Sesquiterpenoids and bibenzyl derivative from Dendrobium hercoglossum.

Three new sesquiterpenoids, dendrohercoglin A - C (1-3), and one new bibenzyl derivative, dendronbiline D (4), together with nine known sesquiterpenoids (5-13) were isolated from Dendrobium hercoglossum. The structures of the new compounds were elucidated by extensive spectroscopic analysis as well as NMR and ECD calculations. All the compounds were evaluated for their neuroprotective and anti-inflammatory activities. Compounds 2 and 3 increased the H2O2-damaged SH-SY5Y cell viabilities from 43.3% to 58.6% and 68.4%, respectively. Compound 4 exhibited pronounced anti-inflammatory activity with IC50 value of 9.5 ± 0.45 µM which was superior to the reference compound quercetin (IC50: 15.7 ± 0.89 µM).

Anti-inflammatory and α-glucosidase inhibitory constituents from Dendrobium nobile Lindl.

Four new compounds ((±)-1-3), including one pair of enantiomers ((±)-1), along with 11 known bibenzyls (4-14) were isolated from Dendrobium nobile. The structures of the new compounds were elucidated by spectroscopic methods including 1D and 2D NMR as well as HRESIMS. The configurations of (±)-1 were established via the electronic circular dichroism (ECD) calculations. Compounds (+)-1 and 13 displayed pronounced α-glucosidase inhibitory activities with IC50 values of 16.7 ± 2.3 and 13.4 ± 0.2 µM, respectively, which were comparable to that of genistein (IC50, 8.54 ± 0.69 µM). Kinetic studies revealed that (+)-1 and 13 were non-competitive inhibitors against α-glucosidase and molecular docking simulations illuminated their interactions with α-glucosidase. All the isolates were also evaluated for their anti-inflammatory activities. Compounds 4, 5, and 11 exhibited superior inhibition activity with IC50 values ranging from 9.2 to 13.8 µM to that of quercetin (IC50, 16.3 ± 1.1 µM).

Seven new 2-(2-phenethyl)chromone derivatives from agarwood of Aquilaria walla.

Two rare flavonoid-2-(2-phenylethyl)chromones and five new dimeric 2-(2-phenylethyl)chromones were isolated from ethanol extract of agarwood of Aquilaria walla by LC-MS-guided fractionation procedure. Their structures were established based on extensive spectroscopic methods including HRESIMS, 1D and 2D NMR, as well as by comparison with the literature. Compound 1 showed cytotoxic activity against five human cancer cell lines with IC50 values ranging from 13.40 to 28.96 µM with cisplatin as the positive control.

Dimeric 2-(2-phenethyl)chromones from agarwood of Aquilaria filaria.

Four new 2-(2-phenethyl)chromone dimers (1-4) were isolated from EtOAc extract of agarwood originating from Aquilaria filaria from Philippines. Their structures were elucidated by spectroscopic analysis (1D and 2D NMR, and HRESIMS) and comparison of the experimental and computed ECD curves. Compounds 1-4 exhibited inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC50 values in the range from 33.94 to 57.53 µM.

LC-MS-guided isolation of 2-(2-phenylethyl)chromone dimers from red soil agarwood of Aquilaria crassna.

Six new 2-(2-phenylethyl)chromone dimers (1-6) were isolated from ethyl ether extract of red soil agarwood of Aquilaria crassna from Vietnam by LC-MS-guided fractionation procedure. Their structures were unambiguously elucidated based on HRESIMS, 1D and 2D NMR spectra. The absolute configuration of 2-(2-phenylethyl)chromone dimers was determined by comparison of the experimental and computed ECD spectra. Compound 6 displayed cytotoxicity against the human myeloid leukemia cell line (K562) with an IC50 value of 39.49 µM.

New sesquiterpenoids bearing 11-methyl ester group of agarwood.

Five new sesquiterpenoids (1-5), together with a known compound 6 was isolated from ethyl ether extract of agarwood. Their structures were elucidated on the basis of spectroscopic techniques (UV, IR, MS, 1D and 2D NMR), as well as by comparison with literature data. Compound 5 exhibited inhibitory activity against acetylcholinesterase with inhibition ratio of 48.33 ± 0.17% at the concentration of 50 µg/mL.

Six new dimeric 2-(2-phenylethyl)chromones from artificial agarwood of Aquilaria sinensis.

Six new dimeric 2-(2-phenylethyl)chromones (1-6) were isolated from the EtOAc extract of artificial agarwood originating from Aquilaria sinensis (Lour.) Glig. Their structures were unambiguously elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR), and HRESIMS analysis, as well as by comparison with the literature. The absolute configurations were determined by ECD spectra.

LC-MS guided identification of dimeric 2-(2-phenylethyl)chromones and sesquiterpene-2-(2-phenylethyl)chromone conjugates from agarwood of Aquilaria crassna and their cytotoxicity.

Four previously unreported dimeric 2-(2-phenylethyl)chromones (1-4a) and three unprecedented sesquiterpene-2-(2-phenylethyl)chromone conjugates (5-7), comprising a sesquiterpenoid and a 5,6,7,8-tetrahydroxy-2-(2-phenylethyl)-5,6,7,8 -tetrahydro-4H-chromone moiety, as well as three known dimeric 2-(2-phenylethyl)chromones (4b, 8a, 8b) were identified from agarwood originating from Aquilaria crassna in Cambodia by LC-MS guided separation. Their structures were elucidated by extensive NMR techniques, HRESIMS and CD. All compounds were evaluated for their cytotoxicity against four human cancer cell lines. Compounds 6, 7, 8a, 8b displayed a range of cytotoxic activities with IC50 values in the rang 10.93-49.0 µM.

New tricyclic prezizaane sesquiterpenoids from agarwood.

Ten new tricyclic prezizaane types sesquiterpenoids (1-10) were isolated from ethyl ether extract of agarwood originated from Aquilaria sp. Their structures were unambiguously elucidated on the basis of 1D and 2D NMR spectra as well as by HRESIMS data. The absolute configuration of the new prezizaenes 1, 2 and 4 was determined by single-crystal X-ray diffraction, while TDDFT-ECD method was applied for 6. Compounds 4 and 5 displayed significant inhibitory activities toward α-glucosidase with IC50 values of 0.22 and 1.99 mM, respectively.

[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)].

[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.

Five new epoxy-5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones from Chinese agarwood by artificial holing.

Five optically active epoxy-5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone derivatives (1-5) with four chirality centers in the condensed cyclohexene ring were isolated from artificial holing agarwood originating from Aquilaria sinensis (Lour.) Gilg. Their structures were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR) and MS analyses. The absolute configuration of 2 was elucidated by TDDFT-ECD calculations and ECD spectra of 1, 3-5 allowed their configurational assignment as well. All of the new compounds contained a condensed oxirane ring, and compound 1 was the only 6,7-epoxy-2-(2-phenylethyl)-5,6,7,8-tetrahydrochromone derivative that has ever been found in agarwood. AChE inhibitory activity was tested for the first time of these new compounds by using modified Ellman's colorimetric method. Compounds 3 and 5 exhibited inhibitory activity against AChE with IC50 value of 441.6, and 155.6 µM, respectively.

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.

Dimeric 2-(2-phenylethyl)chromones from the agarwood of Aquilaria crassna in Laos.

Four new dimeric 2-(2-phenylethyl)chromones (1-4) were isolated from the agarwood of Aquilaria crassna in Laos. All structures were determined based on extensive spectroscopic methods including IR, UV, 1D and 2D NMR, ECD, and HRMS. The structures of compounds 1-3 were characterized by two C-O-C linkages between the two chromone moieties, while compound 4 featured one C-O-C linkage and one CC bond connecting with two chromone moieties. Compounds 1 and 3 showed weak cytotoxicity against human hepatocellular carcinoma BEL-7402 cell line with IC50 values of 44.68 and 42.10 µΜ.

New secondary metabolites from the endophytic fungus Fusarium sp. HP-2 isolated from "Qi-Nan" agarwood.

A novel pyrone derivative (1) bearing two fused five-member rings, together with two new naphthalenone derivatives (2, 3), as well as two known compounds (4, 5) were obtained from the endophytic fungus Fusarium sp. HP-2, which was isolated from "Qi-Nan" agarwood. The structures of the new compounds were elucidated by analysis of 1D and 2D NMR, and by HRESIMS spectra, as well as by comparison with the literature. Bioactivity results indicated that compound 3 showed weak acetylcholinesterase inhibitory activity.

Nematicidal amide alkaloids from the seeds of Clausena lansium.

Five new amide alkaloids (1-3, 5-6) were isolated from the seeds of Clausena lansium together with one new natural product (4) and four known analogues (7-10). The structures of the new amide alkaloids 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 bioactivity results showed that compound 8 expressed potent nematicidal activity against Panagrellus redivevus, with IC50 value of 0.12 mM, while compounds 3 and 5 presented moderate nematicidal activity with IC50 values of 2.75 and 3.93 mM, respectively (abamectin as the positive control with IC50 value of 1.05 mM).

[A new sesquiterpene from Chinese agarwood induced by artificial holing].

In order to study the chemical constituents of n-butanol fraction of ethanol extract from Chinese agarwood induced by artificial holing, various chromatographic techniques were carried out to isolate compounds, and the structures of compounds were determined through a combined analysis of physicochemical properties and spectroscopic evidence. Seven compounds were obtained and identified as selina-3,11-dien-9,15-diol (1), aquilarone D (2), 5α,6ß,7α,8ß-tetrahydroxy-2-[2-(2-hydroxyphenyl)ethyl]-5,6,7,8-tetrahydrochromone (3), 6,7-dimethoxy-2-[2-(4-methoxyphenyl)ethyl]chromone (4), syringin (5), methyl (Z)-p-coumarate (6), and 4'-methoxycinnamic acid (7), among which compound 1 was a new compound and compounds 5-7 were isolated from agarwood for the first time. The bioactivity assay results concluded that compounds 6 and 7 showed certain nematicidal activity against Panagrellus redivivus, and compounds 4, 6 and 7 exhibited cytotoxicity against BEL-7402, SGC-7901 and A549 carcinoma cell lines.

A New Monoterpenoid and a New Flavonoid Glycoside from the Peels of Clausena lansium.

One new monoterpenoid, nerol oxide-8-carboxylic acid (1), and one new flavonoid glycoside, claulansoside A (2), together with six known compounds, clausenamide (3), quercetin (4), isorhamnetin (5), dihydromyric (6), 2",3"-dihydroxyanisolactone (7) and (E,E)-8-(7-hydroxy-3,7-dimethylocta-2,5-dienyloxy)psoralen (8), have been isolated from the peels of Clausena lansium (Lour.) Skeels. Their structures were determined using a combination of 1D, and 2D NMR (HMQC, HMBC, COSY and NOESY) techniques, and HR-ESI-MS analyses. Compounds 1 and 7 exhibited antibacterial activity against Staphylococcus aureus with the diameter of inhibition zones of 11.5 mm and 14.2 mm. Compounds 3 and 6 showed α-glucosidase inhibitory activity in vitro.

A new apotirucallane-type triterpenoid from Atalantia buxifolia.

A new triterpenoid (1) with apotirucallane skeleton was isolated from the ethanol extract of the roots of Atalantia buxifolia (Poir.) Oliv. The complete structural assignment of the new compound was elucidated by a combination of 1D, 2D NMR (HMQC, HMBC, COSY, and NOESY), and HR-ESI-MS analysis. Moreover, this new compound was evaluated in vitro for its cytotoxic, antimicrobial and enzymes inhibitory activities.