Nguyen Thi Cuc

Synthesis of Chromonylthiazolidines and Their Cytotoxicity to Human Cancer Cell Lines

Nine new chromonylthiazolidine derivatives were successfully semi-synthesized from paeonol. All of the compounds, including starting materials, the intermediate compound and products, were evaluated for their cytotoxic effects toward eight human cancer cell lines. The synthesized chromonylthiazolidines displayed weak cytotoxic effects against the tested cancer cell lines, but selective cytotoxic effects were observed. Compounds 3a and 3b showed the most selective cytotoxic effects against human epidermoid carcinoma (IC50 44.1 ± 3.6 μg/mL) and breast cancer (IC50 32.8 ± 1.4 μg/mL) cell lines, respectively. The results suggest that chromoylthiazolidines are potential low-cost, and selective anticancer agents.

1)H and (13)C NMR assignments of sesquiterpenes from Dysidea fragilis.

Sesquiterpenes have been reported as components of the genus Dysidea (Dysideidae). Many chemical investigations have been focused on the marine sponge Dysidea fragilis. The constituents of D. fragilis were identified as sesquiterpenes, steroids and diketopiperazines. They exhibited various biological activities such as anti-inflammatory and cytotoxic activities. Previously, series of new sesquiterpenes were reported from the Vietnamese sponge D. cinerea by our group. In continuing research on bioactive compounds from genus Dysidea, three new and two known sesquiterpenes were isolated from the sponge D. fragilis. Herein, we report the isolation and structure elucidation of these compounds.

Phylogenetic diversity of microorganisms associated with three marine sponges from Mien Trung sea of Vietnam

Using culture independent technique, hypervariabl e V4 region of 16S rDNA library sequencing by MiSeq, the baterial communities of th ree host sponges Rhabdastrellasp. DN, Spheciospongiasp. QT and Clathriasp. NT from Mien Trung sea were characterized. The phylogenetic analysis showed that bacterial communi ty structures of the three investigated sponges similar to each other regarding 10 common p hyla, although abundance of these phyla was different for each sponge. Phylum Thaumarchaeot a was rich component for three sponges, especially in NT sponge (31.89 %). In this sponge, 3 phyla Planctomycetes, Verrucomicrobia and Firmicutes were undetected in other 2 sponge sa mples. Phyla Cyanobacteria was observed only in DN sponge. The obtained amplicons were assigned in different t axonomic levels (class, order, family and genus) based on Silva database. At class level, Gammaproteobacteria was abundant in three sponges; and Caldilineae, Marine-group I were domi nant in DN; mealwile, in QT other dominant classes were Marine-group I and Betaproteo bacteria. For NT, they were Cytophaga and Deferribacteres. In general, all three sponges harbored abundant and genetically diverse microbial associated consortia and they shared seve ral common bacterial operational taxonomic units, although with different abundance.

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.

The hepatoprotective activity of a new derivative kaempferol glycoside from the leaves of Vietnamese Phyllanthus acidus (L.) Skeels

A new derivative kaempferol glycoside, kaempferol-3-O-(2-α-l-rhamnopyranosyl)-β-d-glucuronopyranosyl methyl ester (3), together with six other known kaempferol glycosides, kaempferol-3-O-[α-l-rhamnopyranosyl (1→2)]-β-d-galactopyranoside (1), kaempferol-3-O-(2-α-l-rhamnopyranosyl)-β-d-glucuronopyranoside (2), rutin (4), isoquercitrin (5), quercitrin (6), and myricitrin (7) were isolated from the leaves of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Here, is the first report described the isolation of compound (1) and (2) from the genus Phyllanthus. Compound (1) presents antioxidant activity in 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay. Compound (2) and (3) performed no antioxidant activity in 2,2-diphenyl-1-picryl-hydrazyl-hydrate and thiobarbituric acid reactive substances assays (IC50 > 100 µM). However, compound (2) showed anti-inflammation activity through inhibiting interleukin 6 and tumor necrosis factor alpha production (P < 0.05). Compound (3) also exhibited cytokine modulating activities such as inhibiting tumor necrosis factor alpha, activating interleukin 10 at concentration of 10 µM (P < 0.05). The interleukin 6 cytokine level was also up or down-regulated by compound (3) at two time points; 24 and 48 h. This activeness of compound (3) might induce hepatoprotection in the acute-phase response by activating the signal transducer and activator of transcription 3(STAT3) through cytokine modulation. Together with other kaempferol glycosides, this new derivative compound may mediate the liver-protective activity of the Vietnamese medicinal plant Phyllanthus acidus.

Flavonoid glycosides from Antidesma ghaesembilla

Four flavone glycosides were isolated from the leaves of Antidesma ghaesembilla. They were elucidated to be vitexin, orientin, isovitexin, and homoorientin by 1D- and 2D-NMR and in comparison with literature data. These compounds have been reported from the genus Antidesma for the first time.

INVESTIGATING THE ANTI-INFLAMMATORY ACTIVITY OF AN ETHANOLIC EXTRACT FROM ARTOCARPUS TONKINENSIS LEAVES USING A COLLAGEN ANTIBODY-INDUCED ARTHRITIC MOUSE MODEL

This study was contrived for evaluating the in vitro and in vivo anti-inflammatory effects of an aqueous ethanolic leaf extract of the Vietnamese Artocarpustonkinensis A. Chev. exGagnep. usinglipopolysaccharide-stimulated RAW 264.7 macrophages and a collagen antibody-induced arthritic mouse model as well. The obtained results here demonstrate that the 70 % ethanolic leaf extract of A. tonkinensis(AT2), traditionally used in Vietnamese folk medicine for treating arthritic symptoms, has beneficial effects on pro-inflammatory cytokine inhibition and in an experimental arthritic mouse model.LPS-stimulated RAW 264.7 macrophages treated with AT2 showed a significant decrease in the production of IL-6 and TNF at concentrations of 12.5, 25 and 50 μg/mL (P < 0.05), indicating its potential anti-inflammatory properties. The treatment of CAIA mice with AT2 also led to diminish the incidence of arthritis at doses of 200 and 300 mg/kg body weight.

Mini-Review PROTEASE INHIBITOR (PI) AND PIs FROM SPONGE-ASSOCIATED MICROORGANISMS

Protease inhibitors (PIs) are proteins or peptides inhibiting the activity of protease and constitute a very important mechanism for regulating protease activity. So far, PIs have been used for the study of enzyme structures and reaction mechanisms, but recently they have been used in pharmaceutical, agricultural and industrial fields. Compared to terrestrial counterparts, marine environment possesses their unique characters, therefore, they are capable of producing a wide range of novel bioactive compounds including protease inhibitors. In our review, a brief overview of protease inhibitors (e.g., classification, mechanisms, and characteristics of PIs) and protease inhibitors from marine sponges and sponge-associated microorganisms has been reviewed.

Archaeal and bacterial diversity and community composition from 18 phylogenetically divergent sponge species in Vietnam

Sponge-associated prokaryotic diversity has been studied from a wide range of marine environments across the globe. However, for certain regions, e.g., Vietnam, Thailand, Cambodia, and Singapore, an overview of the sponge-associated prokaryotic communities is still pending. In this study we characterized the prokaryotic communities from 27 specimens, comprising 18 marine sponge species, sampled from the central coastal region of Vietnam. Illumina MiSeq sequencing of 16S ribosomal RNA (rRNA) gene fragments was used to investigate sponge-associated bacterial and archaeal diversity. Overall, 14 bacterial phyla and one archaeal phylum were identified among all 27 samples. The phylum Proteobacteria was present in all sponges and the most prevalent phylum in 15 out of 18 sponge species, albeit with pronounced differences at the class level. In contrast, Chloroflexi was the most abundant phylum in Halichondria sp., whereas Spirastrella sp. and Dactylospongia sp. were dominated by Actinobacteria. Several bacterial phyla such as Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Deferribacteres, Gemmatimonadetes, and Nitrospirae were found in two-thirds of the sponge species. Moreover, the phylum Thaumarchaeota (Archaea), which is known to comprise nitrifying archaea, was highly abundant among the majority of the 18 investigated sponge species. Altogether, this study demonstrates that the diversity of prokaryotic communities associated with Vietnamese sponges is comparable to sponge-prokaryotic assemblages from well-documented regions. Furthermore, the phylogenetically divergent sponges hosted species-specific prokaryotic communities, thus demonstrating the influence of host identity on the composition and diversity of the associated communities. Therefore, this high-throughput 16S rRNA gene amplicon analysis of Vietnamese sponge-prokaryotic communities provides a foundation for future studies on sponge symbiont function and sponge-derived bioactive compounds from this region.

WATER-SOLUBLE COMPONENTS OF Ancistrocladus cochinchinensis

Using various chromatography methods, a saponin, ginsenoside Rg1 ( 1 ), and three phenolic glycosides, tortoside A ( 2 ), phlorizin ( 3 ), and 4-hydroxy-2-methoxyphenyl-6- O -syringyl- b -D-glucopyranoside ( 4 ) were isolated from the water-soluble fraction of Ancistrocladus cochinchinensis. Their structures were elucidated by 1D- and 2D-NMR spectroscopic analyses and comparison with those reported in the literature. Compound 1 was reported from A. cochinchinensis for the first time.