Tran Hong Quang

New monoterpene glycosides from Paeonia lactiflora

Three new monoterpene glycosides named 4-O-methyl-paeoniflorin (1), isopaeoniflorin (2), and isobenzoylpaeoniflorin (3), together with two known monoterpene glycosides, paeoniflorin (4) and benzoylpaeoniflorin (5), were isolated from the roots of Paeonia lactiflora. Their structures were established on the basis of spectral and chemical evidence.

New ent-kauranes from the fruits of Annona glabra and their inhibitory nitric oxide production in LPS-stimulated RAW264.7 macrophages

Three new ent-kaurane diterpenoids, 7β,16α,17-trihydroxy-ent-kauran-19-oic acid (1), 7β,17-dihydroxy-16α-ent-kauran-19-oic acid 19-O-β-d-glucopyranoside ester (2), 7β,17-dihydroxy-ent-kaur-15-en-19-oic acid 19-O-β-d-glucopyranoside ester (3) along with five known compounds, paniculoside IV (4), 16α,17-dihydroxy-ent-kaurane (5), 16β,17-dihydroxy-ent-kaurane (6), 16β,17-dihydroxy-ent-kauran-19-al (7), and 16β,17-dihydroxy-ent-kauran-19-oic acid (8) were isolated from the fruits of Annona glabra. Their chemical structures were elucidated by physical and chemical methods. All compounds were evaluated for inhibitory activity against nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages. As the results, compound 3 showed potent inhibitory LPS-stimulated NO production in RAW 264.7 macrophages with the IC50 value of 0.01±0.01μM; compounds 1 and 7 showed significant inhibitory NO production with the IC50 values of 0.39±0.12μM and 0.32±0.04μM, respectively.

Chemical constituents of the Annona glabra fruit and their cytotoxic activity

Abstract Context: Traditional Chinese medicines have attracted increasing interest as potential sources of novel drugs with a wide range of biological and pharmacological activities. Annona glabra Linn (Annonaceae) is used in traditional medicine as an anticancer drug. Phytochemical investigation of this plant led to the isolation of acetogenins, ent-kauranes, peptides, and alkaloids. In addition, compounds exhibited anticancer, anti-HIV-reserve, and antimalaria. Objective: Isolation, structure determination, and cytotoxic activity evaluation of compounds from the methanol extract from A. glabra fruits. Materials and methods: Using chromatographic methods to isolate compounds from the A. glabra methanol extract. The cytotoxic activity of compounds was evaluated by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. In addition, compounds which showed significant cytotoxic activity were chosen for further study apoptosis characteristics. Results: One new, (2E,4E,1′R,3′S,5′R,6′S)-dihydrophaseic acid 1,3′-di-O-β-d-glucopyranoside, and eight known compounds, (2E,4E,1′R,3′S,5′R,6′S)-dihydrophaseic acid 3′-O-β-d-glucopyranoside (2), icariside D2 (3), icariside D2 6′-O-β-d-xylopyranoside (4), 3,4-dimethoxyphenyl O-β-d-glucopyranoside (5), 3,4-dihydroxybenzoic acid (6), blumenol A (7), cucumegastigmane I (8), and icariside B1 (9), were isolated from the fruits of A. glabra. Icariside D2 (3) was found to show significant cytotoxic activity on the HL-60 cell line with the IC50 value of 9.0u2009±u20091.0u2009µM and did not show cytotoxic activity on the Hel-299 normal cell line. The further test indicated that compound 3 induced apoptosis via alteration of expression of apoptosis-related proteins and decreased phosphorylation of AKT in HL-60 cells. Discussion and conclusion: The results suggested that the constituents from A. glabra may contain effective compounds which can be used as anticancer agents.

Sesquiterpene derivatives from marine sponge Smenospongia cerebriformis and their anti-inflammatory activity

Using various chromatographic methods, five new sesquiterpene derivatives named smenohaimiens A-E (1-5) and five known, 19-hydroxy-polyfibrospongol B (6), ilimaquinone (7), dictyoceratin C (8), polyfibrospongol A (9), and polyfibrospongol B (10) were isolated from the marine sponge Smenospongia cerebriformis Duchassaing & Michelotti, 1864. Their structures were assigned by 1D, 2D NMR spectroscopic analysis, HR ESI MS, and calculations of the electron circular dichroism spectra. All compounds were evaluated for the inhibitory activity against NO production in lipopolysaccharide-stimulated in BV2 microglia cells. As the results, compound 7 significantly inhibited NO production with the IC50 value of 10.40±1.28µM. The remaining compounds showed moderate inhibitory NO production activities with IC50 values ranging from 24.37 to 30.43µM.

Spirostanol saponins from Tacca vietnamensis and their anti-inflammatory activity.

Using various chromatographic methods, five new steroidal saponins named taccavietnamosides A-E (1-5) and three known, (24S,25R)-spirost-5-en-3β,24-diol 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→3)]-β-d-glucopyranoside (6), (24S,25R)-spirost-5-en-3β,24-diol 3-O-α-l-rhamnopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3)]-β-d-glucopyranoside (7), and chantrieroside A (8) were isolated from the rhizomes of Tacca vietnamensis Thin et Hoat. Their chemical structures were elucidated by physical and chemical methods. All compounds were evaluated for the inhibitory activities of nitric oxide production in LPS-stimulated RAW 264.7 macrophages and BV2 cells. As the results, compounds 3-5 showed moderate inhibition on NO production in LPS-stimulated BV2 cells and RAW 264.7 macrophages with the IC50 values ranging from 37.0 to 60.7μM.

Steroidal saponins from Datura metel

&NA; Datura metel L. (Solanaceae) is an annual herb that has been widely used in the traditional medicine for the treatment of coughs, bronchial asthma, and rheumatism. Chemical investigation of an acidic methanol extract of the whole plants of D. metel resulted in the isolation of five new steroidal saponins (1–3, 5, and 6), named metelosides A‐E, and four known compounds (4, 7–9). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. The structures of metelosides A and B were found to be unusual among the reported spirostane‐type steroidal saponins due to the presence of the acetamide groups in the molecules. Compounds 2, 4, 5, and 6 were shown to be cytotoxic against three cancer cell lines, including HepG2, MCF‐7, and SK‐Mel‐2 cells. Furthermore, compounds 3, 4, and 7 exhibited modest anti‐inflammatory effects through inhibition of NO production in LPS‐stimulated BV cells. Graphical abstract Figure. No caption available. HighlightsNine compounds were isolated from Datura metel.The structures of five new steroidal saponins and 4 known compounds were identified by spectroscopic methods.Four compounds were cytotoxic against HepG2, MCF‐7, and SK‐Mel‐2 cells.Three compounds inhibited NO production in LPS‐stimulated BV cells.

Naphtoquinones and Sesquiterpene Cyclopentenones from the Sponge Smenospongia cerebriformis with Their Cytotoxic Activity

Two new naphtoquinones (smenocerones A and B, 1 and 2) and four known sesquiterpene cyclopentenones (dactylospongenones A-D, 3-6) were isolated from sponge Smenospongia cerebriformis living in the Eastern Sea of Vietnam. Their chemical structures were determined by high resolution electrospray ionization (HR-ESI)-MS, NMR spectroscopic analysis, and in comparison with the reported data. The chiroptical properties of compounds 3-6 were examined by experiment and theoretical calculation of circular dichroism (CD) spectra to prove their absolute configurations. Compound 2 significantly exhibited cytotoxic activity towards lung carcinoma (LU-1), hepatocellular carcinoma (HepG-2), promyelocytic leukemia (HL-60), breast carcinoma (MCF-7), and melanoma (SK-Mel-2) human cancer cells with IC50 values of 5.5±0.8, 3.2±0.2, 4.0±0.7, 4.1±0.8, and 5.7±1.1u2009µg/mL, respectively.

Macrolide and phenolic metabolites from the marine-derived fungus Paraconiothyrium sp. VK-13 with anti-inflammatory activity

Five new secondary metabolites, modiolides D-G (1−4) and 1-(2,5-dihydroxyphenyl)-3-methoxy-butan-1-one (8), one new natural product, 1-(2,5-dihydroxyphenyl)-3-hydroxybutan-1-one (7), along with three known compounds, modiolides A (5) and B (6), and 1-(2,5-dihydroxyphenyl)-2-buten-1-one (9) were isolated from a fermentation culture of the marine endophytic fungus Paraconiothyrium sp. VK-13. Their chemical structures were elucidated by the NMR and MS spectroscopic analysis as well as the modified Mosher’s method. Compounds 7 and 9 inhibited the overproduction of proinflammatory mediators NO and PGE2 in LPS-stimulated RAW264.7 cells, with IC50 values ranging from 3.9 to 12.5u2009µM. The inhibitory effects of 7 and 9 on the release of NO and PGE2 were correlated with their significant suppression of iNOS and COX-2 protein expression, respectively. Furthermore, both compounds 7 and 9 inhibited the mRNA expression of proinflammatory cytokines, including TNF-α, IL-1β, IL-6, and IL-12, with IC50 values in a range of 2.4−12.5u2009µM.

Anti-neuroinflammatory effects of cudraflavanone A isolated from the chloroform fraction of Cudrania tricuspidata root bark

Abstract Context: Cudrania tricuspidata Bureau (Moraceae) is an important source of traditional Korean and Chinese medicines used to treat neuritis and inflammation. Objective: The anti-neuroinflammatory effects of cudraflavanone A isolated from a chloroform fraction of C. tricuspidata were investigated in LPS-induced BV2 cells. Materials and methods: Cudraflavanone A was isolated from the root of C. tricuspidata, and its structure was determined by MS and NMR data. Cytotoxicity of the compound was examined by MTT assay, indicating no cytotoxicity at 5–40u2009μM of cudraflavanone A. NO concentration was measured by the Griess reaction, and the levels of PGE2, cytokines and COX-2 enzyme activity were measured by each ELISA kit. The mRNA levels of cytokines were analysed by quantitative-PCR. The expression of iNOS, COX-2, HO-1, NF-κB, MAPKs and Nrf2 was detected by Western blot. Results: Cudraflavanone A had no major effect on cell viability at 40u2009μM indicating 91.5% viability. It reduced the production of NO (IC50u2009=u200922.2u2009μM), PGE2 (IC50u2009=u200920.6u2009μM), IL-1β (IC50u2009=u200924.7u2009μM) and TNF-α (IC50u2009=u200933.0u2009μM) in LPS-stimulated BV2 cells. It also suppressed iNOS protein, IL-1β and TNF-α mRNA expression. These effects were associated with the inactivation of NF-κB, JNK and p38 MAPK pathways. This compound mediated its anti-neuroinflammatory effects by inducing HO-1 protein expression via increased nuclear translocation of Nrf2. Discussion and conclusions: The present study suggests a potent effect of cudraflavanone A to prevent neuroinflammatory diseases. Further investigation is necessary to elucidate specific molecular mechanism of cudraflavanone A.

Macrocyclic bis-quinolizidine alkaloids from Xestospongia muta

Abstract A new stereoisomer Meso-araguspongine C together with nine reported macrocyclic bis-quinolizidine alkaloids araguspongines A, C, E, L, N−P, petrosin, and petrosin A were isolated from marine sponge Xestospongia muta. Stereochemistry of meso-araguspongine C (2) and araguspongines N-P (3−5) were established by their NMR data and conformational analyses. Both araguspongine C (1) and meso-araguspongine C (2) exhibited great cytotoxic activity towards HepG-2, HL-60, LU-1, MCF-7, and SK-Mel-2 human cancer cells (IC50 in the range of 0.43–1.02 μM). At a concentration of 20 μM, isolated compounds (1−10) also showed modest inhibitory effects (from 7.6 to 40.8%) on the NO production in LPS activated RAW264.7 macrophages.