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.

Chemical constituents from the leaves of Sindora siamensis var. maritima and their antimicrobial and α-glucosidase inhibitory activities

Two new glycosides, sindosides A-B (1-2), along with 11 previously identified metabolites (3-13), were isolated from an ethanolic extract of the leaves of Sindora siamensis var. maritima. The structures of the purified phytochemicals were elucidated by interpreting their spectroscopic data (IR, NMR, and HRMS). The absolute configuration of compound 1 was established by experimental and calculated ECD spectra. The antimicrobial results revealed that compound 8 selectively inhibited C. albicans fungal with a MIC value of 64 μg/mL, whereas 11 presented a weak inhibition toward E. faecalis, S. aureus, and B. cereus bacterial strains with the same MIC value of 128 μg/mL. Interestingly, compounds 1, 2, 8, 9, and 11 showed α-glucosidase inhibitory activity with IC50 values ranging from 14.42 ± 0.21 to 30.62 ± 0.18 μM, which were more active than the positive control (acarbose, with an IC50 value of 46.78 ± 1.37 μM). Enzyme kinetic analysis revealed that compounds 1, 2, and 11 behaved as uncompetitive inhibitors with Ki values of 8.60 ± 1.04, 5.16 ± 0.73, and 7.17 ± 0.98 μM, respectively.

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.

Acylated flavonoid glycosides from Barringtonia pendula and their inhibition on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells

Six new acylated flavonoid glycosides namely barringosides J - O (1-6) along with tephrokaempferoside and barringoside D were isolated from the branches and leaves of Barringtonia pendula. The structural elucidation was confirmed by extensive analysis of their spectroscopic data including HRQTOFMS, 1D and 2D NMR experiments. Moderate inhibitory effects on LPS-induced NO production in RAW264.7 cells were observed for barringosides M (4) and N (5) with IC50 values of 48.40 ± 3.01 and 56.61 ± 3.87 μM, whereas weak inhibition was found for compounds 1-3, 6, and 7 with IC50 values ranging from 64.91 ± 3.68 to 79.80 ± 3.90 μM.

Diterpenoid and phenolic constituents from corn silk (Zea mays) with PTP1B inhibitory activity

Chemical investigation of corn silk resulted in the isolation of nine secondary metabolites, including a new ent-kaurane diterpenoid, zeamaysditerpene A (1) and eight known compounds, stigmaydene A (2), stigmaydene J (3), stigmaydene L (4), stigmane D (5), demethyltorosaflavone D (6), chrysoeriol 6-C-β-boivinopyranosyl-7-O-β-D-glucopyranoside (7), deoxypodophyllotoxin (8), and α-peltatin glucoside (9). Their structures were elucidated using a combination of spectroscopic methods, including 1D and 2D NMR and HRESIQTOF mass spectra. The absolute configuration of 1 was deduced by applying electronic circular dichroism (ECD) calculation method. Among the isolates, only 6 displayed significant inhibition against PTP1B activity in a dose-dependent manner, with an IC50 value of 10.7 ± 0.1 µM. Furthermore, molecular docking simulation was carried out to explore the action perspective of 6 inside the enzyme PTP1B. This finding suggests that 6 might be a potential lead for the development of a new anti-diabetic agent.

Isoryanodane diterpene derivatives from Barringtonia macrocarpa

From the MeOH residue of Barringtonia macrocarpa branches and leaves, one new isoryanodane diterpene, barringisol (1), and two new isoryanodane diterpene glucosides, barringisosides A and B (2 and 3), were obtained using various chromatographic isolations. The structural characterization was confirmed by spectroscopic methods including 1D, 2D NMR and HR-ESI-QTOF-MS. This is the first isolation of isoryanodane diterpene derivatives from Barringtonia species. Moreover, the in vitro cytotoxicity of 1-3 on three human cancer cell lines (HepG2, LNCaP and MCF7) was also accessed using SRB assays.

Dammarane-type triterpenoid saponins from the flower buds of Panax pseudoginseng with cytotoxic activity

Phytochemical investigation of a methanol extract of Panax pseudoginseng flower buds resulted in the isolation of 22 dammarane-type triterpenoid saponins, including three new compounds, pseudoginsenosides A-C (1-3), and 19 known analogs. Their chemical structures were identified by the comprehensive spectroscopic methods, including 1 D and 2 D NMR and mass spectra. In addition, their cytotoxic effects toward three human carcinoma cell lines, including liver (HepG2), breast (MCF7), and lung (A549) were also evaluated.

Phenolic glycosides from the leaves of Iodes cirrhosa Turcz. with cytotoxic and antimicrobial effects

In the present study, 14 phenolic glycosides, including one new neolignan glycoside, iodescirrhoside A ( 1 ), three new flavonol glycosides, iodescirrhosides B-D ( 2-4 ), and 10 known metabolites were obtained from the methanol extract of Iodes cirrhosa leaves. Structural elucidation was performed by interpretating the 1D- and 2D- NMR, HRESIMS, and CD spectra in comparison with literature data. All compounds were noncytotoxic to LU-1, HepG2, MCF-7, SK-Mel-2, and LNCaP cancer cell lines. Compound 11 significantly inhibited the growth of E. faecalis . In contrast, weak inhibition was observed for 1-9 and 14 against E. faecalis , for 1 , 6-8 , and 11 against S. aureus , for 6 and 13 against B. cereus , and 2 , 4 , and 6-9 against C. albicans .

Triterpene Tetraglycosides From Stichopus Herrmanni Semper, 1868

Using various column chromatographic methods, 5 triterpene tetraglycosides (1−5), including one new compound, namely holothurin A6 (1), were obtained from the water soluble part of the methanol extract of the sea cucumber Stichopus herrmanni. Their structures were confirmed by careful analysis of the 1D and 2D NMR, and HR ESI QTOF mass spectra. Noteworthily, 24-dehydroechinoside A (3) showed potent cytotoxicity to 5 human cancer cell lines {HepG2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma)} with IC50 values ranging from 0.19 ± 0.03 to 1.17 ± 0.18 µM.

Two new eudesmane sesquiterpene glucosides from the aerial parts of Artemisia vulgaris

Using combined chromatographic methods, two new sesquiterpene glucosides, vulgarosides A (1) and B (2), and two known analogs ainsliaside E (3) and pumilaside A (4) were isolated from the aerial parts of Artemisia vulgaris. Their chemical structures were established by spectroscopic methods, including one and two-dimensional nuclear magnetic resonance (1 D and 2 D-NMR) spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). In addition, their cytotoxicity on five human cancer cell lines, including KB (epidermoid carcinoma), HepG2 (hepatocarcinoma), MCF7 (breast carcinoma), SK-Mel-2 (melanoma), and LNCaP (prostate cancer) was also evaluated by the SRB assay. However, none of the tested eudesmane sesquiterpene glycosides showed significant cytotoxicity (IC₅₀>100 µM).

Cytotoxic and nitric oxide inhibitory activities of triterpenoids from Lycopodium clavatum L

Using combined chromatographic separation techniques, three new triterpenoids named lycomclavatols A-C (1-3), a new natural product, methyl lycernuate-A (4), as well as seven known compounds (5-11), were isolated from the methanol extract of the whole plants of Lycopodium clavatum. Their chemical structures were established based on 1 D/2D NMR and HR-ESI-MS spectroscopic analyses. Among the isolates, compound 1 exhibited inhibitory activity on NO production in LPS-stimulated BV2 cells (IC₅₀ = 36.0 μM). In addition, 1 was cytotoxic against both HepG2 and A549 cancer cell lines, with IC₅₀ values of 40.7 and 87.0 μM, respectively. Compounds 10 and 11 showed cytotoxicity on only HepG2 and A549 cells, with IC₅₀ values of 91.2 and 57.6 μM, respectively. Our results contribute to understanding more the secondary metabolites produced by L. clavatum and provide a scientific rationale for further investigations of anti-inflammatory and anticancer effects for this valuable medicinal plant.

Polyethylene over magnetite-multiwalled carbon nanotubes for kerosene removal from water

In this study, a nano-adsorbent was prepared for kerosene removal from water. Multiwalled carbon nanotubes (MWCNTs) were functionalized with concentrated HNO₃ (nitric acid). Subsequently, Fe₃O₄ (magnetite) nanoparticles were deposited on the MWCNTs to prepare a magnetite/MWCNTs (Fe-MWCNTs) nanocomposite. Then, polyethylene was added to the Fe-MWCNTs to fabricate a polyethylene/magnetite/MWCNTs (PE/Fe-MWCNTs) novel nanocomposite. The nano-adsorbent was characterized using BET, FTIR, Raman, XRD, TEM, and SEM. A kerosene-water model mixture was used for adsorption tests. Several parameters: adsorption time, adsorbent dose, solution pH, solution temperature, and kerosene concentration in the kerosene-water model mixture, were analyzed during adsorption experiments. After each batch experiment, kerosene concentration was determined using high-performance liquid chromatography (HPLC). Magnetic field was used to remove the adsorbent after each experiment. The kerosene adsorption capacity and removal efficiency of the PE/Fe-MWCNTs nanocomposite (3560 mg/g and 71.2 %, respectively) were higher than those of Fe-MWCNTs, ox-MWCNTs, and fresh MWCNTs (3154 mg/g and 63.1 %, 2204 mg/g and 44.0 %, and 2092 mg/g and 41.8 %, respectively). Kerosene adsorption followed a pseudo-second-order kinetic model (R² = 0.999) and the Langmuir isotherm model, suggesting that adsorption was uniform and homogenous process.

Polyhydroxylated steroids from the Vietnamese soft coral Sarcophyton ehrenbergi

Fourteen polyhydroxylated steroids including six new compounds, ehrensteroids A - F (1-6), were isolated from the Vietnamese soft coral Sarcophyton ehrenbergi after applying various chromatographic separations. The structure elucidation was done by detailed analysis of 1D, 2D NMR and HR QTOF mass spectra. In addition, significant cytotoxicity (IC₅₀ values ranging from 8.45 ± 0.56 to 38.27 ± 2.39 μM) against all five tested cancer cell lines as LU-1 (lung cancer), HepG2 (hepatoma cancer), MCF-7 (breast cancer), HL-60 (acute leukemia), and SW480 (colon adenocarcinoma) was observed for compounds 1, 2, 6-10, and 12-14, whereas this activity on LU-1 (IC₅₀ = 21.91 ± 2.72 μM) and HepG2 (IC₅₀ = 20.32 ± 0.03 μM) cell lines was also observed for 4.

Saurobacciosides A - C: three new glycosides from Sauropus bacciformis with their cytotoxic activity

Three new glycosides, named as saurobaccioside A (1), saurobaccioside B (2), saurobaccioside C (3), together with five known magastigmanes, canangaionoside (4), (6S,9S)-roseoside (5), cucumegastigmane I (6), icariside B5 (7), linarionoside A (8) were isolated from the whole plant of Sauropus bacciformis (L.) Airy Shaw. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS and NMR) and by comparison of the spectral data with those reported in the literature. The absolute configurations of compounds 2 and 3 were elucidated by experimental CD spectra. Compounds 1-8 were screened their cytotoxic activities towards CAL27 and MDAMB231 cancer cell lines. Compound 1 exhibited significant cytotoxic activity towards CAL27 and MDAMB231 cell lines with IC₅₀ values of 3.21 ± 0.23 and 4.75 ± 0.17 µM, respectively, which were smaller than those of positive control capecitabine (IC₅₀: 8.20 ± 0.75 and 5.20 ± 0.89 µM). Other compounds (2-8) were inactive.

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 β-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.

Nanoliposomal Cercodemasoide A and Its Improved Activities Against NTERA-2 Cancer Stem Cells

Recently, saponins derived from marine sources have received much attention because of their promising bioactivities, such as anticancer, anti-angiogenesis, and anti-inflammation. In particular, a triterpene saponin from the sea cucumber Cercodemas anceps Selenka, cercodemasoide A (CAN1), showed potent cytotoxicity against various cancer cell lines. Recent evidence has indicated that cancer stem cells (CSCs) could be a novel target for efficient cancer therapies. In order to improve the biopharmaceutical properties of CAN1, the compound was loaded into nanoliposomes as an ideal drug carrier. CAN1 was successfully incorporated into nanoliposomes as small unilamellar liposome vesicles with an average size of 73.39 ± 1.57 nm, zeta potential of −0.299 ± 0.046 mV, polydispersity index of 0.336 ± 0.038, and with an encapsulation efficiency of up to 62.9%. For the first time, CAN1 and its nanoliposomal forms have been shown to have a promising cytotoxic activity against NTERA-2 CSCs, with half-maximal inhibitory concentration (IC50) =1.03 ± 0.04 and 0.41 ± 0.03 µM, respectively. The CAN1 nanoliposomes also presented significantly improved activities in suppressing the growth of NTERA-2 3-dimensional tumorspheres (IC50 = 1.71 ± 0.06 µM) in comparison with the free form ( P < .05). The anti-CSC effects of CAN1 nanoliposomes on NTERA-2 cells were due to their apoptotic induction through enhancing caspase-3 activity (more than 2-fold) and arresting the cell cycle at the S phase ( P < .05). The obtained CAN1-encapsulated nanoliposomes suggest valuable applications in CSC-targeting treatment for more efficient clinical therapy.

Chemical constituents from the branches and leaves of Alchornea annamica

Phytochemical investigation of the branches and leaves of Alchornea annamica led to isolation of ten secondary metabolites, including two new megastigmane glucosides alnamicosides A (1) and B (2). The structure elucidation was confirmed by 1 D and 2 D NMR, ECD as well as HR-QTOF-MS experiments. The megastigmane derivatives 1 - 3 exhibited inhibitory effects on LPS-induced NO production in RAW264.7 cells with IC₅₀ values of 78.72 ± 1.90, 77.40 ± 9.40 and 82.16 ± 4.56 µM, respectively. This is the first report on chemical constituents and biological activity of the plant A. annamica.

Phenolic glycosides from Oroxylum indicum

Two new phenolic glycosides, oroxylumosides A (1) and B (2), along with four known compounds darendoside A (3), leucosceptoside A (4), acteoside (5) and decaffeoylacteoside (6) were isolated from the stem bark of Oroxylum indicum. Their structures were elucidated by extensive analysis of the 1 D and 2 D NMR as well as HR-ESI-QTOF-MS. In addition, compounds 1 - 4 exhibited inhibitory effects on NO production in LPS-stimulated BV2 microglial cell line with IC₅₀ values of 58.2 ± 2.9, 70.6 ± 3.5, 56.8 ± 2.8 and 61.1 ± 3.1 µM, respectively.

Polyacetylene and phenolic constituents from the roots of Codonopsis javanica

Chemical investigation of the roots of Codonopsis javanica resulted in isolation of 12 compounds, including one new polyacetylene, codojavanyol (1), one new phenolic glycoside, codobenzyloside (7), and 10 known compounds, (2E,8E)-9-(tetrahydro-2H-pyran-2-yl)nona-2,8-diene-4,6-diyl-1-ol (2), lobetyol (3), lobetyolin (4), lobetyolinin (5), cordifolioidyne B (6), benzyl-α-L-arabinopyranosyl (1-6)-β-D-glucopyranoside (8), (Z)-8-β-D-glucopyranosyloxycinnamic acid (9), syringin (10), syringaresinol (11), and tryptophan (12). Their structures were elucidated by 1 D and 2 D NMR and MS spectroscopic analyses in comparison with the data reported in the literature. The stereochemistry of the C-2' position of 1 was identified based on time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculation. Among the isolates, compounds 3-5 were shown to have weak cytotoxicity toward three human carcinoma cell lines, including lung (A549), liver (HepG2), and breast (MCF7), with the induction of 41.4 to 55.6% cell death at the concentration of 100 µM.

Polyhydroxylated steroid derivatives from the starfish Pentaceraster regulus

A new polyhydroxysteroid glycoside, regulusoside D (1), and a new polyhydroxylated steroid, (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), together with seven known compounds were purified from the starfish Pentaceraster regulus collected near Con Co Islands, Vietnam. The structure elucidation was confirmed by extensive analysis of their NMR and HR-QTOF mass experiments. Among isolated compounds, regulusoside D (1), (24S)-cholestane-3β,5,6β,8,15α,24-hexol (2), granulatoside A (4), 5α-cholestane-3β,6β,7α,15α,16β,26-hexol (6), 5α-cholestane-3β,6β,7α,8β,15α,16β,26-heptol (7) and 5α-cholestane-3β,6α,8,15α,16β,26-hexol (8) exhibited strong inhibitory effects on LPS-induced NO production in RAW264.7 cells with IC₅₀ values of 9.13 ± 1.17, 9.19 ± 0.77, 8.63 ± 3.31, 12.61 ± 0.51, 14.83 ± 3.02 and 10.98 ± 1.22 µM, respectively.

Limonoids From Choerospondias axillaris

Eight limonoids (1-8), including 1 new compound named as axillariol A (1), were isolated from the dichloromethane extract of Choerospondias axillaris branches and leaves using various chromatographic separations. Their structures were confirmed by detailed analysis of the 1-dimensional (1D), 2D nuclear magnetic resonance, and high-resolution electrospray ionization quadrupole time-of-flight mass spectra. In addition, toonaciliatins N (6) and toonaciliatins O (7) showed selective and significant cytotoxicity on the rhabdomyosarcoma human cancer cell line with half-maximal inhibitory concentration values of 9.12 and 7.79 µM, respectively.

Dendrodoristerol, a cytotoxic C20 steroid from the Vietnamese nudibranch mollusk Dendrodoris fumata

Using various chromatographic separations, four steroids including one new C₂₀ steroid namely dendrodoristerol (1), were isolated from the Vietnamese nudibranch mollusk Dendrodoris fumata. The structure elucidation was confirmed by combination of spectroscopic experiments including 1D and 2D NMR, HR QTOF MS, and CD. Compound 1 was found to exhibit significant in vitro cytotoxic activity against six human cancer cell lines as HL-60, KB, LU-1, MCF-7, LNCaP, and HepG2. In addition, 1 induced HL-60 cancer cell death by apoptosis and necrosis.

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.

Sulphated flavones and pregnane-type steroids from Helicteres viscida

In our search for anti-inflammatory constituents from Vietnamese plants, the methanolic extract of Helicteres viscida was found to exhibit inhibitory effect on LPS-induced NO production in RAW264.7 cells. Phytochemical investigation of this plant led to isolation of four sulphated flavones (1-4), including one new compound 5,3',4'-trihydroxy-7-methoxy-8-O-sulphate flavone (1), and two pregnane-type steroids (5 and 6), including one new compound 7-epi-heligenin B (5). Their structures were elucidated by 1D and 2D NMR as well as HR-QTOF-MS experiments. Among isolated compounds, heligenin B (6) exhibited potent inhibitory effect on LPS-induced NO production in RAW264.7 cells with IC₅₀ of 1.23 ± 0.05 µM. The activity of 6 was comparable to that of the positive control cardamonin.

Sesquiterpenoids from Saussurea costus

Sixteen sesquiterpenoids (1 - 16), including two new compounds namely saussucostusosides A and B (1 and 2), were isolated from the roots of Saussurea costus by various chromatographic separations. Their structures were elucidated by 1 D and 2 D NMR and HR-QTOF-MS experiments. Among isolated compounds, costunlide (6), 3β-[4-hydroxymethacryloyloxy]-8α-hydroxycostunolide (10) and 11β,13-dihydrozaluzanin C (16) exhibited potent inhibitory effects on LPS-induced NO production in RAW264.7 cells with IC₅₀ values of 7.08 ± 0.34, 2.40 ± 0.06 and 5.55 ± 0.24 µM, respectively.

Bicyclic lactones from the octocoral Dendronephthya mucronata

The MeOH extract of the Vietnamese octocoral Dendronephthya mucronata afforded four bicyclic lactones (1-4), including three new compounds namely dendronephthyones A-C (1-3), after subjecting it on various chromatographic separations. The structures of the isolated compounds were established by spectroscopic experiments including 1D, 2D NMR, CD and HR-QTOF-MS. In addition, compounds 1-4 were found to exhibit selective cytotoxicity against the HeLa human cancer cell line with IC₅₀ values of 32.48 ± 2.15, 30.12 ± 1.86, 35.14 ± 1.57 and 14.45 ± 1.34 μM, respectively.

A New 9,11-Secosterol from the Vietnamese Sea Soft Coral, Sarcophyton Mililatensis, Increases the Function of Osteoblastic MC3T3-E1 Cells

Chemical investigation of the Vietnamese soft coral Sarcophyton mililatensis resulted in the isolation of a new 9,11-secosterol, sarcomilasterol (1), along with two known polyhydroxylated sterols, sarcoaldesterol B (2) and ergosta-1β,3β,5α,6β-tetraol (3). Their structures were established on the basis of NMR spectroscopic and MS experiments. Compound 1 (3 μM) significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase activity and nodules mineralization compared to those of the control (P<0.05). These results suggest that compound 1 has a direct stimulatory effect on bone formation in vitro and may contribute to the prevention of osteoporosis.

Acylated flavonoid glycosides from Barringtonia racemosa

Using various chromatographic separations, three new acylated flavonoid glycosides, namely barringosides G-I (1-3), were isolated from the water-soluble extract of Barringtonia racemosa branches and leaves. The structure elucidation was performed by extensive analysis of the 1D and 2D NMR and HR-QTOF-MS data. Of the isolated compounds, barringoside I (3) showed moderate inhibitory effects on LPS-induced NO production in RAW264.7 cells with an IC₅₀ of 52.48 ± 1.04 µM.

A new [7.7]paracyclophane from Vietnamese marine snail Planaxis sulcatus (Born, 1780)

A new [7.7]paracyclophane (1), together with eight known compounds (2-9), were isolated from a MeOH extract of the sea snail Planaxis sulcatus (Born, 1780). Their structures were elucidated by HR-ESI-MS and NMR techniques as well as comparison with those reported in literatures. The absolute configuration of metabolite 1 was determined using ECD spectroscopy. Among nine compounds, 1 exhibited significant cytotoxicity toward all eight cancer cells tested with IC₅₀ values between 1.81 and 3.80 µg/mL.[Figure: see text].

Cytotoxic steroids from the Vietnamese gorgonian Verrucella corona

Using various chromatographic separations, seventeen steroids including seven new compounds, verrucorosteroids A-F (1-6) and verrucorosterone (7), were isolated from the Vietnamese gorgonian Verrucella corona. Their structures were elucidated by spectroscopic analysis, including HR QTOF MS, 1D and 2D NMR. Among isolates, verrucorosterone (7), 5,6α-epoxy-3β-hydroxy-(22E)-ergosta-8,22-dien-7-one (14), and 5,6α-epoxy-3β-hydroxy-(22E)-ergosta-8(14),22-dien-7-one (15) showed significant cytotoxicity (IC₅₀ values ranging from 12.32 ± 1.47 to 33.77 ± 1.28 μM) against eight human cancer cell lines as LNCaP (prostate cancer), HepG2 (hepatoma cancer), KB (epidermoid carcinoma), MCF-7 (breast cancer), SK-Mel2 (melanoma), HL-60 (acute leukemia), LU-1 (lung cancer), and SW480 (colon adenocarcinoma).

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.

Engineering co-culture system for production of apigetrin in Escherichia coli

Microbial cells have extensively been utilized to produce value-added bioactive compounds. Based on advancement in protein engineering, DNA recombinant technology, genome engineering, and metabolic remodeling, the microbes can be re-engineered to produce industrially and medicinally important platform chemicals. The emergence of co-culture system which reduces the metabolic burden and allows parallel optimization of the engineered pathway in a modular fashion restricting the formation of undesired byproducts has become an alternative way to synthesize and produce bioactive compounds. In this study, we present genetically engineered E. coli-based co-culture system to the de novo synthesis of apigetrin (APG), an apigenin-7-O-β-D-glucopyranoside of apigenin. The culture system consists of an upstream module including 4-coumarate: CoA ligase (4CL), chalcone synthase, chalcone flavanone isomerase (CHS, CHI), and flavone synthase I (FNSI) to synthesize apigenin (API) from p-coumaric acid (PCA). Whereas, the downstream system contains a metabolizing module to enhance the production of UDP-glucose and expression of glycosyltransferase (PaGT3) to convert API into APG. To accomplish this improvement in titer, the initial inoculum ratio of strains for making the co-culture system, temperature, and media component was optimized. Following large-scale production, a yield of 38.5 µM (16.6 mg/L) of APG was achieved. In overall, this study provided an efficient tool to synthesize bioactive compounds in microbial cells.

Triterpene tetraglycosides from the sea cucumber Stichopus horrens

Using various chromatographic separations, three triterpene tetraglycosides (1-3), including one new compound, namely stichorrenoside E (1) along with thelenotoside B (2) and deacetyl thelenotoside B (3), were isolated from the MeOH extract of the Vietnamese sea cucumber Stichopus horrens. Their structures were confirmed by spectroscopic experiments, such as 1D and 2D NMR and HR-ESI-MS. Deacetylated thelenotoside B (3) is firstly isolated as a natural product. Among these compounds, thelenotoside B (2) showed strong cytotoxicities against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 0.95 ± 0.08 to 1.90 ± 0.13 μM, whereas stichorrenoside E (1) and deacetyl thelenotoside B (3) exhibited significant activities with the IC₅₀ values from 6.87 ± 0.25 to 11.62 ± 1.05 μM.