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Seven compounds, dihydrosinularin (1), 11‐epi‐sinulariolide acetate (2), 10,18‐diacetoxydilabella‐2,7‐dien‐6‐one (3), 4‐(2′,3′,4′‐trimethylphenyl)‐but‐(3E)‐en‐2‐one (4), 4‐hydroxybenzaldehyde (5), indole‐3‐aldehyde (6), and methyl indole‐3‐carboxylate (7) were isolated from Clathria reinwardti. The isolates were identified by ESIMS, 1D and 2D NMR spectra. Compounds 1‐4significantly exhibited the cytotoxic activity against SK‐LU‐1, MCF‐7, HepG2, and SK‐Mel‐2 cell lines with the IC50values ranging from 3.8 ± 0.1 to 23.0 ± 0.2 μM, compared to the positive control compound (ellipticine, IC50, ranging from 1.4 ± 0.2 to 1.7 ± 0.1 μM). This is the first report of these compounds from C. reinwardti.

From the methanol extract of the Vietnamese marine sponge Rhabdastrella globostellata(Carter, 1883), four diketopiperazines (1‐4) and one indol alkaloid (5) were isolated by various chromatographic methods. Their chemical structures were identified to be cyclo‐(L‐Pro‐L‐Ile) (1), cyclo‐(L‐Pro‐L‐Leu) (2), cyclo‐(D‐Pro‐L‐Ile) (3), cyclo‐(L‐Pro‐L‐Phe) (4), and tryptophol (5) by using a combination of ESI‐MS, 1D and 2D NMR spectral data as well as by comparison with previous literature. This is the first report of these compounds from Rhabdastrella globostellata.

Phytochemical study on the methanol extract of the marine sponge Xestospongia testudinaria(Lamark, 1815) led to the isolation of one new ((6Z,8E,13E,15Z)‐6,14,16‐tribromo‐5,10‐dihydroxyhexadeca‐6,8,13,15‐tetraenoic acid named xestospongiene VN1, 1) and nine known brominated polyunsaturated compounds, xestospongiene z5& z6(2), xestospongiene z9& z10(3), xestospongiene S (4), xestospongic acid (5), xestospongic acid methyl ester (6), (13E,17E)‐18‐bromo‐octadeca‐13,17‐diene‐5,7,15‐triymoic acid (7), xestospongiene I & J (8), xestospongiene K & L (9), and xestospongiene C & D (10). The chemical structures of these compounds were elucidated by extensive spectroscopic analyses including HR‐ESI‐MS, 1D and 2D NMR, circular dichroism, and by comparison of the spectral data with those of previously reported data. This is the first report of these compounds from Vietnamese marine sponge X. testudinaria.

Phytochemical study on the methanol extract of the elephant ear sponge Ianthella basta(Pallas, 1766) led to the isolation of one new (named lanthebastanoside A, 1) and nine known compounds, holothurin A2 (2), desulfoechinoside A (3), echinoside B (4), holothurin A (5), holothurin B (6), adenine (7), adenosine (8), thymidine (9), and thymine (10). The chemical structures of compounds 1‐6were elucidated by extensive spectroscopic analyses including HR‐ESI‐MS, 1D and 2D NMR, and by comparison of the spectral data with those of previously reported data. Compounds 7‐10were identified by 1H NMR data and comparing their retention times with authentic samples by HPLC analysis. This is the first report of compounds 2‐6from marine sponge.

From the methanol extract of the marine sponge Hippospongia fistulosaLendenfeld, 1889, a new meroterpene lactone named as hippolactone A (1), a new alkyl amino alcohol named as 2‐aminotetradec‐13‐ene‐3,4,5,6,7‐pentaol (2), and three known meroterpenes, polyfibrospongol A (3), polyfibrospongol B (4), and 19‐hydroxy‐polyfibrospongol B (5), were isolated. Their structures were elucidated by extensive spectroscopic analyses including IR, HR‐ESI‐MS, 1D and 2D NMR, and by comparison of the spectral data with those of previously reported data. Compounds 1and 2exhibited cytotoxic effects on Hep‐G2, MCF‐7, SK‐LU‐1, and SK‐Mel‐2 human cancer cells with percentages of dead cells in the range from 18.2±1.1 % to 43.4±1.6 %.

Chemical composition and biological activity of sponges have been studied by the authors since 2006. So far, the authors have studied about 30 species of sponges, mainly collected cross in the sea of Northern Vietnam. Over 250 compounds have been isolated and elucidated their chemical structures. Among them, there are more than 50 compounds with new chemical structures. In addition to NMR and HRMS spectra, many compounds with an unequal chemical structure are also determined by Circular Dichroism spectrometry. Some isolated compounds exhibited outstanding potential for cancer cytotoxicity and anti‐inflammatory effects.

Objectives Isolation, structure determination, and antimicrobial activities evaluation of compounds from the methanol extract of the marine microalga Thraustochytrium pachydermumTSL10.Methods Using chromatographic methods to isolate compounds from the methanol extract of the T pachydermum. The chemical structures were elucidated by analyses of HR-ESI-MS and NMR spectral data. The antimicrobial activities of compounds were evaluated using the dilution turbidimetric broth method as the standard protocol published by the Clinical and Laboratory Standard Institute.Results One new sterol, (24R)-ergosta-7,22-diene-3β,5α,9α-triol (1), and 16 known compounds, ergosta-7,22-diene-3β,5α-diol (2), cerevisterol (3), (22E,24S)-5α,6α-epoxy-ergosta-8(9),22-diene-3β,7α-diol (4), ergosterol (5), 5α,8α-epidioxyergosta-6,22-diene-3β-ol (6), linoleic acid (7), 4-((9Z,12Z)-octadeca-9,12-dienoyloxy)butanoic acid (8), 1-linoleoyl-sn-glycero-3-phosphocholine (9), cibotiglycerol (10), gingerglycolipid B (11), oleic acid (12), 4-((9Z)-octadec-9-enoyloxy)butanoic acid (13), (2S)-1-O-(9Z)-octadec-9-enoyl)-3-O-(6-sulfo-D-quinovopyranosyl)glycerol (14), 6′-O-linoleylsucrose (15), gingerglycolipid C (16), and (S)-3-stearoyl-sn-glycerol (17) were identified from the marine microalga Thraustochytrium pachydermumTSL10. Sterols 1–6were found to exhibit significant antimicrobial activities on Gram-( + ) bacteria (Enterococcus faecalisATCC29212, Staphylococcus aureusATCC25923, and Bacillus cereusATCC14579) and the yeast (Candida albicansATCC10231) with MIC values ranging from 32 to 256 µg/mL.Conclusions The results suggested sterols 1–6could be potential antimicrobial agents against Gram-( + ) bacteria.

Two new (1and 2) and six known (3-8) compounds were isolated from the methanolic extract of the Vietnamese marine spider conch Lambis lambisLinnaeus, 1758. Based on comprehensive spectroscopic analyses, particularly HRESIMS, and 1D- and 2D-NMR spectra, their chemical structures were determined to be 25,26,27-tri-nor-cholest-5-ene-2β,3α,24-triol-2,24-disulfate (1), 25,26,27-tri-nor-cholesta-2β,3α,24-triol-3,24-disulfate (2), 25,26,27-tri-nor-cholesta-2β,3α,24-triol-2,3,24-trisulfate (solomonsterol A, 3), 1-O-arachidonoyl-3-O-stearylglycerol (4), eicosapentaenoic acid (5), adenosine (6), adenine (7), and uracil (8). This is the first report of compounds 3-8from L. lambis.

A new sterol (1) and 8 known (2-9) compounds were isolated from the methanol extract of the Vietnamese marine sponge Halichondria panicea(Pallas, 1766) by various chromatographic methods. Their chemical structures were determined as 5α,6α-epoxy-(22E)-ergosta-3β,7α-diol-8,22,25-triene (1), (22E)-ergosta-7,22,25-triene-3β,5α,6β-triol (2), 3β-hydroxycholest-5ene-7-one (3), cholesterol sulfate (4), 3-formamidotheonellin (5), para-hydroxybenzylideneacetone (6), indole-3-carbaldehyde (7), thymidine (8), and adenosine (9) by using a combination of HR-ESI-MS, 1D and 2D NMR spectral data, as well as by comparison with the previous literature. This is the first report of these compounds from H panicea. Compounds 1and 2exhibited cytotoxic effects on Hep-G2, SK-Mel-2, LU-1, and MCF-7 cell lines with IC50values of 9.27 ± 1.25, 11.34 ± 1.18, 15.45 ± 1.47, and 10.85 ± 1.19 µM (for 1), and 6.45 ± 0.77, 9.74 ± 1.03, 7.08 ± 0.64, 5.61 ± 0.39 µM (for 2), compared to the positive control compound, ellipticine, 1.60 ± 0.37, 2.53 ± 0.51, 1.82 ± 0.20, and 2.17 ± 0.66 µM, respectively.

Three new constituents (1-3) were isolated from the whole plant of Balanophora laxiflora. Their chemical structures were elucidated by extensive analysis of high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. Absolute configurations of new compounds were determined by circular dichroism spectra and modified Mosher’s method. The isolated compounds weakly inhibited on both NO production and COX-2 mRNA expression in RAW264.7 macrophages.

Two new steroidal alkaloid saponins, solanigrosides Q and R (1and 2), together with four known compounds khasianine (3), solamargine (4), solasonine (5), and soladulcoside A (6) were isolated from the whole plants of Solanum nigrum. The structures of new compounds (1and 2) were determined by interpretation of HR-ESI-MS, 1D and 2D NMR spectra, and chemical transformation. Compound 4exhibited potent cytotoxic activity against MDA-MB-231, A549, Hep3B, PC3 human cancer cell lines with IC50values of 1.86 ± 0.45, 2.24 ± 0.15, 0.78 ± 0.11, 5.13 ± 1.34 μM, respectively.

Four new 6,6,5-tricyclic terpenoids, named rhabdaprovidines D-G (1–4), were isolated from the Vietnamese sponge Rhabdastrella providentiae. The structures of 1–4were elucidated by extensive analysis of HR-ESI-MS and NMR spectroscopy. The absolute stereochemistry of compounds 3and 4were determined by both experimental and theoretical calculated circular dichroism (CD) spectra. Compounds 1, 2, and 4contained trans-syn-trans6,6,5-tricyclic nucleus meanwhile compound 3possessed trans-syn-cisring junction. Compound 4displayed novel structure by the presence of five rings and nine chiral carbon centers in the isomalabaricane triterpene backbone.

One new tirucallane-typetriterpene glycoside, antidesoside (1), along with two biflavones, podocarpusflavone A (2) and amentoflavone (3) and two megastigmane glycosides, byzantionoside B (4), and (6S,9R)-roseoside (5) were isolated from the methanol extract of Antidesma buniusleaves. Their structures were determined by spectroscopic methods and in comparison with the published data. Compounds 1- 3were found to show strong inhibitory effect of NO production in BV2 cells and RAW264.7 macrophages LPS-stimulated, with IC50values ranging from 8.5 to 26.9 μM.

Using combined chromatographic methods, two new compounds, 6β,9β:9,13-diepoxymegastig-4-en-3β-ol (1), 5α,6α-epoxy D:C-friedoolean-8-en-3β-ol (2)were isolated from the methanol extract of the leaves of Glochidion obliquumDecne. Their structures were elucidated by 1D- and 2D-NMR spectra and in comparison with those reported in the literature.

Two new sesquiterpenes and one new bis-sesquiterpene, named dysinidins C-E (1–3)along with three known sterols, dysideasterol F, 9α,11α-epoxycholest-7-en-3β,5α,6α-triol, and 9α,11α-epoxycholest-7-en-3β,5α,6α,19-tetrol 6-acetate (4–6)were isolated from the Vietnamese marine sponge Dysidea fragilis(Montagu, 1814). Their structures were determined by 1D- and 2D-NMR spectroscopies and HR-ESI-MS, as well as by comparison with reported literature data. Compounds 4–6were found to inhibit eight human cancer cell lines (KB, LU-1, HL-60, LNCaP, SK-Mel-2, HepG-2, MCF-7, and PC-3), with IC50values ranging from 7.3 to 31.5 μM.

Two new sesquiterpenes, named dysinidins A-B (3, 4)along with two known sesquiterpenes, furodysinin lactone (1)and O-methyl furodysinin lactone (2), were isolated from the Vietnamese marine sponge Dysidea fragilis. Their structures were determined by 1D- and 2D-NMR spectroscopies and HR ESI MS, as well as by comparison with reported literature data. None of compounds showed inhibitory growth of human lung cancer cell lines, A-549 and H-1975 (IC50> 30μM).

A new ent-kaurane glycoside, annoglabasin H (1), and three known ent-kauranes, annoglabasin E (2), annoglabasin B (3), and 19-nor-ent-kaurent-4-ol-17-oic acid (4) were isolated from the fruits of Annona glabra. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D- and 2D-NMR spectroscopy, as well as by comparison with the NMR data reported in the literature. The cytotoxic activities of these compounds were evaluated on four human cancer cell lines, LU-1, MCF-7, SK-Mel2, and KB. Compound 1exhibited significant cytotoxic activity on all tested human cancer cell lines with IC50values ranging from 3.7 to 4.6 μM.

Two new isoflavone glycosides, dalspinosin 7-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (1) and caviunin 7-O-(5-O-trans-p-coumaroyl)-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (2), and two known compounds, caviunin 7-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (3) and caviunin (4) were isolated from the stems of Dalbergia vietnamensis. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D- and 2D-NMR spectroscopy, as well as by comparing with the NMR data reported in the literature.

Four new cucurbitane-typetriterpene glycosides, charantosides D-G (1–4) were isolated from a methanol extract of Momordica charantiafruits. The structures of these compounds were determined by chemical and spectroscopic methods to be (19R)-5β,19-epoxy-25-methoxycucurbita-6,23-diene-3β,19-diol 3-O-β-D-glucopyranoside, (19R)-5β,19-epoxy-25-methoxycucurbita-6,23-diene-3β,19-diol 3-O-β-D-allopyranoside, 7β-methoxycucurbita-5,23E,25-triene-3β-ol 3-O-β-D-allopyranoside, and 3β,7β-dihydroxycucurbita-5,23E,25-triene-19-al 3-O-β-D-allopyranoside.

One new megastigmane glycoside, ficalloside (1), and eleven known compounds, were isolated from methanol extract of Ficus callosaleaves by repeated column chromatography. Their structures were established on the basis of spectral and chemical evidence. The antioxidant activities of these compounds were measured using the oxygen radical absorbance capacity (ORAC) assay. Compound 8exhibited potent antioxidant activity of 10.6 μM trolox equivalents at the concentration of 2 μM. At this concentration, compounds 4-7and 9-12showed significant antioxidant activity with ranging of 2.1~6.1 μM trolox equivalents.