Agarwood Essential Oil Research Articles

Metabolic Engineering of Saccharomyces cerevisiae for Production of Fragrant Terpenoids from Agarwood and Sandalwood

Sandalwood and agarwood essential oils are rare natural oils comprising fragrant terpenoids that have been used in perfumes and incense for millennia. Increasing demand for these terpenoids, coupled with difficulties in isolating them from natural sources, have led to an interest in finding alternative production platforms. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fragrant terpenoids from sandalwood and agarwood. Specifically, we constructed strain FPPY005_39850, which overexpresses all eight genes in the mevalonate pathway. Using this engineered strain as the background strain, we screened seven distinct terpene synthases from agarwood, sandalwood, and related plant species for their activities in the context of yeast. Five terpene synthases led to the production of fragrant terpenoids, including α-santalene, α-humulene, δ-guaiene, α-guaiene, and β-eudesmol. To our knowledge, this is the first demonstration of β-eudesmol production in yeast. We further improved the production titers by downregulating ERG9, a key enzyme from a competing pathway, as well as employing enzyme fusions. Our final engineered strains produced fragrant terpenoids at up to 101.7 ± 6.9 mg/L. We envision our work will pave the way for a scalable route to these fragrant terpenoids and further establish S. cerevisiae as a versatile production platform for high-value chemicals.

Chemical Composition and Potential Properties in Mental Illness (Anxiety, Depression and Insomnia) of Agarwood Essential Oil: A Review.

As a valuable medicinal herb and spice, agarwood is widely used in the fields of daily chemistry, traditional medicine, religion and literary collection. It mainly contains sesquiterpenes and 2-(2-phenylethyl)chromones, which are often used to soothe the body and mind, relieve anxiety, act as an antidepressant and treat insomnia and other mental disorders, presenting a good calming effect. This paper reviews the chemical composition of the essential oils of different sources of agarwood, as well as the progress of research on the sedative and tranquilizing pharmacological activity and mechanism of action of agarwood essential oil (AEO), and then analyzes the current problems of AEO research and its application prospects in the treatment of mental diseases.

Effective Components and Molecular Mechanism of Agarwood Essential Oil Inhalation and the Sedative and Hypnotic Effects Based on GC-MS-Qtof and Molecular Docking.

Agarwood has been used for the administration of hypnotic therapy. Its aromatic scent induces a relaxed state. However, its aromatic constituents and the underlying molecular effect are still unclear. This study aims to determine the active substance and molecular mechanism of the hypnotic effect of agarwood essential oil (AEO) incense inhalation in insomniac mice. Insomnia models were induced by para-chlorophenylalanine (PCPA, 300 mg/kg) in mice. The sleep-promoting effect was evaluated. Neurotransmitter levels and its receptor were detected to explore the molecular mechanism. The effective components were analyzed by GC-Q/TOF-MS of AEO. The binding mechanisms of the core compounds and core targets were verified by molecular docking. These results showed that AEO inhalation could significantly shorten sleep latency and prolong sleep time, inhibit autonomous activity and exert good sedative and sleep-promoting effects. A mechanistic study showed that AEO inhalation increased the levels of γ-aminobutyric acid (GABAA), the GABAA/glutamic acid (Glu) ratio, 5-hydroxytryptamine (5-HT) and adenosine (AD), upregulated the expression levels of GluR1, VGluT1 and 5-HT1A and downregulated 5-HT2A levels. Component analysis showed that the most abundant medicinal compounds were eremophilanes, cadinanes and eudesmanes. Moreover, the docking results showed that the core components stably bind to various receptors. The study demonstrated the bioactive constituents and mechanisms of AEO in its sedative and hypnotic effects and its multicomponent, multitarget and multipathway treatment characteristics in PCPA-induced insomniac mice. These results provide theoretical evidence for insomnia treatment and pharmaceutical product development with AEO.

Morphological, physiological, biochemical and molecular analyses reveal wounding-induced agarwood formation mechanism in two types of Aquilaria sinensis (Lour.) Spreng

Agarwood, a resinous portion of injured Aquilaria trees, has become scarce and precious because of its low yields in ordinary Aquilaria sinensis. A new type of A. sinensis, namely easier induced agarwood A. sinensis germplasm (EIAA), has recently been selected and cultivated. However, no information has been reported about its agarwood formation mechanism yet. Multiple approaches, including anatomical, physiological, biochemical and molecular profiling, were employed in this study to investigate wounding-induced agarwood formation in two types of A sinensis. After mechanical damage, the related physiological and biochemical parameters regulating defense response were increased significantly, while the related parameters regulating growth were decreased significantly in two types of A sinensis. The strength of defense response was decreased and the growth performance was recovered over time. Compared to ordinary A. sinensis, EIAA showed higher hormones levels of salicylic acid, jasmonic acid and ethylene, higher activities of antioxidant enzymes, more total phenols and terpenes, higher net photosynthetic rate and photochemical efficiency of PSII, more consumption of non-structural carbohydrates, higher agarwood yield and oil content. There were marked differences in the components of agarwood essential oils between two types of A. sinensis. In particularly for 2-(2-phenylethyl) chromone and 2-[2-(4′-methoxybenzene) ethyl] chromone, their richness in agarwood essential oil of EIAA was significantly higher in contrast with the ordinary A. sinensis agarwood. Differentially expressed genes further ensured the differences in defense responses to wounding stress and secondary metabolism patterns between two types of A. sinensis. These data collectively demonstrate that there is a tradeoff between growth and defense during wounding-induced agarwood formation and EIAA had stronger defense ability in physiological and biochemical levels compared with ordinary A. sinensis. This is the physiological mechanism by which EIAA has higher agarwood yield and essential oil content. Moreover, the differential expression of flavonoid biosynthesis-related genes explained the different chromone synthesis pathways between two types of A. sinensis. These findings provide new insights into wounding-induced agarwood formation mechanism in A. sinensis, especially for EIAA.

Boxplot analysis of 4 grade agarwood essential oil for various grades

Agarwood essential oil is used in most perfumery ingredients, as an incense and in traditional medical preparations. Agarwood essential oil, called "Black Gold," is extremely valued to the global community due to its numerous benefits. As of now, there is still no standard technique of grading different grades of agarwood essential oil. The current grading technique is inefficient since the agarwood essential oil is graded by using human sensory panel. Different people might have different perspective on grading the agarwood essential oil hence, the technique is not practical to adapt it globally. Due to the current technology, numerous intelligent techniques for verifying the grades of agarwood essential oil have been proposed and implemented. The study has conducted a statistical analysis on 4 grade agarwood essential oil using boxplot. Boxplot analysis summarizes the abundances for each chemical compounds from four different grades of agarwood essential oil with a high grade as a reference. This study shows the analysis of boxplot investigated 10-epi-δ-eudesmol, α-agarofuran, β-agarofuran, δ-eudesmol and dihydrocollumellarin as most important chemical compounds in high grade of agarwood essential oil. The chemical compounds that have been identified in high grade of agarwood essential oil can be a reference for future research studies.

The Chemistry of Agarwood Odorants.

The phytochemistry of the fragrant infected heartwood of Aquilaria and Gyrinops species, agarwood (oud), is critically reviewed, highlighting the use of this remarkable natural raw material in perfumery. The chemistry of the two main groups of constituents of agarwood (sesquiterpenoids and chromones) is discussed, focusing particularly on the former structural type. The identities of the main key odorants of agarwood essential oil and of the smoke produced by heating the wood of agarwood are also discussed.

Ekstraksi Minyak Gaharu dengan Pelarut Etanol secara Maserasi

Agarwood is one of the forest products that can be utilized and has a high selling value. Agarwood contains essential oils which have many active compounds and contains a specific aromatic resin that is naturally formed as a form of defense against physical damage or microbial infection. Agarwood essential oil with good quality has a high economic value. This study aims to extract agarwood essential oil using ethanol as a solvent. The optimal yield of agarwood essential oil can be obtained by varying the particle size, the ratio of the weight of the agarwood biomass (kg) to the volume of the solvent (L), and the length of maceration (h). The results showed that the particle size of agarwood did notaffect the yield of agarwood essential oil. The results of the comparison of agarwood biomass with the volume of the solvent showed that the ratio of 1:9 (w/v) obtained the highest yield of 4.02% and the longest maceration time with the highest yield of 4.12% for 72 hours. However, 48 hours of maceration had a greater increase in yield compared to 72 hours of maceration. The increase in yield at 48 hours to 72 hours of maceration was only 0.22% when compared to the increase in yield at 24 hours to 48 hours of maceration, which was 0.56%.

Protection of agarwood essential oil aroma by nanocellulose-graft-polylactic acid

Essential oil products are often volatile, and their aromas cannot be effectively preserved over long periods of time. In this study, nanocellulose crystals were modified, and an amphiphilic copolymer was prepared by ring-opening polymerisation to produce wall materials. A nanocellulose crystal-grafted polylactic acid copolymer was successfully synthesised and characterised using nuclear magnetic resonance spectrometry, Fourier transform infrared spectrometry, X-ray diffraction, and thermogravimetric analysis. Because of the amphiphilic properties of the synthesised copolymer, an agarwood essential oil nanoemulsion system was prepared. Using transmission electron microscopy and dynamic laser light scattering, the nanoemulsion was observed to have an apparent shell–core structure. The nanoemulsion was uniformly distributed, and the system had good stability. Finally, the electronic nose results showed that the nanocellulose crystal-grafted polylactic acid copolymer micelle effectively protected agarwood essential oil aromas.

Properties and potential of agarwood hydrosol as a drink: a review

Agarwood is resinous valuable heartwood of Aquilaria tree resulting from self–defence mechanism towards injuries or damages exerted on the tree. Agarwood essential oil is usually extracted through a process of hydrodistillation or steam distillation which is beneficial for commercial purposes such as perfumeries and cosmetics. Hydrosol, a byproduct of the process produced in abundance and underutilized particularly in the agarwood industry. Hydrosol of agarwood is an aromatic compound that is believed to have chemical properties similar to essential oils that consist of positive antioxidant activity and positive biological activity for living cells. Several studies on properties of hydrosol of agarwood show that it contained zero nutrient but varied with minerals in the appropriate proportion that safe for human consumption. Thus, this review was aimed to discuss the agarwood hydrosol processing methods, characteristics, antioxidants properties and its comparisons to other plants hydrosol that have been commercially used as human consumption as in flavoured and non-flavoured beverages

Bioactive composition, antifungal, antioxidant, and anticancer potential of agarwood essential oil from decaying logs (Gyrinops spp.) of Papua Island (Indonesia)

Decaying logs of Gyrinops spp. are an important agarwood source originating from Papua Island and have been exploited since 2004. It is well known as the resinous heartwood used as a pharmaceutical resource and was listed under the trading name “filaria” before 2020. The bioactive and chemical composition of agarwood essential oil (AEO) from decaying logs (Gyrinops spp., M1) was studied to ensure its potential in comparison with AEO from a 1.5-year-old inoculated agarwood tree (M2) and that of ordinary commercial AEO (M3). The chemical composition analyzed by the retention index showed that M1 had quite a similar profile to that of M2, while M1 was different from M3. Ten compounds in M1 were responsible for determining specific agarwood odor: agarospirol, dehydrojinkoh-eremol, baimuxinal, selina-3,11-dien-9-ol, selina-3,11-dien-14-al, selina-3,11-dien-14-ol, selina-4,11-dien-14-al, guaia-1(10),11-dien-15-ol, dihydrokaranone, and guaia-1(10),11-dien-15-al. The AEO of M1 had higher inhibition to the growth of Fusarium solani and showed the highest antioxidant activities compared to AEO of M2 and M3. Furthermore, all AEOs showed anticancer properties against breast cancer (MCF-7) in the range from 0.8% to 15.1% at the concentration of 0.1 mg ml−1. This study indicated that decaying logs (Gyrinops spp.) had antifungal, antioxidant, and anticancer potentials and could be further used as pharmaceutical resources.

Morphology and properties of agarwood-waste-filled natural rubber latex foam

Agarwood (Aquilaria crassna) (ACW) waste is widely available as a by-product of agarwood essential oil production. In this study, ACW waste was ball milled into ACW powder (passed through 120 mesh) and used as filler in natural rubber latex foam (NRLF) prepared by the Dunlop method. The effects of the ACW filler on cell morphology and properties of the NRLF were determined. It was found that the ACW filler loading affected cell morphology of the NRLF. The cell size of the ACW-filled NRLF increased with ACW loadings of 1.5 parts per hundred parts of latex (phr) and 2.5 phr, compared with that of control NRLF. A bimodal cell size distribution (with large and small cells) was dominant in the ACW-filled NRLF at loadings of 3.5 phr, 4.5 phr, 5.5 phr, and 6.5 phr. The cell walls also became thicker, causing inferior compression set behavior. In addition, the density and hardness of the ACW-filled NRLF increased with ACW filler loading.

Solvent used in extraction process of agarwood: a systematic review

The method of extraction of Agarwood is usually dependent on the purpose of the extract. This systematic review aims to look at the number of studies that use different types of solvents in the process of extraction. There are 3 types of solvents commonly used in the extraction of agarwood essential oils namely methanol, ethanol and water. Each solvent produces different extracts in terms of quantity and quality of the final product. However, there is controversy over the use of solvents as it may cause a cytotoxic effect on the user. Another common type of solvent is water. Although water is a cheap solvent and relatively safe, aqueous extracts have more impurities that make isolating the desired compound difficult. After the extraction process, the crude extract was fractionated into the desired compounds and this technique is widely applied, especially in the whole process of extraction of the agarwood. In conclusion, extraction solvents have certain advantages and disadvantages, and this is one of the reasons why this extraction method depends on the purpose of using the final product such as agarwood essential oil.

MEDICINAL USAGE OF AGARWOOD RESIN IN FORM OF ESSENTIAL OIL: A REVIEW

Agarwood is a high value of non-timber commodities from Indonesia. Agarwood trade on Indonesia mostly being sold in form of raw material. This raw material is agarwood resin or also well known as ”gubal’. Processing gubal into essential oil will improve the quality and price of this commodity. Furthermore, agarwood essential oil has been reported being used as traditional medication in some countries. This medicinal activity of agarwood essential oil has been confirmed by clinical research and resulted that this material has antioxidant, antibacterial, antifungal and anticancer activity. This material also has neural activity on the nervous system and becomes a potential antidepressant, relaxative, sedative and analgesic agent. The promising of the medicinal use of agarwood essential oil suggested that processing agarwood resin into essential oil should be the number one priority on agarwood trade.

Encapsulation of Agarwood Essential Oil with Maltodextrin and Gum Arabic

Encapsulation of Agarwood Essential Oil with Maltodextrin and Gum Arabic

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.

Composition analysis,antioxidative and antibacterial activities comparison of agarwood oils extracted by supercritical and steam distillation

Agarwood is a traditional and precious medicinal material and natural spice in China and other southeast Asian countries.As the head of all spices,agarwood has many pharmacological activities such as analgesia,antidiarrheal,anti-inflammatory and antibacterial effects. Due to its high price and scarce resources,there were just a few previous studies on it,mainly focusing on the chemical compositions of the agarwood essential oil and solvent extract mixture. The components of agarwood oils obtained by supercritical extraction and steam distillation were analyzed by using Gas Chromatography-Mass Spectrometer( GC-MS),and then the agarwood oils compositions and contents were compared between the traditional extraction method and the recently emerging supercritical extraction method. Antioxidant experiments of scavenging DPPH,ABTS,hydroxyl radical,total reducing power and MIC experiments of five kinds of tester strains such as staphylococcus aureus were combined to illustrate the differences between these two kinds of agarwood oils in terms of antioxidant and bacteriostatic activities. The results showed that the main components of agarwood oil were sesquiterpenoids( 68. 68%) in steam distillation extraction method,but sesquiterpenoids( 23. 78%) and chromones( 29. 42%) in supercritical extraction method. Fourteen common components included benzyl acetone,α-santalol,γ-eudesmol,agarospirol and guaiol etc. The antioxidant activity and inhibitory MIC of agarwood oils in supercritical extraction method were better than those in steam distillation method,and the inhibitory effect of agarwood oil on the growth of bacillus subtilis was found for the first time.

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.

Agarwood Essential Oil Ameliorates Restrain Stress-Induced Anxiety and Depression by Inhibiting HPA Axis Hyperactivity.

In our previous investigation, we found that agarwood essential oil (AEO) has a sedative-hypnotic effect. Sedative-hypnotic drugs usually have an anxiolytic effect, where concomitant anxiety and depression are a common comorbidity. Therefore, this study further investigated the anxiolytic and antidepressant effects of AEO using a series of animal behavior tests on a restraint stress-induced mice model. The elevated plus maze (EPM) test, the light dark exploration (LDE) test, and the open field (OF) test demonstrated that AEO has a significant anxiolytic effect. Simultaneously, the tail suspension (TS) test and the forced swimming (FS) test illuminated that AEO has an antidepressant effect with the immobility time decreased. Stress can cause cytokine and nitric oxide (NO) elevation, and further lead to hypothalamic-pituitary-adrenal (HPA) axis hyperactivity. AEO was shown to dose-dependently inhibit the levels of cytokines, including interleukin 1α (IL-1α), IL-1β, and IL-6 in serum, significantly decrease the mRNA level of neural nitric oxide synthase (nNOS) in the cerebral cortex and hippocampus, and inhibit the nNOS protein level in the hippocampus. Concomitant measurements of the HPA axis upstream regulator corticotropin releasing factor (CRF) and its receptor CRFR found that AEO significantly decreases the gene expression of CRF, and significantly inhibits the gene transcription and protein expression of CRFR in the cerebral cortex and hippocampus. Additionally, AEO dose-dependently reduces the concentrations of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) downstream of the HPA axis, as measured by ELISA kits. These results together demonstrate that AEO exerts anxiolytic and antidepressant effects which are related to the inhibition of CRF and hyperactivity of the HPA axis.

Agarwood Leaf Essential Oil Characterization and Effects on MCF-7 Breast Cancer Cells

Breast cancer continues to remain as the leading cause of cancer mortality among women worldwide. Agents for prevention and cure for breast cancer are contiuously being researched. Ä°n particular, agarwood essential oil from resin infiltrated heartwood has been reported to have substantial evidences of medicinal benefits. Nevertheless, there is very limited report on agarwood leaf essential oil (ALEO). Hence, this present study was conducted to evaluate the physicochemical properties, chemical constituents and anticancer activity of ALEO. ALEO was observed to be of pale-yellow colour with sweet smell. Other physicochemical properties include refractive index of 1.44, specific gravity of 0.886, saponification value of 131.88 mg KOH/g, acid value of 2.80 mg KOH/g and iodine value of 105.07 gI2/100g. The profiling of chemical constituents using gas chromatography-mass spectrometry (GCMS) revealed 19 compounds. Hexadecanoic acid was the major compound (64.41%). The biomarkers of agarwood; azulene (0.619%) and guaiol (0.2997%) were also detected. ALEO was tested for anticancer activity against MCF-7 cancer cells using WST-8 assay. ALEO showed the IC50 value of 31% (v/v) against MCF-7 cells after 36 hours of treatment. In conclusion, this study provides information on ALEO physicochemical properties and chemical constituents that can be used as benchmark for quality assurance as well as proof that ALEO holds a potential as anticancer agent.

Incubation of Aquilaria subintegra with Microbial Culture Supernatants Enhances Production of Volatile Compounds and Improves Quality of Agarwood Oil

Incubation with microbial culture supernatants improved essential oil yield from Aquilaria subintegra woodchips. The harvested woodchips were incubated with de man, rogosa and sharpe (MRS) agar, yeast mold (YM) agar medium and six different microbial culture supernatants obtained from Lactobacillus bulgaricus, L. acidophilus, Streptococcus thermophilus, Lactococcus lactis, Saccharomyces carlsbergensis and S. cerevisiae prior to hydrodistillation. Incubation with lactic acid bacteria supernatants provided higher yield of agarwood oil (0.45% w/w) than that obtained from yeast (0.25% w/w), agar media (0.23% w/w) and water (0.22% w/w). The composition of agarwood oil from all media and microbial supernatant incubations was investigated by using gas chromatography-mass spectrometry. Overall, three major volatile profiles were obtained, which corresponded to water soaking (control), as well as, both YM and MRS media, lactic acid bacteria, and yeast supernatant incubations. Sesquiterpenes and their oxygenated derivatives were key components of agarwood oil. Fifty-two volatile components were tentatively identified in all samples. Beta-agarofuran, α-eudesmol, karanone, α-agarofuran and agarospirol were major components present in most of the incubated samples, while S. cerevisiae-incubated A. subintegra provided higher amount of phenyl acetaldehyde. Microbial culture supernatant incubation numerically provided the highest yield of agarwood oil compared to water soaking traditional method, possibly resulting from activity of extracellular enzymes produced by the microbes. Incubation of agarwood with lactic acid bacteria supernatant significantly enhanced oil yields without changing volatile profile/composition of agarwood essential oil, thus this is a promising method for future use.