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ChemInform Abstract: Chemical Constituents of Agarwood Originating from the Endemic Genus Aquilaria Plants
... Recently, the metabolite analysis of agarwood has gained increasing attention as some studies showed that there is correlation of agarwood quality to its resin yield and metabolite constituents (Pasaribu et al., 2015;Liu et al., 2017). Many studies have been conducted to clarify the metabolite composition of agarwood obtained either from wild or artificially induced methods (Chen et al., 2012;Gao X. et al., 2014;Hashim et al., 2014) [24,47] . It was concluded that the composition of agarwood resin is mainly composed of the mixtures of sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) (Naef, 2011;Chen et al., 2012;Subasinghe and Hettiarachchi, 2015) [24,78] . ...
... Recently, the metabolite analysis of agarwood has gained increasing attention as some studies showed that there is correlation of agarwood quality to its resin yield and metabolite constituents (Pasaribu et al., 2015;Liu et al., 2017). Many studies have been conducted to clarify the metabolite composition of agarwood obtained either from wild or artificially induced methods (Chen et al., 2012;Gao X. et al., 2014;Hashim et al., 2014) [24,47] . It was concluded that the composition of agarwood resin is mainly composed of the mixtures of sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) (Naef, 2011;Chen et al., 2012;Subasinghe and Hettiarachchi, 2015) [24,78] . ...
... Many studies have been conducted to clarify the metabolite composition of agarwood obtained either from wild or artificially induced methods (Chen et al., 2012;Gao X. et al., 2014;Hashim et al., 2014) [24,47] . It was concluded that the composition of agarwood resin is mainly composed of the mixtures of sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) (Naef, 2011;Chen et al., 2012;Subasinghe and Hettiarachchi, 2015) [24,78] . Meanwhile, the constituents of agarwood essential oil were shown primarily to be sesquiterpenoids (Fazila and Halim, 2012;Hashim et al., 2014;Jayachandran et al., 2014) [38,47,54] . ...
... Sesquiterpenoids and 2-(2-phenylethyl) chromones (PECs) are the vital constituents in agarwood as they imparts its unique odor to this precious natural product [107][108][109]. Till date, >180 sesquiterpenoids, 200 2-(2-phenyl) chromones and 10 sesquiterpenoid-chromone derivatives has been identified in agarwood [50,51,107]. ...
... Sesquiterpenoids and 2-(2-phenylethyl) chromones (PECs) are the vital constituents in agarwood as they imparts its unique odor to this precious natural product [107][108][109]. Till date, >180 sesquiterpenoids, 200 2-(2-phenyl) chromones and 10 sesquiterpenoid-chromone derivatives has been identified in agarwood [50,51,107]. As per previous reports, the members CYP71AV, CYP71BA, CYP71BL, CYP71D, and CYP71BE are involved in biosynthesis of sesquiterpenoids in a number of plant species including Artemisia annua, Zingiber zerumbet, Helianthus annuus, Hyoscyamus muticus and Catharanthus roseus [110]. ...
... Partners in the pathway are chalcone synthase (CHS), benzalacetone synthase (BAS), polyketide synthase (PKS), flavonoid 3 ′ hydroxylase (F3H), reductases, and cyclases. The hydroxylases (probably by CYPs) and oxygenases (probably by CYPs), O-methyltransferase (OMT) and epoxide hydrolases might be involved in the conversion between the type of phenylethyl chromones i.e., Flindersia type (FTPECs), diepoxy-5,6,7,8-tetrahydro type (DEPECs), mono-epoxy-5,6,7,8-tetrahydro type (EPECs), 5,6,7,8-tetrahydro type (THPECs), dimeric type (DPECs), trimeric type (TPECs) identified in Aquilaria[50,51,107]. B) Biosynthesis of phenolics and derivatives by AaCYP73A1, AaCYP73A2, AaCYP84A1, AaCYP84A2, and AaCYP98A1 through phenylpropanoid pathway. ...
Agarwood is a dark resinous wood, produced when Aquilaria tree responds to wounding and microbial infection resulting in the accumulation of fragrant metabolites. Sesquiterpenoids and 2-(2-phenylethyl) chromones are the major phytochemicals in agarwood and Cytochrome P450s (CYPs) are one of the important enzymes in the biosynthesis of these fragrant chemicals. Thus, understanding the repertoire of CYP superfamily in Aquilaria can not only give insights into the fundamentals of agarwood formation, but can also provide a tool for the overproduction of the aroma chemicals. Therefore, current study was designed to investigate CYPs of an agarwood producing plant, Aquilaria agallocha. We identified 136 CYP genes from A. agallocha genome (AaCYPs) and classified them into 8 clans and 38 families. The promoter regions had stress and hormone-related cis-regulatory elements which indicate their participation in the stress response. Duplication and synteny analysis revealed segmental and tandem duplicated and evolutionary related CYP members in other plants. Potential members involved in the biosynthesis of sesquiterpenoids and phenylpropanoids were identified and found to be upregulated in methyl jasmonate-induced callus and infected Aquilaria trees by real-time quantitative PCR analyses. This study highlights the possible involvement of AaCYPs in agarwood resin development and their complex regulation during stress exposure.
... Sesquiterpene is one of the main compounds in agarwood [13,14] and plays vital roles in plant defence against external stimuli [15,16]. Sesquiterpene is not found in healthy A. sinensis and can only be formed in stems, branches or roots subjected to wounding stress. ...
... Sesquiterpene is not found in healthy A. sinensis and can only be formed in stems, branches or roots subjected to wounding stress. The synthesis of a variety of sesquiterpenoids is induced in wounded A. sinensis [14]. The high content of sesquiterpene and the diversity of their components determine the resin yield and unique fragrance of agarwood to some extent. ...
... The high content of sesquiterpene and the diversity of their components determine the resin yield and unique fragrance of agarwood to some extent. Sesquiterpene has been an important criterion to evaluate agarwood quality [14]. The synthetic efficiency of sesquiterpenoids induced by injury could reflect the capacity of agarwood production in A. sinensis. ...
Background
Agarwood is a valuable Chinese medicinal herb and spice that is produced from wounded Aquilaria spp., is widely used in Southeast Asia and is highly traded on the market. The lack of highly responsive Aquilaria lines has seriously restricted agarwood yield and the development of its industry. In this article, a comparative transcriptome analysis was carried out between ordinary A. sinensis and Chi-Nan germplasm, which is a kind of A. sinensis tree with high agarwood-producing capacity in response to wounding stress, to elucidate the molecular mechanism underlying wounding stress in different A. sinensis germplasm resources and to help identify and breed high agarwood-producing strains.
Results
A total of 2427 and 1153 differentially expressed genes (DEGs) were detected in wounded ordinary A. sinensis and Chi-Nan germplasm compared with the control groups, respectively. KEGG enrichment analysis revealed that genes participating in starch metabolism, secondary metabolism and plant hormone signal transduction might play major roles in the early regulation of wound stress. 86 DEGs related to oxygen metabolism, JA pathway and sesquiterpene biosynthesis were identified. The majority of the expression of these genes was differentially induced between two germplasm resources under wounding stress. 13 candidate genes related to defence and sesquiterpene biosynthesis were obtained by WGCNA. Furthermore, the expression pattern of genes were verified by qRT-PCR. The candidate genes expression levels were higher in Chi-Nan germplasm than that in ordinary A. sinensis during early stage of wounding stress, which may play important roles in regulating high agarwood-producing capacity in Chi-Nan germplasm.
Conclusions
Compared with A. sinensis , Chi-Nan germplasm invoked different biological processes in response to wounding stress. The genes related to defence signals and sesquiterepene biosynthesis pathway were induced to expression differentially between two germplasm resources. A total of 13 candidate genes were identified, which may correlate with high agarwood-producting capacity in Chi-Nan germplasm during the early stage of wounding stress. These genes will contribute to the development of functional molecular markers and the rapid breeding highly of responsive Aquilaria lines.
... Sesquiterpenoids and 2-(2-phenylethyl) chromones (PECs) are the vital constituents in agarwood as they imparts its unique odor to this precious natural product [107][108][109]. Till date, >180 sesquiterpenoids, 200 2-(2-phenyl) chromones and 10 sesquiterpenoid-chromone derivatives has been identified in agarwood [50,51,107]. ...
... Sesquiterpenoids and 2-(2-phenylethyl) chromones (PECs) are the vital constituents in agarwood as they imparts its unique odor to this precious natural product [107][108][109]. Till date, >180 sesquiterpenoids, 200 2-(2-phenyl) chromones and 10 sesquiterpenoid-chromone derivatives has been identified in agarwood [50,51,107]. As per previous reports, the members CYP71AV, CYP71BA, CYP71BL, CYP71D, and CYP71BE are involved in biosynthesis of sesquiterpenoids in a number of plant species including Artemisia annua, Zingiber zerumbet, Helianthus annuus, Hyoscyamus muticus and Catharanthus roseus [110]. ...
... Partners in the pathway are chalcone synthase (CHS), benzalacetone synthase (BAS), polyketide synthase (PKS), flavonoid 3 ′ hydroxylase (F3H), reductases, and cyclases. The hydroxylases (probably by CYPs) and oxygenases (probably by CYPs), O-methyltransferase (OMT) and epoxide hydrolases might be involved in the conversion between the type of phenylethyl chromones i.e., Flindersia type (FTPECs), diepoxy-5,6,7,8-tetrahydro type (DEPECs), mono-epoxy-5,6,7,8-tetrahydro type (EPECs), 5,6,7,8-tetrahydro type (THPECs), dimeric type (DPECs), trimeric type (TPECs) identified in Aquilaria[50,51,107]. B) Biosynthesis of phenolics and derivatives by AaCYP73A1, AaCYP73A2, AaCYP84A1, AaCYP84A2, and AaCYP98A1 through phenylpropanoid pathway. ...
P450 superfamily (CYPs) has been known as contributors to the metabolites's diversity and their promiscuous nature has led to the flexibility in substrate specificity and functional diversity. Current study was designed to investigate CYPs in the genome of an agarwood producing plant species named Aquilaria agallocha. Agarwood, the resinous fragrant wood with numerous phytochemicals, produced when an Aquilaria plant respond to wound and microbial infection. These chemicals are of great interest to industries ascribing it a high economic value. However, the pathways for the biosynthesis of these metabolites have not been studied in context of Aquilaria CYPs. We identified 136 A. agallocha CYP proteins from the genome, characterized and classified them into 8 clans and 38 families. Functional analysis unveiled their participation in terpenoids, phenolics, flavonoids and other valuable metabolites biosynthesis. Conserved motifs were detected and evolutionary analysis revealed duplicated and orthologous pairs. Potential members for the biosynthesis of sesquiterpenoids and phenylpropanoids reported in Aquilaria and agarwood were elucidated and validated through expression profiles in stress induced callus tissues and infected Aquilaria tress. This study provides a strong foundation for biochemical characterization of Aquilaria CYPs which will aid heterologous production of valuable phytochemicals and untangle molecular mechanism of agarwood formation.
... Several aromatic compounds such as benzylacetone were detected in this sample ( Fig. 4 and SI Appendix, Table S3). Compared with the published literature (35)(36)(37)(38)(39)(40)(41), it is confirmed that the chromatographic peaks I to X corresponding to the fraction in 40 to 50 min are 2-(2-phenylethyl)chromones ( Fig. 4 and SI Appendix, Table S4), which are the main active constituents existing in the scented parts of agarwood. Agarwood is the fragrant resinous heartwood from certain trees in the genus Aquilaria within the family Thymelaeaceae, which cannot be formed in healthy wood tissues but may be generated when the Aquilaria plants are injured by insects, physical cuts, chemical stimulation, or bacterial infections, and it is generally believed that high-quality agarwood is that with more resin content and a longer time of aroma formation (36,(42)(43)(44). ...
... Compared with the published literature (35)(36)(37)(38)(39)(40)(41), it is confirmed that the chromatographic peaks I to X corresponding to the fraction in 40 to 50 min are 2-(2-phenylethyl)chromones ( Fig. 4 and SI Appendix, Table S4), which are the main active constituents existing in the scented parts of agarwood. Agarwood is the fragrant resinous heartwood from certain trees in the genus Aquilaria within the family Thymelaeaceae, which cannot be formed in healthy wood tissues but may be generated when the Aquilaria plants are injured by insects, physical cuts, chemical stimulation, or bacterial infections, and it is generally believed that high-quality agarwood is that with more resin content and a longer time of aroma formation (36,(42)(43)(44). Apart from agarwood, 2-(2-phenylethyl)chromone compounds have only been detected in small quantities in Bothriochloa ischemum (45) and Cucumis melo L. var. ...
... Other conditions are the same as above. The compound identification was based on the comparison with NIST library and with published literature (35)(36)(37)(38)(39)(40)(41). ...
Significance
Incense has been linked to ceremonies, religions, medicines, and cosmetics worldwide for thousands of years. While Chinese texts in the Tang dynasty (618 to 907 CE) indicate that numerous exotic aromatic substances were already being introduced into China through the land and maritime Silk Road, this has been rarely demonstrated archaeologically. This study identifies three types of incense associated with the sacred sarira of Sakyamuni Budda from the underground palace of Famen Royal Temple in central China, providing direct evidence of aromatics including elemi, agarwood, and frankincense as well as their composite product, namely Hexiang (blending of aromatics), in Buddhist activities, which may have promoted the spread of incense and the development of aromatic knowledge systems in medieval China.
... Agarwood is composed of 52% sesquiterpenes and 41% 2-(2-phenylethyl)-4H-chromen-4one derivatives (Chen et al. 2012a). These two types of chemical compounds are not found in healthy trees of Aquilaria (Tamuli et al. 2005). ...
... The chemical constituents of agarwood originating from Aquilaria, including agarwood essential oil, feature over 150 compounds (Chen et al. 2012a). Agarwood contains many chemical components and they are diverse, complex and most of them are biologically and pharmacologically active, including neural activity, gastrointestinal regulation, antibacterial, antiinflammation, and cytotoxicity (Wang et al. 2018a). ...
... Sesquiterpenes, 2-(2phenylethyl)-4Hchromen-4-one derivatives, aromatics and triterpenes are the main compounds of agarwood (Kalra & Kaushik 2017, Yang et al. 2019) demonstrated the sedation effect of 8 2-(2phenylethyl)-4Hchromen-4-one derivatives extracted from agarwood. Ueda et al. (2006) isolated a sesquiterpene that can be used as a sedative, and similar results were also reported that 2-(2-[phenylethyl)chromone from agarwood have anticancer activity (Chen et al. 2012a, Liu et al. 2016. Chen et al. (2012a) mentioned that sesquiterpenes and 2-(2-phenylethyl)-4Hchromen-4-one derivatives contribute to the characteristics of resin-infiltrated wood. ...
Agarwood, a precious natural product, can be defined as fragrant dark resinous heartwood of diseased timber of Aquilaria and Gyrinops. Agarwood has been used for thousands of years in several countries as incense, perfumes, and multifunctional pharmaceutical product. The main compounds in agarwood include sesquiterpenes, 2-(2-phenylethyl)-4H-chromen-4-one and its derivatives (PeCs), aromatics, triterpenes and five other categories. Natural agarwood resin production is inefficient and and low yield; thus, it is difficult to meet global demand. Different methods have been implemented to stimulate biological agarwood induction, and the use of endophytic fungi is one of the methods. In this review, we summarize the endophytic fungi and their chemical compounds reported in agarwood.
... It should be noted that many publications have published the species under the synonym Aquilaria agallocha. Major secondary metabolites reported include alkaloids, benzophenones, coumarins, fatty acids, flavonoids, steroids, saponins, tannins, terpenoids, tocopherols, and xanthones (Batubara et al. 2018;Chen et al. 2012;Eissa et al. 2020;Nik Wil et al. 2014;Said et al. 2016). ...
... ,7R,8S)-5,6,7,8-tetrahydro-5,6,7-trihydroxy-4-oxo-2-(2-phenylethyl)-4Hchromen-8-yl]oxy}-4H-chromen-4-one, 7-hydroxy-6-methoxy-2-[2-(4-methoxyphe nyl)ethyl]-4H-1-benzopyran-4-one, 7-(benzyloxy)-5-hydroxy-2-methylchromone, 8,12-epoxyeremophila-9,11(13)-diene, 8βH-dihydrogmelofuran, 9-hydroxyselina-4,11-dien-14-oic acid, 12-deoxy-13-O-acetylphorbol-20-(90Z)-octadecenoate, 12-O-(20E,40E)-6-oxohexa-20,40-dienoylphorbol-13-acetate, 12-O-(20E,40E)-60, 70-(erythro)-dihydroxytetradeca-20,40-dienoylphorbol-13-acetate, 12-O-(20E,40 E)-60,70-(threo)-dihydroxytetradeca-20,40-dienoylphorbol-13-acetate, 24(4R,5R, 7R)-11-hydroxyspirovetiv-1(10)-en-2-one, (2-hydroxyphenyl)ethyl]-4H-chromen-4-one, 5α,6β,7β,8α-tetraacetoxy-5,6,7,8-tetrahydro-2-[2-(4-methoxyphenyl)ethyl)]-4H-chromen-4-one, (2R,3S)-2,3-dimethyl-2-(3-methylbut-2-en-1-yl)-cyclohexanone, (2R,4aS)-1,2,3,4,4a,5,6,7-octahydro-4amethyl-2-(1-methylethenyl)-naphthalene, (3R,5aR,9S,9aS)-Octahydro-2,2,5a-trimethyl-2H-3,9a-methano-1-benzoxepi ne-9-carbaldehyde, (3R,5aS,9aR)-octahydro-2,2,5a-trimethyl-2H-3,9a-methano-1benzoxepine, (3R,5aS,9R,9aR)-octahydro-2,2,5a-trimethyl-2H-3,9a-methano-1-benzoxepin-9-ol, (4aS)-1,2,3,4,4a,5,6,7-octahydro-4a-methyl-2-(1-methylethylidene) naphthalene, (5S,6R,7S,8R,7'R)-hydroxyisoagarotetrol, (5S,6R,7S,8R,7'S)-hydroxyisoagarotetrol, (5R,6R,7S,8R)-5,6,7,8-tetrahydro-5,6,7,8-tetrahydroxy-2-(2-phenylethyl)-4H-chromen-4-one, (5S,6S,7R)-5,6,7-triacetoxy-2-[2-(2-acetoxyphenyl) ethyl]-5,6,7,8-tetrahydro-4H-chromen-4-one, and (8aS)-1,2,3,7,8,8a-hexahydro-8amethyl-6-(1-ethylethyl)naphthalene (Ahmaed and Kulkarni 2017;Chen et al. 2012;Hashim et al. 2014;Hoon 2014;Liu et al. 2018;Ma et al. 2017;Nasution et al. 2019;Senarath et al. 2016;Wagh et al. 2017;Wang et al. 2018;Wu et al. 2012). The shoot also contain cucurbitacin (Chen et al. 2014). ...
... Available reports of bioactivities include the ability to affect the central nervous systems by acting as anesthetic, sedative, and sleep inducer. Other activities including analgesic, antibacterial, anticonvulsant, antidiabetic, antifungal, antihistamine, antinociceptive, antioxidant, antiulcer, antitumor, antimicrobial, anxiolytic, hepatoprotective, and laxative have also been reported (Adam et al. 2017;Alam et al. 2015Alam et al. , 2017Chen et al. 2012;Hashim et al. 2016;Okugawa et al. 1993;Takemoto et al. 2008). Antimicrobial: The roots have antimicrobial properties. ...
... In agarwood extracts, sesquiterpenes and 2-(2-phenylethyl)chromones, as the predominant components, show various pharmacological activities, such as antibacterial, antifungal, and anti-inflammatory properties [4]. Additionally, the content and concentration of sesquiterpenes can be the criteria to evaluate the quality of agarwood [4,5]. Increasing attention has been paid recently to methods that induce agarwood formation [6][7][8][9]. ...
... Sesquiterpenes are the important components of agarwood, and their content could be used to judge the agarwood quality [4,5]. Terpenes are biosynthesized in plants from the two pathways, the mevalonic acid pathway (MVA pathway) in the cytoplasm, and methylerythritol 4-phosphate pathways (MEP pathway) in the plastids [61]. ...
Plants respond to wounding by reprogramming the expression of genes involved in secondary metabolism. Aquilaria trees produce many bioactive secondary metabolites in response to wounding, but the regulatory mechanism of agarwood formation in the early response to mechanical wounding has remained unclear. To gain insights into the process of transcriptome changes and to determine the regulatory networks of Aquilaria sinensis to an early response (15 days) to mechanical wounding, we collected A. sinensis samples from the untreated (Asc1) and treated (Asf1) xylem tissues and performed RNA sequencing (RNA-seq). This generated 49,102,523 (Asc1) and 45,180,981 (Asf1) clean reads, which corresponded to 18,927 (Asc1) and 19,258 (Asf1) genes, respectively. A total of 1596 differentially expressed genes (DEGs) were detected in Asf1 vs. Asc1 (|log2 (fold change)| ≥ 1, Padj ≤ 0.05), of which 1088 were up-regulated and 508 genes were down-regulated. GO and KEGG enrichment analysis of DEGs showed that flavonoid biosynthesis, phenylpropanoid biosynthesis, and sesquiterpenoid and triterpenoid biosynthesis pathways might play important roles in wound-induced agarwood formation. Based on the transcription factor (TF)-gene regulatory network analysis, we inferred that the bHLH TF family could regulate all DEGs encoding for farnesyl diphosphate synthase, sesquiterpene synthase, and 1-deoxy-D-xylulose-5-phosphate synthase (DXS), which contribute to the biosynthesis and accumulation of agarwood sesquiterpenes. This study provides insight into the molecular mechanism regulating agarwood formation in A. sinensis, and will be helpful in selecting candidate genes for improving the yield and quality of agarwood.
... (2) 인도네시아산 침향의 향기성분 특성 (시료 2) (Yoneda et al., 1983), B (Shin et al., 2011), C (Ismail et al., 2015), D (Pripdeevech et al., 2011), E (Chen et al., 2012), and F (Ishihara et al., 1993). (Shin et al., 2011;Yoneda et al., 1984). ...
... Ref. : A(Yoneda et al., 1983), B(Shin et al., 2011), C(Ismail et al., 2015), D(Pripdeevech et al., 2011), E(Chen et al., 2012), and F(Ishihara et al., 1993).http://www.e-ajbc.org 하였다(Figure 1 ...
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.
... Eighty-three pathways were related to the set of genes with increased transcript abundances. Six of the most significantly enriched pathways (Table S5) corresponded to phenylpropanoid biosynthesis (19), plant-pathogen interaction (18), MAPK-signaling pathway (15), biosynthesis of amino acids (15), carbon metabolism (14), and plant hormone signal transduction (12). Similarly, forty-three pathways were annotated for genes with decreased transcript abundances. ...
... In addition, the SAR1A (secretion-associated Ras-related GTPase 1A) and SAR1B, were increased in abundance. The SCL14 (scarecrow-like protein 14), which functions in activating stress-induced promoters, was increased in abundance. Additionally, the transcript abundance of the members of the homeobox family, ATHB-12 (Arabidopsis thaliana homeobox 12) and WOX4 (WUSCHEL-related homeobox 4), which act as regulators of plant growth, were increased. ...
Plants repair their mechanical wounds by reprogramming secondary metabolism. However, which genes are reprogrammed during this repair process in Aquilaria sinensis has rarely been studied. Here, we used high-throughput RNA sequencing to explore the changes in the transcriptome of Aquilaria’s xylem, six months after the stem was subjected to mechanical wounding. In total, 1165 transcripts were differentially accumulated, of which 1002 transcripts were increased and 163 were decreased in their abundances (|log2 (fold change)| ≥ 1 and FDR ≤ 0.05). The majority of these genes encode products involved in plant secondary metabolism, transcription regulation, and phytohormone metabolism and signaling. The up-regulated genes were classified into 15 significantly enriched GO terms and were involved in 83 pathways, whereas the down-regulated genes were classified into 5 significantly enriched GO terms and represented 43 pathways. Gene annotation demonstrated that 100 transcripts could encode transcription factors (TFs), such as WRKY, AP2, MYB, and Helix-loop-helix (HLH) TFs. We inferred that the differential expression of TFs, genes associated with plant hormones, phenylpropanoid biosynthesis, and sesquiterpenoid biosynthesis may contribute to the repair of the stem after mechanical wounding in A. sinensis. Using co-expression analysis and prediction of TF binding sites, a TF–gene regulatory network for Aquilaria lignin biosynthesis was constructed. This included the MYB, HLH, WRKY, and AP2 TFs, and the COMT1, 4CLL7, and CCR1 genes. The changes in 10 candidate genes were validated by quantitative reverse-transcription PCR, indicating significant differences between the treated and untreated areas. Our study provides global gene expression patterns under mechanical wounding and would be valuable to further studies on the molecular mechanisms of plant repair in A. sinensis.
... Hence, it is of great interest to unveil the molecular mechanism to thereby artificially manipulate the process of agarwood formation. It has been demonstrated that the formation of agarwood is characteristically accompanied by the synthesis and accumulation of sesquiterpenoids and 2-(2-phenylethyl)chromones (PECs), which are the principal constituents contributing to the important biological activities and the pleasant fragrance of agarwood [14][15][16][17] . To decipher the molecular mechanism of agarwood formation, great efforts have been made in the past decade to explore the biosynthesis of these two classes of chemicals in agarwood. ...
... PECs are a subgroup of chromones that characteristically bear a phenylethyl group at the C-2 position. Since the first natural PEC, flindersiachromone, was elucidated in 1976 25 , nearly 250 PECs have been isolated exclusively from agarwood [14][15][16][17][26][27][28][29] . In the Chinese pharmacopeia, PECs were legally assigned as diagnostic constituents for evaluating the quality of agarwood. ...
2-(2-Phenylethyl)chromones (PECs) are the principal constituents contributing to the distinctive fragrance of agarwood. How PECs are biosynthesized is currently unknown. In this work, we describe a diarylpentanoid-producing polyketide synthase (PECPS) identified from Aquilaria sinensis . Through biotransformation experiments using fluorine-labeled substrate, transient expression of PECPS in Nicotiana benthamiana , and knockdown of PECPS expression in A. sinensis calli, we demonstrate that the C 6 –C 5 –C 6 scaffold of diarylpentanoid is the common precursor of PECs, and PECPS plays a crucial role in PECs biosynthesis. Crystal structure (1.98 Å) analyses and site-directed mutagenesis reveal that, due to its small active site cavity (247 Å ³ ), PECPS employs a one-pot formation mechanism including a “diketide-CoA intermediate-released” step for the formation of the C 6 –C 5 –C 6 scaffold. The identification of PECPS, the pivotal enzyme of PECs biosynthesis, provides insight into not only the feasibility of overproduction of pharmaceutically important PECs using metabolic engineering approaches, but also further exploration of how agarwood is formed.
... Sukkaew et al. [36] isolated and identified volatile compounds from agarwood by GC-MS. Yang et al. [37] isolated and identified a monoterpene derivative [(-)-bornyl ferulate]. According to the chemical structure, sesquiterpenes isolated from agarwood are divided into different categories including agarofurans, eudesmanes, eremophilanes, guaianes, agarospirols, and cadinanes [38,39]. ...
... Tian and Haigang [45] used petroleum ether and ethanol to extract 10 diterpenoids from agarwood. (-)-bornyl ferulate [37] Steriods Some steroids, such as β-sitosterol and 12 flavonoids, were isolated [48]. ...
Agarwood is a highly valuable fragrant wood of Aquilaria spp. (Thymelaeaceae) which has been widely utilized in traditional medicine, religious rites, and cultural activities. This study sum-marizes a review on the identification of Aquilaria cultivars, volatile and non-volatile phyto-chemicals, pharmacological uses, and agarwood grading system to determine its quality, and different agarwood induction methods. Due to the highly demanding and depleted natural re-sources, the research on agarwood is still insufficient, and it has broad research and develop-ment prospects in many industries. However, due to the significant scientific nature of agar-wood application, developing high-quality products and drugs from agarwood have become highly important, while no one has discussed in detail the phytochemicals uses and provided a summary until now. The main phytochemicals of agarwood include terpenoids, dominated by sesquiterpenes. For centuries, terpenoids have been used in traditional Chinese medicine and have been shown to possess various pharmacological properties, including bacteriostatic, anti-bacterial, sedation, analgesia, anti-inflammation, anti-asthmatic, hypoglycemic, antidepressant, and many others. Alongside biological activity screening, phytochemical advances and phar-macological research have also made certain progress. Therefore, this review discusses the re-search progress of agarwood in recent years and provides a reference basis for further study of Aquilaria plants and agarwood.
... It is obtained by distillation and is the most principal ingredient for premium perfumes due to its unique fragrance and long-lasting odor. Several studies have been previously conducted to determine AEO qualities (Ismail et al., 2014), to enhance AEO yield by several pretreatments (Yoswathana et al., 2012), and to investigate its phytochemical constituents and their bioactive properties (Abdullah et al., 2007;Ahmaed et al., 2017;Azah et al., 2008;Chen et al., 2012;Dahham et al., 2015;Hashim et al., 2014;Hoque et al., 2018;Ibrahim et al., 2011;Ismail et al., 2014;Radzi et al., 2018;Tajuddin and Yusoff, 2010;Thuy et al., 2019;Wang et al., 2018;Zhang et al., 2014a). On the contrary, there is no record of the study on AEO originating from decaying logs (Gyrinops spp.). ...
... In all AEO assays from different sources, 63 compounds could be identified and 58 of them were found in M1 AEO. All of the detected compounds were commonly found in agarwood from different qualities and sources (Ahmaed and Kulkarni, 2017; Chen et al., 2012;Naef, 2011;Thuy et al., 2019;Wetwitayaklung et al., 2009;Yusoff et al., 2015). ...
... The original agarwood plants are Aquilaria sinensis, A. malaccensis, and A. agallocha, which belong to the family Thymelaeaceae, and the heartwood of their wood or root is used as agarwood. The principal components of agarwood are 2-(2-phenylethyl) chromones (PECs) [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The PEC monomers are structurally classified into three types, flindersiachromones (FDC), oxidoagarochromones (OAC), and agarotetrolchromones (ATC), and these monomers, as well as their dimers and trimers, and the hybrid types combined with sesquiterpenes, have been identified as the aromatic components of agarwood (Fig. 1). ...
Agarwood has been valued as an exquisite, high-grade fragrant wood since ancient times. Due to the scarcity of high-quality agarwood, it is quite expensive, and the number of original plants has been drastically reduced due to overharvesting, including illegal logging. Despite this, a reliable method of agarwood cultivation has yet to be developed. Thus, identifying the biosynthetic pathways of the fragrant components in agarwood might help developers to optimize the culture conditions and create artificial agarwood, by monitoring the expression of the biosynthetic enzymes or their genes. This review presents the characteristics of our recently identified key enzyme, 2-(2-phenylethyl)chromone precursor synthase (PECPS), which generates the common precursor of 2-(2-phenylethyl)chromones (PECs), the main fragrances in agarwood, as well as our reasoning to reach these conclusions. We also discuss the biosynthetic pathway of PECs, unveiled following the identification of PECPS.
... The agarwood oil is composed of more than 300 chemical compounds Naef (2011), Chen et al. (2012), Wang et al. (2018). The chemical contituents are extracted by a series of steam distillation process. ...
Agarwood is a highly valuable fragrant wood of Aquilaria spp. It is used for incense, perfume, traditional medicine, and other products in all over the world. The chemical constitutes of agarwood include 2-(2-phenylethyl)-4H-chromen-4-one derivatives, terpenoids (sesquiterpenes), flavonoids etc.The aromatic properties and resin character of agarwood are influence by the species, geographical distribution. This review emphasizes the mass cultivation of Aquilaria tree. Mass cultivation by various induction technologies which serve as a sustainable source to obtain agarwood is necessary in order to increase agarwood supply in the global market.
... Several reviews have compiled the agarwood chemical constituents identified from various Aquilaria species revealing the complexity of the chemical constituent of the resin [10][11][12]. All authors agreed that sesquiterpenes and 2-(2-phenylethyl)-4H-chromen-4one (chromones) derivatives are agarwood's predominant constituents. ...
Agarwood is a resinous wood of great economic value produced by trees from the Thymelaeaceae family in response to stress. The natural formation of agarwood can take decades after exposure to the stressors. Artificial agarwood induction by inoculating the stem with fungi has been successfully demonstrated, but resin accumulation occurs very slowly. Cell suspension and callus cultures may serve as an alternative solution to provide a fast-growing plant material to produce artificial agarwood in a short period. Here, we induced agarwood formation in callus cultures of Aquilaria malaccensis by application of crude mycelial extracts of Fusarium solani strains GSL1 or GSL2, or methyl jasmonate (MeJA). After 20 days of treatment with elicitors, all treated calluses had less dry weight than the control group. The gas chromatography–mass spectrometry analysis identified 33 different secondary metabolites among all samples, four of which were present in all treatments and control, i.e., 1-docosene and 1-octadecene (alkenes), 4-di-tert-buthylphenol (phenolic), and benzenepropanoic acid (fatty acid). The 6-methoxy-2-(4-methoxyphenethyl)-4H-chromene-4-one, a chromone derivative, was only detected in callus elicited with the F. solani strain GSL2 and MeJA. All treated calli produced more fatty acid derivatives than the control group. We conclude that elicitors used in this study can induce the production of agarwood-related chemicals such as chromone and fatty acid in callus culture.
... Studies have shown that the specific leaf weight has a certain relationship with the plant's resistance to stress [23], and agarwood is the resin-shaped heartwood formed when agarwood plants are subjected to external stress. Agarwood formation is a stress-resistant process [24]. A larger specific leaf weight represents a better leaf water retention capacity, higher dry matter accumulation and photosynthetic efficiency, and is a result of stronger stress resistance and higher agarwood production. ...
Agarwood is the dark resinous heartwood of injured ordinary Aquilaria sinensis (OA). Recently, some new clones of A. sinensis (Qi-Nan) that intensively produce high-quality agarwood were selected and cultivated by grafted clonal seedlings. However, very little is known about their agarwood formation mechanism, and it is unclear whether the current method of distinguishing Qi-Nan from OA by observing its leaf apparent morphology is scientifically reliable. In this study, the differences between OA and Qi-Nan clones in agarwood formation and their correlation with morphological, anatomical and physiological characteristics were investigated in two types of A. sinensis trees. After the mechanical injury, agarwood yield and essential oil content in agarwood of Qi-Nan were significantly higher than that of OA. There was no significant difference in leaf shape parameters between Qi-Nan and OA, but Qi-Nan showed higher specific leaf weight, total leaf chlorophyll, leaf nitrogen content and net photosynthetic rate. A xylem anatomical analysis showed that Qi-Nan had significantly smaller vessel wall thickness, greater ray cell wall thickness and larger interxylary phloem area than OA. Moreover, Qi-Nan had a greater consumption of non-structural carbohydrates than OA. Agarwood yield and oil content in agarwood showed significantly positive correlations with leaf photosynthetic capacity, the wall thickness of xylem ray cell, interxylary phloem area, starch utilization rate of trees, and a significantly negative correlation with the wall thickness of xylem vessel of trees. In brief, Qi-Nan has a stronger photosynthetic basis to supply more carbon sources, a more efficient xylem structural basis for agarwood production and a higher carbon source utilization rate, leading to a higher agarwood yield and oil content. It is not reliable to distinguish Qi-Nan from OA simply by observing leaf apparent morphology.
... The main fragrant compounds in agarwood are sesquiterpenes and phenylethyl chromone derivatives, but the sesquiterpenes are more abundant and provide aromatic qualities suitable for perfumes (Ogita et al. 2015;Kristanti et al. 2018). Agarwood contains at least 210 sesquiterpenes, which vary in the type of skeletons, including eudesmanes, eremophilanes, guaianes, agarospiranes, acoranes, cadinanes, prezizaanes, zizaanes and humulanes (Chen et al. 2012;Gao et al. 2019;Li et al. 2021b). Terpene synthases (TPSs) are the key enzymes for the biosynthesis of terpenes, including sesquiterpenes. ...
Sesquiterpenes are the major pharmacodynamic components of agarwood, a precious traditional Chinese medicine obtained from the resinous portions of Aquilaria sinensis trees that form in response to environmental stressors. To characterize the sesquiterpene synthases responsible for sesquiterpene production in A. sinensis , a bioinformatics analysis of the genome of A. sinensis identified six new terpene synthase genes, and 16 sesquiterpene synthase genes were identified as type TPS-a in a phylogenetic analysis. The expression patterns for eight of the sesquiterpene synthase genes after treatment with various hormones or hydrogen peroxide were analyzed by real-time quantitative PCR. The results suggest that 100 μM methyl jasmonate, ethephon, ( ±)-abscisic acid or hydrogen peroxide could be effective short-term effectors to increase the expression of sesquiterpene synthase genes, while 1 mM methyl salicylate may have long-term effects on increasing the expression of specific sesquiterpene synthase genes (e.g., As-SesTPS , AsVS , AsTPS12 and AsTPS29 ). The expression changes in these genes under various conditions reflected their specific roles during abiotic or biotic stresses. Heterologous expression of a novel A. sinensis sesquiterpene synthase gene, AsTPS2 , in Escherichia coli produced a major humulene product, so AsTPS2 is renamed AsHS1 . AsHS1 is different from ASS1, AsSesTPS, and AsVS, for mainly producing α -humulene. Based on the predicted space conformation of the AsHS1 model, the small ligand molecule may bind to the free amino acid by hydrogen bonding for the catalytic function of the enzyme, while the substrate farnesyl diphosphate (FPP) probably binds to the free amino acid on one side of the RxR motif. Arg450, Asp453, Asp454, Thr457, and Glu461 from the NSE/DTE motif and D307 and D311 from the DDxxD motif were found to form a polar interaction with two Mg ²⁺ clusters by docking. The Mg ²⁺ -bound DDxxD and NSE/DTE motifs and the free RXR motif are jointly directed into the catalytic pocket of AsHS1. Comparison of the tertiary structural models of AsHS1 with ASS1 showed that they differed in structures in several positions, such as surrounding the secondary catalytic pocket, which may lead to differences in catalytic products. Based on the results, biosynthetic pathways for specific sesquiterpenes such as α- humulene in A. sinensis are proposed. This study provides novel insights into the functions of the sesquiterpene synthases of A. sinensis and enriches knowledge on agarwood formation.
... These studies came out with a huge number of compounds many of which have proven multiple types of actions on live cells as well as on laboratory animals. The two major components found in agarwood-producing trees are sesquiterpenes and chromones among others such as aromatics, phenols, and triterpenes [98]. ...
The inflammatory response is a central aspect of the human immune system that acts as a defense mechanism to protect the body against infections and injuries. A dysregulated inflammatory response is a major health concern, as it can disrupt homeostasis and lead to a plethora of chronic inflammatory conditions. These chronic inflammatory diseases are one of the major causes of morbidity and mortality worldwide and the need for them to be managed in the long term has become a crucial task to alleviate symptoms and improve patients’ overall quality of life. Although various synthetic anti-inflammatory agents have been developed to date, these medications are associated with several adverse effects that have led to poor therapeutic outcomes. The hunt for novel alternatives to modulate underlying chronic inflammatory processes has unveiled nature to be a plentiful source. One such example is agarwood, which is a valuable resinous wood from the trees of Aquilaria spp. Agarwood has been widely utilized for medicinal purposes since ancient times due to its ability to relieve pain, asthmatic symptoms, and arrest vomiting. In terms of inflammation, the major constituent of agarwood, agarwood oil, has been shown to possess multiple bioactive compounds that can regulate molecular mechanisms of chronic inflammation, thereby producing a multitude of pharmacological functions for treating various inflammatory disorders. As such, agarwood oil presents great potential to be developed as a novel anti-inflammatory therapeutic to overcome the drawbacks of existing therapies and improve treatment outcomes. In this review, we have summarized the current literature on agarwood and its bioactive components and have highlighted the potential roles of agarwood oil in treating various chronic inflammatory diseases.
... Agarwood is a highly valuable, fragrant, and dark resinous heartwood of trees in the family Thymelaeaceae [1][2][3][4]. Agarwood is also known under different names in different regions, including agar (Hindi), akil (Tamil), aloe wood (Indonesian), chen xiang (Chinese), chim-hyuang (Korean), eaglewood (Papua New Guinea), gaharu (Malaysian), jin-koh (Japanese), mai ketsana (Lao), mai kritsana (Thai), oud (Arabic), oud or agar attar (Middle Eastern), sasi or sashi (Assamese), and tramhuong (Vietnamese) [5][6][7]. The plants in the family Thymelaeaceae, especially the genera Aquilaria and Gyrinops, are well known for agarwood production, and these are grown in several countries in Southeast Asia (e.g., Borneo, Cambodia, China, India, Indonesia, Laos, Malaysia, New Guinea, Thailand, Philippines, and Vietnam) [2,3,8,9]. ...
Agarwood is a fragrant dark resin produced in plants belonging to the family Thyme-laeaceae and which has a high economic value. The unique fragrance and medicinal applications intensify the value of agarwood. The wild populations of agarwood trees are highly threatened by high economic demand. Therefore, it is worthwhile to develop an artificial agarwood induction technology for the countries that rely on agarwood from the natural habitat of the plants. Fungal induction of agarwood has been shown to be an efficient method. Interestingly, most of the fungi known from agarwood are endophytic. In this paper, we supplement and update the bioactivity of fungi associated with agarwood and their ability to induce agarwood formation. According to the existing literature, 59 endophytic fungal strains of 16 genera induce agarwood production, most of which belong to Fusarium (28 identified strains). Hence, Fusarium is a good candidate for further studies on fungal induced agarwood production.
... and Gyrinops reported that only 7-10% of tree contains agarwood, which sesquiterpenes and 2-(2-phenylethyl)-4H-chromen-4-one was the major chemical constituent (Naef, 2011;Chen et al., 2012). Although terpenoids have been found in the host plant (agarwood) as well as on the potential endophytic fungi in this study, the relationship between them are still unclear; whether it is mutualistic, symbiotic, antagonistic, or slightly pathogenic. ...
... Agarwood is a resinous material mainly produced from heartwood of various Aquilaria and Gyrinops species of the family Thymelaeaceae. 1,2 It is distributed in the areas ranging from India eastwards throughout Southeast Asia, as well as in southern China including Guangdong, Guangxi, Hainan and Fujian. 3 Interestingly, agarwood is hardly formed in the normal tree, while infected by fungi or naturally wounded such as wind, lightning strikes and the gnawing of ants to the tree may stimulate the accumulation of resin. ...
Background:
Agarwood, as a traditional Chinese medicine, has great potential value for the treatment of tranquilization. However, its potential mechanisms and biomarkers are still unclear.
Methods:
In this study, ultra-high performance liquid chromatography-quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS)-based metabonomics was adopted to discover the potential biomarkers in mice after agarwood incense smoke (AIS) intervention. Furthermore, the chemical components in agarwood were identified based on UHPLC-Q-Exactive Orbitrap-MS. The global view of potential compound-target-pathway (C-T-B) network was constructed through network pharmacology to understand the potentially material basis of biomarkers.
Results:
Metabolic profiling indicated that the metabolic changed significantly in mice serum after AIS intervention. A total of 18 potential biomarkers closely related to insomnia and emotional disease were identified, mainly involving in tryptophan metabolism, arginine and proline metabolism, cysteine and methionine metabolism and steroid hormone biosynthesis pathways. A total of 138 components in agarwood were identified based on UHPLC-Q-Exactive Orbitrap-MS. The results showed that mainly compounds such as flidersia type 2-(2-phenylethyl) chromones (FTPECs) and sesquiterpenes exerted good docking abilities with key target proteins, which were involved in multiple diseases including depression and hypnosis.
Conclusion:
In conclusion, this study enhanced current understanding of the change of metabolic markers after AIS intervention. Meanwhile, it also confirmed the feasibility of combining metabolomics and network pharmacology to identify active components and elucidate the material basis of biomarkers and mechanisms.
... A number of previous studies reported that 2-(2-phenylethyl) chromones and derivates are key components in agarwood formation and quality [29,[40][41][42][43]. For a practical genetic improvement, it has been shown that 2-(2-phenylethyl) chromones and derivates were the key biomarkers for agarwood formation in A. sinensis [8]. ...
Background
Agarwood is a highly sought-after resinous wood for uses in medicine, incense, and perfume production. To overcome challenges associated with agarwood production in Aquilaria sinensis , several artificial agarwood-induction treatments have been developed. However, the effects of these techniques on the metabolome of the treated wood samples are unknown. Therefore, the present study was conducted to evaluate the effects of four treatments: fire drill treatment (F), fire drill + brine treatment (FS), cold drill treatment (D) and cold drill + brine treatment (DS)) on ethanol-extracted oil content and metabolome profiles of treated wood samples from A. sinensis .
Results
The ethanol-extracted oil content obtained from the four treatments differed significantly (F < D < DS < FS). A total of 712 metabolites composed mostly of alkaloids, amino acids and derivatives, flavonoids, lipids, phenolic acids, organic acids, nucleotides and derivatives, and terpenoids were detected. In pairwise comparisons, 302, 155, 271 and 363 differentially accumulated metabolites (DAM) were detected in F_vs_FS, D_vs_DS, F_vs_D and FS_vs_DS, respectively. The DAMs were enriched in flavonoid/flavone and flavonol biosynthesis, sesquiterpenoid and triterpenoid biosynthesis. Generally, addition of brine to either fire or cold drill treatments reduced the abundance of most of the metabolites.
Conclusion
The results from this study offer valuable insights into synthetically-induced agarwood production in A. sinensis .
... Results of the analysis on chemical composition are presented in Table 1. Chemical composition of agarwood extracts was characterized by mainly the compounds of sesquiterpene group and of chromone derivative group [5,14]. The presence of sesquiterpene compounds as contained in agarwood resins could bring about their sweet-smelling smell aroma. ...
This research aimed to study about chemical composition and anti-cancer activities of natural agarwood and cultivated agarwood ( Gyrinops vertegii [Gilg.] Domke). Agarwood used in the research was of lowest qualities, which comprised agarwood with natural kemedangan type (A), with cultivated kemedangan-I type (B1), and with cultivated kemedangan-II type (B2), all after methanol extraction. Chemical composition was examined using GC-MS instrument, meanwhile tests on lungs associated anticancer activities (A549’s cancer cells) were performed using MTT method. Chemical composition in low-quality agarwoods was predominantly sesquiterpene compounds, comprising among others guaiacol, cumene, aromadendrene, aplha-humulene, velleral, etc; and conservely did not contain chromone derivative compounds which are compounds characterizing quality agarwood. Low-quality agarwood extracts afforded efficacious potency as anticancer actions against A549’s lungs-attacking cancer cells with IC 50 values at 144.92 µgmL ⁻¹ (A); IC 50 at 206.88 µgmL ⁻¹ (B1), and IC 50 187.97 µgmL ⁻¹ (B2).
... Agarwood is a famous traditional Chinese medicine that has been used for more than a thousand years for the treatment of various diseases; especially in the treatment of gastrointestinal diseases have better curative effect [2,3]. It has been shown that sesquiterpenes and 2-(2-phenylethyl)chromone derivatives are two predominant constituents of agarwood [4,5]. Our previous study showed that the components of WTAAE included sesquiterpenes (10.615%), chromone (31.678%), aromatics (31.831%), and other known compounds (25.760%) and also showed that sesquiterpenes and chromone are two predominant constituents of agarwood [6]. ...
Background:
Agarwood has been used for centuries, especially for treatment of gastrointestinal diseases. Earlier studies of our laboratory suggested that agarwood alcohol extracts (AAEs) provided gastric mucosal protection. This study aims to investigate the ameliorative effect of AAEs on ethanol-induced gastric ulcers and its mechanism.
Methods:
Mice were given agarwood induced by the whole-tree agarwood-inducing technique alcohol extract (WTAAE, 0.71, 1.42, and 2.84 g/kg), wild agarwood induced by axe wounds alcohol extract (WAAE, 2.84 g/kg), and burning-chisel-drilling agarwood alcohol extract (FBAAE, 2.84 g/kg) orally, respectively. After 7 days' pretreatment with AAEs, the gastric ulcers were induced by absolute ethanol. The ulcer index, gastric histopathology, biochemical parameters, and inflammatory proteins were evaluated.
Results:
Pharmacological results showed AAEs (1.42 and 2.84 g/kg) reduced the gastric occurrence and ulcer inhibition rates up to more than 60%. AAEs decreased the level of nitric oxide (NO) and increased glutathione (GSH) and superoxide dismutase (SOD) levels. Besides, AAEs decreased the levels of interleukin-1β (IL-1β) and interleukin-6 (IL-6), but the interleukin-10 (IL-10) was upregulated. The expressions of nuclear factor kappa B (NF-κB) and phosphorylated protein 38 (p-P38) were inhibited. The effect of WTAAE was better than that of FBAAE and similar to that of WAAE at the dose of 2.84 g/kg.
Conclusions:
These results demonstrate that agarwood alleviates the occurrence and development of gastric ulcers via inhibiting oxidation and inflammation.
... The localized of resin accumulation due to the continuously induction mechanism caused by the slow release system (Fig. 5). Agarwood oil is a complex mixture of aromatic terpene compounds included monoterpenes, sesquiterpenes and diterpenes (Naef, 2011;Chen et al., 2012). The main compounds present in agarwood oil have been identified as the sesquiterpenes. ...
Agarwood is a type of resin impregnated wood produced from the wounded Aquilaria trees. This agarwood gives a pleasant fragrant when it is burned. It becomes high-priced and increase demanded in the world due to the depletion of wild agarwood in the forest caused by illegal poaching activities. Agarwood resin can only be produced by injuring caused by lightning or wounded by animals under natural conditions. However, the natural process of resin accumulation is uncertain and time-consuming. Therefore, we developed an agarwood inducement technique that served as the alternative way to induce the agarwood formation in a short time. Three inducement techniques, including the injecting method, knocking method and combination of injecting & knocking method were applied to induce resin formation. In this study, we evaluated the technique for producing agarwood in species Aquilaria beccariana, which is native and only can be found in Borneo Malaysia. For A. beccariana trees treated with the inducement technique, resin formed and spread throughout the cell in the trunk. The evaluation results showed that the agarwood yield per tree reached around 5 to 7 kilogram. Furthermore, this agarwood derived from the induction was found to have a similar quality with the wild agarwood. This indicates the inducement technology had successfully produced agarwood resin in A. beccariana with a grade similar to the wild agarwood.
... Agarwood is resinous wood obtained from wounded Aquilaria tree, which is a genus belonging taxonomically to the ymelaeaceae family [1]. e main constituents in agarwood are volatile constituents and semi-volatile components [2]. ...
Wild Chi-Nan agarwood is regarded as the highest quality agarwood from Aquilaria spp. However, the comprehensive research on chemical composition of wild Chi-Nan agarwood is limited. An integrated strategy using SHS-GC-MS and UPLC-Q/Tof-MS was applied to explore the phytochemical characteristics of a kind of agarwood induced from a newly identified germplasm of Chi-Nan A. sinensis. Progenesis QI and MS-Dial were used to preprocess the UPLC-Q/Tof-MS and GC-MS raw data, respectively. Principle component analysis (PCA) and orthogonal partial least squares to latent structure-discriminant analysis (OPLS-DA) models were built to discriminate Chi-Nan agarwood from ordinary agarwood and to screen potential distinguishing components between them. In this study, we clarified the distinguishing differences between Chi-Nan agarwood and ordinary agarwood. The difference is mainly manifested in the average contents of 2-(2-phenylethyl)chromone and 2-[2-(4′-methoxybenzene)ethyl]chromone, which are 170 and 420 times higher in Chi-Nan agarwood than in ordinary agarwood, respectively, while the contents of 5,6,7,8-diepoxy-2-(2-phenylethyl)chromones(DEPECs), 5,6-epoxy-2-(2-phenylethyl)chromones(EPECs), and 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones(THPECs) such as agarotetrol are extremely low. The content of the main sesquiterpenes in Chi-Nan agarwood was higher than that in ordinary agarwood, especially in regard to guaiane and eudesmane derivatives. In addition, there were significant differences in the contents of low-molecular-weight aromatic compounds such as 2-methyl-4H-1-benzopyran-4-one, 4-methoxybenzaldehyde, and 2-hydroxybenzaldehyde between Chi-Nan agarwood and ordinary agarwood. All the mentioned main chemical characteristics of this new Chi-Nan agarwood were coincident with those of the rare wild Chi-Nan agarwood from A. malaccensis, A. sinensis, and A. crassna. We reported differences in 2-(2-phenylethyl)chromones, sesquiterpenes, and low-molecular-weight aromatic compounds between Chi-Nan agarwood and ordinary agarwood from A. sinensis for the first time; it is necessary to evaluate the agarwood from the new-found Chi-Nan germplasm.
1. Introduction
Agarwood is resinous wood obtained from wounded Aquilaria tree, which is a genus belonging taxonomically to the Thymelaeaceae family [1]. The main constituents in agarwood are volatile constituents and semi-volatile components [2]. The former include low-molecular-weight aromatic compounds and sesquiterpene derivatives, and the latter principally consist of 2-(2-phenylethyl)chromone derivatives [3]. Sesquiterpenes, including agarofurans, cadinanes, eudesmanes, eremophilanes, guaianes, and agarospiranes, are considered to be the prominent contributors to agarwood aroma [4]. 2-(2-phenylethyl)chromone monomers can be divided into four categories based on the A ring of 2-(2-phenylethyl)chromones, namely, 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones (THPECs), diepoxy-tetrahydro-2-(2-phenylethyl)chromones (DEPECs), epoxy-tetrahydro-2-(2-phenylethyl)chromones (EPECs), and flindersia type 2-(2-phenethyl)chromones (FTPECs) [2, 5].
Chi-Nan agarwood (CNA), a high-quality agarwood, is also called Qi-Nan or Jar-Nan in China, Kanankoh or Kyara in Japan, and Tagara in India [6]. In China, wild CNA is considered representative of high-quality agarwood, whose price is increasing up to thousands of RMB yuan per gram [7, 8]. Wild Chi-Nan agarwood is valued for its mysterious and elegant oriental odour that could be obviously smelt without heating, which make it discriminate from other kinds of agarwood. Investigations on wild CNA have rarely been reported, in contrast to abundant reports related to ordinary agarwood. In 1985, Hashimoto proved that benzaldehyde and 4-methoxybenzaldehyde originated from the pyrolysis of 2-(2-phenylethyl)chromone and 2-[2-(4′-methoxyphenyl)ethyl]chromone, respectively, in the neutral part of Kyara [9]. Ishihara discovered that the relative contents of 2-(2-phenylethyl)chromone and 2-[2-(4′-methoxyphenyl)ethyl]chromone from Kanankoh (A.agallocha, synonym: A. malaccensis) [10] smoke were much higher than those from Jinkoh [11]. In addition, taking four types of wild CNA (A. sinensis and A. agallocha) as materials, Dai showed that there were abundant 2-(2-phenylethyl)chromones and 2-[2-(4′-methoxyphenyl)ethyl]chromones [6, 12]. It is not difficult to notice that previous studies took only the 2-(2-phenylethyl)chromones into account. In addition, Chinese pharmacologist Xie Zongwan described the morphological characteristics of CNA but failed to provide information on the original plant [13]. Due to the confusion regarding the original plant, relevant information on wild CNA has seldom been described in the mentioned studies.
In recent years, a kind of special agarwood germplasm of A. sinensis has been introduced and domesticated from the wild population and propagated by grafting with ordinary germplasm of A. sinensis. Agarwood with more than 40% of the alcohol soluble extractive content can be obtained after this kind of tree is wounded with the drilling method over one year. However, for ordinary germplasm of A. sinensis, it is almost impossible to obtain agarwood with more than 10% of the alcohol soluble extractive content with the same inducing method [14]. Because of the similarity of characteristics such as appearance, form, texture, color, smell, and taste to wild CNA, this new-found agarwood is also called CNA. To date, there has been only one report by Li [15]in which the chemical properties of this kind of CNA have been tested by TG-FTIR and HS-GC-MS, and these authors named it Kynam. However, the authors did not clarify the specific components to distinguish CNA in terms of fragrance and the chemical characteristics of CNA. Here, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) were used to analyze the differences between CNA induced from new-found germplasm and ordinary agarwood (OA) to obtain a deep knowledge of phytochemical characteristics.
2. Materials and Methods
2.1. Agarwood Materials
Thirteen agarwood samples were analyzed as shown in Table 1 and Figure S1. They are divided into CNA (Chi-Nan agarwood) and OA (ordinary agarwood) group. The seven CNA samples were collected from new-introduced germplasms A. sinensis tree that were provided by three farmers from different planting bases of Hainan and Guangdong province in China. As for the OA group, we chose six ordinary agarwood induced with three kinds of common agarwood-inducing methods, including whole-tree agarwood-inducing technique (Agar-Wit) [16], burning-chisel-drilling (BCD), and wild.
Num.
Species
Agarwood induction method
Place of production
Description
Sinkage
CNA1
A. sinensis
3-year-old Chi-Nan germplasm by drilling for 15 months
Ding’an, Hainan province
Irregular pieces, black brown resin bands alternate with yellow white wood stripes, sufficient resin, rich of aromas, acrid in taste, soft and glutinous
x
CNA2
A. sinensis
3-year-old Chi-Nan germplasm by drilling for 14 months
Ding’an, Hainan province
Irregular strips, brown resin bands and white wood are distributed alternately, strong fragrance, cool feeling, bitter in taste, hard texture, slightly sticky
x
CNA3
A. sinensis
5-year-old Chi-Nan germplasm by drilling for 18 months
Ding’an, Hainan province
Irregular pieces, black brown resin scatter like spots, adequate resin, the aroma is thick, numb the tongue, hard texture, sticky
√
CNA4
A. sinensis
10-year-old Chi-Nan germplasm by drilling for 12 months
Maoming, Guangdong province
Irregular strips, apparent brown resin spread throughout the surface, intense aroma, taste peppery, hard texture, sticky
√
CNA5
A. sinensis
3-year-old Chi-Nan germplasm by drilling for 12 months
Maoming, Guangdong province
Irregular pieces, black brown resin scatter like spots, saturated with resin, fragrance is elegant, spicy and numb, tough, sticky
x
CNA6
A. sinensis
20-year-old Chi-Nan germplasm by drilling for 18 months
Maoming, Guangdong province
Irregular pieces, black brown resin scatter like spots or stripe, quite strong aroma, little spicy and numb, tough, sticky
√
CNA7
A. sinensis
3-year-old Chi-Nan germplasm by drilling for 12 months
Maoming, Guangdong province
Irregular pieces, obvious black brown resin scatter like spots or stripe, cool feeling, taste peppery and numb, tough, soft and glutinous
√
OA1
A. sinensis
6-year-old trees induced by Agar-Wita for 18 months
Haikou, Hainan province
Irregular slices, brown resin bands alternate with yellow white wood stripe, pleasant fragrance, crisp
x
OA2
A. sinensis
6-year-old trees induced by Agar-Wit for 8 months
Danzhou, Hainan province
Irregular thin slices, saturated with resin brown resin, sweet fragrance, crisp
x
OA3
A. sinensis
Wild agarwood
Hainan province
Irregular pieces, massive protrusions and patches distribute throughout the appearance, slight aroma, soft
x
OA4
A. sinensis
Wild agarwood
Hainan province
Irregular pieces, many protrusions and patches distribute throughout the appearance, tawny resin scatter like spots, slight aroma, crisp
x
OA5
A. sinensis
5-year-old trees induced by BCDb for 12 months
Maoming, Guangdong province
Irregular pieces or slices, tawny resin and white wood are distributed alternately, many fibers in the cross section, slight aroma, resilient
x
OA6
A. sinensis
5-year-old trees induced by BCD for about 12 months
Maoming, Guangdong province
Irregular pieces, brown resin scatter like spots, cheerful, aroma, crisp
x
aThe abbreviation of whole-tree agarwood-inducing technique is Agar-Wit. bThe abbreviation of burning-chisel-drilling is BCD. “√”: the agarwood sample could sink in water. “x”: the agarwood sample could not sink in water.
Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) are among the leading causes of mortality worldwide. Cigarette smoking is among the main aetiologic factors for both ailments. These diseases share common pathogenetic mechanisms including inflammation, oxidative stress, and tissue remodelling. Current therapeutic approaches are limited by low efficacy and adverse effects. Consequentially, LC has a 5-year survival of < 20%, while COPD is incurable, underlining the necessity for innovative treatment strategies. Two promising emerging classes of therapy against these diseases include plant-derived molecules (phytoceuticals) and nucleic acid-based therapies. The clinical application of both is limited by issues including poor solubility, poor permeability, and, in the case of nucleic acids, susceptibility to enzymatic degradation, large size, and electrostatic charge density. Nanoparticle-based advanced drug delivery systems are currently being explored as flexible systems allowing to overcome these limitations. In this review, an updated summary of the most recent studies using nanoparticle-based advanced drug delivery systems to improve the delivery of nucleic acids and phytoceuticals for the treatment of LC and COPD is provided. This review highlights the enormous relevance of these delivery systems as tools that are set to facilitate the clinical application of novel categories of therapeutics with poor pharmacokinetic properties.
Graphical abstract
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Introduction
Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported.
Objective
To conduct a rapid untargeted liquid chromatography–mass spectrometry (LC–MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value.
Method
A MN‐assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α‐glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application.
Results
Five main chemical groups including phenol C‐glycosides, organic acids, 2‐(2‐phenylethyl) chromones, benzophenone O‐glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty‐one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C‐glycosides and benzophenone C‐glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α‐glucosidase inhibitory fraction, respectively.
Conclusion
Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high‐quality development of agarwood industry.
Sesquiterpenes are characteristic components and important quality criterions for agarwood. Although sesquiterpenes are well-known to be biosynthesized by sesquiterpene synthases (TPSs), to date, only a few TPS genes involved in agarwood formation have been reported. Here, two new TPS genes, namely, TPS9 and TPS12 , were isolated from Aquilaria sinensis (Lour.) Gilg, and their functions were examined in Escherichia coli BL21(DE3), with farnesyl pyrophosphate (FPP) and geranyl pyrophosphate (GPP) as the substrate of the corresponding enzyme activities. They were both identified as a multiproduct enzymes. After incubation with FPP, TPS9 liberated β -farnesene and cis-sesquisabinene hydrate as main products, with cedrol and another unidentified sesquiterpene as minor products. TPS12 catalyzes the formation of β -farnesene, nerolidol, γ -eudesmol, and hinesol. After incubation with GPP, TPS9 generated citronellol and geraniol as main products, with seven minor products. TPS12 converted GPP into four monoterpenes, with citral as the main product, and three minor products. Both TPS9 and TPS12 showed much higher expression in the two major tissues emitting floral volatiles: flowers and agarwood. Further, RT-PCR analysis showed TPS9 and TPS12 are typical genes mainly expressed during later stages of stress response, which is better known than that of chromone derivatives. This study will advance our understanding of agarwood formation and provide a solid theoretical foundation for clarifying its mechanism in A. sinensis .
Al-Qanun Fi’l Tibb II merupakan buku materia medica karya Ibnu Sina yang terkenal di dunia. Buku tersebut menjelaskan secara rinci mengenai monografi tanaman berkhasiat terhadap organ tubuh, salah satunya terhadap tulang dan sendi. Akan tetapi dalam buku tersebut belum memuat komponen major metabolit sekunder yang diduga berperan penting dalam memberikan efek farmakologis. Penelitian ini ditujukan untuk menginventarisasi tumbuhan yang terdapat di dalam buku Al-Qanun Fi’l Tibb II dan melakukan literatur review terkait kandungan metabolit sekunder yang terdapat dalam tanaman tersebut. Metode penelitian dilakukan dengan literature review melalui studi kepustakaan. Hasil pengambilan data menunjukan terdapat 74 tanaman yang berkhasiat terhadap tulang dan sendi diantaranya memiliki komponen major metabolit sekunder seperti senyawa terpen, flavonoid, alkaloid, tanin, alil isotiosianat, saponin, glikosida, alkohol lemak, asam fenolat, benzofenon, kuinon, sekoiridoid, kumarin, stilbene, anthrone, naftalen, benzaldehida dan asam karboksilat. Terpen merupakan metabolit sekunder yang paling banyak ditemukan dalam tanaman yang berkhasiat terhadap tulang dan sendi. Bioaktivitas yang ditemukan pada tanaman diantaranya antigout, antioksidan, osteoprotektif, antiosteoporosis, antibakteri, antiinflamasi dan analgesik.
Agarwood, a resinous heartwood derived from injured Aquilaria plants, is widely used in cosmetics and pharmaceuticals. Sesquiterpenes are among the main active components of agarwood. Agarwood sesquiterpene synthase 1 (ASS1), a typical wound-inducible synthase, is a key sesquiterpene biosynthesis enzyme. Previously, we reported that the transcription repressor AsWRKY44 inhibits the expression of ASS1 and relieves this inhibition by degrading itself in response to treatment with MeJA (methyl jasmonate). Yet the molecular mechanisms underlying this wound-induced AsWRKY44 degradation remain unknown. Here, we demonstrate that a C3HC4-type E3 ubiquitin ligase, RING3, shows ubiquitin activity and regulates the degradation of WRKY44 in response to an exogenous MeJA treatment. AsWRKY44 protein degraded more slowly in the RING3-RNAi lines than the CK group, suggesting that RING3 contributes to AsWRKY44 protein stability. RING3 interacted with AsWRKY44 in vitro and in vivo, and RING3 ubiquitinated AsWRKY44 in vitro. Downregulation of RING3 remarkably reduced the levels of α-guaiene, humulene, and δ-guaiene, which are the main catalytic products of ASS1. These findings reveal a critical mechanism by which RING3 positively regulates sesquiterpene biosynthesis by mediating AsWRKY44 degradation in response to wound stimuli in A. sinensis. Here, we provide a novel view of the regulation of transcriptional inhibition in other medicinal plants. Our results might help elucidate plants’ direct induction of natural secondary metabolites.
2-(2-phenylethyl)chromone derivatives are regarded as key components in agarwood. An oxygen-containing heterocycle with a benzoannelated γ-pyrone moiety form the bioactive core of 2-(2-phenylethyl)chromones. With different substituents and positions, 2-(2-phenylethyl)chromone derivatives exhibit diverse biological properties, such as antioxidant, neuroprotective, anti-inflammatory, and acetylcholinesterase inhibitory activities. In this review, we summarized the studies (from January 1976 to September 2021) on phytochemistry, bioactivity and quality control of 2-(2-phenylethyl)chromones. These studies aimed to clarify the chemical specificity, diversity and structure-activity relationship of 2-(2-phenylethyl)chromones. In addition, we assumed that diverse factors contribute to the chemical diversity of 2-(2-phenylethyl)chromones. Furthermore, this review contends that different types of 2-(2-phenylethyl)chromones should be utilized in the quality control methods of agarwood.
The first syntheses of the enantiomers of naturally occurring aquilanols A and B, two unprecedented 7/10 bicyclic sesquiterpenoids, are presented. Key features are a retro-cycloisomerization event on (-)-caryophyllene oxide to formulate the 11-membered carbocycle and an intramolecular epoxide opening to construct the bicyclic skeleton. The latter provides evidence of the plausible biosynthesis of natural compounds, rendering our syntheses biomimetic. Selective access to other medium-sized carbocyclic oxygenated compounds was achieved, enhancing the structural diversity of the final products.
Agarwood has been valued since ancient times as a noble, high-grade fragrant wood. Because of its rarity, agarwood is traded at a high price, and the number of its original plants has been drastically reduced due to a succession of overharvesting. However, an efficient agarwood cultivation method has not yet been developed. The fragrance of agarwood is mainly derived from 2-(2-phenylethyl)chromones (PECs). Recently, we identified a key enzyme that forms the PEC skeleton. This paper outlines the characteristics of the enzyme, and the biosynthetic pathway of PECs.
Aquilaria sinensis is a species of plant endemic to China, which is typical wound-induced economic plant. It is widely used in the production of perfume, incense and traditional Chinese medicine. A healthy A. sinensis tree cannot produce agarwood. It forms agarwood only when wounded. Sesquiterpenes and phenylethyl chromone derivatives have been demonstrated to be the main active compounds in agarwood, but little is known about jasmonate (JA) signaling that regulates the biosynthesis of agarwood sesquiterpenes. In this work, we firstly cloned the full-length cDNA sequence of a JA signaling suppressor gene (JAZ) from A. sinensis, and then characterized its roles through bioinformatics prediction, tissue expression, wounding-induced expression, subcellular localization, protein interaction and overexpression analysis in Arabidopsis thaliana. The results showed that the full-length cDNA sequence of JAZ gene (termed as AsJAZ1, GenBank accession number: KP677281) is 1507 bp, containing a complete open reading frame (ORF) of 990 bp. The bioinformatics analysis shows that the deduced amino acid residues contain a tify (ZIM) domain, the same as A. thaliana JAZ3 protein. Mechanical wounding and MeJA were found to up-regulate the expression level of the AsJAZ1 gene. The AsJAZ1 could interact with the MYC2 transcription factor in vitro. The MYC2 transcription factor in Arabidopsis thaliana (AtMYC2) was minimally expressed in transgenic plants and had a weak response to MeJA treatment. The AsJAZ1 overexpression in A. thaliana was observed to down-regulate the expression of sesquiterpene synthase genes (TPS21 and TPS11), suggesting that AsJAZ1 might serve as a repressor to regulate the expression of sesquiterpene synthase genes in Aquilaria plants. Taken together, this work may lay a foundation for identifying the JA signaling pathway and exploring the role of JA signaling in agarwood sesquiterpene biosynthesis in A. sinensis trees.
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.
Aquilaria crassna Pierre ex Lecomte, Thymelaeaceae, is cultivated for producing resinous heartwood, also called agarwood. Its leaves are a source of herbal tea in Vietnam due to its rich content of polyphenols. However, the α-glucosidase inhibition activity and the contents of phenolic compounds in leaves of different ages have not yet been determined. In the current study, 7 polyphenols [iriflophenone 3,5-C- β-D-diglucoside (1), iriflophenone 3-C- β-D-glucoside (2), mangiferin (3), iriflophenone 2- O- α-rhamnoside (4), genkwanin 5- O- β-primeveroside (5), genkwanin 4′-methyl ether 5- O- β-primeveroside (6), and genkwanin (7)] were isolated from the leaves of A crassna. Among them, genkwanin (7), an O-methylated flavone, was the most active compound that inhibited α-glucosidase activity, with an IC 50 value of 24.0 μM. Molecular docking studies were performed to understand the binding interactions of the active compounds. In addition, a reliable and straightforward reversed-phase HPLC method was developed to determine the content of compounds in different leaves of A crassna. Mangiferin (3) showed the highest content. The contents of 1-4 contributed to the total polyphenolic contents and significantly decreased from the youngest to the oldest leaf. The contents of 5-7 fluctuated through various ages of leaves. Compounds 5 and 6 showed a low accumulation in the first and second leaves, then obtained high contents among middle leaves and declined in the oldest. These results suggested that A crassna and its polyphenols may prevent the development and progression of diabetes through α-glucosidase inhibition. Also, the analysis of the polyphenol content in A crassna may be helpful for tea product manufacture.
Spiroaquilarenes A–E (1–5), a class of sesquiterpene polymers featuring unusual furaneol rings connecting sesquiterpene units, were isolated from agarwood of Aquilaria sinensis and structurally characterized.
Aquilaria sinensis (Lour.) Gilg is the resin-containing wood of the Aquilaria. Agarwood is a traditional Chinese medicine included in the 2020 edition of Chinese Pharmacopoeia. The main phytochemicals of agarwood include terpenoids, dominated by sesquiterpenes. For centuries, terpenoids have been used in traditional Chinese medicine and have been shown to possess various pharmacological properties, including bacteriostatic, antibacterial, sedation, analgesia, anti-inflammation, anti-asthmatic, hypoglycemic, antidepressant, and many others. Alongside biological activity screening, phytochemical advances and pharmacological research have also made certain progress.
Aquilaria sinensis)为对象，基于高通量测序方法，分析 2 个不同区域生境中 4 个品种白木香结香部位真菌群落结构多样性及分布规律，结合不同品种的结香特性，进一步挖掘 与白木香结香显著相关的真菌类群，促进结香技术的提升。结果表明：相同生境条件下，同种白木香不同高度结香位 点真菌组成结构非常相似，但不同真菌的丰度存在差异；不同区域生境下，相同品种结香部位真菌群落组成结构存在 显著差异，生境差异可能是导致结香部位真菌群落结构差异的主要因素之一；同一区域生境下，不同品种白木香结香 部位的真菌群落结构存在显著差异，品种差异可能是导致白木香结香部位真菌群落结构差异的主要因素之一，同时特 有真菌类群的存在也可能是影响白木香结香特性的关键。Fusarium spp. 和 Hypomontagnella spp. 等真菌在易结香品种 分布广泛且丰度极高，可能与易结香品种的结香特性相关，具有重要的应用潜力。 关键词：白木香；结香技术；真菌多样性；高通量测序 中图分类号：S567.1 文献标识码：A Abstract: Aquilaria sinensis (Lour.) Spreng, an economic plant in Guangdong, was selected as the object of this study. Using the high-throughput sequencing method, we analyzed the community structure and distribution of fungi in agar-wood wound locations of four agarwood varieties in Maoming and Dongguan, China. Combining the agarwood formation characteristics of different varieties, fungal groups were further investigated which were significantly related to the agarwood formation. Under the same habitat condition, fungi community structure at different height sampling sites in the same varieties were remarkably similar, despite the different fungi abundance. The fungal community composition were significantly different in the same varieties under different habitats, and the difference of habitat may be one of the main factors leading to the difference of fungal community structure. There were significant differences in the fungal community structure among different varieties under the same habitat condition. Different agarwood varieties may be one of the main factors leading to the difference of fungal community structure. The unique fungi with high abundance maybe result in special feature of agarwood formation. Fusarium spp. and Hypomontagnella spp., which are widely distributed with high abundance in the easy agarwood formation varieties, are the best illustrations for this conclusion.
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.
Agarwood has high economic value and wide uses, however, the amount of wild agarwood is scarce. Wild agarwood with high oil content may contain strains associated with agarwood production. To improve the formation of agarwood, we produced fungal inducers from a high-oil wild agarwood block containing enrichment fungi. We investigated the composition of strains and inoculated the fungal inducers into Aquilaria trees. We analyzed the content of alcohol-soluble extract, essential oil, agarotetraol, 2-(2-phenylethyl)chromone, 6,7-dimethoxy-2-(2-phenylethyl)chromone and total chromone, and the chemical components of alcohol-soluble extract. We aimed to assess agarwood quality through these evaluations. The results demonstrated that fungi extracted from wild agarwood with high oil content can effectively improve the yield and quality of agarwood, and Gongronella butleri, Saitozyma podzolica, Cladorrhinum bulbillosum, Humicola grisea and Tetracladium marchalianum were the species found novel as inoculant for agarwood formation. After 12 months of inoculation, agarwood produced using A. sinensis had higher quality, the contents of alcohol-soluble extract, essential oil, total chromones, and the total relative contents of sesquiterpenes and chromones were 21.73 % ±2.97 %, 6.07 % ±0.47 %, 12.30 % ±2.21 %, and 97.59 %, respectively. Over 6–18 months of inoculation, agarotetrol content decreased, and 2-(2-phenylethyl) chromone and 6,7-dimethoxy-2-(2-phenylethyl)chromone content first increased and then decreased.
Eleven previously unreported sesquiterpenes, including nine eudesmane-type (agalleudesmanol A-I) and two agarospirane-type sesquiterpenes (agarospiranic aldehyde A-B), together with eight known sesquiterpenes, were isolated from the agarwood of Aquilaria agallocha Roxb. The structures were established based on extensive spectroscopic analyses, including infrared (IR), high-resolution electrospray ionisation mass spectrometry (HRESIMS), nuclear magnetic resonance (NMR), X-ray diffraction, quantum chemical calculations based on empirical electronic circular dichroism (ECD) data, and DP4+ probability analysis. The bioactivity of these undescribed compounds against lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells was evaluated. Compounds 1 and 2 exhibited significant anti-inflammatory activities, with IC50 values of 5.46–14.07 μM (aminoguanidine as positive control, IC50 20.33 ± 1.08 μM).
Agarwood, one of the precious woods in the globe, is produced by Aquilaria plant species during an upshot of wounding and infection. Produced as a defence response, the dark, fragrant resin gets secreted in the plant's duramen, which is impregnated with fragrant molecules with the due course. Agarwood has gained worldwide popularity due to its high aromatic oil, fragrance, and pharmaceutical value, which makes it highly solicited by numerous industries. Predominant chemical constituents of agarwood, sesquiterpenoids, and 2-(2-phenylethyl) chromones have been scrutinized to comprehend the scientific nature of the fragrant wood and develop novel products. However, the genes involved in the biosynthesis of these aromatic compounds are still not comprehensively studied in Aquilaria. In this study, publicly available genomic and transcriptomics data of Aquilaria agallochum were integrated to identify putative functional terpene synthase genes (TPSs). The in silico study enabled us to identify ninety-six TPSs, of which thirty-nine full-length genes were systematically classified into TPS-a, TPS-b, TPS-c, TPS-e, TPS-f, and TPS-g subfamilies based on their gene structure, conserve motif, and phylogenetic comparison with TPSs from other plant species. Analysis of the cis-regulatory elements present upstream of AaTPSs revealed their association with hormone, stress and light responses. In silico expression studies detected their up-regulation in stress induced tissue. This study provides a basic understanding of terpene synthase gene repertoire in Aquilaria agallochum and unlatches opportunities for the biochemical characterization and biotechnological exploration of these genes.
Supplementary information:
The online version contains supplementary material available at 10.1007/s12298-021-01040-z.
Callus browning, a common feature in plant cell cultures, has hardly been explored in Aquilaria sinensis. Here, the volatile organic compounds (VOCs) were characterized during the browning of A. sinensis cells using Gas Chromatography-Mass Spectrometry (GC–MS), and total sesquiterpene accumulation was significantly induced and peaked during A. sinensis callus browning, after 60 days of callus growth. Additionally, 14 types of sesquiterpenes were detected in the browning A. sinensis callus, with greater sesquiterpene diversity than in the ones treated with methyl jasmonate and salicylic acid (SA) in a previous study. To further evaluate the mechanism of regulation of agarwood sesquiterpenes during cell browning in A. sinensis, changes on phytohormone concentrations were explored using ultra-performance liquid chromatography-electrospray tandem mass spectrometry system (UPLC-ESI-MS/MS). Both endogenous jasmonic acid and SA, key plant defense hormones, increased during A. sinensis callus browning. 1-aminocyclopropanecarboxylic acid, an ethylene (ET) precursor, decreased significantly after A. sinensis callus browning. Conversely, two primary growth hormones, auxin and cytokinin, exhibited opposite trends, suggesting that they also play roles in agarwood sesquiterpene accumulation. Our results potentially offer novel insights that could facilitate the production valuable phytochemical compounds such as agarwood sesquiterpenes, using plant cell cultures treated with appropriate phytohormone combinations.
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
Ethnopharmacological relevance
Stress is a state of feeling that inhibits one from responding properly in the face of a threat. Agarwood smoke has been used in traditional medicine as a sedative anti-anxious, and anti-restless therapy. Its scent emitted from heat induces people to enter a stable state; however, the underlying molecular effect is still unclear.
Aim of the study
This study analyzed novel biological events and gene expression signatures induced by agarwood incense smoke in mice.
Materials and Methods
Incense smoke was produced by heating at 150 ºC for 30 min in a headspace autosampler oven. We treated mice with exposure to incense smoke from Kynam agarwood for 45 min/day for 7 consecutive days. After a 7-day inhalation period, the potent agarwood smoke affected-indicators in serum were measured, and the RNA profiles of the mouse brains were analyzed by microarray to elucidate the biological events induced by agarwood incense smoke.
Results
Chemical profile analysis showed that the major component in the incense smoke of Kynam was 2-(2-phenylethyl) chromone (26.82%). Incense smoke from Kynam induced mice to enter a stable state and increased the levels of serotonin in sera. The emotion-related pathways, including dopaminergic synapse, serotonergic synapse, GABAergic synapse, long-term depression and neuroactive ligand-receptor interaction, were significantly affected by incense smoke. Moreover, the expression of Crhr2 and Chrnd genes, involved with neuroactive ligand-receptor interaction pathway, was upregulated by incense smoke.
Conclusions
By a newly-established incense smoke exposure system, we first identified that anti-anxious and anti-depressant effects of agarwood incense smoke were likely associated with the increase of serotonin levels and multiple neuroactive pathways in mice.
To analyze the constituents of essential oil from Chinese eaglewood [resinous wood of Aquilaria sinensis (Lour.) Gilg] and its anti-methicillin-resistant Staphylococcus aureus (MRSA) activity. The essential oil was extracted by water-steam distillation and analyzed by GC/MS method. The relative contents of the compounds were determined by normalization. The compounds were characterized by NIST05 and WILEY275L database matching and comparison of their MS spectra with those of literature data. Antibacterial activity of the oil was assayed by the filter paper disc agar diffusion method. The oil showed sig-nificant antibacterial activity against MRSA. Sixty-six chromatographic peaks were detected, among them thirty compounds com-prising 59.80% of the total essential oil were characterized. Twenty-six compounds comprising 54.26% of the oil were identified as sesquiterpenes. β-Agarofuran (8.96%), kusunol (7.82%), (-)-jinkoh-eremol (5.04%), agarospirol (4.53%), baimuxifuranic acid (4.09%) were the major sesquiterpenes. Four nor-sesquiterpenes and some other sesquiterpenes, such as 10-epi-γ-eudesmol, α-agarofuran, epi-ligulyl oxide, etc. were detected in Chinese eaglewood oil for the first time. This is the first report about anti-MRSA activity of Chinese eaglewood oil from A. sinensis. there are few studies on the Chinese eaglewood oil from A. sinensis. In our recent research on the oils of five different kinds of Chinese eaglewood, several sesquiterpenes, such as hinesol, nootkatone, valerenic acid, velleral, viridiflorol, etc., were found to be present in the oils by GC/MS analysis for the first time [4] . The present paper describes the GC/MS analysis and anti-methicillin-resistant Staphylococcus aureus (MRSA) results of a new sample of Chinese eaglewood oil, in which some sesquiterpenes, especially four nor-sesquiterpenes were characterized for the first time. 2. Experimental 2.1. Sample preparation Naturally produced Chinese eaglewood from the tree of A. sinensis was collected in Tunchang county of Hainan Province of China in February 2007. The plant was identified by associate Professor Zheng-Fu Dai and a voucher specimen (No. 070286) is deposited at the Institute of Tropical Bioscience and Biotechnology. Hydrodistillation of 260 g of the milled Chinese eagle-wood was carried out using a Clevenger-type appa-ratus for 4 h. After drying with anhydrous sodium sulfate, 0.55 mL pale yellow oil with pleasant odour was obtained and the yield was 0.21% (v/w).
Aquilaria agallocha Roxb, family Th ymelaeaceae, is an evergreen plant of India, China and Tibet, commonly described as aloe wood or agar wood. Traditionally, bark, root and heartwood are used for their medicinal properties as a folk medicine to treat infl ammation, arthritis, vomiting, cardiac disorders, cough, asthma, leprosy, anorexia, headache and gout. Th e present study was carried out to investigate the antioxidant activity of ethyl acetate extract of Aquilaria agallocha (EAA). EAA was tested in vitro at diff erent concentrations for inhibitory eff ect on nitrite-induced oxidation of haemoglobin in human blood hemolysate. Results indicate a strong antioxidant eff ect of EAA in a concentration range of 500-3500 μg/ml. However, pro-oxidant activity was observed at higher concentrations of these compounds. Key words: Aquilaria agallocha, antioxidant, nitrite-radical, methemoglobin
The resinous portions of Aquilaria plants, called agarwood, have been used as medicines and incenses. Agarwood contains a great variety of sesquiterpenes, and a study using cultured cells of Aquilaria showed the production of sesquiterpenes (α-guaiene, α-humulene, and δ-guaiene) to be induced by treatment with methyl jasmonate (MJ). In this study, the accumulation and production of sesquiterpenes were quantified. The amounts accumulated and produced reached a maximum at 12 h, and the most abundant product was α-humulene at 6 h and δ-guaiene after 12 h. However, a headspace analysis of the cells revealed that α-humulene is likely to be volatilized; so overall, the most abundant sesquiterpene in the cells was δ-guaiene. A cDNA library from RNA isolated from MJ-treated cells was screened using PCR methodologies to isolate five clones with very similar amino acid sequences. These clones were expressed in Escherichia coli, and enzymatic reactions using farnesyl pyrophosphate revealed that three of the clones yielded the same compounds as extracted from MJ-treated cells, the major product being δ-guaiene. These genes and their encoded enzymes are the first sesquiterpene synthases yielding guaiane-type sesquiterpenes as their major products to be reported. Expression of a fourth terpene synthase gene in bacteria resulted in the accumulation of the protein in insoluble forms. Site-directed mutagenesis of the inactive clone and three-dimensional homology modeling suggested that the structure of the N-terminal domain was important in facilitating proper folding of the protein to form a catalytically active structure.
Two new 2-(2-phenylethyl)chromones, (5S(*),6R(*),7S(*))-5,6,7-trihydroxy-2-(3-hydroxy-4-methoxyphenethyl)-5,6,7,8-tetrahydro-4H-chromen-4-one (1) and (5S(*),6R(*),7R(*))-5,6,7-trihydroxy-2-(3-hydroxy-4-methoxyphenethyl)-5,6,7,8-tetrahydro-4H-chromen-4-one (2), were isolated from the Chinese eaglewood of Aquilaria sinensis (Lour.) Gilg. Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with the literature data.
A new 2-(2-phenylethyl)chromone, 5,6,7,8-tetrahydroxy-2-(3-hydroxy-4-methoxyphenethyl)-5,6,7,8-tetrahydro-4H-chromen-4-one (1) was isolated from the Chinese eaglewood [Aquilaria sinensis (Lour.) Gilg]. Its structure was established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.
Objective: To study the chemical constituents of Aquilaria sinensis. Methods: Column chromatographic technique was employed for the isolation and purification of its constituents by solvent, the ether fraction of ethanol extract of A. sinensis was conducted gradient elution by petroleum ether and ethyl acetate in different proportions. Their structures were identified by physicochemical constant and spectral analysis (IR, UV, EI-MS, 1H-NMR, 13C-NMR, and HMBC). Results: The compounds were identified from their ethanol extracts as: 6, 8-dihydroxy-2-[2-(3′-methoxy-4′-hydroxyl phenylethyl)] chromone (I) and 6-methoxy-2-[2-(3′-methoxy- 4′-hydroxyl phenylethyl)] chromone (II). Conclusion: Compound I is a novel compound and II is a known one.
New tetraphydroxy-2-(2-phenylethyl)chromone, tentatively named AH16 was isolated from agalwood, "Jinko", and the structure was characterized as (5R__-, 6R__-, 7S__-, 8R__-)-2-(2-phenylethyl)-5e', 6a, 7e, 8e'-tetraphydroxy-5, 6, 7, 8-tetraphydrochromone, assuming the cyclohexenyl ring to have a boat conformation.
New dioxan-linked bi-2-(2-phenylethyl)chromone, tentatively named AH21 was isolated from a pridine extract of agalwood "Jinko" and structurally characterized using proton and carbon-13 nuclear magnetic resonance spectra.
Calli and suspension cell culture were established from Aquilaria species whose resinous portion was called agarwood and used as medicine and incense. Four different strains of calli were analyzed for fragrant compounds such as sesquiterpenoids and chromone derivatives which were the major components of agarwood. Main sesquiterpenoids detected from calli were α-guaiene, α-humulene and δ-guaiene, and those of chromone derivatives were phenylethylchromones (AH3, AH4, AH5, AH6). Amount of these compounds differed among the four strains, indicating that Aquilaria plants may have variation in capacity for fragrant compound production. Incubation temperature analysis was also done from 20°C to 40°C and resulted that cell growth was the best at 25°C, whereas the amount of fragrant compounds was largest at 20°C. Salicylic acid (SA) and methyl jasmonate (MJ) were added to calli and suspension cell culture respectively in order to induce production of fragrant compounds. Both SA and MJ apparently induced production of three sesquiterpenoids, α-guaiene, α-humulene, and δ-guaiene at early stage of treatment of SA or MJ, but did not induce that of chromone derivatives directly. Further studies of time course of chromone production and cell viability suggested that cell death may take part in chromone production, and that phenylethylchromones would be produced via oxydoagarochromones (OACs). These results indicate that sesquiterpenoids are synthesized in living cells, but chromone derivatives may be produced from debris of dying cells. © 2009 The Japanese Society for Plant Cell and Molecular Biology.
Two new phenylethylchromone derivatives were isolated from a methanol soluble portion of pyridine extract of agalwood (Jinko). Their structures were elucidated as (5S, 6R, 7S, 8R, 7'R)-7'-hydroxyisoagarotetrol (1) and its (7'S)-isomer (2), respcetively.
Three new bi-2-(2-phenylethyl)chromones, tentatively named AH12, AH13and AH14, were isolated from agalwood "Jinko" along with AH10, AH11 and AH15. The structures of AH12 and AH13 were elucidated as (5S, 6R, 7R, 8S)-2-(2-phenyletyl)-5, 6, 7-trihydroxy-5, 6, 7, 8-tetrahydro-8-[2-(2-phenylethyl)-7-methoxychromonyl-6-oxy]chromone and its de-7-methoxylate, respectively. AH14 was concluded to be (5S, 6S, 7S, 8R)-2-(2-phenylethyl)-6, 7, 8-trihydroxy-5, 6, 7, 8-tetrahydro-5-[2-(2-phenylethyl)chromonyl-6-oxy]chromone. Elucidation of 5, 6' and 8, 6'-ether bonding in bi-2-(2-phenylethyl)chromones was done by detailed analyses of the proton and carbon-13 nuclear magnetic resonance (1H and 13C-NMR) spectra, and measuring nuclear Overhauser effect (NOE) difference values.
Six kinds of chromone derivatives, named AH1, AH2, AH3, AH4, AH5 and AH6, were isolated from agarwood (Jinko) from Kalimantan. Four constituents, AH3, AH4, AH6 and AH5, were characterized as 6-hydroxy-(I), 6-methoxy-(II) and 6, 7-dimethoxy-2-(2-phenylethyl) chromone (IV) and 6-methoxy-2-[2-(3-methoxyphenyl) ethyl] chromone (III), respectively.
Three new kinds of phenylethylchromone derivatives, called AH17 AH20 and AH23, were isolated from acetone and pyridine extracts of agalwood (Jinko) from Kalimantan. The structures of AH17 and AH23 were characterized as 5α, 6β, 7β-trihydroxy-8α-methoxy-2-(2-phenylethyl-5, 6, 7, 8-tetrahydrochromone and 5α, 6β, 7β, 8α-tetrahydroxy-2-[2-(2-hydroxyphenyl)ethyl]5, 6, 7, 8-tetrahydrochromone, respectively. AH20 was found to be a trimer formed by the ether-linkage made of 2-(2-phenylethyl)chromone and 2mol of agarotetrol at C5, 8' and C6, 5'.
New bi- and tri-2- (2-phenylethyl) chromones, tentatively named AH15 and AH18 were isolated from Agalwood “Jinko” and their structures were determined.
A new chromone, 2-(2-4'-methoxyphenylethyl)chromone (I) was isolated together with 2-(2-phenylethyl)chromone (II: flidersiachromone) from agarwood (Japanese name; JINKOH). On pyrolysis at 150°C. I and II were found to produce 4-methoxybenzaldehyde and benzaldehyde, respectively. It is considered that these chromones, which are odorless at room temperature, contribute to the pleasant, lasting odor obtained when agarwood is burnt as an incense. © 1985, The Pharmaceutical Society of Japan. All rights reserved.
New bi-2-(2-phenylethyl) chromones, tentatively named AH10 and AH11 were isolated from Agalwood "Jinko" and their structures were determined.
The structures of two compounds, AH1 and AH2, isolated from agalwood "Jinko" were studied. AH1 was obtained as needles having a melting point different from that of agarotetrol (powder) isolated and characterized by Yoshii et al. However, the carbon-13 nuclear magnetic resonance (13C-NMR) data and [α]D values of the two compounds were identical, and AH1 was concluded to have the same structure, including stereochemistry, as agarotetrol. The half-chair conformation of the hexenyl ring moiety assumed by Yoshii et al. was confirmed by detailed analyses of the proton nuclear magnetic resonance (1H-NMR) and 2D-COSY spectra.AH2 was assigned the structure (5S, 6R, 7R, 8S)-2-(2-phenylethyl)-5e', 6e, 7e, 8'e-tetrahydroxy-5, 6, 7, 8-tetrahydrochromone, a stereo-isomer of agarotetrol (7S, 8R), on the basis of the 1H-NMR, X-ray analysis and circular dichroism (CD) spectral data. It was named isoagarotetrol. The hexenyl ring moiety of isoagarotetrol was found to have a half-chair conformation identical to that of agarotetrol in the crystalline state as well as in solution.
Three new phenylethylchromone derivatives, tentatively named AH7, AH8 and AH9, were isolated from acetone and pyridine extracts of agalwood (jinko) from Kalimantan. AH7 from the pyridine extract was characterized as 5, 8-dihydroxy-2-(2-phenylethyl)chromone, and AH8 from the acetone extract was elucidated to be 6, 7-dimethoxy-2-[2-(4-methoxyphenyl)chromone. AH9, acetylated in order to separate it from the mixture, was concluded to be (5S, 6S, 7R)-5a', 6a, 7a-triacetoxy-2-[2-(2-acetoxyphenyl)ethyl]-5, 6, 7, 8, 8-pentahydrochromone on the basis of the proton nuclear magnetic resonance (1H-NMR) spectrum, dihedral angle and circular dichroism (CD) spectral data.
Three new kinds of phenylethyl chromone derivatives, named AH1A, AH2a and AH2b, were isolated from the crude AH1 (agarotetrol) and AH2 (isoagarotetrol) fractions of agalwood (Jinko)from Kalimantan. AH<1A> separated from the crude AH1 fraction through the process of acetylation was characterized as 2-[2-(4-methoxyphenyl)ethyl]-5α, 6β, 7β, 8α-tetraacetoxy-5, 6, 7, 8-tetrahydro-chromone, and AH2a and AH<2b>, from crude AH2 fraction, were established to be 2[2-(4-methoxyphenyl)ethyl]- and 2-[2-(2-hydroxyphenyl)ethyl]-5α, 6β, 7α, 8β-tetrahydroxy-5, 6, 7, 8-tetrahydrochromone, respectively.
The fragrant sesquiterpene (−)-guaia-1(10),11-dien-15,2-olide (8), isolated from agarwood (Aquilaria agallocha Roxb.), was synthesized starting from (−)-1,10-epoxybulnesene, which is readily available from α-bulnesene in patchouli oil. The absolute configuration of the natural 8 was established by direct comparison of its optical rotation with that of the synthesized 8. It was found that (−)-2α-hydroxyguaia-1(10),11-dien-15-oic acid (9), a synthetic intermediate of 8, also occurs in agarwood.
Degradative studies and physical measurements supported by an unambiguous synthesis of the derived ketone (XVa) have led to the assignment of a novel spiro-skeleton to agarospirol (Ia), a sesquiterpene alcohol isolated from the essential oil of infected agarwood (Aquilaria agallocha Roxb.). The corresponding carbon skeleton (VI) has been named agarospirane. Agarospirol is the second spiro-terpenoid to be isolated from Nature. The most probable stereochemistry of agarospirol appears to be as in XXXIX.
Three new sesquiterpenes, (−)-guaia-1(10),11-dien-15-al, (−)-selina-3,11-dien-9-one, and (+)-selina-3,11-dien-9-ol, have been isolated from Aquilaria agollocha (agarwood). Their structures have been established on the bases of detailed spectroscopic analyses and synthesis. The odoriferous properties of these compounds are also described.
Seven new sesquiterpenes, all of which have a guaiane skeleton, i.e. (−)-guaia-1(10),11-dien-15-ol, (−)-guaia-1(10),11-diene-15-carboxylic acid, methyl guaia-1(10),11-diene-15-carboxylate, (+)-guaia-1(10),11-dien-9-one, (−)-1,10-epoxyguai-11-ene, (−)-guaia-1(10),11-dien-15,2-olide and (−)-rotundone, have been isolated from Aquilaria agallocha (agarwood). Their structures have been established on the bases of detailed spectroscopic analyses and synthesis.
Two new tri-2-(2-phenylethyl)chromones, tentatively named AH19a and AH19b, were isolated from agalwood ‘Jinkō’ and structurally characterized using 1H and 13C NMR spectra.
From an agarwood (Aquilaria sp.; probably Aquilaria malaccensis Benth.) which is different from that obtained from Aquilaria agallocha Roxb., two new sesquiterpene alcohols, which we have named jinkoh-eremol (3) and jinkohol II (5), have been isolated, together with agarospirol (1), kusunol (2), and jinkohol (4), as major sesquiterpene constituents and their structures have been established.
Four new compounds have been isolated from agarwood oil (Aquilaria agallocha Roxb.) and their structures confirmed by synthesis: (1R,2R,6S,9R)-6,10,10-trimethyl-ll-oxatricyclo[7.2.1.01,6]dodecane-2-spiro-2′-oxirane (1) (epoxy-β-agarofuran), (1S,2S,6S,9R)-6,10,10-trimethyl-11-oxatricyclo[7.2.1.01,6]dodecane-2-carbaldehyde (2), (E)-8,10-undecadien-2-one (3) and 2,t-3-dimethyl-r-2-(3-methyl-2-butenyl)-l-cyclohexanone (4, absolute configuration unknown). Several of their diastereoisomers, such as (1R,2S,6S,9R)-6,10,10-trimethyl-11-oxatricyclo [7.2.1.01,6]dodecane-2-spiro-2′-oxirane (5), (1S,2R,6S,9R)-6,10,10-trimethyl-11-oxatricyclo[7.2.1.01,6] dodecane-2-carbaldehyde (6), (Z)-8,10-undecadien-2-one (7) and racemic 2,c-3-dimethyl-r-2-(3-methyl-2-butenyl)-1-cyclohexanone (8, racemate) were also synthesized and fully characterized. The 13C NMR data of agarospirol (9), published earlier,1are corrected. The assignments are supported by 1D-INADEQUATE experiments.
Six new nor-sesquiterpenoids with the 10-epi-eudesmane skeleton were isolated from agarwood oil (Aquilaria agallocha Roxb.): (2R,4aS)-2-(4a-methyl-1,2,3,4,4a,5,6,7-octahydro-2-naphthyl)-propan-2-ol (5a), (S)-4a-methyl-2-(1-methylethyl)-3,4,4a,5,6,7-hexahydronaphthalene (6), (S)-4a-methyl-2-(1-methylethylidene)-1,2,3,4,4a,5,6,7-octa-hydronaphthalene (7), (2R,4aS)-4a-methyl-2-(1-methylethenyl)-1,2,3,4,4a,5,6,7-octahydronaphthalene (8), (1R,6S, 9R)-6,10,10-trimethyl-11-oxatricyclo[7.2.1.01.6]dodecane (9) and (1R,2R,6S,9R)-6,10,10-trimethyl-11-oxatricyclo [7.2.1.01.6]dodecan-2-ol (10).
Three new sesquiterpenic furanoids of the selinane group have been isolated from agarwood oil, obtained from the fungus infected plant Aquillaria agallocha Roxb. and their structures and absolute configurations determined (XXII, XX, XXXI) by degradative studies and physical measurements.
The profile of the total extract of agarwood oil (Aquilaria agallocha Roxb.) is discussed and eight new sesquiter-penoids are presented: two with the eremophilane-skeleton (rel-(2R,8S,8aR)-2-(1,2,3,5,6,7,8,8a-octahydro-8,8a-dimethy1-2-naphthyl)-prop-2-en-1-ol (1, eremophila-9,11(13)-dien-12-ol) and rel-(3R,7R,9R,10S)-9,10-dimethyl-6-methylene-4-oxatricyclo[7.4.0.03,7]tridec-1-ene (2, 8,12-epoxy-eremophila-9,11(13)-diene)), one with the valencane-skeleton (rel-(2R,8S,8aR)-2-(1,2,6,7,8,8a-hexahyro-8,8a-dimethyl-2-naphthyl)-propan-2-ol (3, valenca-1(10),8-dien-11-ol)) and four with the vetispirane-skeleton (rel-(5R,10R)-(2-isopropylidene-10-methyl-spiro[4,5]dec-6-ene-6-carbaldehyde (4, vetispira-2(11),6-dien-14-al), rel-(5R,7R,10R)-2-isopropylidene-10-methyl-6-rnethylene-spiro[4.5]decan-7-01 (5, vetispira-2(11),6(14)-dien-7-01), rel-(1R,2R)-9-isopropyl-2-rnethyl-8-oxatricyclo[7.2.1.01,6]dodec-5-ene (6, 2,14-epoxy-vetispir-6-ene) and rel-(1R,2R)-(9-isopropyl-2-methyl-8-oxatricyclo[7.2.1.01,6]dodeca-4,6-diene (7, 2,14-epoxy-vetispira-6(14),7-diene)). 2-(1,2,3,5,6,7,8,8a-octahydro-8,8a-dimethyl-2-naphthyl)-propanal (8, valenc- or eremophil-9-en-12-al) is tentatively identified.
Three fragrant sesquiterpenes have been isolated as major constituents from the wood of Aquilaria malaccensis and identified as α-agarofuran, (−)-10-epi-γ-eudesmol and oxo-agarospirol.
Two new sesquiterpene aldehydes, (−)-selina-3,11-dien-14-al and (+)-selina-4,11-dien-14-al, methyl ester derivatives of three new sesquiterpene carboxylic acids, (−)-methyl selina-3,11-dien-14-oate, (+)-methyl selina-4.11-dien-14-oate, and (+)-methyl 9-hydroxyselina-4,11-dien-14-oate, and a new nor-sesquiterpene ketone, (+)-1,5-epoxy-nor-ketoguaiene, have been isolated from Aquilaria agallocha (agarwood). Their structures have been established on the bases of detailed spectroscopic analyses and synthesis. The occurrences of dehydrojinkoh-eremol and neopetasane in agarwood were also confirmed by comparison of their mass spectral data and Rinn, on capillary GC with those of synthesized samples. The odoriferous properties of some natural and synthesized sesquiterpenes are also described.
Aquillochin, isolated from the whole plant of Aquilaria agallocha, has been shown to be a coumarinolignan, and a structure has been proposed on the basis of chemical and physical studies.