Glycoside constituents from Cayratia geniculata.

Using various chromatographic separations, six glycoside derivatives (1-6), including one new ent-labdane glucoside named cayratioside (1), were isolated from the methanol extract of Cayratia geniculata stems and leaves. Their structures were elucidated by detailed analysis of the 1D, 2D NMR, and HRESIQTOF mass spectra. The inhibitory effect of 1-6 on LPS-induced NO production in RAW264.7 cells was also evaluated. Among isolated compounds, 1 exhibited moderate activity with an IC50 value of 59.65 ± 1.85 µM.

Asterosaponins from the starfish Protoreaster nodosus.

Five asterosaponins (1-5), including one new compound named protonodososide (1), were isolated from the methanol extract of the starfish Protoreaster nodosus, after subjecting to various chromatographic separations. The structural elucidation was confirmed by careful analysis of the 1D, 2D NMR, and HR ESI QTOF mass spectra. The cytotoxicity of isolated compounds was evaluated on five human cancer cell lines including HepG2, KB, MCF7, LNCaP, and SK-Mel2.

Sulfated Naphthopyrones and Anthraquinones from the Vietnamese Crinoid Comanthus delicata.

Three new sulfated naphthopyrone derivatives namely delicapyrons F-H (1-3) and two new sulfated anthraquinone derivatives namely delicaquinons A (4) and B (5), together with 6-methoxycomaparvin-5-methylether-8-O-sodium sulfate (6), 6-methoxycomaparvin-8-O-sodium sulfate (7), comaparvin-8-O-sodium sulfate (8), and 3-propyl-1,6,8-trihydroxy-9,10-anthraquinone-6-O-sodium sulfate (9) were isolated from the Vietnamese crinoid Comanthus delicata. Their chemical structures were elucidated by extensive analysis of the one dimensional (1D) and 2D-NMR, high resolution electrospray ionization quadrupole time-of-flight (HR-ESI-QTOF) mass spectra as well as calculation of optical rotation. In addition, significant cytotoxicity was observed for 6 against LNCaP (prostate cancer) cell line with IC50 value of 20.29 ± 2.43 µM, whereas moderate or weak cytotoxic effects were observed for 1-3 and 5-8 on SK-Mel-2 (melanoma) cell line and 7 and 8 against LNCaP cell line, with IC50 values ranging from 49.96 ± 1.74 to 76.92 ± 5.85 µM.

Chemical Constituents from the Branches and Leaves of Alchornea trewioides.

Two new megastigmane glucosides namely trewiosides A (1) and B (2), along with 20α-hydroxypregn-4-en-3-one ß-D-glucopyranoside (3), sugeroside (4), and schizandriside (5) were isolated from the branches and leaves of Alchornea trewioides. The structure elucidation was confirmed by extensive analysis of the one and two dimensional (1 and 2D) NMR, electronic circular dichroism (ECD) as well as high resolution electrospray ionization quadrupole time-of-flight (HR-ESI-QTOF) mass spectra. Noteworthily, the isolation of compounds 1 and 2 represents the second finding of megastigmane derivatives with a methoxycarbonyl group at C-5 to date. In addition, compound 3 showed weak cytotoxicity against three human cancer cell lines as A549 (lung carcinoma), HepG2 (hepatocarcinoma), and MCF7 (breast carcinoma). Besides, compounds 2 and 3 exhibited moderate inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells. Whereas, the remaining compounds 1, 4 and 5 showed weak inhibitory activity.

Diterpenoids and Flavonoids from Andrographis paniculata.

Chemical investigation of the aerial parts of Andrographis paniculata resulted in isolation of nine compounds, including a new ent-labdane diterpenoid, andrographic acid methyl ester (1), a new chalcone glucoside, pashanone glucoside (5), and seven known metabolites, andrograpanin (2), andrographolide (3), andropanolide (4), andrographidine A (6), andrographidine F (7), 6-epi-8-O-acetyl-harpagide (8), and curvifloruside F (9). Their chemical structures were elucidated based on comprehensive analyses of the spectroscopic data, including NMR and MS. Among the isolated compounds, andropanolide exerted cytotoxicity toward LNCaP, HepG2, KB, MCF7, and SK-Mel2 carcinoma cells, with IC50 values ranging from 31.8 to 45.9 µM. In addition, andropanolide significantly inhibited the overproduction of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, with an IC50 value of 13.4 µM.

Anthraquinone and Butenolide Constituents from the Crinoid Capillaster multiradiatus.

Seven anthraquinones including two new compounds namely capillasterquinones A and B (1 and 2) and one new butenolide namely capillasterolide (8) were isolated and structurally elucidated from the crinoid Capillaster multiradiatus. The inhibitory effect of compounds 1-8 on lipopolysaccharide (LPS)-induced nitric oxide (NO) production as well as inhibition of 1 on expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) proteins in RAW264.7 cells were also evaluated. As the obtained results, capillasterquinone A (1) showed strong NO production inhibitory activity with an IC50 of 5.89±0.11 µM. In addition, compound 1 reduced the LPS-induced iNOS and COX-2 expressions in a dose-dependent manner.

Two new guaiane sesquiterpene lactones from the aerial parts of Artemisia vulgaris.

Two new guaiane sesquiterpene lactones, vulgarolides A and B (1 and 2), were isolated from Artemisia vulgaris aerial parts using various chromatographic separations. The structure elucidation was performed by combination of spectroscopic experiments including 1D and 2D NMR, HR ESI MS, and CD. Their in vitro cytotoxic activities against five human cancer cell lines were also evaluated using SRB method.

Flavonoid glycosides from Barringtonia acutangula.

Using various chromatographic separation techniques, ten flavonoid glycosides, including six new compounds namely barringosides A-F (1-6), were isolated from a methanol extract of the Barringtonia acutangula leaves. The structure elucidation was confirmed by spectroscopic analyses, including 1D and 2D NMR, and HR ESI MS. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were also evaluated. Among the isolated compounds, quercetin 3-O-ß-d-(6-p-hydroxybenzoyl)galactopyranoside (9) showed significant effect with an IC50 of 20.00±1.68µM. This is the first report of these flavonoid glycosides from Barringtonia genus and their inhibition on LPS-induced NO production in RAW264.7 cells was reported here for the first time.

Triterpene saponins and megastigmane glucosides from Camellia bugiamapensis.

Two new triterpene saponins, camelliosides I and J (1 and 2), two new megastigmane glycosides, camellistigosides A and B (3 and 4), and two known megastigmane glycosides, icariside B1 (5) and (6S,9R)-roseoside (6), were isolated from a methanol extract of the Camellia bugiamapensis leaves using various chromatographic separation techniques. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, CD, 1D and 2D NMR. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were evaluated. This is the first report of the chemical constituents and biological activity of C. bugiamapensis.

Cytotoxic triterpene diglycosides from the sea cucumber Stichopus horrens.

Using various chromatographic separation techniques, eight triterpene diglycosides (1-8), including four new compounds namely stichorrenosides A-D (1-4), were isolated from a methanol extract of the Vietnamese sea cucumber S. horrens. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, 1D and 2D NMR. Their in vitro cytotoxic activity against five human cancer cell lines, Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma), was evaluated using SRB methods. Stichorrenoside D (4), stichoposide A (5), and 3ß-O-[ß-d-xylopyranosyl-(1→2)-ß-d-xylopyranosyl]-23S-acetoxyholost-7-ene (7) showed strong cytotoxicity on all five tested cancer cell lines, whereas significant effect was observed for stichorrenoside C (3) and stichoposide B (6).

Cytotoxic Steroids from the Vietnamese Soft Coral Sinularia leptoclados.

Fifteen steroids, including two new compounds, leptosteroid (1) and 5,6ß-epoxygorgosterol (2), were isolated and structurally elucidated from the Vietnamese soft coral Sinularia leptoclados. Their cytotoxic effect against a panel of eight human cancer cell lines was evaluated using sulforhodamine B (SRB) method. Significant cytotoxicity against hepatoma cancer (HepG2, IC50=21.13±0.70 µM) and colon adenocarcinoma (SW480, IC50=28.65±1.53 µM) cell lines were observed for 1 and against acute leukemia (HL-60, IC50=20.53±2.26 µM) and SW480 (IC50=26.61±1.59 µM) for ergost-5-en-3ß,7ß-diol (8). In addition, 3ß,7ß-dihydroxyergosta-5,24(28)-diene (13) showed significant cytotoxic activity on all tested cell lines with IC50 values ranging from 13.45±1.81 to 29.01±3.21 µM.

Steroid glycosides from the starfish Pentaceraster gracilis.

Using combined chromatographic separations, two new steroid glycosides namely pentacerosides A (1) and B (2), and four known compounds were isolated from the methanol extract of the starfish Pentaceraster gracilis. Their structures were determined on the basis of spectroscopic data (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, ROESY, and FT-ICR-MS) and by comparing obtained results to the literature values. Among the isolated compounds, only maculatoside (5) showed significant cytotoxic effect against Hep-G2 (IC50 = 16.75 ± 0.69 µM) and SK-Mel2 (IC50 = 19.44 ± 1.45 µM) cell lines and moderate effect on KB (IC50 = 36.53 ± 0.78 µM), LNCaP (IC50 = 39.75 ± 3.34 µM), and MCF7 (IC50 = 47.34 ± 7.01 µM) cell lines.

Pyrrole Oligoglycosides from the Starfish Acanthaster planci Suppress Lipopolysaccharide-Induced Nitric Oxide Production in RAW264.7 Macrophages.

Two new pyrrole oligoglycosides, plancipyrrosides A and B (1 and 2), were isolated from methanol extract of the Vietnamese starfish Acanthaster planci using various chromatographic procedures. Their structures were elucidated by spectroscopic methods including one and two dimensional (1D- and 2D)-NMR and Fourier transform ion cyclotron resonance (FT-ICR)-MS. The finding of 1 and 2 represents the third case of pyrrole oligoglycosides obtaining reported to date. Moreover, plancipyrroside B (2) exhibits a potent inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells with IC50 of 5.94±0.34 µM, whereas plancipyrroside A (1) shows this inhibitory activity with IC50 of 16.61±1.85 µM.

Further Highly Hydroxylated Steroids from the Vietnamese Starfish Archaster typicus.

Eight highly hydroxylated steroids (1-8), including three new compounds as sodium salts of (24S)-5α-cholestane-3ß,4ß,5,6α,7ß,8,14,15α,24-nonaol 6-sulfate (1), (24E)-5α-cholest-24-ene-26-yde-3ß,6α,8,14,15α-pentaol 15-sulfate (2), and 5α-cholest-3ß,6α,8,14,15α,24,25,26-octaol 15-sulfate (3), were isolated and elucidated from the methanol extract of the Vietnamese starfish Archaster typicus. The structure elucidation was done by spectroscopic methods including one and two dimensional (1D-, 2D-)NMR and Fourier transform ion cyclotron resonance (FT-ICR)-MS. The isolated compounds can be used as chemical markers for taxonomic identification of the starfish A. typicus.

Cytotoxic triterpene saponins from Cercodemas anceps.

Seven holostane-type triterpene saponins (1-7), including five new compounds namely cercodemasoides A-E (2-6), were isolated from the sea cucumber Cercodemas anceps. Their structures were elucidated on the basis of spectroscopic evidence including HR ESI MS, ESI MS/MS, 1D and 2D NMR. The cytotoxic effects of isolated compounds were evaluated by SRB method on five human cancer cell lines including Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma). Compounds 1-7 showed potent cytotoxicity on five tested cancer cell lines with IC50 values ranging from 0.03 ± 0.01 to 7.36 ± 0.46 µM. With respect to the potent cytotoxicity of the isolated saponins, further studies are required to confirm efficacy in vivo and the mechanism of cytotoxic effects.

Cytotoxic Biscembranoids from the Soft Coral Sarcophyton pauciplicatum.

Ten biscembranoids (1-10), including the two new compounds sarcophytolides M and N (1 and 2), were isolated from the methanol extract of the Vietnamese soft coral Sarcophyton pauciplicatum. Their structures were elucidated by spectroscopic methods including one dimensional (1D)- and 2D-NMR, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and circular dichroism (CD). The in vitro cytotoxic activity of all isolated compounds against a panel of eight human cancer cell lines including HepG2 (hepatoma cancer), HL-60 (acute leukemia), KB (epidermoid carcinoma), LNCaP (prostate cancer), LU-1 (lung cancer), MCF7 (breast cancer), SK-Mel2 (melanoma), and SW480 (colon adenocarcinoma) was evaluated using the sulforhodamine B colorimetric assay. Among the isolated biscembranoids, 1, 3, 4, 7, 9, and 10 exhibited significant cytotoxic effects and may be selected for further studies of their anticancer activity.

Asterosaponins and glycosylated polyhydroxysteroids from the starfish Culcita novaeguineae and their cytotoxic activities.

Using combined chromatographic methods, two asterosaponins (compounds 1 and 2), including a new compound novaeguinoside E (compound 1), and six glycosylated polyhydroxysteroids (compounds 3-8) were isolated from a methanol extract of the starfish Culcita novaeguineae. Their structures were determined on the basis of spectroscopic data ((1)H and (13)C NMR, HSQC, HMBC, (1)H-(1)H COSY, ROESY, and HRESI-MS) and by comparison with the literature values. The new compound 1 represents the third example of asterosaponins containing the 5α-cholesta-9(1l)-en-3ß,6α,20,22-tetraol aglycone. Among isolated compounds, 4-7 exhibited moderate to weak cytotoxic activities against five human cancer cell lines such as Hep-G2 (hepatoma), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma).

Two new neoclerodane diterpenoids from Scutellaria barbata D. Don growing in Vietnam.

Various chromatographic separations of the aerial parts of Scutellaria barbata afforded two new neoclerodane diterpenoids, scutebatas S and T (1 and 2), along with scutebata D (3). Their structures were elucidated by spectroscopic methods including high-resolution electrospray ionization mass spectrometry, 1D and 2D NMR and comparison with the literature values. Compounds 1 and 3 exhibited moderate cytotoxic activities against HL-60 (promyeloblast) human cancer cells. Weak cytotoxic effects toward four tested human cancer cell lines including KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), MCF7 (breast cancer), and Hep-G2 (hepatoma cancer) were observed for 1 and 3; whereas 2 was inactive on all five tested cell lines.

Caffeoylquinic acid esters, lignans and flavones from Yua thomsonii with cytotoxic and nitric oxide inhibitory activities.

Phytochemical study on the aerial parts of Yua thomsonii resulted in the isolation of 11 secondary metabolites, including a new caffeoyl quinic acid derivative, 3-O-trans-caffeoyl-4-O-acetylquinic acid methyl ester (1), a new dihydrobenzofuran neolignan, 3,5-dimethoxy-4-(1″,3″-dihydroxy-2″-propyloxyl)-4',7-epoxy-8,5'-neolignan-4,9,9'-triol (3) and nine known compounds, methyl 4-O-coumaroylquinate (2), (7S*,8S*)-3-methoxy-3',7-epoxy-8,4'-oxyneolignan-4,9,9'-triol (4), kompasinol A (5), lyoniresinol (6), schizandriside (7), (-)-isolariciresinol 3a-O-ß-D-xylopyranoside (8), lyoniside (9), vitexin (10) and luteolin 4'-O-ß-glucopyranoside (11). Their structures were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR and HRESI mass spectra. The absolute configurations of 1 and 3 were deduced by electronic circular dichroism spectroscopy. Compounds 1, 3, 5 and 6 exhibited nitric oxide (NO) inhibitory effects, with IC50 values ranging from 12.18 to 29.45 µM. However, compounds 1, 3, 6 and 8 were non-cytotoxic towards HepG2 and MCF-7 carcinoma cells.

Pyrrole and furan oligoglycosides from the starfish Asterina batheri and their inhibitory effect on the production of pro-inflammatory cytokines in lipopolysaccharide-stimulated bone marrow-derived dendritic cells.

Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, astebatherioside D (4), were isolated from the starfish Asterina batheri by various chromatographic methods. Their structures were elucidated by spectroscopic and chemical methods. Compounds 2, 3, and 4 moderately inhibited IL-12 p40 production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) with IC50 values of 36.4, 31.6, and 22.8µM, respectively.