Antimicrobial constituents from the leaves of <i>Hibiscus tiliaceus</i> L.

Repeated column chromatography resulted in the isolation of two new megastigmane derivatives, methyl-tiliaceates A and B (1 and 2), along with four known metabolites (3–6) from the leaves of Hibiscus tiliaceus L. The structures of the purified phytochemicals were elucidated by interpreting their NMR, HRESIMS, and CD spectroscopic data, as well as comparison with the previous literature. The compounds isolated were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms (Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans). Compound 1 showed obvious selective inhibition against the B. cereus strain, whereas 3 − 5 showed weak inhibitory activities against E. faecalis and S. aureus bacterial, and C. albicans fungal strains (with MIC values ranging from 128 to 256 µg/mL).</p

Two new guaiane sesquiterpene lactones from the aerial parts of <i>Artemisia vulgaris</i>

<p>Two new guaiane sesquiterpene lactones, vulgarolides A and B (<b>1</b> and <b>2</b>), were isolated from <i>Artemisia vulgaris</i> 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 <i>in vitro</i> cytotoxic activities against five human cancer cell lines were also evaluated using SRB method.</p

Anti-inflammatory Asterosaponins from the Starfish <i>Astropecten monacanthus</i>

Four new asterosaponins, astrosteriosides A–D (<b>1</b>–<b>3</b> and <b>5</b>), and two known compounds, psilasteroside (<b>4</b>) and marthasteroside B (<b>6</b>), were isolated from the MeOH extract of the edible Vietnamese starfish <i>Astropecten monacanthus</i>. Their structures were elucidated by chemical and spectroscopic methods including FTICRMS and 1D and 2D NMR experiments. The effects of the extracts and isolated compounds on pro-inflammatory cytokines were evaluated by measuring the production of IL-12 p40, IL-6, and TNF-α in LPS-stimulated bone marrow-derived dendritic cells. Compounds <b>1</b>, <b>5</b>, and <b>6</b> exhibited potent anti-inflammatory activity comparable to that of the positive control. Further studies are required to confirm efficacy <i>in vivo</i> and the mechanism of effects. Such potent anti-inflammatory activities render compounds <b>1</b>, <b>5</b>, and <b>6</b> important materials for further applications including complementary inflammation remedies and/or functional foods and nutraceuticals

Sesquiterpene constituents from the soft coral <i>Sinularia nanolobata</i>

<p>Using various chromatographic separations, four sesquiterpenes (<b>1</b>–<b>4</b>), including two new compounds, nanolobatols A and B (<b>1</b> and <b>2</b>), were isolated from the Vietnamese soft coral <i>Sinularia nanolobata</i>. Their structures were determined on the basis of spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H–¹H COSY, NOESY and FT-ICR-MS) and by comparison with the literature values. The cytotoxic activity of isolated compounds against a panel of eight human cancer cell lines was also evaluated.</p

Steroid constituents from the soft coral <i>Sinularia microspiculata</i>

<p>A methanol extract of the soft coral <i>Sinularia microspiculata</i> revealed five sterols, including two new compounds. Using combined chromatographic and spectroscopic experiments, the new compounds were found to be 7-oxogorgosterol (<b>1</b>) and 16α-hydroxysarcosterol (<b>2</b>). Their structures were determined on the basis of spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, NOESY, and FT-ICR-MS) and by comparing obtained results to the values indicated in previous studies. Among the isolated compounds, <b>3</b> showed weak cytotoxic effects against HL-60 (IC₅₀ =  89.02  ±  9.93 μM) cell line, whereas <b>5</b> was weakly active against HL-60 (IC₅₀ =  82.80  ±  13.65 μM) and SK-Mel2 (IC₅₀ =  72.32  ±  1.30 μM) cell lines.</p

Cytotoxic triterpene saponins from the mangrove <i>Aegiceras corniculatum</i>

<p>Using various chromatographic separations, sixteen compounds, including one new triterpene saponin named aegicoroside A (<b>1</b>), were isolated from the leaves of the Vietnamese mangrove <i>Aegiceras corniculatum</i>. Their structures were determined by spectroscopic methods such as 1D and 2D NMR and HR-ESI-MS. The cytotoxic activities of the isolated compounds against MCF7 (breast), HCT116 (colon), B16F10 (melanoma), and A549 (adenocarcinoma) cancer cell lines were also evaluated. Strong cytotoxicity was observed for sakurasosaponin (<b>2</b>) against all four cancer cell lines and for sakurasosaponin methyl ester (<b>3</b>) against MCF7, A549, and HCT116 cell lines with IC₅₀ values ranging from 2.89 ± 0.02 to 9.86 ± 0.21 μM.</p

Polar steroid derivatives from the Vietnamese starfish <i>Astropecten polyacanthus</i>

<p>Five polar steroid derivatives, including one new glycosylated polyhydroxysteroid namely polyacanthoside A (<b>1</b>), were isolated from the water-soluble materials from the MeOH extract of the Vietnamese starfish <i>Astropecten polyacanthus</i> using various chromatographic separations. The structure elucidation was confirmed by spectroscopic experiments such as HR-ESI-MS, 1D and 2D NMR. Among the isolated compounds, (20<i>R</i>,24<i>S</i>)-3<i>β</i>,6<i>α</i>,8,15<i>β</i>,24-pentahydroxy-5<i>α</i>-cholestane (<b>3</b>) showed significant cytotoxic effect against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 18.03 ± 2.63 to 21.59 ± 3.23 μM.</p

Eudesmane and aromadendrane sesquiterpenoids from the Vietnamese soft coral <i>Sinularia erecta</i>

<p>Using various chromatographic separations, eight sesquiterpenoids (<b>1</b>–<b>8</b>), including one new compound 3<i>β</i>,5<i>α</i>-dihydroxyeudesma-4(15),11-diene (<b>1</b>), were isolated from the MeOH extract of the Vietnamese soft coral <i>Sinularia erecta</i>. The structure elucidation was confirmed by spectroscopic experiments including 1D and 2D NMR and HR-ESI-MS. The cytotoxic activities against three human cancer cell lines (A-549, HeLa and PANC-1) of all isolated compounds were evaluated by MTT-based colorimetric assays. Compound <b>1</b> exhibited selective cytotoxicity against the A549 cell line with IC₅₀ of 14.79 ± 0.91 μM.</p

Two new simple iridoids from the ant-plant <i>Myrmecodia tuberosa</i> and their antimicrobial effects

<p>Six iridoid derivatives (<b>1–6</b>), including two new compounds myrmecodoides A and B (<b>1</b> and <b>2</b>), were isolated from the ant-plant <i>Myrmecodia tuberosa</i>. Their structures were determined on the basis of spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, NOESY and HR-ESI-MS) and by comparison with the literature values. Among isolates, <b>3</b> and <b>4</b> exhibit weak antibacterial effect against <i>Staphylococcus aureus</i> subsp. <i>aureus</i> with MIC value of 100.0 μg/mL.</p

Steroid glycosides from the starfish <i>Pentaceraster gracilis</i>

<p>Using combined chromatographic separations, two new steroid glycosides namely pentacerosides A (<b>1</b>) and B (<b>2</b>), and four known compounds were isolated from the methanol extract of the starfish <i>Pentaceraster gracilis</i>. 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 (<b>5</b>) 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.</p