Cryptobuchanosides A-G: seven previously undescribed triterpene glycosides from Cryptolepis buchananii R.Br. ex Roem. and Schult. with nitric oxide production inhibition activity.

In this study, nine triterpene glycosides including seven previously undescribed compounds (1-7), were isolated from leaves of Cryptolepis buchananii R.Br. ex Roem. and Schult. using various chromatographic methods. The chemical structures of the compounds were elucidated to be 3-O-ß-D-glucopyranosyl-(1 → 6)-ß-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (1), 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (2), 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosyluncargenin C 28-O-ß-D-glucopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (3), 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranosylhederagenin 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (4), 3-O-ß-D-glucopyranosylarjunolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (5), 3-O-ß-D-glucopyranosyl-(1 → 2)-ß- D-glucopyranosyl-6ß,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (6), 3-O-ß-D-glucopyranosyl-6ß,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (7), asiatic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (8), and 3-O-ß-D-glucopyranosylasiatic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl ester (9), through infrared, high-resolution electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance spectral analyses. The isolates inhibited nitric oxide production in lipopolysaccharide-activated RAW 264.7 cells, with half-maximal inhibitory concentration (IC50) values of 18.8-58.5 µM, compared to the positive control compound, dexamethasone, which exhibited an IC50 of 14.1 µM.

Undescribed (2-7')-neolignans and polyoxygenated cyclohexene glycosides from the aerial parts of Piper mutabile C. DC. and their inhibitory effects on nitric oxide production.

A phytochemical study of the aerial parts of Piper mutabile C. DC. revealed seven undescribed compounds [two (2-7')-neolignans and five polyoxygenated cyclohexene glycosides] and six known propenylcatechol derivatives. The chemical structures of the isolated compounds were elucidated by extensive HR-ESI-MS and NMR analyses, as well as comparison with the literature. The absolute configurations of the (2-7')-neolignans were confirmed by GIAO 13C NMR calculations with a sorted training set strategy and TD-DFT calculation ECD spectra. The (2-7')-neolignans and polyoxygenated cyclohexene glycosides are unusual in natural sources. Undescribed neolignans 1 and 2 inhibited NO production in RAW 264.7 cells, with respective IC50 values of 14.4 and 9.5 µM.

Undescribed Triterpenes from the Leaves of Syzygium myrsinifolium with Their α-Glucosidase and α-Amylase Inhibition Activity.

Two undescribed triterpenes, syzyfolium A (1) and syzyfolium B (2), together with twelve known compounds, terminolic acid (3), actinidic acid (4), piscidinol A (5), threo-dihydroxydehydrodiconiferyl alcohol (6), lariciresinol-4-O-ß-D-glucoside (7), icariol A2 (8), 14ß,15ß-dihydroxyklaineanone (9), garcimangosone D (10), (+)-catechin (11), myricetin-3-O-α-L-rhamnopyranoside (12), quercitrin (13), and 3, 4, 5-trimethoxyphenyl-(6'-O-galloyl)-O-ß-D-glucopyranoside (14) were isolated from the leaves of Syzygium myrsinifolium. Their chemical structures were determined by IR, HR-ESI-MS, 1D and 2D NMR spectra. Compounds 3 and 4 inhibited significantly α-glucosidase with IC50 values of 23.99 and 36.84, respectively, and compounds 1 and 2 inhibited significantly α-amylase with IC50 values of 35.48 and 43.65 µM, respectively.

Phytochemical constituents from the rhizomes of Kaempferia parviflora Wall. ex Baker and their acetylcholinesterase inhibitory activity.

Phytochemical study on the rhizomes of Kaempferia parviflora led to the isolation of twenty-three compounds including six phenolic glycosides (1-6), thirteen flavones (7-19), and five phenolic compounds (20-23). Of these, the new compounds were determined to be 2,4-dihydroxy-6-methoxyacetophenone-2-ß-D-apiofuranosyl-(1→6)-ß-D-glucopyranoside (1), 2-hydroxy-4-propionyl-phenyl O-ß-D-glucopyranoside (2), and 4-hydroxy-3,5-dimethoxyacetophenone 8-O-α-L-rhamnopyranosyl-(1→6)-ß-D-glucopyranoside (3) and named as kaempanosides A-C, respectively. Their chemical structures were established based on HR-ESI-MS, 1D and 2D NMR spectra. All compounds 1-23 exhibited acetylcholinesterase inhibitory activity with IC50 values ranging from 57.76 to 253.31 µM.

Chemical constituents from the heterotrophic marine microalgae Aurantiochytrium sp. SC145 and their antimicrobial activities.

One new indol, N-methoxymethyltryptophol (1), one new phenolic, (2 R)-2-(4-hydroxyphenyl)ethyl 2-hydroxy-3-phenylpropanoate (2) and fifteen known compounds (3-17) were isolated from the methanol extract of the fermentation of marine microalgae Aurantiochytrium sp. SC145. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, quantum chemical calculation methods and by comparing their NMR data with those reported in the literature. All compounds were evaluated for their antimicrobial activities against microorganisms. Compounds 2, 3 and 11 significantly exhibited antimicrobial activities on all tested Gram-(+), Gram-(-) bacteria and the yeast C. albicans with MIC values ranging from 32 to 256 µg/mL.

Four Steroidal Saponins from the Trunks of Dracaena cambodiana with Inhibition of NO Production in LPS Activated RAW264.7 Cells.

Dracaena cambodiana Pierre ex Gagnep. is well known as a medicinal plant and widely distributed in Vietnam. Phytochemical investigation on the trunks of D. cambodiana lead to the isolation of four undescribed compounds (1-4) together with seven known ones (5-11). Their structures were determined to be pennogenin-24-yl-O-ß-D-glucopyranoside (1), 17α-hydroxycambodianoside C (2), (25R)-27-hydroxypenogenin 3-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (3), (3ß,25R)-17α,22α-dihydroxy-furost-5-en-3-yl-O-α-L-rhamnopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (4), dracagenin A (5), 1-O-ß-D-glucopyranosyl-2-hydroxy-4-allylbenzene (6), 1-O-α-L-rhamnopyranosyl-(1→6)-ß-D-glucopyranosyl-2-hydroxy-allylbenzene (7), 2-O-α-L-rhamnopyranosyl-(1→6)-ß-D-glucopyranosyl-1-hydroxy-allylbenzene (8), cinnamrutinoside A (9), icariside D1 (10), and seco-isolariciresinol 9-O-ß-glucopyranoside (11) by extensive spectroscopic investigation, HR-ESI-MS, 1D and 2D NMR spectra. The anti-inflammatory activity of the isolated compounds was evaluated on macrophages. Compounds 1-6 significantly inhibited nitric oxide production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Among them, compound 1 showed the best inhibitory activity with an IC50 value of 8.90±0.56 µM.

Acetylcholinesterase inhibition studies of alkaloid components from Crinum asiaticum var. sinicum: in vitro assessments by molecular docking and molecular dynamics simulations.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1-7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease.

Three Undescribed Iridoid Derivatives Isolated from the Fruits of Vitex trifolia with Their Cytotoxic and Antimicrobial Activities.

Vitex trifolia L. is a medicinal plant and widely distributed in the northern mountainous areas of Vietnam. Phytochemical study on the fruits of this plant led to the isolation of nine iridoid derivatives (1-9) including three undescribed compounds (1-3). Their structures were elucidated to be 3''-hydroxyscrophuloside A1 (1), 3''-hydroxycallicoside D (2), 2'-p-hydroxybenzoylaucubin (3), 6'-p-hydroxybenzoylmussaenosidic acid (4), nishindaside (5), agnuside (6), 10-O-vanilloylaucubin (7), 6'-O-p-hydroxybenzoyl-gardoside (8), and buddlejoside B (9) based on extensive analyses of HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1, 2, 4, and 8 significantly posessed anti-barterial activity against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa strains with MIC values in range of 16-64 µg/mL. At concentration of 20 µM, compounds 1-9 did not show cytotoxic effects against human lung cancer cells (PC9).

Discovery of Four New Compounds from Macropanax membranifolius and Their Cytotoxic Activity.

A phytochemical investigation of the methanolic extract of the Macropanax membranifolius C.B. Shang leaves led to the isolation of three new flavans, (2R,3R)-4'-O-methylcatechin 5-O-ß-D-glucopyranoside (1), (2S,3S)-4'-O-methylcatechin 5-O-ß-D-glucopyranoside (2), (2S,3R)-4'-O-methylcatechin 5-O-ß-D-glucopyranoside (3), one new triterpene glycoside 3-O-ß-D-xylopyranosyl-(1→6)-[ß-D-xylopyranosyl-(1→2)]-ß-D-glucopyranosyl-oleanolic acid 28-O-ß-D-glucopyranoside (4), together with nine known compounds (5-13). Their chemical structures were elucidated based on HR-ESI-MS, NMR spectroscopic data. The absolute configurations of compounds 1-3 were established by electronic circular dichroism (ECD) spectra. At concentration of 20 µM, compounds 1-13 showed the percentages of dead cell in the range of 2.14 % to 33.61 % against KB, HepG2, HL60, P388, HT29, and MCF7 cancerous cell lines by SRB assay.

Four New Stilbene Derivatives Isolated from Gnetum latifolium var. funiculare Markgr. and Their Inhibition of NO Production in LPS-activated RAW264.7 Cells.

Gnetum latifolium var. funiculare Markgr. is a medicinal plant and widely distributed in mountainous areas of Vietnam. Phytochemical investigation on the trunks of this plant afforded eight stilbene derivatives (1-8) including for new compounds (1-4). Their structures were determined based on extensive analyses of HR-ESI-MS, 1D and 2D NMR spectra. Among the isolates, compounds 1-3 showed moderate NO production inhibition in LPS-activated RAW264.7 cells with the IC50 values ranging from 46.81 to 68.10 µM, compounds 4 and 6 showed weak effects with the IC50 values of 96.57 and 79.46 µM, respectively, compared to that of the positive control compound, dexamethasone (IC50 14.20 µM).

Undescribed 2,9-deoxyflavonoids and flavonol-diamide [3+2] adduct from the leaves of Aglaia odorata Lour. Inhibit nitric oxide production.

Phytochemical study on the methanol extract of Aglaia odorata leaves resulted in the isolation of four previously undescribed compounds, including three 2,9-deoxyflavonoids and one flavonol-diamide [3 + 2] adduct, and 13 known compounds. The chemical structures of the four undescribed compounds were elucidated on the basis of their IR, HR-ESI-MS, 1D and 2D NMR, and ECD spectra. The results revealed an unprecedented 2,9-deoxyflavonoid framework, which was confirmed by TD-DFT, ECD, and GIAO 13C-NMR calculations using sorted training set methods. The 17 compounds were examined for their ability to inhibit NO production activity in cultured lipopolysaccharide-activated RAW264.7 cells with aglaodoratas A-C, odorine, and epi-odorine inhibiting NO production, with IC50 values in the range of 16.2-24.3 µM. The other investigated compounds had either weak or no activity.

Four new lignans obtained from the leaves of Schisandra cauliflora and their effect on skeletal muscle cell proliferation.

Plants of the Schisandra genus are commonly used in folk medicinal remedies. Some Schisandra species and their lignans have been reported to improve muscle strength. In the present study, four new lignans, named schisacaulins A-D, together with three previously described compounds ananonin B, alismoxide, and pregomisin were isolated from the leaves of S. cauliflora. Their chemical structures were determined by extensive analyses of HR-ESI-MS, NMR, and ECD spectra. Schisacaulin D and alismoxide significantly stimulated skeletal muscle cell proliferation by increasing the number of fused myotubes and expression of myosin heavy chain (MyHC) which may be good candidates for the treatment of sarcopenia.

New nitric oxide production inhibitors from Syzygium bullockii.

Three undescribed triterpene glycosides syzybullosides A-C (1-3) along with fourteen known compounds were isolated from the leaves of Syzygium bullockii (Hance) Merr.& L.M. Perry, including six triterpene glycosides (1-6), four phenolics (7-9, 17), four megastigmanes (10-13), and three flavonoids (14-16). The structures of 1-17 were elucidated by extensive spectroscopic analysis, including IR, HR-ESI-MS, 1D and 2D NMR spectra. Compounds 1-10 and 12-17 inhibited nitric oxide (NO) production in lipopolysaccharide activated RAW264.7 cells with IC50 values ranging from 1.30 to 13.70 µM, lower than that of the positive control compound, L-NMMA (IC50 = 33.8 µM).

Polypunctosides E-K: seven new steroidal saponins from Polygonatum punctatum Royle ex Kunth and their nitric oxide production inhibitory activities.

Polygonatum punctatum Royle ex Kunth is a high-value medicinal plant found in old natural forests. A phytochemical study on the roots of this plant led to the isolation of seven new steroidal saponins including four furostans (1-4) and three furospirostans (5-7). Their structures were elucidated as (25R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-3ß,17α,22α,26-tetraol 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (1), (25R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-3ß,14α,17α,22α,26-pentaol 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (2), (25R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3ß,17α,26-triol 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (3), (25R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3ß,17α,26-triol 3-O-[α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)]-[acetoxy-(→ 6)]-ß-D-galactopyranoside (4), 26-O-(ß-D-glucopyranosyl)-14α,17α-dihydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (5), 26-O-(ß-D-glucopyranosyl)-17α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (6), and 26-O-(ß-D-glucopyranosyl)-14α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 4)-ß-D-galactopyranoside (7) by extensive spectroscopic analyses, including infrared, high-resolution electrospray ionization mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopy. Compounds 1-7 inhibited nitric oxide production in lipopolysaccharide activated RAW264.7 cells with IC50 values ranging from 41.5 ± 3.2 to 62.2 ± 3.7 µM, compared to 33.8 ± 2.6 µM for the positive control compound L-NMMA.

One new furostane saponin from Allium ramosum and lipid accumulation inhibitory activity.

A new furostane saponin, ramosaponin (1), and four known furostane saponins, protodioscin (2), dehydrotomatoside (3), (25 R)-26-O-(ß-D-glucopyranosyl)-furost-5-ene-3ß,22α,26-triol 3-O-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranoside (4), and anguivioside A (5) were isolated from the methanol extract of Allium ramosum seeds. Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for reduction of lipid accumulation in HepG2 cell line. As a result, compound 1 showed significant lipid accumulation inhibitory activity with an IC50 value of 64.32 ± 3.87 µM.

Furostane Saponins from the Seeds of Allium ramosum and Their Lipid Accumulation Inhibitory Activity.

Three new furostane saponins, ramofurosides A-C (1-3), and two known saponins, fistulosaponin B (4) and (25R)-26-O-ß-D-glucopyranosyl-1ß,3ß,26-trihydroxyfurosta-5,20(22)-diene-1-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (5) were isolated from the methanol extract of Allium ramosum seeds. Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for reduction of lipid accumulation in HepG2 cell lines. As a result, compounds 1 and 3 showed a significant reduction in total lipid content by 27.93±3.05 and 27.54±1.68 %, respectively, at a concentration of 100 µM.

Dihydrostilbene glycosides from Camellia sinensis var. assamica and their cytotoxic activity.

Three undescribed dihydrostilbene glycosides, 3,5-dihydroxyldihydrostilbene 4'-O-[6''-O-(4'''-hydroxylbenzoyl)]-ß-D-glucopyranoside (1), 3,5-dihydroxyldihydrostilbene 4'-O-(6''-O-galloyl)-ß-D-glucopyranoside (2), and 3,5-dihydroxyldihydrostilbene 4'-O-[6''-O-(3''',4'''-dimethoxyl)galloyl]-ß-D-glucopyranoside (3), and seven known compounds, kaempferol 3-O-ß-D-glucopyranoside (4), isoquercitrin (5), kaempferol 3-O-α-L-rhamnoside (6), quercitrin (7), (6S,9R)-roseoside (8), (-)-epicatechin 3-O-gallate (9), and (-)-epigallocatechin 3-O-gallate (10) have been isolated from the methanol extract of the leaves of Camellia sinensis var. assamica (J.W.Mast.) Kitam. (synnonym of Camellia assamica (Mast.) H.T.Chang) (Theaceae). Their structures were elucidated by spectroscopic methods (1 D-, 2 D-NMR) and mass spectra. All compounds were evaluated for cytotoxic activity against human oral cancer (CAL27) and human breast cancer (MDAMB231) cell lines. Compound 10 showed significant cytotoxic activity against CAL27 and MDAMB231 cell lines with IC50 values of 9.78 ± 0.25 and 3.27 ± 0.18 µM, respectively, compared to those of positive control, capecitabine (IC50 values of 8.20 ± 0.75 and 5.20 ± 0.89 µM).

New phenolics from Uraria crinita (L.) DC.

Reinvestigation of a methanol extract of Uraria crinita afforded a new 3- hydroxyisoflavanone, 3,5,7,2',4'-pentahydroxyisoflavanone (1), two new monoaryl glucosides, 3,4-dimethoxyphenyl 1-O-(6'-O-acetyl)-ß-D-glucopyranoside (2) and 3,4,5-trimethoxyphenyl 1-O-(6'-O-acetyl)-ß-D-glucopyranoside (3), in addition to three known compounds, 3'-O-methylorobol (4), robusflavone B (5), and apigenin (6). The structural elucidation of these compounds was achieved by analyses of their spectroscopic data (HR-ESI-MS, 1 D- and 2 D-NMR) and acidic hydrolysis. The U. crinita extracts and compounds 1-6 exhibited weak or no cytotoxic activity against KB, HepG2, Lu and MCF7 cell lines.

New phenolics from Dianella ensifolia.

Phytochemical investigation and chromatographic separation of extracts from the aerial parts of Dianella ensifolia (L.) DC. (synonym Dianella nemorosa Lam. Ex. Schiler f.) led to the isolation of 10 compounds, the structures of which were determined by HR-ESI-MS and 1 D- and 2 D-NMR spectroscopies, and by comparisons with published studies. Among the isolated compounds were three flavans, a biflavan, a biflavone, a tetralone, a naphthalen glycoside, an aromatic compound, and two steroids. Six of these were known chemicals, while three were identified as new compounds: 7-acetyl-4R,8-dihydroxy-6-methyl-1-tetralone, 2(S),2',4'-dihydroxy-7-methoxyflavan, and diaensi-biflavan. 2(S),7,4'-dimethoxy flavan was obtained for the first time as a natural product.

Two new terpenoids from the leaves of callicarpa macrophylla.

Two new terpenoids (1-2) and seven known compounds (3-9) were isolated from methanol extract of Callicarpa macrophylla leaves. Their structures were determined to be ent-7α,16ß,17,18-tetrahydroxykaur-15-one (1), 3ß-acetoxy-urs-12-ene-11-one-12-ol (2), ent-1ß-acetoxy-7α,14ß-dihydroxykaur-16-en-15-one (3), 3ß-acetoxy-11α,13ß-dihydroxyolean-12-one (4), ß-amyrin (5), spinasterol (6), ursolic acid (7), ß-sitosterol (8), and daucosterol (9) by analyses of their MS, NMR spectroscopic data and by comparison with those reported in the literature. Compounds 1 - 4, and 7 displayed potential cytotoxic activity towards HepG-2, LU-1, and MCF-7 human cancer cell lines with IC50 values ranging from 0.46 ± 0.21 to 18.14 ± 0.33 µM. Compound 6 showed IC50 values of 14.17 ± 0.21 and 5.72 ± 0.42 µM against Hep-G2 and MCF-7 cell lines, respectively.