Oleanane-type saponins from Lysimachia laxa Baudo and their anti-bacterial activities.

Seven new oleanane-type triterpene saponins, lysimaponins A-G, were isolated from aerial parts of Lysimachia laxa Baudo. Their chemical structures have been elucidated by analysis of spectroscopic and chemical methods. All compounds were evaluated for their anti-bacterial effects against Microcystis aeruginosa, Vibrio parahaemolyticus, V. harveyi, V. vulinificus, V. cholerae, and V. alginolyticus. All compounds showed potent anti-bacterial activities against the cyanobacteria M. aeruginosa with IC50 values ranging from 14.4 ± 1.2 to 35.3 ± 2.2 µg/mL. Compounds 1, 2, 4-7 inhibited V. parahaemolyticus with MIC values ranging from 64 to 256 µg/mL. The results suggested that saponins from L. laxa could be potential anti-cyanobacteria agents.

Mussel - Inspired biosorbent combined with graphene oxide for removal of organic pollutants from aqueous solutions.

In this work, we develop a mussel-inspired biosorbent combined with graphene oxide for removal of organic dyes in water sources. The composite was prepared via self-polymerization of dopamine in weak alkaline solution containing graphene oxide at ambient condition. Morphological and structural studies revealed that polydopamine has gradually grown to cover the surface of graphene oxide flakes, partially reduced these flakes, and somehow form many grains (size around 20 nm) on the flakes instead of making very large aggregates as usual. The mass ratio between two components of the composite was also investigated to find the optimal one which provides enough surface area (20 m2.g-1) and maintain adhesive sites in order to ensure high-efficiency removal of organic molecules. The adsorption kinetics and isotherms of as-prepared adsorbent towards methylene blue were found to fit well with pseudo-first order kinetics model and Langmuir isotherm. The maximum adsorption capacity (qm) and Langmuir constant (kL) were estimated to be 270 mg.g-1 and 0.49 L. mg-1. The as-prepared bio-sorbent is very promising for remediation of water sources contaminated with cationic organic molecules and heavy metal ions.

Atractylodes macrocephala Rhizomes Contain Anti-inflammatory Sesquiterpenes.

Two new compounds, named eudesm-4(15),7-diene-3α,9ß,11-triol (1) and eudesm-4(15),7-diene-1ß,3α,9ß,11-tetraol (2) together with three known sesquiterpene lactones (1S,5R,7R,10R)-secoatractylolactone (3), (1S,5R,7R,10R)-secoatractylolactone-11-O-ß-D-glucopyranoside (4) atractylenolide III (5) were isolated from the rhizomes of Atractylodes macrocephala. Their structures were elucidated by using one-dimensional (1D) and 2D-NMR spectra and high resolution electrospray ionization (HR-ESI)-MS data. Compound 5 exhibited the most active anti-inflammatory activity with IC50 values of 27.5 µM in inhibiting of nitric oxide production. Compounds 1, 2, and 3 showed moderate effects while compound 4 was inactive.

Acetylcholinesterase inhibition studies of alkaloid components from Crinum asiaticum var. sinicum: in vitro assessments by molecular docking and molecular dynamics simulations.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1-7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease.

Wedtrilosides A and B, two new diterpenoid glycosides from the leaves of Wedelia trilobata (L.) Hitchc. with α-amylase and α-glucosidase inhibitory activities.

In the ongoing research to find new diabetes constituents from the genus Wedelia, the chemical constituent of Wedelia trilobata leaves, a Vietnamese medicinal plant species used to treat type 2 diabetes mellitus, was selected for detailed investigation. From a methanolic extract, two new ent-kaurane diterpenoids, wedtrilosides A and B (1 and 2), along with five known metabolites (3-7), were isolated from W. trilobata. The chemical structures of (1-7) were assigned via spectroscopic techniques (IR, 1D, 2D NMR and HR-QTOF-MS data) and chemical methods. The isolates were evaluated for α-amylase and α-glucosidase inhibitory activities compared to the clinical drug acarbose. Among them, compounds 4, 6, and 7 showed the most potent against α-glucosidase enzyme with IC50 values of 27.54 ±â€¯1.12, 173.78 ±â€¯2.37, and 190.40 ±â€¯2.01 µg/mL. While moderate inhibitory effect against α-amylase was observed with compounds 6 and 7 (with IC50 = 181.97 ±â€¯2.62 and 52.08 ±â€¯0.56 µg/mL, respectively). The results suggested that the antidiabetic properties from the leaves of W. trilobata are not simply a result of each isolated compound, but are due to other factors such as the accessibility of polyphenolic groups to α-amylase and α-glucosidase activities.

Hypoglycemic property of triterpenoid saponin PFS isolated from Polyscias fruticosa leaves.

This paper evaluated the inhibitory effect of 3-O-[ß-d-glucopyranosyl-(1→4)-ß-d-glucuronopyranosyl] oleanolic acid 28-O-ß-d-glucopyranosyl ester (PFS), a major saponin isolated from Polyscias fruticosa leaves, on α-amylase and α-glucosidase, and its potential for reducing the postprandial blood glucose level in mice. In enzyme inhibition assays, PFS strongly inhibited porcine pancreas α-amylase and yeast α-glucosidase. Using the Lineweaver-Burk equation, we found that PFS inhibited porcine pancreas α-amylase in a mixed noncompetitive mode, and yeast α-glucosidase via noncompetitive inhibition. In the sucrose tolerance test, PFS at 100 mg/kg body weight significantly decreased the postprandial blood glucose level in mice fed a high-sucrose diet. These findings suggest that P. fruticosa leaves and their major saponin PFS can be used to prevent and treat diabetes and its complications.

Inhibition Potential of Cycloartane-Type Glycosides from the Roots of Cimicifuga dahurica against Soluble Epoxide Hydrolase.

A phytochemical assay-guided fractionation of the 95% ethanol extract of Cimicifuga dahurica roots afforded 29 9,19-cycloartane triterpenoid glycosides, including the new cimiricasides A-F (1-6). The structures of 1-6 were established using contemporary NMR methods and from the HRESIMS data, and the sugar moiety in each case was confirmed by acid hydrolysis and subsequent GC/MS analysis. Compounds 2, 4, 5, 7-9, 18, 25, and 29 showed soluble epoxide hydrolase inhibitory effects with IC50 values of 0.4 ± 0.1 to 24.0 ± 0.2 µM. The compounds were analyzed by enzyme kinetic studies to explore the binding mode between the ligand and receptor. Compounds 4 (mixed type), 8, 18, and 29 (noncompetitive type) bound to a preferred allosteric site, while compounds 2, 5, 7, 9, and 25 had competitive interactions at the active site. The binding mechanism of selected inhibitors was investigated using molecular docking and dynamics simulations.

Cytotoxic Homoisoflavonoids from Ophiopogon japonicus Tubers.

A phytochemical fractionation of a methanol extract of Ophiopogon japonicus tubers led to the isolation of a new homoisoflavanone, homoisopogon A (1), and three new homoisoflavanes, homoisopogon B-D (2-4). Their chemical structures were elucidated by mass, NMR, and circular dichroism (CD) spectroscopic methods. Homoisopogon A (1) exhibited potent cytotoxicity against human lung adenocarcinoma LU-1, human epidermoid carcinoma KB, and human melanoma SK-Mel-2 cancer cells with IC50 values ranging from 0.51 to 0.66 µM.

Identification, characterization, kinetics, and molecular docking of flavonoid constituents from Archidendron clypearia (Jack.) Nielsen leaves and twigs.

In our search for natural soluble epoxide hydrolase (sEH) inhibitors from plants, we found that the methanolic extract of the leaves and twigs of Archidendron clypearia (Jack.) Nielsen (Fabaceae) significantly inhibits sEH in vitro. In a phytochemical investigation of the water layer of A. clypearia, we isolated two new chalcones, clypesides A-B (1-2), 13 flavonoid derivatives (3-15) and established their structures based on an extensive 1D and 2D NMR, CD data, and MS analysis. All of the flavonoid derivatives inhibited sEH enzymatic activity in a dose-dependent manner, with IC50 values ranging from 10.0±0.4 to 30.1±2.1µM. A kinetic analysis of compounds 4, 8-10, 12, 13, and 15 revealed that the compounds 8-10 were non-competitive, 4, 13, and 15 were mixed-type, and 12 was competitive inhibitors. Additionally, molecular docking increased our understanding of their receptor-ligand binding. These results demonstrated that flavonoid derivatives from A. clypearia are potential sEH inhibitors.

Methanol extract from Vietnamese Caesalpinia sappan induces apoptosis in HeLa cells.

BACKGROUND: This study evaluated the cytotoxic activity of extracts from Caesalpinia sappan heartwood against multiple cancer cell lines using an MTT cell viability assay. The cell death though induction of apoptosis was as indicated by DNA fragmentation and caspase-3 enzyme activation. RESULTS: A methanol extract from C. sappan (MECS) showed cytotoxic activity against several of the cancer cell lines. The most potent activity exhibited by the MECS was against HeLa cells with an IC50 value of 26.5 ± 3.2 µg/mL. Treatment of HeLa cells with various MECS concentrations resulted in growth inhibition and induction of apoptosis, as indicated by DNA fragmentation and caspase-3 enzyme activation. CONCLUSION: This study is the first report of the anticancer properties of the heartwood of C. sappan native to Vietnam. Our findings demonstrate that C. sappan heartwood may have beneficial applications in the field of anticancer drug discovery.

Chemical constituents from the heterotrophic marine microalgae Aurantiochytrium sp. SC145 and their antimicrobial activities.

One new indol, N-methoxymethyltryptophol (1), one new phenolic, (2 R)-2-(4-hydroxyphenyl)ethyl 2-hydroxy-3-phenylpropanoate (2) and fifteen known compounds (3-17) were isolated from the methanol extract of the fermentation of marine microalgae Aurantiochytrium sp. SC145. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, quantum chemical calculation methods and by comparing their NMR data with those reported in the literature. All compounds were evaluated for their antimicrobial activities against microorganisms. Compounds 2, 3 and 11 significantly exhibited antimicrobial activities on all tested Gram-(+), Gram-(-) bacteria and the yeast C. albicans with MIC values ranging from 32 to 256 µg/mL.

Cytotoxic activity of new phenolic compounds from Vietnamese Caesalpinia sappan.

Two new phenolic compounds, caesalpiniaphenols G-H (1 and 2), were isolated from Vietnamese Caesalpinia sappan heartwood. The chemical structures were established mainly by extensive spectroscopic studies and chemical evidence. Compounds 1 and 2 showed potent inhibitory activity against HL-60 cancer cell lines with respective IC50 values of 16.7 and 22.5 µg/mL. Treating HL-60 cells with various concentrations of 1 resulted in growth inhibition and the induction of apoptosis.

Toxicity, analgesic and anti-inflammatory activities of tectorigenin.

OBJECTIVE: Belamcanda chinensis has been used in oriental medicine for the treatment of inflammatory diseases. Tectorigenin is a main compound in B. chinensis and possess inhibitory activity against inflammatory responses. Thus, the current study aimed at evaluating toxicity as well as analgesic and anti-inflammatory effects of tectorigenin in animal models. METHODS: Tectorigenin was employed to evaluate acute and subacute toxicity. Acetic acid-induced writhing in mice was used for analgesic test. The anti-inflammatory activity was tested in carrageenan-induced paw edema. RESULTS: LD(50) of tectorigenin was 1.78 g/kg p.o. in mice and no toxic symptoms were observed at doses up to 300 mg/kg in a subacute toxicity test during 28-day treatment. Tectorigenin at doses of 50 and 100 mg/kg had an analgesic effect on acetic acid-induced acute visceral pain in mice. In inflammatory rat model, tectorigenin at 60 mg/kg significantly reduced carrageenan-induced edema. CONCLUSION: We demonstrated that tectorigenin is a safe and promising analgesic and anti-inflammatory agent.

Undescribed chalcone and stilbene constituents from Lysimachia baviensis and their anti-inflammatory effect.

The chemical composition and anti-inflammatory activity of the endemic Lysimachia baviensis were investigated for the first time in this study. A phytochemical fractionation of the methanol extract of L. baviensis resulted in the isolation of a new stilbene (bavienside A, 1) and two new chalcone glycosides (baviensides B and C, 2 and 3). Their structures were elucidated via the interpretation of NMR and HRESIMS spectroscopic data. Compounds 1-3 strongly inhibited the production of nitric oxide in LPS-induced RAW264.7 cells with the IC50 values of 6.23, 2.86 and 3.51 µM, respectively. The C-acetylstilbene and carbomethyl chalcone structures in compound 1 and 3 were found for the first time from natural source and could be important markers for chemotaxonomy of Lysimachia baviensis.

Chitosan membrane drafting silver-immobilized graphene oxide nanocomposite for banana preservation: Fabrication, physicochemical properties, bioactivities, and application.

In this study, silver-immobilized graphene oxide/chitosan (AGC/CTS) membranes were assembled by the solvent evaporation method, wherein Curcuma longa extract was used to synthesize silver-immobilized graphene oxide (AGC) nanocomposite. The characterization results showed that the AGC was successfully synthesized with AgNPs distributed quite evenly on GO sheets. The as-prepared AGC also exhibited high antibacterial activity and low cytotoxicity towards normal cell lines compared to human epithelial carcinoma cell lines. Besides, the fabrication of AGC/CTS membranes was additionally assessed with different AGC ratios and thicknesses. The results revealed the membrane containing 3 wt% of AGC with great hygroscopicity and elastic modulus of 27.03 ± 3.07 MPa. The samples also performed excellent bactericidal capability, along with good mechanical properties for banana preservation. Therewithal, the membrane-coated bananas were also elucidated to ripen at slower paces and less damage, with no appearance of patches of mold on the banana peel surface, eventually prolonging the shelf life of bananas up to 10 days as compared to the non-coated ones. The aforesaid results confirm the potential application of the AGC/CTS membrane as a safe and alternative fruit preservation agent in the food industry.

Yangonin blocks tumor necrosis factor-α-induced nuclear factor-κB-dependent transcription by inhibiting the transactivation potential of the RelA/p65 subunit.

The nuclear factor-κB (NF-κB) transcription factors control many physiological processes including inflammation, immunity, and apoptosis. In our search for NF-κB inhibitors from natural resources, we identified yangonin from Piper methysticum as an inhibitor of NF-κB activation. In the present study, we demonstrate that yangonin potently inhibits NF-κB activation through suppression of the transcriptional activity of the RelA/p65 subunit of NF-κB. This compound significantly inhibited the induced expression of the NF-κB-reporter gene. However, this compound did not interfere with tumor necrosis factor-α (TNF-α)-induced inhibitor of κBα (IκBα) degradation, p65 nuclear translocation, and DNA-binding activity of NF-κB. Further analysis revealed that yangonin inhibited not only the induced NF-κB activation by overexpression of RelA/p65, but also transactivation activity of RelA/p65. Moreover, yangonin did not inhibit TNF-α-induced activation of p38, but it significantly impaired activation of extracellular signal-regulated kinase 1/2 and stress-activated protein kinase/c-Jun NH(2)-terminal kinase. We also demonstrated that pretreatment of cells with this compound prevented TNF-α-induced expression of NF-κB target genes, such as interleukin 6, interleukin 8, monocyte chemotactic protein 1, cyclooxygenase-2 and inducible nitric oxide. Taken together, yangonin could be a valuable candidate for the intervention of NF-κB-dependent pathological conditions such as inflammation.

Sanggenon C and O inhibit NO production, iNOS expression and NF-κB activation in LPS-induced RAW264.7 cells.

OBJECTIVE: The NO production through the iNOS induction by activation of nuclear factor (NF-κB) is known to involve in various inflammatory conditions. Sanggenon C and O, two Diels-Alder type adducts isolated from Morus alba, a plant has been used for the anti-inflammatory purpose in the Oriental medicine, were investigated for their effect on the NO production, iNOS expression and NF-κB activity. METHODS: The inhibitory effects of sanggenon C and O on the NF-κB activity were investigated in LPS-stimulated RAW264.7 cells by SEAP reporter assay. The regulation of the iNOS expression and IκBα activation by two compounds was also evaluated by Western blot. RESULTS: Both compounds strongly inhibited NO production and NF-κB activation in a dose-dependent manner. The expression of the iNOS protein was also suppressed by treatment of the compounds (10 and 1 µM). Sanggenon O showed stronger inhibition than the diastereomer sanggenon C. Both compounds prevented the phosphorylation and degradation of IκBα protein. CONCLUSION: We demonstrated that sanggenon C and O inhibited NO production and iNOS expression by suppressing NF-κB activity and IκBα activation.

A new prenylated aurone from Artocarpus altilis.

Phytochemical study of the methanol extract of Artocarpus altilis resulted in the isolation of a new prenylated aurone, artocarpaurone (1), together with eight known compounds including two prenylated chalcones (2 and 3), three prenylated flavanones (4-6), and three triterpenes (7-9). The structure of 1 was elucidated as 6-hydroxy-2-[8-hydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-5-ylmethylene]-3(2H)-benzofuranone by spectroscopic methods including 1D and 2D NMR spectra and FT-ICR-MS. Compound 1 showed moderate nitric oxide radical scavenging activity, whereas 2 and 3 had moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging effect, compared with the positive control (+)-catechin.

Laparoscopic Surgery for Intestinal Obstruction Caused by an Internal Paracecal Hernia.

Paracecal hernia is rarely associated with ischemia and has seldom been reported in the few published studies in the review literature. We present a case of incarcerated paracecal hernia with intestinal obstruction that was effectively treated with laparoscopic intervention. A 64-year-old woman who had not previously undergone any intestinal surgery arrived complaining of abdominal pain and vomiting at our hospital. Abdominal computed tomography suggested intestinal obstruction. A laparoscopic emergency procedure demonstrated an incarcerated small bowel loop in the paracecal region. The confined small bowel was removed from the paracecal area. On the fourth postoperative day, the patient was discharged. This case is unusual because the patient presented with small bowel strangulation, leading to intestinal obstruction. Laparoscopic surgery is beneficial for diagnosing internal hernias and curing small-bowel obstructions caused by paracecal hernias.

Pattern and perceived changes in quality of life of Vietnamese medical and nursing students during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic and governments' response lead to dramatical change in quality of life worldwide. However, the extent of this change in Vietnamese medical and nursing students has not been documented. OBJECTIVES: The study aims to describe the quality of life and changes in quality of life of medical and nursing students during the COVID-19 pandemic and examine the association of quality of life and changes in quality of life with fear of COVID-19 and other socio-economic and demographic factors. METHODS: The study was a cross-sectional study on all students of Hanoi Medical University from 3 majors: General Medicine, Preventive Medicine, Nursing (3672 invited students); from 7th to 29th of April 2020; using an online questionnaire that included demographic and academic information, the Vietnamese version of the SF-36 Quality of Life questionnaire and the Fear of COVID-19 Scale (FCV-19S). Linear and modified Poisson regression was used to examine the association between quality of life, changes in quality of life and other factors. RESULTS: The number of participants was 1583 (response rate 43%). Among 8 dimensions of the SF-36 (ranged 0-100), Vitality had the lowest score with a median score of 46. The median physical composite score (PCS) of the sample was 40.6 (IQR:20.8-53.2), 33.5% of the sample had an above-population average PCS score. The median mental composite score (MCS) of the sample was 20.3 (IQR:3.8-31.7), and 98.2% had an MCS score below average. 9.9% (95%CI:8.5%-11.4%) of the population reported a significant negative change in the quality of life. Fear of COVID-19 was not associated with significant changes in quality of life, nor MCS while having some association with PCS (Coef:-5.39;95%CI:-3to-7.8). Perceived reduction in quality of life was also associated with: being on clinical rotation COVID-19 (PR:1.5;95%CI:1.05-2.2), difficulties affording health services (PR:1.4;95%CI:1.02-1.95), obesity (PR:2.38;95%CI:1.08-5.25) and chronic disease (PR:1.92;95%CI:1.23-3), typical symptoms (PR:1.85; 95%CI:1.23-2.78) and atypical symptoms of COVID-19 (PR:2.32;95%CI:1.41-3.81). CONCLUSION: The majority of medical and nursing students had below average quality of life, with lower vitality and mental composite health score in the settings of COVID-19. Perceived decrease in quality of life was associated with clinical rotation, difficulties affording healthcare services and was not associated with Fear of COVID-19.