Cembranoids from the Vietnamese soft coral Sarcophyton ehrenbergi.

Using various chromatographic separations, two new cembranoids, ehrenbergols F and G (1 and 2), along with three known analogs ehrenbergol D (3), (+)-isosarcophine (4) and sinulariol Z2 (5) were isolated from the soft coral Sarcophyton ehrenbergi. The structural elucidation was done by extensive analysis of the 1 D and 2 D NMR, HR-ESI-QTOF-MS as well as CD experiments. In addition, compounds 1 (IC50 of 38.38 ± 2.89 µM), 3 (IC50 of 37.14 ± 3.22 µM) and 4 (IC50 of 45.01 ± 2.49 µM) revealed moderate inhibitory activity on LPS-induced NO production in RAW264.7 cells, whereas 2 (IC50 of 73.32 ± 1.95 µM) and 5 (IC50 of 64.48 ± 4.93 µM) exhibited weak effect.

Bioactive compounds from Physalis angulata and their anti-inflammatory and cytotoxic activities.

A new compound, physalucoside A (1), together with seven withanolides (2-8) and three flavonoids (9-11), were isolated from Physalis angulata L. (Solanaceae), a medicinal plant native to Vietnam. The chemical structures of these compounds were elucidated by one- and two-dimensional NMR spectra, high-resolution electrospray ionization mass spectrometry analyses, and chemical reactivity. The anti-inflammatory and cytotoxic activities of isolated compounds were also evaluated. These data suggest that the anti-inflammatory activity of P. angulata is due primarily to its withanolide content. This study demonstrates the potential of withanolides as promising candidates for the development of new anti-inflammatory drugs.

Triterpene glycosides from the Vietnamese sea cucumber Holothuria edulis.

From the MeOH extract of the Vietnamese sea cucumber Holothuria edulis, eight triterpene glycosides (1-8), including one new compound namely holothurin A5 (1), were isolated by using various chromatographic separations. Their structures were established by spectroscopic experiments including 1D, 2D NMR and HR-ESI-MS. Holothurin A5 (1) has a hydroperoxy group at C-25. To the best of our knowledge, this is the first report of this group in triterpene saponins obtained from sea cucumbers to date. In addition, the in vitro cytotoxicity against five human cancer cell lines (HepG2, KB, LNCaP, MCF7 and SK-Mel2) of all isolated compounds was also evaluated using SRB assays.

Briarane-type diterpenoids from the Vietnamese gorgonian Junceella fragilis.

Ten briarane-type diterpenoids (1-10), including one new stereoisomer 17-epi-junceellolide B (1), were isolated from the MeOH extract of the Vietnamese gorgonian Junceella fragilis. Their structures were elucidated by spectroscopic experiments including 1D and 2D NMR, and HR-QTOF-MS. In addition, the in vitro cytotoxic activity against eight human cancer cell lines (LNCaP, HepG2, KB, MCF-7, SK-Mel2, HL-60, LU-1 and SW480) of all isolated compounds was evaluated by SRB assays.

Cycloartane-type triterpene glycosides anopanins A-C with monoacyldigalactosylglycerols from Anodendron paniculatum.

Three cycloartane-type triterpene glycosides (anopanins A-C), together with three known monoacyldigalactosylglycerols gingerglycolipids A-C and (2S)-1-O-palmitoyl-3-O-[α-d-galactopyranosyl-(1→6)-ß-d-galactopyranosyl]-sn-glycerol, were isolated from the aerial parts of Anodendron paniculatum collected in Viet Nam. The chemical structures of the present compounds were elucidated by means of 1D and 2D NMR and HRESIMS spectroscopy, and by comparing to the reported data in the literature. These compounds did not show significant growth inhibitory activities (IC50 > 100 µg/mL) against the tested cancer cell lines LU-1 (lung adenocarcinoma), KB (epidermoid carcinoma), Hep-G2 (hepatoma cancer), MKN-7 (stomach cancer), and SW-480 (colon adenocarcinoma).

Pregnane steroids from the Vietnamese octocoral Carijoa riisei.

Six pregnane steroids including one new compound namely 15ß-hydroxypregna-4,20-dien-3-one (1), were isolated and structurally elucidated from the octocoral Carijoa riisei. The cytotoxic activity against a panel of eight human cancer cell lines of isolated compounds was also evaluated by SRB method. As the results, 18-acetoxypregna-1,4,20-trien-3-one (5) showed significant cytotoxicity against all the tested cell lines with the IC50 values from 22.29 ± 1.47 to 48.73 ± 3.93 µM, whereas 15ß-acetoxypregna-1,4,20-trien-3-one (3) and 20R-acetoxypregna-1,4-dien-3-one (6) only exhibited weak effect on KB cell line with IC50 values of 93.62 ± 7.32 and 71.38 ± 5.45 µM, respectively.

Cytotoxic steroid derivatives from the Vietnamese soft coral Sinularia brassica.

Using various chromatographic separations, six ergostane-type steroids, including one new compound sinubrassione (1), and two pregnene-type steroid glycosides, including one new compound sinubrassioside (7), were isolated from methanol extract of the Vietnamese soft coral Sinularia brassica. The structure elucidation was confirmed by spectroscopic methods including 1D, 2D NMR and HR-ESI-MS. The cytotoxic activities of all the isolated compounds against three human cancer cell lines were also evaluated using MTT-based colorimetric assays.

A new lignan glycoside from the aerial parts and cytotoxic investigation of Uvaria rufa.

Chemical investigation of the aerial parts of Uvaria rufa (Dunal) Blume collected from Vietnam yielded one new lignan glycoside, ufaside (1), along with six known compounds, oxoanolobine (2), ergosta-4,6,8(14),22-tetraen-3-one (3), catechin (4), epicatechin (5), daucosterol (6) and glutin-5-en-3-one (7). Their chemical structures were determined by using NMR, HR-MS spectroscopic analyses and in comparison with the reported data. A cytotoxic analysis of U. rufa herb extracts was performed for the first time using nine human cancer cell lines (MCF-7, MDA-MB-231, LNCaP, MKN7, SW480, KB, LU-1, HepG2 and HL-60) derived from different tumour types. Of these seven constituents, compounds 2 and 3 displayed moderate cytotoxicity against the human lung adenocarcinoma cell line (LU-1) with IC50 values of 9.22 ± 1.02 µg/mL and 10.21 ± 1.16 µg/mL, respectively.

Anti-inflammatory Triterpenes and Glyceryl Glycosides from Kandelia candel (L.) Druce

Phytochemical investigation of Kandelia candel resulted in the isolation of six triterpenes (1 - 5) and two glyceryl glycosides (6 and 7) and their structures were determined by comparing the spectroscopic data with those of reported values. In present study, we described the inhibitory effects of fractions and isolated compounds from K. candel on pro-inflammatory cytokines (IL-12 p40, IL-6, and TNF-alpha) production in lipopolysaccharide (LPS) stimulated bone marrow-derived dendritic cells (BMDCs). Results indicated that compounds 3, 6, and 7 showed potent inhibition on IL-6 production (IC50 values at less than 0.5 microM, respectively). Meanwhile, compounds 6 and 7 exhibited strong inhibitory effects on the production of TNF-alpha (IC50 values of 1.7 +/- 0.1 and 5.5 +/- 0.2 microM). Compounds 1 and 3 were also showed the inhibitory effects on IL-12 p40 production (IC50 values of 8.9 +/- 0.4 and 3.3 +/- 0.1 microM, respectively).

Antifouling 26,27-cyclosterols from the Vietnamese marine sponge Xestospongia testudinaria.

Three new C29 sterols with a cyclopropane ring cyclized between C-26 and C-27 of the side chain, aragusterol I (1), 21-O-octadecanoyl-xestokerol A (4), and 7ß-hydroxypetrosterol (5b), were isolated from the Vietnamese marine sponge Xestospongia testudinaria, along with the known compounds, aragusterol B (2), xestokerol A (3), 7α-hydroxypetrosterol (5a), 7-oxopetrosterol (6), and petrosterol (7). The structures of the new compounds were established by analysis of spectroscopic data including 1D and 2D NMR, and high-resolution electrospray ionization mass spectrometry (HRESIMS). Their capacity to inhibit the adhesion of isolated bacteria from marine biofilms was evaluated against the bacterial strains Pseudoalteromonas sp. D41, Pseudoalteromonas sp. TC8, and Polaribacter sp. TC5. Aragusterol B (2) and 21-O-octadecanoyl-xestokerol A (4) exhibited the most potent antifouling activity with EC50 values close to these reported in the literature for tributyltin oxide, a marine anti-biofouling agent now considered to be a severe marine pollutant. Due to its comparable activity to tributyltin oxide and its absence of toxicity, the new 26,27-cyclosterol, 21-O-octadecanoyl-xestokerol A (4) constitutes a promising scaffold for further investigations.

Cytotoxic and antioxidant activities of diterpenes and sterols from the Vietnamese soft coral Lobophytum compactum.

Two new diterpenes, lobocompactols A (1) and B (2), and five known compounds (3-7) were isolated from the methanol extract of the soft coral Lobophytum compactum using combined chromatographic methods and identified based on NMR and MS data. Each compound was evaluated for cytotoxic activity against A549 (lung) and HL-60 (acute promyelocytic leukemia) human cancer cell lines. Among them, compound 5 exhibited strong cytotoxic activity against the A549 cell line with an IC(50) of 4.97 ± 0.06 µM. Compounds 3, 4, and 7 showed moderate activity with IC(50) values of 23.03 ± 0.76, 31.13 ± 0.08, and 36.45 ± 0.01 µM, respectively. The cytotoxicity of 5 on the A549 cells was comparable to that of the positive control, mitoxantrone (MX). All compounds exhibited moderate cytotoxicity against the HL-60 cell line, with IC(50) values ranging from 17.80 ± 1.43 to 59.06 ± 2.31 µM. Their antioxidant activity was also measured using oxygen radical absorbance capacity method, compounds 1 and 2 exhibiting moderate peroxyl radical scavenging activity of 1.4 and 1.3 µM Trolox equivalents, respectively, at a concentration of 5 µM.

Antioxidant activity of a new C-glycosylflavone from the leaves of Ficus microcarpa.

By bioactive-guided fractionation of methanol extract of the Ficus microcarpa leaves, one new C-glucosylflavone, ficuflavoside (1), one new megastigmane glycoside, ficumegasoside (8), and twelve known compounds including flavonoids (2-6), phenylpropanoids (7), megastigmanes (9-11) and sterol derivatives (12-14) were isolated. Their chemical structures were elucidated by mass, 1D, and 2D NMR spectroscopies. The antioxidant activities of these compounds were measured using the oxygen radical absorbance capacity methods. Compounds 1-6 exhibited potent antioxidant activities of 6.6-9.5µM Trolox equivalents at the concentration of 2.0µM. The results indicated 2, 3, and 5 having meaningful reducing capacity of copper (I) ions concentration of 6.1-8.4µM.

A new monoterpenoid glycoside from Myrica esculenta and the inhibition of angiotensin I-converting enzyme.

One new monoterpenoid glycoside, myresculoside (1), and eleven known compounds, were isolated from methanol extract of Myrica esculenta leaves by repeated column chromatography. The effects of these compounds on angiotensin I-converting enzyme (ACE) inhibition were investigated. Compounds 3 and 4 showed the most potent ACE inhibition with rates of 29.97% and 25.63% at concentration of 100 µM, respectively. Compounds 5, 6, and 11 showed weak activity with inhibitory rates of 0.07-1.41% at concentration of 100 µM.

Chemical components from the Vietnamese soft coral Lobophytum sp.

Chromatographic separation resulted in the identification of one new squalene derivative, named lobophytene (1), three cembranoid diterpenes (2-4), and two sterols (5 and 6) from the Vietnamese marine soft coral Lobophytum sp. Their structures were identified on the basis of extensive spectroscopic data and comparison of those with reported data. Compounds 1 and 2 showed significant cytotoxic activities against lung (A549) and colon (HT-29) cell lines with IC(50) values of 8.2 and 5.6 microM for 1; 5.1 and 1.8 microM for 2, respectively.

Cucurbitane-type triterpene glycosides from the fruits of Momordica charantia.

The chemical study of Momordica charantia fruits led to the isolation of three new cucurbitane triterpene glycosides, momordicosides U, V, and W (1-3). The structures of these compounds were determined to be (19R, 23R)-5beta, 19-epoxy-19-methoxycucurbita-6,24-diene-3beta, 23-diol 3-O-beta-D-allopyranoside (1), (23R)-5beta, 19-epoxycucurbita-6,24-diene-3beta, 23-diol 3-O-beta-D-allopyranoside (2), and (19R)-5beta, 19-epoxy-19,25-dihydroxycucurbita-6,23(E)-diene-3beta-ol 3-O-beta-D-glucopyranoside (3), by chemical and spectroscopic methods.

Two new C-glucosyl benzoic acids and flavonoids from Mallotus nanus and their antioxidant activity.

Two new 2-C-beta-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were isolated from the methanolic extract of the leaves of Mallotus nanus along with five known flavonoids, kaempferin (3), juglanin (4), quercitrin (5), myricitrin (6), and rhoifolin (7). Their structures were established on the basis of spectral and chemical evidence. Their antioxidant activities were shown to depend on the number of hydroxyl groups, and the location and species of sugar moiety.

Aporphine alkaloids, clerodane diterpenes, and other constituents from Tinospora cordifolia.

Phytochemical investigation of the methanol extract of Tinospora cordifolia aerial parts led to the isolation of four new and seven known compounds. The structures of two new aporphine alkaloids, N-formylasimilobine 2-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (tinoscorside A, 1) and N-acetylasimilobine 2-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (tinoscorside B, 2), a new clerodane diterpene, tinoscorside C (3), and a new phenylpropanoid, sinapyl 4-O-beta-D-apiofuranosyl-(1-->6)-O-beta-D-glucopyranoside (tinoscorside D, 6) were determined by extensive spectroscopic methods including FTICR-MS and 1D and 2D NMR.

Lupane-type triterpene glycosides from the leaves of Acanthopanax koreanum and their in vitro cytotoxicity.

Three new lupane triterpene glycosides, acankoreosides J-L ( 1- 3), were isolated from the leaves of Acanthopanax koreanum. Based on the spectroscopic data, the chemical structures were determined as 3 alpha-hydroxy-20-oxo-30-norlupane-23,28-dioic 28- O- alpha- L-rhamnopyranosyl-(1 --> 4)- beta- D-glucopyranosyl-(1 --> 6)- beta- D-glucopyranosyl ester ( 1); 3 alpha,20,29-trihydroxylupane-23,28-dioic 28- O- alpha- L-rhamnopyranosyl-(1 --> 4)- beta- D-glucopyranosyl-(1 --> 6)- beta- D-glucopyranosyl ester ( 2); and (20S)-3 alpha-hydroxy-29,29-dimethoxylupane-23,28-dioic 28- O- alpha- L-rhamnopyranosyl-(1 --> 4)- beta- D-glucopyranosyl-(1 --> 6)- beta- D-glucopyranosyl ester ( 3). Compounds 1- 3 were evaluated for their cytotoxicity and showed moderate activity against four cell lines, A549 (lung), HL-60 (leukemia), MCF-7 (breast), and U937 (leukemia), with IC (50) values of 23.4, 36.5, 22.6, and 18.5 microM for 1; 6.8, 18.6, 23.1, and > 100 microM for 2; and 28.9, 21.8, 11.0, and 27.5 microM for 3, respectively.

C29 sterols with a cyclopropane ring at C-25 and 26 from the Vietnamese marine sponge Ianthella sp. and their anticancer properties.

Two new C(29) sterols with a cyclopropane ring at C-25 and C-26, petrosterol-3,6-dione (1) and 5alpha,6alpha-epoxy-petrosterol (2), along with petrosterol (3), were isolated from the Vietnamese marine sponge Ianthella sp. The structures of the new compounds were elucidated by comprehensive spectroscopic analyses. Compounds 1-3 showed cytotoxic activities on A549, HL-60, MCF-7, SK-OV-3, and U937 cancer cell lines with IC(50) in the range of 8.4-22.6 microM, whereas compounds 1-3 exhibited only weak cytotoxic activities on HT-29 cell. After HL-60 cells were treated with the compounds, several apoptosis events like chromatin condensation and the increase of the population of sub-G1 hypodiploid cells were observed. These data supported that the compounds might have potential for leukemia treatment.