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.

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.

Recent advances in g-C3N4-based photocatalysis for water treatment: Magnetic and floating photocatalysts, and applications of machine-learning techniques.

Over the past decade, there has been a substantial increase in research investigating the potential of graphitic carbon nitride (g-C3N4) for various environmental remediations. Renowned for its photocatalytic activity under visible light, g-C3N4 offers a promising solution for treating water pollutants. However, traditional g-C3N4-based photocatalysts have inherent drawbacks, creating a disparity between laboratory efficacy and real-world applications. A primary practical challenge is their fine-powdered form, which hinders separation and recycling processes. A promising approach to address these challenges involves integrating magnetic or floating materials into conventional photocatalysts, a strategy gaining traction within the g-C3N4-based photocatalyst arena. Another emerging solution to enhance practical applications entails merging experimental results with contemporary computational methods. This synergy seeks to optimize the synthesis of more efficient photocatalysts and pinpoint optimal conditions for pollutant removal. While numerous review articles discuss the laboratory-based photocatalytic applications of g-C3N4-based materials, there is a conspicuous absence of comprehensive coverage regarding state-of-the-art research on improved g-C3N4-based photocatalysts for practical applications. This review fills this void, spotlighting three pivotal domains: magnetic g-C3N4 photocatalysts, floating g-C3N4 photocatalysts, and the application of machine learning to g-C3N4 photocatalysis. Accompanied by a thorough analysis, this review also provides perspectives on future directions to enhance the efficacy of g-C3N4-based photocatalysts in water purification.

Sulfated Naphthopyrones and Anthraquinones from the Vietnamese Crinoid Comanthus delicata.

Three new sulfated naphthopyrone derivatives namely delicapyrons F-H (1-3) and two new sulfated anthraquinone derivatives namely delicaquinons A (4) and B (5), together with 6-methoxycomaparvin-5-methylether-8-O-sodium sulfate (6), 6-methoxycomaparvin-8-O-sodium sulfate (7), comaparvin-8-O-sodium sulfate (8), and 3-propyl-1,6,8-trihydroxy-9,10-anthraquinone-6-O-sodium sulfate (9) were isolated from the Vietnamese crinoid Comanthus delicata. Their chemical structures were elucidated by extensive analysis of the one dimensional (1D) and 2D-NMR, high resolution electrospray ionization quadrupole time-of-flight (HR-ESI-QTOF) mass spectra as well as calculation of optical rotation. In addition, significant cytotoxicity was observed for 6 against LNCaP (prostate cancer) cell line with IC50 value of 20.29 ± 2.43 µM, whereas moderate or weak cytotoxic effects were observed for 1-3 and 5-8 on SK-Mel-2 (melanoma) cell line and 7 and 8 against LNCaP cell line, with IC50 values ranging from 49.96 ± 1.74 to 76.92 ± 5.85 µM.

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 ß-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.

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.

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.

Chemical constituents from Vietnamese mangrove Calophyllum inophyllum and their anti-inflammatory effects.

In a search for anti-inflammatory activity in resources from Vietnamese mangroves, we found that a methanolic extract from the leaves of Calophyllum inophyllum (CIL) showed significant anti-inflammatory effects in vitro. Using various chromatographic techniques, we subsequently isolated 12 compounds (1-12) from a methanolic extract of CIL, including two novel compounds (1-2). The inhibitory effects of these compounds on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells were also evaluated. Compound 1 significantly suppressed NO production (IC50 = 2.44 ±â€¯0.88 µM), the secretion of pro-inflammatory cytokines (including interleukin-1 beta and tumor necrosis factor alpha), and the expression of inducible nitric oxide synthase through downregulation of nuclear factor-kappa-B signaling cascades. These results suggest that C. inophyllum leaves might be a useful resource for the development of drugs for the treatment of inflammation.

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-ß-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.

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.

Escherichia coli modular coculture system for resveratrol glucosides production.

In bio-based fermentation, the overall bioprocess efficiency is significantly affected by the metabolic burden associated with the expression of complete biosynthetic pathway as well as precursor and cofactor generating enzymes into a single microbial cell. To attenuate such burden by compartmentalizing the enzyme expression, recently synthetic biologists have used coculture or poly-culture techniques for biomolecules synthesis. In this paper, coculture system of two metabolically engineered Escherichia coli populations were employed which comprises upstream module expressing two enzymes converting para-coumaric acid into resveratrol and the downstream module expressing glucosyltransferase to convert the resveratrol into its glucosidated forms; polydatin and resveratroloside. Upon optimization of the initial inoculum ratio of two E. coli populations, 92 mg resveratrol glucosides/L (236 µM) was produced i.e. achieving 84% bioconversion from 280 µM of p-coumaric acid in 60 h by 3 L fed batch fermentor. This is the report of applying coculture system to produce resveratrol glucosides by expressing the aglycone formation pathway and sugar dependent pathway into two different cells.

Cytotoxic triterpene diglycosides from the sea cucumber Stichopus horrens.

Using various chromatographic separation techniques, eight triterpene diglycosides (1-8), including four new compounds namely stichorrenosides A-D (1-4), were isolated from a methanol extract of the Vietnamese sea cucumber S. horrens. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, 1D and 2D NMR. Their in vitro cytotoxic activity against five human cancer cell lines, Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma), was evaluated using SRB methods. Stichorrenoside D (4), stichoposide A (5), and 3ß-O-[ß-d-xylopyranosyl-(1→2)-ß-d-xylopyranosyl]-23S-acetoxyholost-7-ene (7) showed strong cytotoxicity on all five tested cancer cell lines, whereas significant effect was observed for stichorrenoside C (3) and stichoposide B (6).

Triterpene saponins and megastigmane glucosides from Camellia bugiamapensis.

Two new triterpene saponins, camelliosides I and J (1 and 2), two new megastigmane glycosides, camellistigosides A and B (3 and 4), and two known megastigmane glycosides, icariside B1 (5) and (6S,9R)-roseoside (6), were isolated from a methanol extract of the Camellia bugiamapensis leaves using various chromatographic separation techniques. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, CD, 1D and 2D NMR. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were evaluated. This is the first report of the chemical constituents and biological activity of C. bugiamapensis.

Flavonoid glycosides from Barringtonia acutangula.

Using various chromatographic separation techniques, ten flavonoid glycosides, including six new compounds namely barringosides A-F (1-6), were isolated from a methanol extract of the Barringtonia acutangula leaves. The structure elucidation was confirmed by spectroscopic analyses, including 1D and 2D NMR, and HR ESI MS. Their inhibitory effects on LPS-induced NO production in RAW264.7 cells were also evaluated. Among the isolated compounds, quercetin 3-O-ß-d-(6-p-hydroxybenzoyl)galactopyranoside (9) showed significant effect with an IC50 of 20.00±1.68µM. This is the first report of these flavonoid glycosides from Barringtonia genus and their inhibition on LPS-induced NO production in RAW264.7 cells was reported here for the first time.

Cytotoxic Steroids from the Vietnamese Soft Coral Sinularia leptoclados.

Fifteen steroids, including two new compounds, leptosteroid (1) and 5,6ß-epoxygorgosterol (2), were isolated and structurally elucidated from the Vietnamese soft coral Sinularia leptoclados. Their cytotoxic effect against a panel of eight human cancer cell lines was evaluated using sulforhodamine B (SRB) method. Significant cytotoxicity against hepatoma cancer (HepG2, IC50=21.13±0.70 µM) and colon adenocarcinoma (SW480, IC50=28.65±1.53 µM) cell lines were observed for 1 and against acute leukemia (HL-60, IC50=20.53±2.26 µM) and SW480 (IC50=26.61±1.59 µM) for ergost-5-en-3ß,7ß-diol (8). In addition, 3ß,7ß-dihydroxyergosta-5,24(28)-diene (13) showed significant cytotoxic activity on all tested cell lines with IC50 values ranging from 13.45±1.81 to 29.01±3.21 µM.

Cytotoxic Steroids from the Vietnamese Soft Coral Sinularia conferta.

Twelve steroids, including five new compounds 1-5, were isolated and structurally elucidated from a methanol extract of the Vietnamese soft coral Sinularia conferta. Their cytotoxic effects against three human cancer cell lines, lung carcinoma (A-549), cervical adenocarcinoma (HeLa), and pancreatic epithelioid carcinoma (PANC-1), were evaluated using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assays. Among isolated compounds, 10 exhibited potent cytotoxic effects on all three tested cell lines with IC50 values of 3.64±0.18, 19.34±0.42, and 1.78±0.69 µM, respectively.

Steroid glycosides from the starfish Pentaceraster gracilis.

Using combined chromatographic separations, two new steroid glycosides namely pentacerosides A (1) and B (2), and four known compounds were isolated from the methanol extract of the starfish Pentaceraster gracilis. Their structures were determined on the basis of spectroscopic data (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, ROESY, and FT-ICR-MS) and by comparing obtained results to the literature values. Among the isolated compounds, only maculatoside (5) showed significant cytotoxic effect against Hep-G2 (IC50 = 16.75 ± 0.69 µM) and SK-Mel2 (IC50 = 19.44 ± 1.45 µM) cell lines and moderate effect on KB (IC50 = 36.53 ± 0.78 µM), LNCaP (IC50 = 39.75 ± 3.34 µM), and MCF7 (IC50 = 47.34 ± 7.01 µM) cell lines.

Steroid Constituents from the Soft Coral Sinularia nanolobata.

Six steroids (1-6), including the two new compounds 3ß,4α-dihydroxyergosta-5,24(28)-diene (1) and 24(S),28-epoxyergost-5-ene-3ß,4α-diol (2), were isolated from the methanol extract of the Vietnamese soft coral Sinularia nanolobata. Their structures were elucidated by spectroscopic methods including one and two dimensional (1D- and 2D)-NMR, Fourier transform ion cyclotron resonance (FT-ICR)-MS, and circular dichroism (CD). Compound 2 exhibited moderate cytotoxicity against the acute leukemia (HL-60) cell line with IC50 value of 33.53±4.25 µM and weak effect on the hepatoma cancer (HepG2) and colon adenocarcinoma (SW480) cell lines with IC50 values of 64.35±7.00 and 71.02±4.00 µM, respectively.