Two new anti-inflammatory trachylobane diterpenoids from Euphorbia atoto.

Two new rare trachylobane euphoratones A-B (1-2), together with five known diterpenoids (compounds 3-7), were isolated from the aerial parts of Euphorbia atoto. Their structures were unambiguously elucidated through HRESIMS, 1D and 2D NMR spectral analysis. Compounds 1, 3, 4 and 7 showed weak anti-inflammatory activities (IC50 77.49 ± 6.34, 41.61 ± 14.49, 16.00 ± 1.71 and 33.41 ± 4.52 µM, respectively), compared to the positive control quercetin (IC50 15.23 ± 0.65 µM).

New 2-(2-Phenylethyl)chromone derivatives from agarwood originating from Aquilaria sinensis.

Two new dimeric 2-(2-phenylethyl)chromones, aquilasinenones L and M (1 and 2), and one new monomer analogue, 5S, 6 R, 7S, 8 R-tetrahydroxy-[2-(3-methoxy-4-hydroxyphenyl)ethyl]- 5,6,7,8-tetrahydrochromone (3), together with two known compounds, were isolated from the artificial agarwood originating from Aquilaria sinensis. Compound 1 was the first structure found with C8-O-C4"' linkage among 2-(2-phenylethyl)chromone dimers. Their structures were unambiguously elucidated based on 1 D and 2 D NMR spectroscopy, as well as by comparison with the literature. The absolute configuration was determined by ECD calculation. None of the compounds exhibited acetylcholinesterase inhibitory activity.

Natural products in agarwood and Aquilaria plants: chemistry, biological activities and biosynthesis.

Covering: Up to the end of 2019.Agarwood is a resinous portion of Aquilaria trees, which is formed in response to environmental stress factors such as physical injury or microbial attack. It is very sought-after among the natural incenses, as well as for its medicinal properties in traditional Chinese and Ayurvedic medicine. Interestingly, the chemical constituents of agarwood and healthy Aquilaria trees are quite different. Sesquiterpenes and 2-(2-phenethyl)chromones with diverse scaffolds commonly accumulate in agarwood. Similar structures have rarely been reported from the original trees that mainly contain flavonoids, benzophenones, xanthones, lignans, simple phenolic compounds, megastigmanes, diterpenoids, triterpenoids, steroids, alkaloids, etc. This review summarizes the chemical constituents and biological activities both in agarwood and Aquilaria trees, and their biosynthesis is discussed in order to give a comprehensive overview of the research progress on agarwood.

Two new 2-phenylethylchromones from artificial agarwood by holing method.

Two new 2-(2-phenylethyl)chromone derivatives (1-2) were isolated from the ethyl acetate extract of artificial agarwood induced by holing method originating from Aquilaria sinensis (Lour.) Gilg, and they were isolated from this genus for the first time. The structures of these two new compounds were elucidated by extensive spectroscopic analyses, including UV, IR, one- and two-dimensional NMR and HRESIMS measurements. Bioassay tests of these two new compounds showed compounds 1 and 2 had weak inhibitory activity against acetylcholinesterase at a concentration of 50.0 µg/ml.

New antifungal cycloheximide epimers produced by Streptomyces sp. YG7.

A couple of new cycloheximide epimers, 13(α)-acetoxy-anhydroisoheximide (1) and 13(ß)-acetoxy-anhydroisoheximide (2), together with six known compounds (3-8), were obtained from the cultures of Streptomyces sp. YG7. The structures were elucidated based on a comprehensive spectroscopic data analysis including 1D and 2D NMR, as well as HRESIMS, and by comparison with the literature. The X-ray crystal analysis of 1 further confirmed the structure. All the compounds were tested for antifungal activity. Compounds 1, 2 and 5-8 showed moderate Canidia albicans inhibitory activity, while 5 and 6 presented moderate Pyricularia oryzae inhibitory activity. [Formula: see text].

Zizaane-Type Sesquiterpenoids and Their Rearranged Derivatives from Agarwood of an Aquilaria Plant.

Nine new sesquiterpenoids (1-9) were isolated from ethyl ether extract of agarwood originated from Aquilaria sp., including three novel sesquiterpenoids (1-3) derived from zizaane, together with six zizaane-type sesquiterpenoids (4-9). All structures were unambiguously elucidated based on 1D and 2D NMR spectra as well as by HRESIMS data. The absolute configuration of sesquiterpenoids was determined by comparison of the experimental and computed ECD spectra. In vitro anti-inflammatory assessment showed that compound 9 exhibited inhibition of NO production in LPS-stimulated RAW264.7 cells with an IC50 value of 62.22 ± 1.27 µM.

The Characteristic Fragrant Sesquiterpenes and 2-(2-Phenylethyl)chromones in Wild and Cultivated "Qi-Nan" Agarwood.

Recently, cultivated "Qi-Nan" (CQN) agarwood has emerged as a new high-quality agarwood in the agarwood market owing to its similar characteristics, such as high content of resin and richness in two 2-(2-phenylethyl)chromone derivatives, 2-(2-phenylethyl)chromone (59) and 2-[2-(4-methoxyphenyl)ethyl]chromone (60), to the wild harvested "Qi-Nan" (WQN) agarwood. In this study, we compared the chemical constituents and fragrant components of two types of WQN agarwood from A. agallocha Roxb. and A. sinensis, respectively, with CQN agarwood and ordinary agarwood varieties. Additionally, we analyzed different samples of WQN agarwood and CQN agarwood by GC-MS, which revealed several noteworthy differences between WQN and CQN agarwood. The chemical diversity of WQN was greater than that of CQN agarwood. The content of (59) and (60) was higher in CQN agarwood than in WQN agarwood. For the sesquiterpenes, the richness and diversity of sesquiterpenes in WQN agarwood, particularly guaiane and agarofuran sesquiterpenes, were higher than those in CQN. Moreover, guaiane-furans sesquiterpenes were only detected by GC-MS in WQN agarwood of A. sinensis and could be a chemical marker for the WQN agarwood of A. sinensis. In addition, we summarized the odor descriptions of the constituents and established the correlation of scents and chemical constituents in the agarwood.

Two new sesquiterpenoids from agarwood originated from Aquilaria sp.

Two new sesquiterpenoids (1 and 2), together with two known sesquiterpenoids (3 and 4), were isolated from agarwood originated from Aquilaria sp. Their structures were elucidated by extensive spectroscopic methods including 1D and 2D NMR, IR, HRESIMS, and comparison with the literatures. All compounds were evaluated for cytotoxicity against five human cancer cell lines, but none of them displayed significant activity. [Formula: see text].

[A new cytotoxic isoflavane from Dalbergiae Odoriferae Lignum].

Fourteen compounds were isolated from the ethanol extract of Dalbergiae Odoriferae Lignum by various chromatographic techniques, including column chromatographies on silica gel, Sephadex LH-20 and semi-preparative HPLC. Their structures were determined by spectroscopic techniques as S-3'-hydroxy-7,2',4'-trimethoxyisoxane(1), 2-(2',4'-dimethoxyphenyl)-6-hydroxybenzofuran(2), 2-(2'-hydroxy-4'-methoxyphenyl)-6-methoxybenzofuran(3), 7,2',4'-trimethoxydihydroisoflavone(4), sativanone(5), 3,9-dimethoxy-6H-benzofuro[3,2-c]chromen-6-one(6),(6 aS,11 aS)-homopterocarpin(7),(6 aS,11 aS)-8-hydroxy-3,9-dimethoxypterocarpan(8),(6 aS,11 aS)-3,8,9-trimethoxypterocarpan(9), isodalbergin(10), isoliquiritigenin(11), butein(12), butin(13) and 3,7,4'-trihydroxyflavone(14). Among them, compound 1 was a new compound, while 2 and 3 were new natural products, 6, 8, 9 and 14 were isolated for the first time from Dalbergiae Odoriferae Lignum. Compounds 1-14 were tested for their cytotoxic activity against human hepatoma cell line BEL-7402, human gastric cancer cell line SCG-7901, human lung cancer cell line A549, human chronic myeloid leukemia cell line K562 and HeLa human cervical cancer cellline by MTT method. Compound 1 exhibited significant cytotoxicity with IC_(50) values ranging from 2.85 to 11.62 µg·mL~(-1). In addition, 2, 11 and 12 showed weak cytotoxic activities.

Sesquiterpenoids and 2-(2-phenylethyl)chromones respectively acting as α-glucosidase and tyrosinase inhibitors from agarwood of an Aquilaria plant.

The ethyl ether extract of agarwood from an Aquilaria plant afforded six new sesquiterpenoids, Agarozizanol A - F (1-6), together with four known sesquiterpenoids and six known 2-(2-phenylethyl)chromones. Their structures were elucidated via detailed spectroscopic analysis, X-ray diffraction, and comparisons with the published data. All the isolates were evaluated for the α-glucosidase and tyrosinase inhibitory activities in vitro. Compounds 5, 7, 8, and 10 showed significant inhibition of α-glucosidase with IC50 values ranging between 112.3 ± 4.5 and 524.5 ± 2.7 µM (acarbose, 743. 4 ± 3.3 µM). Compounds 13 and 14 exhibited tyrosinase inhibitory effect with IC50 values of 89.0 ± 1.7 and 51.5 ± 0.6 µM, respectively (kojic acid, 46.1 ± 1.3). In the kinetic studies, compounds 5 and 14 were found to be uncompetitive inhibitors for α-glucosidase and mixed type inhibitors for tyrosinase, respectively. Furthermore, molecular docking simulations revealed the binding sites and interactions of the most active compounds with α-glucosidase and tyrosinase.

Two new compounds from the roots of Swietenia macrophylla.

Phytochemical investigation on the roots of Swietenia macrophylla yielded one new pharagmalin-type limonoid named 2-dehydroxyl-swietephragmin C (1) and one new xanthone, 1,5-dihydroxy-6-methoxy-6',6'-dimethyl-2H-pyrano[2',3':3,2]xanthone (2), in addition to three known compounds. The structures of the new compounds were unambiguously determined by comprehensive spectroscopic methods (NMR, UV, IR, MS), as well as by comparison with the reported data in the literature. Xanthones were reported from Swietenia genus for the first time.

Chemical constituents from Dendrobium hainanense.

A new phenolic derivative (1) and a new dihydrophenanthrene (2) were isolated from the aerial part of Dendrobium hainanense rofe, along with 12 known compounds. The structures of the new compounds were elucidated by spectroscopic analysis，and the relative configuration of compound 1 was determined by J-based configuration analysis (JBCA) method. Bioassay result indicated that compound 1 exhibited weak antibacterial activity against Canidia albicans and Ralstonia solanaceanum.

Two New AChE Inhibitors Isolated from Li Folk Herb Heilaohu "Kadsura coccinea" Stems.

Two new triterpenoids, named kadsuricoccins A and B, together with three known ones, were isolated from the Li folk herb Heilaohu, the stems of Kadsura coccinea (Lem.) A. C. Smith, which was used for food and as a healthy supplement. Their structures were elucidated by comprehensive analyses of mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopic data. To search healthy components, an acetylcholinesterase (AChE) inhibitory activity test by Ellman's Method was conducted, kadsuricoccins A and B showed activity with the AChE inhibit index (AII) up to 68.96% ± 0.19% and 57.8% ± 0.11% at 94 nM (compared with positive control tacrine AII 79.80% ± 0.20%, 9.4 nM), respectively.

Polyacetylenes from the Roots of Swietenia macrophylla King.

A phytochemical investigation of the roots of Swietenia macrophylla led to the isolation of seven polyacetylenes, including five new compounds (1-5) and two known ones (6-7). Their structures were elucidated by extensive spectroscopic analysis and detailed comparison with reported data. All the isolates were tested for their cytotoxicity against the human hepatocellular carcinoma cell line BEL-7402, human myeloid leukemia cell line K562, and human gastric carcinoma cell line SGC-7901. Compounds 1 and 6 showed moderate cytotoxicity against the above three human cancer cell lines with IC50 values ranging from 14.3 to 45.4 µM. Compound 4 displayed cytotoxicity against the K562 and SGC-7901 cancer cell lines with IC50 values of 26.2 ± 0.4 and 21.9 ± 0.3 µM, respectively.

Three New 2-(2-Phenylethyl)chromone Derivatives of Agarwood Originated from Gyrinops salicifolia.

Two new 2-(2-phenylethyl)chromone derivatives (1⁻2), comprising 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone and benzylacetone moieties, together with one new 2-(2-phenylethenyl)chromone (3) were isolated from the ethyl acetate extraction of agarwood originated from Gyrinops salicifolia Ridl. All structures were unambiguously elucidated on the basis of 1D and 2D NMR spectra as well as by HRESIMS data. All isolated compounds were tested for acetylcholinesterase (AChE) inhibitory activity and cytotoxic activity against human myeloid leukemia cell line (K562). However, none of the compounds displayed AChE inhibitory activity at a concentration of 50 µg mL-1 or cytotoxic activity against K562 cell line.

[A new eudesmane type sesquiterpene from cultivated Clerodendranthus spicatus in Hainan].

Six compounds were isolated from the aerial part of cultivated Clerodendranthus spicatus in Hainan with various chromatographic techniques,and their structures were determined as:1-dehydroxy-1-oxo-rupestrinol(1),N-trans-feruloyltyramine(2),methyl 3,4-dihydroxyphenyllactate(3),caffein acid(4),methyl caffeate(5) and ethyl caffeate(6),via analysis of physicochemical properties and spectroscopic evidence.Compound 1 was a new compound,while compounds 2 and 3 were isolated from C.spicatus for the first time.Biological activity results showed that compounds 2-4 exhibited α-glucosidase inhibitory activity with different inhibition ratio.

[Study on sesquiterpenes from agarwood originating from Gyrinops salicifolia].

Two sesquiterpenes were isolated from the agarwood originating from Gyrinops salicifolia with various chromatographic techniques, and their structures were determined as 12-hydroxy-dihydrocyperolone(1) and(rel)-4ß,5ß,7ß-eremophil-9-en-12,8α-olide(2), through a combined analysis of physicochemical properties and spectroscopic evidence. Compound 1 was a new compound. Compound 2 showed cytotoxicities against K562 and BEL-7401 cell lines, with IC_(50) values of(17.85±0.04) and(21.82±0.07) mg·L~(-1), respectively [taxol as positive control, with IC_(50) values of(1.97±0.11) and(6.31±0.08) mg·L~(-1)].

Identification, characterization and expression analysis of genes involved in steroidal saponin biosynthesis in Dracaena cambodiana.

Dracaena cambodiana is a traditional medicinal plant used for producing dragon's blood. The plants and dragon's blood of D. cambodiana contain a rich variety of steroidal saponins. However, little is known about steroidal saponin biosynthesis and its regulation in D. cambodiana. Here, 122 genes encoding enzymes involved in steroidal saponin biosynthesis were identified based on transcriptome data, with 29 of them containing complete open reading frames (ORF). Transcript expression analysis revealed that several genes related to steroidal saponin biosynthesis showed distinct tissue-specific expression patterns; the expression levels of genes encoding the key enzymes involved in the biosynthesis and early modification of steroidal saponins were significantly down-regulated in the stems in response to the inducer of dragon's blood, exhibiting positive correlations with the content of steroidal saponins. These results provide insights on the steroidal saponins biosynthetic pathway and mechanisms underlying induced formation of dragon's blood in D. cambodiana.

Two new alkaloids from the twigs of Trigonostemon filipes.

A phytochemical investigation of the alkaloid constituents from Trigonostemon filipes Y. T. Chang et S. L. Mo led to the isolation of two new indole alkaloids, trigonostemine G (1) and trigonostemone J (2), together with two known ones, trigonostemine A (3) and trigonostemine B (4). Their structures were determined by extensive spectroscopic methods. Compounds 1-4 exhibited moderate AChE inhibitory activity with inhibition ratio of 31.6, 31.7, 41.7, and 42.4%, respectively. In addition, compounds 1-2 showed weak cytotoxicity against K562 and BEL-7402 human cancer cell lines.

Two new 2-(2-Hydroxy-2-phenylethyl)chromens from agarwood originating from Aquilaria crassna.

Two new 2-(2-hydroxy-2-phenylethyl)chromones (1‒2), along with three known 2-(2-phenylethyl)chromones (3‒5), were isolated from the agarwood originating from Aquilaria crassna Pierre ex Lecomte. Their structures were determined by the spectroscopic methods including 1D and 2D NMR analysis and comparison with reported data in the literature. All the compounds were isolated from agarwood of A. crassna for the first time. Compounds 1 and 2 exhibited inhibitory activity against acetylcholinesterase (AChE) with 17.4 ± 0.6 and 15.8 ± 0.7%, respectively, at a concentration of 50 µg/ml. Besides, Compound 3 expressed antibacterial activities against Ralstonia solanacearum with diameter of the inhibition zone of 6.80 ± 0.08 mm at a concentration of 10 mg/ml.