunei and Nha Trang agarwood had abundant sesquiterpenoids, exhibiting notable pharmacological efficacy in relieving anxiety. Malaysian and Irian agarwood had abundant alcohols and aldehydes, qualifying them as high-quality spices. Compound-target-disease network and pathway enrichment analysis were further employed to predict 79 gene targets and 20 pathways associated with the anxiolytic effects based on the 62 sesquiterpenoids. The correlated relationships among the sesquiterpenoids and targets suggest that agarwood treats anxiety via multiple compounds acting on multiple targets. Varying levels of sesquiterpenes across agarwood groups might lead to differences in the anxiolytic effects via signaling pathways, such as neurotransmitter- and hormone-regulated pathways. Our study originally evaluates agarwood quality and its anxiolytic effect by linking the characteristic compounds to potential gene targets and pathways.

GC-MS olfactometry reveals sesquiterpenes α-humulene and δ-cadinene significantly influence the aroma of treated Aquilaria malaccensis essential oil

Aquilaria malaccensis is a tropical woody tree that produces agarwood, which is valued for its aromatic properties. Agarwood is widely used in traditional medicines and the cosmetics industry. Natural agarwood production in the wild, which occurs due to fungal infection, is scarce and cannot meet the market demand. Hence, many artificial techniques have been employed to stimulate the production of agarwood. Although many studies have determined the volatile compounds present in naturally produced agarwood, the characterisation of these compounds from differentially treated agarwood samples, particularly A. malaccensis, is still limited. This study was conducted to identify and differentiate the volatiles present in treated and healthy A. malaccensis wood and essential oil using the solid phase microextraction (SPME) and hydrodistillation techniques, respectively, coupled with gas chromatography-mass spectrometry (GC-MS) analysis. Subsequently, the olfactory active compounds in the treated agarwood essential oil were determined via gas chromatography-mass spectrometry, coupled with olfactometry analysis (GC-MS/O) with four panellists. The essential oil from the treated agarwood was found to be abundant in sesquiterpene and aromatic compounds (80.61%), which was a similar result to that obtained from the volatiles of the wood that yielded 86.94%. Among the major sesquiterpene constituents in the essential oil are α-cadinol (19.40%) and 10-epi-γ-eudesmol (13.39%), whereas α-humulene (13.33%), α-copaene (12.49%) and δ-guaiene (10.41%) predominated in the SPME extract. Meanwhile, GC-MS/O analysis revealed that the sweet, woody agarwood aroma is an orchestra of olfactory active compounds that are significantly influenced by sesquiterpenes such as α-humulene and δ-cadinene. This study highlights that although treated agarwood is rich in secondary metabolites, only a handful, particularly those belonging to sesquiterpenes, are actual aroma impact compounds

Population genomic analyses of protected incense trees Aquilaria sinensis reveal the existence of genetically distinct subpopulations

The incense tree Aquilaria sinensis (Thymelaeaceae) can produce agarwood with commercial values and is now under threat from illegal exploitation in Hong Kong, impairing the local population and biodiversity. Together with other species of Aquilaria, it is listed in the CITES Appendix II, which strictly regulates its international trade. To understand the population structure of A. sinensis and to make relevant conservation measures, we have sequenced 346 individuals collected in Hong Kong and southern mainland China. Population genomic analyses including principal component analysis, neighbor-joining tree construction, ADMIXTURE, and hierarchical pairwise-FST analyses suggested that genetically distinct populations are contained in certain areas. Genomic scan analyses further detected single-nucleotide polymorphism (SNP) outliers related to plant defense, including the CYP71BE gene cluster. In addition to the population analyses, we have developed a modified hexadecyltrimethyl-ammonium bromide (CTAB) DNA extraction protocol for obtaining DNA from agarwood samples in this study, and resequencing of DNA extracted from two agarwood samples using this method allows us to successfully map to the sample corresponding localities in the phylogenetic tree. To sum up, this study suggested that there is a genetically distinct subpopulation of incense tree in Hong Kong that would require special conservation measures and established a foundation for future conservation measures.

Identification of aroma‐active components from cultivated agarwood ‘Qi‐Nan’ based on GC‐O‐MS combined with aroma extract dilution analysis

AbstractAgarwood ‘Qi‐Nan’ is commonly regarded as the highest quality agarwood, and has been highly valued for its fragrance. With the increasing amount of cultivated agarwood ‘Qi‐Nan’ in recent years, evaluation of the aroma compounds was drawn attention. Therefore, the volatile compounds in three cultivated ‘Qi‐Nan’ agarwood samples were extracted by simultaneous distillation‐extraction (SDE) and analysed by GC‐O‐MS, combined with aroma extract dilution analysis (AEDA). A total of 70 volatile compounds were identified from three samples, in which sesquiterpenes and aromatics were characterized as key aroma‐active components. Nine compounds were considered as common aroma‐active volatiles in these three essential oils according to their flavour dilution (FD) activity and relative flavour activity (RFA) value, and among them, dihydro‐β‐agarofuran and 4‐methoxy‐benzaldehyde were the most important aroma‐active compounds. Additionally, three ‘Qi‐Nan’ agarwood samples showed different aroma specificity. TD agarwood was characterized by sweet sandalwood odour due to the dominant aroma‐active compound of β‐Santalol. WS agarwood was distinguished by its woody odour because α‐kessyl acetate was its primary aroma. HQ agarwood was featured by woody, spicy and balsamic odour on account of its main aroma compounds of agarospirol and β‐elemene.

AN ITS GENE-MEDIATED MOLECULAR DETECTION OF FUNGI ASSOCIATED WITH NATURAL AND ARTIFICIAL AGARWOOD FROM Aquilaria malaccensis

The current study examined fungal diversity in manufactured and natural agarwood samples perceived from A. malecensis trees in a plantation and the East Malaysia rainforest. Isolated fungi were also subjected to molecular analysis. The fungal community composition of healthy and damaged tree samples from both plantation and the wild forest was identified using PCR amplification of the internal transcribed spacer (ITS) region from fungal isolates. Meanwhile, ten groups of fungi isolates are expected to be placed in both natural and inoculated based on 1000 bootstrap values. They validated earlier genomic identification; 55 fungal isolates were discovered in artificial and natural agarwood, including agarwood and healthy wood. Ten fungal groupings were developed based on morphological characterization similarities. Based on NCBI BLAST analysis, molecular identification revealed Fusarium solani, Botryosphaeria theobromae, Polyporales spp, Schizophyllum commune, Aspergillus aculeatus, and Lasiodiplodia theobromae. Fusarium solani excelled in A. aculeatus and Polyporales spp. in agarwood samples and healthy wood. The presence of more fungi species in natural agarwood than in artificial agarwood may be due to the favourable humid and shaded habitat for fungal growth. Nonetheless, synthetic agarwood was able to synthesize agarwood-related chemical compounds. Considering F. solani was often identified in both agarwood, agarwood inoculant may act as a booster for F. solani to begin pathogenicity in artificial agarwood. The current research shows that artificial agarwood may provide quality comparable to natural agarwood and is not influenced by fungus interacting with the tree.

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.

Comprehensive Comparisons between Grafted Kynam Agarwood and Normal Agarwood on Traits, Composition, and In Vitro Activation of AMPK.

Agarwood, a highly valuable resin/wood combination with diverse pharmacological activities but scarce supply, has a long history of being used as a medicine in several medical systems. Grafted Kynam agarwood (GKA) has been cultivated successfully recently and has the qualities meeting the definition of premium Kynam agarwood. However, there are few comprehensive comparisons between GKA and normal agarwood in terms of traits, global composition, and activity, and some key issues for GKA to be adopted into the traditional Chinese medical (TCM) system have not been elaborated. The two types of agarwood samples were evaluated in terms of trait characteristics, physicochemical indicators, key component groups, and global compositional profile. Furthermore, a molecular docking was performed to investigate the active ingredients. In vitro activity assays were performed to evaluate the activation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) by GKA and normal agarwood. The results revealed that, overall, the traits, microscopic characteristics, chemical composition types, and bioactivity between GKA and normal agarwood were similar. The main differences were the content of resin (ethanolic extract content), the content of key component groups, and the composition of the different parent structural groups of 2-(2-phenethyl) chromones (PECs). The contents of total PEC and ethanol extract content of GKA were significantly higher than those of normal agarwood. The MS-based high-throughput analysis revealed that GKA has higher concentrations of sesquiterpenes and flindersia-type 2-(2-phenylethyl) chromones (FTPECs) (m/z 250-312) than normal agarwood. Molecular docking revealed that parent structural groups of FTPECs activated multiple signaling pathways, including the AMPK pathway, suggesting that FTPECs are major active components in GKA. The aim of this paper is to describe the intrinsic reasons for GKA as a high-quality agarwood and a potential source for novel drug development. We combined high-throughput mass spectrometry and multivariate statistical analysis to infer the different components of the two types of agarwood. Then we combined virtual screening and in vitro activity to construct a component/pharmacodynamic relationship to explore the causes of the activity differences between agarwood with different levels of quality and to identify potentially valuable lead compounds. This strategy can also be used for the comprehensive study of other TCMs with different qualities.

A Comparative Analysis of the Volatile Components of Agarwood from Vietnam and other Regions

Purpose: The objective of this study was to evaluate the quality of five different types of agarwood from Vietnam and 4 other areas and analyze the volatile chemical components by gas chromatography mass spectrometry (GC-MS). We attempted to identify the ingredients that have previously been reported to have skin health benefits, and reviewed their potential future use as raw materials for natural cosmetics.Methods: The five sources of Aquilaria crassna (A. crassna) were from Vietnamese, Indonesian, Malaysian, Myanmar, and Cambodian agarwoods. The volatile chemical components of each agarwood were analyzed by GC-MS. The Vietnamese agarwood was selected as a standard by identifying A. crassna through DNA analysis.Results: GC-MS analysis revealed that ‘sesquiterpene’ was contained in all the agarwood samples. The four sesquiterpene components, italicene ether, epi-γ-eudesmol, δ-guaiene, and α-agarofuran were commonly detected in all agarwood samples. Eight simple volatile aromatic compound components (1-octanol, 4-(4-methoxyphenyl)-2-butanone, 4-phenyl-2-butanone, benzaldehyde, ethylbenzene, nonanal, octanal, and 2-ethyl-1-hexanol) were commonly detected. The sesquiterpene components, α-agarofuran, β-selinene, α-curcumene, and α-santalol have been reported to have anti-inflammatory, antioxidant, antibacterial, and anti-skin cancer properties, respectively.Conclusion: This study demonstrated a substantial difference in the quality of the volatile component composition in each of the four source areas other than A. crassna from Vietnam. Agarwood contains sesquiterpene, which has a unique fragrance and is beneficial for skin health, and it is expected to be utilized as a raw material for natural cosmetics and developed in the future as a functional cosmetic with high added value.

Integrating Multiple Omics Identifies Phaeoacremonium rubrigenum Acting as Aquilaria sinensis Marker Fungus to Promote Agarwood Sesquiterpene Accumulation by Inducing Plant Host Phosphorylation.

ABSTRACTThe present study aimed to explore the factors that promote persistent agarwood accumulation. To this end, we first investigated the morphological changes and volatile compound distribution in five layers of “Guan Xiang” agarwood. The agarwood-normal transition layer (TL), an essential layer of persistent agarwood accumulation, showed clear metabolic differences by microscopy and GC-MS analysis. Microbiome analysis revealed that Phaeocremonium rubrigenum was the predominant biomarker fungus in the TL of “Guan Xiang” agarwood samples. Among the seven isolated fungi, P. rubrigenum exhibited a significantly heightened ability to induce the production in Aquilaria sinensis seedlings, especially for sesquiterpene. Tracing the proteome profile changes in P. rubrigenum-induced A. sinensis calli for 18 ds showed that the fungus-induced sesquiterpene biosynthesis increased mainly through the mevalonate (MVA) pathway. Specifically, the phosphorylation modification level, instead of the protein abundance of transcription factors (TFs), showed corresponding changes during sesquiterpene biosynthesis, thus indicating that induced phosphorylation is the key reason for enhanced sesquiterpene production.IMPORTANCE Agarwood is an expensive resinous portion derived from Aquilaria plants and has been widely used as medicine, incense, and perfume. The factors involved in steady agarwood accumulation remain elusive. Our current study suggests that as a TL marker fungus, P. rubrigenum could persistently promote agarwood sesquiterpene accumulation by inducing phosphorylation of the TFs-MVA network in A. sinensis. Moreover, our work provides strategies to improve agarwood industry management and sheds light on the potential molecular mechanisms of plant adaptation to native microbial conditions.

An integrated chemical characterization based on FT-NIR, GC–MS and LC-MS for the comparative metabolite profiling of wild and cultivated agarwood

Agarwood is a well-known and precious traditional Chinese medicine, has been widely applied as drugs and spices for century. The large demand for this material has deeply stimulated the emergence of numerous cultivated products. However, it is difficult to distinguish wild agarwood from cultivated agarwood, and the chemical composition difference between them is not clear. In this study, an integrated method of Fourier transform near-infrared (FT-NIR), gas chromatography-mass spectrometry (GC–MS) and ultraperformance liquid chromatography Quadrupole-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap/MS) was developed to explore chemical variation between wild and cultivated agarwood in combination with multivariate statistical analysis. Twenty-four wild and cultivated agarwood samples were collected from different regions. FT-NIR profiles were used to obtain the holistic metabolic characterization in combination with principal component analysis (PCA). A total of seventy-six and seventy-nine metabolites, including volatile components and 2-(2-phenethyl) chromones derivatives, were successfully identified by GC–MS and UHPLC-Q-Exactive Orbitrap/MS, respectively. Thereafter, the orthogonal-partial least square method-discriminant analysis (OPLS-DA) and variable importance in the projection (VIP) were used to screen potential characteristic chemical components (VIP > 1) in wild and cultivated agarwood, respectively. Finally, eight key chemical markers were putatively identified by two techniques to distinguish agarwood from different origins, which can be found that sesquiterpenes, aromatics, terpenoids, 2-(2-phenylethyl) chromones of the flidersia type (FTPECs) and tetrahydro-2-(2-phenylethyl) chromones (THPECs) are the most important metabolites. Summary, this research presented a comprehensive metabolomic variation between wild and cultivated agarwood on the basis of a multi-technology platform, which laid a foundation for distinguishing the two ecotypes of agarwood and was conducive to the quality control of this resource.

Characterization of Agarwood by Gas Chromatography–Mass Spectrometry and a Random Forest Model

Agarwood, resin produced by wounded Aquilaria plants, is widely used in perfume and medicine. In this study, artificial agarwood induced by physical injury, chemical stimulation, fungal infection, and comprehensive stimulation, which are the common induction methods, was collected. After gas chromatography–mass spectrometry (GC–MS) analysis, the total ion chromatogram/mass ion chromatogram (TIC/MIC) and qualitative peak data from artificial agarwood were used as training sets in discriminant analysis to examine the formation modes of natural agarwood by a random forest model which was shown to be superior to discriminate the formation of natural agarwood. The results implied that natural agarwood is likely formed through four formation modes. The discriminant result from random forest model showed that 17.1% of natural agarwood samples were formed by physical injury, 22.9% by chemical stimulation, 2.9% by fungal infection, and 57.1% by comprehensive stimulation. 2-Butanone-4-phenyl-, benzenepropanoic acid, guaiol, baimuxinal, and 2-(2-phenylethyl) chromone were the main chemical markers of the agarwood. The apparent abundance from the GC–MS fingerprints was used to distinguish agarwood formed by different formation processes.

Comparative Analysis of Biological Activity of Artificial and Wild Agarwood

Agarwood is a highly economically important medicinal herb with widespread uses; however, the difference between the biological activities of artificial and wild agarwood is unclear. In this study, the alcohol-soluble extracts of agarwood produced by fungi and natural agarwood were used to determine the differences between the overall biological activities. The antioxidant ability (the clearance rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals, and total reducing power), anti-acetylcholinesterase, and anti-α-glucosidase activity were determined by ultraviolet-visible spectrophotometry. The results indicated that with 2 mg/mL alcohol-soluble extracts, the scavenging DPPH radical rates of the artificial agarwood samples were 93.74–102.31% of that of the wild agarwood, and the ABTS+ radical clearance rates of the artificial agarwood samples were 75.38–95.52% of that of the natural agarwood. With 3.5 mg/mL alcohol-soluble extracts, the artificial agarwood samples had a total reducing power of 63.07–80.29% of that of the wild agarwood. With 4 mg/mL alcohol-soluble extract, the acetylcholinesterase activity inhibition rates of the artificial agarwood samples were 102.56–109.16% of that of the wild agarwood. With 1 mg/mL alcohol soluble extracts, the α-glucosidase effect inhibitions rates of the artificial agarwood samples were 68.32–100.39% of that of the wild agarwood.

Exploratory Designing a Magnetic Induction Tomography Sensor Coil Circuit for Agarwood

Magnetic induction tomography (MIT) is an imaging modality focused on tracing the transmission of electrical conductivity within the body. This technique used to image electromagnetic properties of an object by using the eddy current effect. This paper explains the primary analog transceiver circuit of MIT. This is a surrogate design of the analog system in the electronic components for pattern recognition and conditioning. This MIT system operating with a single excitation signal frequency at 10MHz. The input voltage received by the receiver sensor would become the circuit input which contained information. The four stages process in the receiver circuit successfully captured the signal from the transmitter. These subsystems have their functions and can be put into effect in many ways. Therefore, the circuit was used to be reliable at agarwood samples. The approach transceiver circuit were successful and functional for MIT coil sensing. The input voltage feedback depending on the conductivity of the samples. As the dielectric properties of samples are high, the input voltage at the receiver also high. Therefore, 10MHz can use for agriculture while this range of frequency is usually used in biomedical applications. Series – parallel circuit gives a greater induction factor and therefore more induced voltage for the load of the receiver.

Rapid authentication of agarwood by using liquid extraction surface analysis mass spectrometry (LESA-MS).

Agarwood is a highly valuable fragrant resinous wood which is widely used as traditional Chinese medicines, perfumes, incense and decorations. Due to its high economic value and excessive demand, this leads to a rising price and proliferation of fake commodities. Thus, strict authenticity identification and quality evaluation of agarwood are of great significance. To establish a simple, rapid and non-destructive technique for identifying the authenticity of agarwood. Liquid extraction surface analysis mass spectrometry (LESA-MS) was firstly proposed to identify the authenticity of 62 agarwood samples without sample preparation. In addition, multivariate statistical models and thin-layer chromatography (TLC) method were used to analyse and verify the results of LESA-MS. Representative compounds of agarwood were detected by LESA-MS. A characteristic 2-(2-phenylethyl)chromone compound (m/z 319.1) was treated as a key chemical marker to identify agarwood and its counterfeits rapidly. Several other chromones ions were identified and used as additional evidence for authentic samples. A total of 62 samples were visually discriminated as two groups by principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA), and the specific characteristic marker was highlighted. Moreover, the qualitative results of the conventional TLC method were in agreement with the LESA-MS approach. The proposed LESA-MS method was successfully applied in the direct qualitative analysis of agarwood from different sources. This study indicated great feasibility and practicality of LESA-MS in the rapid identification of agarwood, and provided a non-destructive and meaningful preliminary screening tool for the agarwood industry.

Chemical Components of Agarwood (Aquilaria crassna) Essential Oils Grown in Various Regions of Asia

This study presents a chemometric study on agarwood (Aquilaria crassna) essential oils extracted from selected agarwood samples grown in various regions of Asia. Adopting gas chromatography-mass spectrometry (GC-MS) technique, it was revealed that essential oils, produced by hydrodistillation,constitutes mainly volatile aromatic compounds. Several major components are shared in all samples including dihydro-agarofuran-15-al, jinkoeremol, 10-epi-γ-eudesmol, agarospirol, valerianol, n-hexadecanoic acid, neopetasane and dihydrokaranone. Despite differences in composition, extraction yield and detected constituents found in analyzed samples, characteristic aromatic compounds were abundantly found in the Agarwood essential oil. These discrepancies could be due to cultivation season, climatic conditions and extraction methods. Unambiguous identification of components in agarwood essential oils thereby opens new potential in the application of high-value aromatic compounds in agarwood essential oil in cosmetic products, perfumes, and pharmaceuticals.

Agarotetrol in agarwood: its use in evaluation of agarwood quality.

Agarwood, which is used as medicine and incense, contains sesquiterpenes and chromones. Agarotetrol is a chromone derivative found in high concentrations in the water-extract fraction of agarwood and thus may be present in pharmaceutical products made from decoctions of agarwood. Agarotetrol has been reported to be present at the early stages of cell death in calli. We therefore examined the presence of agarotetrol in medical- and incense-grade agarwood, in agarwood-source plants lacking resin deposits, and in artificially made agarwood. Agarotetrol appeared as a large peak in the HPLC chromatograms of all samples of medical-grade and artificially made agarwood, and in most incense-grade agarwood samples. In contrast, agarwood samples lacking resin deposits did not contain agarotetrol. These results show that agarotetrol is characteristic of resin formation. Agarotetrol was also detected in decoctions of agarwood. A newly developed TLC method for the detection of agarotetrol in agarwood is described.

Isolation Process and Compound Identification of Agarwood Essential Oils from Aquilaria crassna Cultivated at Three Different Locations in Vietnam

Agarwood and agarwood essential oils are commodities with great commercial value. In Vietnam, the agarwood industry has been growing, with more than 10,000 ha of forest land reserved for the cultivation of Aquilaria crassna, an agarwood-producing tree. The aim of this study was to present a hydrodistillation process to recover agarwood essential oil and to compare chemical compositions of agarwood samples harvested from various locations in Vietnam. Three agarwood samples representing products from A. crassna trees cultivated in the provinces of Bac Giang and Khanh Hoa, and on the Phu Quoc island (Kien Giang province) of Vietnam were subjected to hydrodistillation, resulting in essential oil yields of 0.32%, 0.27%, and 0.25% (w/w), respectively. Using GC–MS analysis, a total of 44 volatile compounds were identified in the obtained oils. Most of the constituents were oxygenated sesquiterpenes and had been previously found in other agarwood oil samples. Notable compounds of other chemical classes were aromatics and fatty acids. The three oil samples showed a common volatile profile, which is characterized by the dominance of eremophilane, agarofurans, and eudesmane sesquiterpenes, while vetispirane and guaiane sesquiterpenes were found in smaller quantities. Desired compounds, such as neopetasane (7.47–8.29%), dihydrokaranone (2.63–3.59%), β-agarofuran (3.04–6.18%), and agarospirol (2.98–3.42%), were present in substantial quantities, suggesting that the essential oils could be commercialized as fragrant materials of high value.