Agarwood Essential Oil Research Articles

Sesquiterpenoids in Agarwood: Biosynthesis, Microbial Induction, and Pharmacological Activities.

Agarwood, derived from the Aquilaria genus, is widely utilized in perfumery, traditional medicine, and cultural practices throughout Asia. Agarwood is rich in terpenes, especially sesquiterpenes, which are considered to be the source of its rare and exquisite fragrance. This Review consolidates recent research on sesquiterpene biosynthesis in agarwood and the influence of fungi on these processes, alongside a discussion of the potential medicinal value of agarwood sesquiterpenes. This Review commences by elucidating the general biosynthesis of sesquiterpenes and identifying the main enzymes and transcription factors involved in the production of agarwood sesquiterpenes. This Review also summarizes the fungi associated with agarwood and highlights how commensal fungi stimulate agarwood and sesquiterpene production. We then scrutinize the pharmacological properties of sesquiterpenes, underscoring their anti-inflammatory and antimicrobial effects, which are closely linked to cellular signaling pathways, such as the NF-κB and MAPK pathways. Additionally, we review the potential therapeutic benefits of agarwood essential oil for its antidepressant properties, which are linked to the regulation of stress-related neurochemical and hormonal pathways. This Review also addresses the challenges of sustainable agarwood production, highlighting issues such as overharvesting and habitat loss while discussing the potential strategy of harnessing microbes in agarwood production to support the ecological preservation of wild resources. By advancing our knowledge of agarwood and sesquiterpene characteristics, we propose potential directions for the future application and sustainable development of agarwood research.

Chemical Investigation on the Volatile Part of the CO2 Supercritical Fluid Extract of Infected Aquilaria sinensis (Chinese Agarwood).

This work is focused on the characterization of the composition of a CO2 supercritical fluid extract of Aquilaria sinensis (Chinese agarwood) collected in the Dongguan area (China) and infected by mechanical methods. The constituents of this extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified accurately by gas chromatography with a flame ionization detector (GC-FID), using an internal reference and predicted response factors. Since a significant number of components of this extract remained non-identified after the initial GC-MS analysis of the whole extract, its fractionation by chromatography on silica gel helped to characterize several additional constituents by isolation and structural analysis by NMR spectroscopy. The main components are the classical agarwood chromones (Flindersia chromone and its mono-, di-, and trimethoxylated analogues (respectively, 11.01% and 0.11-4.02%) along with sesquiterpenic constituents typically found in agarwood essential oils, like baimuxinal (1.90%) and kusunol (1.24%), as well as less common selinane dialdehydes (1.58-2.27%) recently described in the literature. Moreover, the structure and stereochemistry of a new sesquiterpenic alcohol, 14β,15β-dimethyl-7αH-eremophila-9,11-dien-8β-ol (0.67%), was determined unambiguously by the combination of structural analysis (NMR, MS), hemisynthesis, and total synthesis, leading to dihydrokaranone and a neopetasane epimer.

Chemical composition and bioactivity variability of two-step extracts derived from traditional and “QiNan” agarwood (Aquilaria spp.)

One of the primary applications for agarwood lies in the extracts, instead, there are obvious differences in the demands for agarwood components with different application fields. To obtain the rough separation and clarify each part's activity, four extracts of essential oil, hydrolat, extractum, and ethanol precipitation from traditional agarwood (TraA) and “Qinan” agarwood (QinA) were obtained by steam-solvent multistage extraction and ethanol precipitation. We investigated the chemistry and biological activity of multistage extracts using gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC), and in vitro activity testing. The results demonstrated that two kinds of agarwood essential oils contained mainly sesquiterpenoids, yet the sesquiterpene species were remarkably diverse in two kinds of agarwood essential oils. Then, the TraA and QinA hydrolat, all predominantly aromatic and sesquiterpene, but with differences from the essential oil ingredients. Additionally, the extractum chiefly contained chromones and the ethanol precipitation method worked well to separate the impurities in the TraA extract, however, it was ineffective for the QinA extract. Ultimately, essential oils and extractums all have antioxidant properties, with extractums outperforming essential oils. Moreover, both extractums and essential oils exhibited excellent broad-spectrum antimicrobial activity and anti-inflammatory activity. The findings pointed to the feasibility of separating the primary components from TraA and QinA using a multi-stage extraction technique, providing a scientific basis for the efficient utilization of all components of agarwood, as well as the functional product development and differentiated utilization of extract products in incense, fragrance, perfume, and daily chemicals.

Determination of Antitumor Active Ingredients in Agarwood Essential Oil by Gas Chromatography-Mass Spectrometry (GC-MS) and Grey Relational Analysis

Agarwood essential oil (AEO) holds significant medicinal and economic value. While its antitumor activity is reported in the literature, the active ingredients remain unexplored. In this study, the chemical composition of AEO extracted by steam distillation (SD) and fungal fermentation-assisted SD (FFSD) was evaluated by gas chromatography-mass spectrometry (GC-MS). The antitumor activity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Subsequently, the key active ingredients and targets of antitumor activity were evaluated using grey relational analysis and network pharmacology. The relative content of active ingredients in the AEOs extracted from different Aquilaria trees was compared. GC-MS tentatively identified 32 compounds, primarily sesquiterpenoids and aromatic compounds. Eight components with relative content differences were screened using orthogonal partial least squares-discriminant analysis (OPLS-DA), indicating that α-costal, guaiol, β-santalol may play important roles in the antitumor activity. Both SD and FFSD-extracted AEOs demonstrated the ability to inhibit the proliferation and survival of four cancer cell lines, with slightly stronger inhibitory effects observed in AEO extracted by SD. α-Costal, aristolone, 10-epi-γ-eudesmol, γ-eudesmol, agarospirol, hinesol, guaiol, β-santalol, and 6-isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-naphthalen-2-ol were antitumor ingredients of AEO. The relative content of total active ingredients in agarwood (Aquilaria malaccensis) essential oil was higher, suggesting higher efficacy. This study confirmed the antitumor activity of AEO and identified its active ingredients. These findings provide a basis for further research on the antitumor mechanism of AEO.

Pattern analysis on <em>Aquilaria Malaccensis</em> using machine learning

Aquilaria Malaccensis was found to generate agarwood. Because of its multiple benefits, agarwood essential oil, sometimes known as “black gold” is highly regarded universally. There is currently no accepted method for classifying various grades of agarwood essential oil. Due to the fact that the agarwood essential oil is assessed using a human sensory panel, the existing grading method is ineffective. Since different people may have different viewpoints on how to grade agarwood essential oil, it is not practical to apply the method universally. Several innovative methods for determining the classification of agarwood essential oil have been proposed and put into practise as a result of advanced technology. The study has constructed a pattern analysis on different grades of agarwood essential oil using 2D scatter plot. The results successfully indicate the scatter plots are scattered groupedly.

Chemical profiling and cytotoxicity screening of agarwood essential oil (Aquilaria sinensis) in brine shrimp nauplii and cancer cell lines.

Agarwood essential oil (AEO) has gained attention from healthcare industries due to its numerous pharmacological properties. However, a comprehensive understanding of the chemical composition and its cytotoxic property is lacking. The objective of this study was to investigate the chemical profile as well as the cytotoxic concentration range of AEO derived from Aquilaria sinensis agarwood. Gas chromatography-mass spectrometry (GC-MS) was employed to identify the AEO components. Results showed that sesquiterpenes and sesquiterpenoids constitute 95.85% of the AEO. Among the major compounds identified are allo-aromadendrene (13.04%), dihydro-eudesmol (8.81%), α-eudesmol (8.48%), bulnesol (7.63%), τ-cadinol (4.95%), dehydrofukinone (3.83%), valerenol (3.54%), cis-nerolidol (2.75%), agarospirol (2.72%), dehydrojinkoh-eremol (2.53%), selina-3,11-dien-9-al (2.36%), guaiol (2.12%) and caryophyllene oxide (2.0%). The presence of volatile quality marker compounds such as 10-epi-ϒ-eudesmol, aromadendrane, β-agarofuran, α-agarofuran, γ-eudesmol, agarospirol and guaiol, with no contaminants detected, indicates that the extracted AEO is of high purity. Interestingly, the AEO displayed moderate to high toxicity in brine shrimp lethality test (BLST). All studied tumor cell lines (MDA-MB-231, HepG2, B16F10) exhibited varying degrees of sensitivity to AEO, which resulted in time and dose-dependent reduction of cell proliferation. Moreover, flow cytometry analysis revealed that AEO could induce apoptosis in treated HepG2 cells. Our findings showed that AEO contains bioactive components that may be exploited in future studies for the development of anti-cancer therapeutics.

Protective role of agarwood essential oil and compounds thereof in crop‐associated fungal pathogens

AbstractThe potential risk of fungal pathogen infection in agriculture has great adverse effects on agricultural development and human health. In this study, we explored the application of agarwood essential oil (AEO) and its main components in the development of agricultural fungicides. The compositions of AEO produced in Maoming City of Guangdong Province, China was firstly analysed by GC–MS. AEO and compounds thereof including carvacrol and longifolene were then used to perform a series of antifungal activity evaluations in vitro and in vivo against agricultural and foodborne pathogens. The in vitro results showed that the antifungal activities of AEO were comparable to those of hymexazol (a positive control), and carvacrol exhibited stronger efficacy. In vivo studies also showed that AEO and carvacrol could significantly inhibit the damage effect of Curvularia mebaldsii on the germination rate of wheat roots. Further, it was found that the germination rate exhibited a downward trend with the dose increase of AEO and carvacrol.

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

Chemical Compositions of Essential Oil of Agarwood <i>(Aquilaria crassna)</i> Harvested in Phu Quoc Island, Vietnam

The importance of natural products derived from Agarwood species is increasingly emphasized in the production of perfumery or cosmetic products made on Agarwood species. On the other hand, due to the predominant amount of aromatic compounds in essential oils, frankincense essential oil is increasingly popular with high economic value. Therefore, in this study, we focused on the extraction process of essential oils and evaluated the chemical composition present in the essential oils by the GC-MS method. Differences in the composition of essential oils between natural and artificial agarwood may be due to species, habitat conditions, climate, geographical conditions, and extraction methods in different regions. Specifically, volatile components in essential oils were identified as Neopetasone (14.43%); Dihydroagarofuran-15-al (9.20%); Jinko-cramol (5.02%); Valeriano (4.94%); Agarofuran <b-> (8.02%); Dihydrokaranone (3.25%), Valenca-1 (10), 8-dien-11-ol (5.95%) and Selina-4,11-dien-14-al (2.73%), contribute to determining the main aroma in Agarwood essential oil.

Supercritical extraction technique of agarwood essential oil induced by plant hormones

Samples of agilawood (agarwood), which were studied in this work, were produced in Zhongshan City, Guangdong Province, China. To enhance incense production, a specific concentration of plant hormone is employed for induction. The extraction technology of agilawood essential oil was explored using supercritical carbon dioxide fluid, which exhibited a more pronounced induction effect. The pressure, temperature, and flow rate, respectively, were 8, 16, and 24 MPa; 35, 45, and 55 °C; and 20, 30, and 40 L/h. A Box-Behnken analysis was adopted for experimental data, which involved 33 experiments. The data were fitted with the equation Y = 2.18 + 0.1312X1 – 0.025X2 + 0.1236X3 – 0.0025X1X2 – 0.0125X2X3 + 0.0175X12 + 0.035X22 – 0.1275X32. Hence, the optimal process parameters in the supercritical extraction of agarwood essential oil were as follows: the pressure, temperature, and flow rate of 24 MPa, 35 °C, and 33 L/h, respectively. An analysis was conducted with the statistical analysis software Design-Expert 11, which indicated that the extraction yield of agarwood essential oil by supercritical carbon dioxide was mainly affected by the pressure and flow rate. The yield was proportional to the pressure and flow, and inversely proportional to the temperature.

Agarwood (Aquilaria malaccensis L.) a quality fragrant and medicinally significant plant based essential oil with pharmacological potentials and genotoxicity

Aquilaria malaccensis (agarwood essential oil), is a highly priced medicinal and most expensive aromatic oil in the industry. The purpose of the current study was to assess the chemical makeup of a naturally insect infested agarwood essential oil and its potential therapeutic uses. Essential oil of infected agarwood was extracted using Clevenger apparatus and the chemical analysis of essential oil was carried out using GC/MS technique. Pharmacology evaluation includes – tyrosinase inhibitory, anti-cholinesterase (AChE), anti-urolithic, anti-inflammatory, anti-diabetic, and antioxidant assays. Standard methodologies such as tyrosinase inhibitor, α-amylase inhibitor, AChE inhibitory, aggregation, protease inhibitor, DPPH, ABTS, and metal chelating assays were used for evaluation of pharmacological potential. GC/MS analysis revealed cubenol (22.26%), agarospirol (14.35%) and aristolene (13.22%) as major compounds. Radical scavenging activity of agarwood essential oil showed 50% inhibition (IC50 using XLSTAT software) at the concentration of 40.14 ± 0.0192 µL/mL. Furthermore, the antioxidant capacity from ABTS assay, α-amylase inhibitory potential, tyrosinase inhibitory activity, AChE inhibitory assay, anti-urolithic activity and in-vitro anti-inflammatory activity protein denaturation assay were confirmed with IC50 values of 76.95 ± 0.0090 µL/mL, 30.78 ± 0.0018 µL/mL, 38.06 ± 0.0016 µL/mL, 13.41 ± 0.0374 µL/mL, 34.14 ± 0.0202 µL/mL and 22.42 ± 0.0560 µL/mL respectively. At 1 µL/mL concentration Allium cepa genotoxicity assay resulted agarwood essential oil Mitotic Index (MI) value of 14.26%, with a chromosomal aberration of 9.30%. Genotoxicity results for A. malaccensis essential oil showed negative toxic effect at 1 µL/mL concentration. The essential oil did not exhibit any anti-microbial activity against all the tested microbial strains. From the study it is concluded that agarwood essential oil could be used for antioxidant, anti-diabetic, skin whitening, and anti-inflammatory drug formulations in near future.

Microencapsulation of agarwood (Aquilaria crassna) essential oil by spray drying

Agarwood essential oil is the essential oil extracted from the heartwood of agarwood trees (Aquilaria sp.) after inoculation or natural infection of one of several fungal species. The essential oil is proved to carry antioxidant, antimicrobial and anti-stress activities. Microencapsulation of essential oil included emulsification of oil into maltodextrin solution and spray drying of emulsion at different levels of inlet temperature and compressed air pressure. Microencapsulation process was qualified based on following parameters including process’s microencapsulation yield, moisture content of powder, powder particle size, encapsulated oil’s composition, oil recovery and drying yield. Microencapsulation yield was affected by inlet temperature whereas drying yield changed as air pressure varied from 1.5 to 2.5 kgf/cm2. Other parameters were impacted by both variables. Besides, oil composition changed at an acceptable degree after microencapsulation process, in which there were an increase in percentage and the presence of some components but the main components still remained in the encapsulated oil. Finally, the drying air temperature of 150 °C and air pressure of 2.5 kgf/cm2 were the best parameters to obtain both microencapsulation yield of 89.12% and drying yield of 79.00%.

Agarwood Oil Nanoemulsion Attenuates Cigarette Smoke-Induced Inflammation and Oxidative Stress Markers in BCi-NS1.1 Airway Epithelial Cells

Chronic obstructive pulmonary disease (COPD) is an irreversible inflammatory respiratory disease characterized by frequent exacerbations and symptoms such as cough and wheezing that lead to irreversible airway damage and hyperresponsiveness. The primary risk factor for COPD is chronic cigarette smoke exposure, which promotes oxidative stress and a general pro-inflammatory condition by stimulating pro-oxidant and pro-inflammatory pathways and, simultaneously, inactivating anti-inflammatory and antioxidant detoxification pathways. These events cause progressive damage resulting in impaired cell function and disease progression. Treatments available for COPD are generally aimed at reducing the symptoms of exacerbation. Failure to regulate oxidative stress and inflammation results in lung damage. In the quest for innovative treatment strategies, phytochemicals, and complex plant extracts such as agarwood essential oil are promising sources of molecules with antioxidant and anti-inflammatory activity. However, their clinical use is limited by issues such as low solubility and poor pharmacokinetic properties. These can be overcome by encapsulating the therapeutic molecules using advanced drug delivery systems such as polymeric nanosystems and nanoemulsions. In this study, agarwood oil nanoemulsion (agarwood-NE) was formulated and tested for its antioxidant and anti-inflammatory potential in cigarette smoke extract (CSE)-treated BCi-NS1.1 airway basal epithelial cells. The findings suggest successful counteractivity of agarwood-NE against CSE-mediated pro-inflammatory effects by reducing the expression of the pro-inflammatory cytokines IL-1α, IL-1β, IL-8, and GDF-15. In addition, agarwood-NE induced the expression of the anti-inflammatory mediators IL-10, IL-18BP, TFF3, GH, VDBP, relaxin-2, IFN-γ, and PDGF. Furthermore, agarwood-NE also induced the expression of antioxidant genes such as GCLC and GSTP1, simultaneously activating the PI3K pro-survival signalling pathway. This study provides proof of the dual anti-inflammatory and antioxidant activity of agarwood-NE, highlighting its enormous potential for COPD treatment.

Anxiolytic and antidepressant effects of agarwood inhalation and its mechanism

This study used m-chloropheniperazine(MCPP) and chronic unforeseeable mild stress(CUMS) to induce the rat models of anxiety and depression, respectively. The behaviors of rats were observed by the open field test(OFT), light-dark exploration test(LDE), tail suspension test(TST), and forced swimming test(FST), and the antidepressant and anxiolytic effects of agarwood essential oil(AEO), agarwood fragrant powder(AFP), and agarwood line incense(ALI) were explored. The enzyme-linked immunosorbent assay(ELISA) was used to determine the levels of 5-hydroxytryptamine(5-HT), glutamic acid(Glu), and γ-aminobutyric acid(GABA_A) in the hippocampal area. The Western blot assay was used to determine the protein expression levels of glutamate receptor 1(GluR1) and vesicular glutamate transporter type 1(VGluT1), exploring the anxiolytic and antidepressant mechanism of agarwood inhalation. The results showed that compared with the anxiety model group, the AEO, AFP, and ALI groups decreased the total distance(P<0.05), decreased the velocity of movements(P<0.05), prolonged the immobile time(P<0.05), and reduced the distance and velocity of the rat model of anxiety in the dark box(P<0.05). Compared with the depression model group, the AEO, AFP, and ALI groups increased the total distance and average velocity(P<0.05), reduced the immobile time(P<0.05), and reduced the forced swimming and tail suspension time(P<0.05). In terms of transmitter regulation, the AEO, AFP, and ALI groups decreased the level of Glu in the rat model of anxiety(P<0.05) and increased the levels of GABA_A and 5-HT(P<0.05), while the AEO, AFP, and ALI groups all increased the level of 5-HT in the rat model of depression(P<0.05) and decreased the levels of GABA_A and Glu(P<0.05). At the same time, the AEO, AFP, and ALI groups all increased the protein expression levels of GluR1 and VGluT1 in the hippocampus of the rat models of anxiety and depression(P<0.05). In conclusion, AEO, AFP, and ALI exert anxiolytic and antidepressant effects, and the mechanism might be related to the regulation of the neurotransmitter and the protein expression of GluR1 and VGluT1 in the hippocampus.

Preliminary study on agarwood essential oil and its classification techniques using machine learning

Using essential oils derived from trees for pharmaceutical purposes, incense, aromatherapy, and other areas has expanded its popularity on the international market. However, since human sensory evaluation is still the primary technique used to grade essential oils in Malaysia, the classification technique for determining their grade is still below standard. Nonetheless, prior studies established new approaches for classifying the grade of essential oils by studying their chemical compounds. Therefore, agarwood essential oil was selected for the suggested model due to the increasing demand and the high cost of the world's natural raw materials. The support vector machine (SVM) using one versus all (OVA) approach was selected as the classifier for agarwood essential oil. This study provides an overview of essential oils and their prior research techniques. In addition, a review of SVM is conducted to demonstrate that the technique is appropriate for future studies.

Agarwood essential oil inhalation exerts antianxiety and antidepressant effects via the regulation of Glu/GABA system homeostasis.

Depression and anxiety are common diseases that endanger the physical and mental health of individuals. Agarwood incense inhalation has been used as a traditional Chinese medicine for relaxation and to improve sleep for centuries. In a previous study by the authors it was demonstrated that agarwood essential oil (AEO) injection exerted anxiolytic and antidepressant effects. Therefore the present study further investigated the anxiolytic and antidepressant effects of AEO inhalation on anxiolytic mice induced by M-chlorophenylpiperazine and depressive mice induced by chronic unpredictable mild stress. The results demonstrated that AEO exerted a significant anxiolytic effect, whereby autonomous movements were inhibited during the light dark exploration test and open field test. Furthermore, the tail suspension test and the forced swimming test demonstrated that AEO also exerted an antidepressant effect, whereby the immobility times were decreased. Moreover, AEO was determined to increase the levels of 5-hydroxytryptamine, γ-aminobutyric acid (GABA) A receptor (GABAA) and glutamate (Glu) in anxiolytic mice and inhibit the levels of GABAA and Glu in depressive mice. Further investigations into how AEO affected the Glu/GABA system demonstrated that AEO markedly increased the protein expression levels of GABA transaminase (GABAT), glutamate metabotropic receptor 5 (GRM5), glutamate ionotropic receptor AMPA type subunit 1 (GluR1) and vesicular glutamate transporter 1 (VGluT1). Furthermore, AEO reduced the expression levels of GABAT, glutamate ionotropic receptor NMDA type subunit 2B and GRM5, and enhanced the expression levels of GluR1 and VGluT1. These results demonstrated that AEO potentially possesses antianxiety and antidepressant properties. The present study determined that the mechanism was related to the regulation of Glu/GABA neurotransmitter system homeostasis.

The Effect of Chinese Agarwood Essential Oil with Cyclodextrin Inclusion against PCPA-Induced Insomnia Rats.

To study the extraction process of agarwood active ingredients (AA) and investigate the safety and effectiveness of AA in the treatment of insomnia rats by nasal administration. A β-cyclodextrin (β-CD) inclusion compound (a-β-CD) was prepared from agarwood essential oil (AEO), and the preparation process was optimized and characterized. The safety of AA in nasal mucosa was evaluated through Bufo gargarizans maxillary mucosa and rat nasal mucosa models. Insomnia animal models were replicated by injecting p-chlorophenylalanine (PCPA), conducting behavioral tests, and detecting the expression levels of monoamine neurotransmitters (NE and 5-HT) and amino acids (GABA/Glu) in the rat hypothalamus. The optimum inclusion process conditions of β-CD were as follows: the feeding ratio was 0.35:1.40 (g:g), the inclusion temperature was 45 °C, the inclusion time was 2 h, and the ICY% and IEO% were 53.78 ± 2.33% and 62.51 ± 3.21%, respectively. The inclusion ratio, temperature, and time are the three factors that have significant effects on the ICY% and IEO% of a-β-CD. AA presented little damage to the nasal mucosa. AA increased the sleep rate, shortened the sleep latency, and prolonged the sleep time of the rats. The behavioral test results showed that AA could ameliorate depression in insomnia rats to a certain extent. The effect on the expression of monoamine neurotransmitters and amino acids in the hypothalamus of rats showed that AA could significantly reduce NE levels and increase the 5-HT level and GABA/Glu ratio in the hypothalamus of insomnia rats. The preparation of a-β-CD from AEO can reduce its irritation, improve its stability, increase its curative effect, and facilitate its storage and transport. AA have certain therapeutic effects on insomnia. The mechanism of their effect on rat sleep may involve regulating the expression levels of monoamine neurotransmitters and amino acids in the hypothalamus.

An integrated approach utilizing raman spectroscopy and chemometrics for authentication and detection of adulteration of agarwood essential oils.

Agarwood is a precious aromatic plant which has good pharmacological effects such as antidepressant and sedation. It also has good ornamental and collection value. However, due to it is long and complex production process, the output of agarwood essential oils (AEOs) is scarce, so the price is expensive, the quality is uneven, and the adulteration events is endless. From the commercial and pharmaceutical point of view, the authenticity and quality of the commercial products labeled as AEOs is very important. This paper tested the applicability of Raman spectroscopy combined with chemometrics in classification and authenticity identification of AEOs. In this study, Raman spectroscopy and principal component analysis (PCA) combined with partial least square discriminant analysis (PLS-DA) were used to comprehensively evaluate AEOs from different geographical origins and/or extracted by different methods which showed different characteristic bands. The characteristic component of AEOs, chromone derivatives, and two commonly used adulterants were also detected. These characteristic bands provide spectrum information of AEO samples and reference materials, which can be used as Raman spectral markers for the qualitative identification of AEOs. This study can provide a novel, fast and convenient method for identification of AEOs.

A novel application of artificial neural network for classifying agarwood essential oil quality

<p><span lang="EN-US">This work studies the agarwood oil classification into high and low quality by using two different techniques. Initially, the Forest Research Institute Malaysia (FRIM) and Universiti Malaysia Pahang (UMP) are where the sample preparation and compound extraction of agarwood oil is collected. The data collections were done from the previous researcher consists of 96 samples from seven significant agarwood oil compounds. The artificial neural network (ANN) and the proposed stepwise regression technique were used in this study. The stepwise regression was done the feature selection and successfully reduced agarwood oil compounds from seven to four. Then, the ANN technique was used to classify agarwood oil into high and low using input from seven and four compounds separately. The performance of ANN with different inputs is compared (ANN with seven inputs compared with ANN with four inputs). All the experimental work was performed using the MATLAB R2017b using the “patternet” implemented Levenberg Marquardt algorithm and ten hidden neurons. It was found that the ANN technique using seven compounds obtained the best performance according to high accuracy and lower mean square error (MSE) value. Finally, 1 hidden neuron in ANN with seven inputs selected as the best neuron for grading the agarwood oil compounds.</span></p>

A Ppreliminary study on the intelligent model of k-nearest neighbor for agarwood oil quality grading

Essential <span>oils extracted from trees has various usages like perfumes, incense, aromatherapy and traditional medicine which increase their popularity in global market. In Malaysia, the recognition system for identifying the essential oil quality still does not reach its standard since mostly graded by using human sensory evaluation. However, previous researchers discovered new modern techniques to present the quality of essential oils by analyse the chemical compounds. Agarwood essential oil had been chosen for the proposed integrated intelligent models with the implementation of k-nearest neighbor (k-NN) due to the high demand and an expensive natural raw world resource. k-NN with Euclidean distance metrics had better performance in terms of its confusion matrix, sensitivity, precision accuracy and specificity. This paper presents an overview of essential oils as well as their previous analysis technique. The review on k-NN is done to prove the technique is compatible for future research studies based on its performance.</span>