Catalytic and Biological Activity of Silver and Gold Complexes Stabilized by NHC with Hydroxy Derivatives on Nitrogen Atoms

In this paper is reported the synthesis of N,N′ hydroxy derivative of NHC silver (3a–4a) and gold(I) (3b–4b) complexes of general formula [M(NHC)2]+ [MX2]−. All compounds were characterized by spectroscopic and analytic techniques. The complexes turned out to be effective in both catalytic and biological applications. They catalyzed the coupling of aldehyde, piperidine, and phenylacetylene in A3-reaction to produce propargylamines and showed antimicrobial activity. In fact, minimal inhibition concentration (MIC) tests with Gram-positive and Gram-negative bacteria demonstrated that the silver compounds are selective toward E. coli, whereas the gold analogues are active against S. aureus. Moreover, the N,N′ hydroxy derivative of NHC silver complexes 3a and 4a exhibited good anticancer activity on the HeLA cancer cells (3a-IC50 = 12.2 ± 0.1 µM, 4a-IC50 = 11.9 ± 1.2 µM), whereas gold complex 4b displayed good anticancer activity towards the MCF-7 cells (IC50 = 12.2 ± 1.2 µM).

Screening Chemical Composition and Bioactive Properties of Mentha x piperita L. Essential Oil and Extract

In recent years, medicinal and aromatic herbs, which contain variety of antimicrobial compounds and have no risk to human health in terms of antibiotic resistance, are increasingly used as alternatives to antibiotics. In the study, chemical composition, total phenolic content, antioxidant and antimicrobial activity of essential oil and extract of Mentha x piperita L. growing wild in Eskisehir were investigated. Carvone (55.8%), limonene (12.8%), 1.8-cineole (8.7%) and trans-dihydrocarvone (6.4%) were determined as the main constituents of the essential oil, while the major components of the extract were carvone (56.4%), 1.8-cineole (14.1%) and trans-dihydrocarvone (8.4%). The total phenolic contents of essential oil (2204.33 µg GAE/g) were significantly higher than of extract (744 µg GAE/g). The essential oil and the extract were inhibited 84.08% and 42.59% by the DPPH radical, 91.87% and 48.40% by the ABTS radical, respectively. The highest inhibition zone was observed against S. aureus (23 mm). However, minimum inhibition concentration (MIC) values of the essential oil were ranged between 2.5% and 10% (v/v), while MIC values of the extract were determined as 10% and >10% (v/v). The present study demonstrated that M. piperita could be used in pharmaceutical and food applications as a natural antioxidant and antimicrobial substance.

Poly(vinyl alcohol)-tannic Acid Cryogel Matrix as Antioxidant and Antibacterial Material

The biocompatible, viscoelastic properties of poly(vinyl alcohol) (PVA) in combination with the antimicrobial and antioxidant natural polyphenolic, tannic acid (TA), and the natural flavonoid and antioxidant curcumin (Cur), were used in the preparation of PVA:TA and PVA:TA:Cur cryogel composites using cryotropic gelation to combine the individually beneficial properties. The effect of TA content on the antioxidant and antimicrobial activities of PVA:TA cryogel composites and the antioxidant activities of PVA:TA:Cur cryogel composites was determined using Trolox equivalent antioxidant capacity (TEAC) and total phenol content (TPC) assays, and were compared. The PVA:TA:Cur cryogel composite showed the highest antioxidant activity, with a TEAC value of 2.10 ± 0.24 and a TPC value of 293 ± 12.00. The antibacterial capacity of the PVA:TA and PVA:TA:Cur 1:1:0.1 cryogel composites was examined against two different species of bacteria, E. coli and S. aureus. It was found that the minimum inhibition concentration (MIC) value of the PVA:TA:Cur 1:1:0.1 cryogel composites varied between 5 and 10 mg/mL based on the type of microorganism, and the minimum bactericidal concentration (MBC) value was 20 mg/mL irrespective of the type of microorganism. Furthermore, the hemocompatibility of the PVA:TA cryogel composites was evaluated by examining their hemolytic and coagulation behaviors. PVA:TA 1:1 cryogels with a value of 95.7% revealed the highest blood clotting index value amongst all of the synthesized cryogels, signifying the potential for blood contacting applications. The release of TA and Cur from the cryogel composites was quantified at different pH conditions, i.e., 1.0, 7.4, and 9.0, and additionally in ethanol (EtOH) and an ethanol–water (EtOH:Wat) mixture. The solution released from the PVA:TA cryogels in PBS was tested for inhibition capability against α-glucosidase (E.C. 3.2.1.20). Concentration-dependent enzyme inhibition was observed, and 70 µL of 83 µg/mL PVA:TA (1:1) cryogel in PBS inhibited α-glucosidase enzyme solution of 0.03 unit/mL in 70 µL by 81.75 ± 0.96%.

Synergism in Antiplasmodial Activities of Artemether and Lumefantrine in Combination with Securidaca longipedunculata Fresen (Polygalaceae)

Malaria is the most lethal parasitic disease in the world. The frequent emergence of resistance by malaria parasites to any drug is the hallmark of sustained malaria burden. Since the deployment of artemisinin-based combination therapies (ACTs) it is clear that for a sustained fight against malaria, drug combination is one of the strategies toward malaria elimination. In Sub-Saharan Africa where malaria prevalence is the highest, the identification of plants with a novel mechanism of action that is devoid of cross-resistance is a feasible strategy in drug combination therapy. Thus, artemether and lumefantrine were separately combined and tested with extracts of Securidaca longipedunculata, a plant widely used to treat malaria, at fixed extract–drug ratios of 4:1, 3:1, 1:1, 1:2, 1:3, and 1:4. These combinations were tested for antiplasmodial activity against three strains of Plasmodium falciparum (W2, D6, and DD2), and seven field isolates that were characterized for molecular and ex vivo drug resistance profiles. The mean sum of fifty-percent fractional inhibition concentration (FIC50) of each combination and singly was determined. Synergism was observed across all fixed doses when roots extracts were combined with artemether against D6 strain (FIC50 0.403 ± 0.068) and stems extract combined with lumefantrine against DD2 strain (FIC50 0.376 ± 0.096) as well as field isolates (FIC50 0.656 ± 0.067). Similarly, synergism was observed in all ratios when leaves extract were combined with lumefantrine against W2 strain (FIC50 0.456 ± 0.165). Synergism was observed in most combinations indicating the potential use of S. longipedunculata in combination with artemether and lumefantrine in combating resistance.

Phytochemical and proximate content of Carapa procera bark and its antimicrobial potential against selected pathogens

Medicinal plants represent a great source of antimicrobial and phytochemical constituents which are increasingly used to treat microbial infections and other ailments such as tuberculosis, anemia, and trachoma. Despite the use of antibiotics, antimicrobial resistance continues to be a world issue, in as much as nutrition. This study investigated the presence of phytochemicals, proximate compositions, and antimicrobial activity of methanolic extract of Carapa procera bark. The bark of Carapa procera was collected, cleaned and air dried for 72 h. The powder obtained was treated with diethyl ether and soaked in methanol (99%) for 72 h to obtain crude extract. The extract was used to test for the presence of phytochemicals and antimicrobial activities. The raw bark was used for proximate analysis. The result showed presence of steroids, tannins and saponins, but no alkaloids present. The 100 mg/mL extract had the highest inhibition zone on all tested organisms from 24.00 ± 0.94 to 26.67 ± 1.18, and 50 mg/mL showed the least (16.67 ± 1.24) on Candida albicans. Staphylococcus aureus showed the lowest minimum inhibition concentration (MIC) of 3.12 mg/mL, whereas the Gram-negative bacteria exhibited variations in their sensitivity with E. coli having the highest MIC of 25 mg/mL. The extract had high MIC (6.25 mg/mL) on Candida albicans than clotrimazole (50 mg/mL). The proximate compositions of Carapa procera were moisture (6.07 ± 0.07%), ash (12.46 ± 0.46%), crude protein (9.54 ± 0.12%), crude fat (1.42 ± 0.06%) and carbohydrate (70.50 ± 0.35%). The energy value was 1413.17 kj. Thus, Carapa procera possesses both antimicrobial and nutritional potentials worth exploring and domesticating for sustainable management and conservation.

EasyFlow: User-friendly Workflow for Image-based Droplet Analysis with Multipurpose Modules

Droplet-based experimental platforms allow researchers to perform massive parallelization and high-throughput studies, such as single-cell experiments. Even though there are various options of image analysis software to evaluate the experiment, selecting the right tools require experience and is time consuming. Experts and sophisticated workflow are required to perform the analysis, especially to detect the droplets and analyze their content. There is need for user-friendly droplet analysis pipelines that can be adapted in laboratories with minimum learning curve. Here, we provide a user-friendly workflow for image-based droplet analysis. The workflow comprises of a) CellProfiler-based image-analysis pipeline and b) accompanied with web application that simplifies the analysis and visualization of the droplet-based experiment. We construct necessary modules in CellProfiler (CP) to detect droplets and export the results into our web application. Using the web application, we are able to process and provide basic profiles of the droplet experiment (droplet sizes, droplet signals, sizes-signals plot, and strip plot for each label/condition). We also add a specific module for growth heterogeneity studies in bacteria populations that includes single cell viability analysis and probability distribution of minimum inhibition concentration (MIC) values in population. Our pipeline is usable for both poly- and monodisperse droplet emulsions.

Interaction of Long-Chain Alcohol with Dry Yeast, Cholesterol, and Sea Firefly Luciferase

Background: A hand sanitizer containing alcohol, usually ethanol or isopropanol, is typically used for disinfection, but given that cholesterol is one of the main components of virus envelopes, long-chain alcohol may be more effective. To better understand the potential disinfection activity of long-chain alcohols, we studied their interactions with dry yeast, cholesterol, and sea firefly luciferase. Methods and Results: We measured, at 30oC and 39oC, the minimum inhibition concentration (MIC) of dry yeast fermentation and the stability of cholesterol and sea firefly luciferase with alcohols, diols, cetyltrimethylammonium chloride, and stearyltrimethylammonium chloride. The MIC decreased with the chain length at C≤12 for dry yeast and cholesterol with alcohol at 30oC. At C13 and higher, the cut-off region was observed. At 39oC, the cut-off region shifted to C15 and higher. The reduction of MIC was measured with the diol or sea firefly luciferase at C≤14. Conclusion: The presence of the cut-off region is suggested to be related to whether the alcohol is in the liquid state. For the liquid alcohol, the longer the chain length, the lower the MIC. This suggests a potential disinfection activity of long-chain alcohol.

Effectiveness of Guava Leaf Steep water against the bacterial growth of S. Mutans with Microdillution Method

Indonesia is famously known for its rich plant biodiversity with medicinal properties. Guava (Psidium guajava Linn.) is one of medicinal plants which can be used as alternative for treating diseases. Guava leaf contains flavonoids, saponins, and tannins, that can act as inhibitors against bacteria, antioxidants, and antibacterial. Numerous dental and oral diseases are caused by bacteria, one of which is dental caries. Principally, dental caries can be prevented by maintaining the oral cavity hygiene, chemically or mechanically, using antiseptics possessing antibacterial activities. The aim of this study was to investigate the effectiveness of guava leaves steep water against S. Mutans bacterium using microdilution method. The aim also included the investigation of inhibition concentration of guava leaves steep water. This research was experimental in nature, by using the guava leaves steep water as the sample with various concentrations (0.753%, 1.563%, 3.125%, 6.25%, 12.5%, 25%, 50%, 100%). S. Mutans was obtained from the laboratory of veterinary Universitas Syiah Kuala (Unsyiah). The results of this research revealed that the guava leaves steep water was effective in inhibiting S. Mutans with Minimum Inhibitory Concentration (MIC) of 6.25% In conclusion, we would like to investigate the guava leaves steep water as a mouthwash in our research with a preclinical trial.

Ecofriendly Synthesis of Silver Nanoparticles Using Ananas comosus Fruit Peels: Anticancer and Antimicrobial Activities

Metallic nanoparticles are valuable materials and have a range of uses. Nanoparticles synthesized from plant wastes by environment-friendly methods have attracted the attention of researchers in recent years. Also, the advantages of biological resources and synthesis methods are attracting attention. In this study, silver nanoparticles were synthesized from Ananas comosus fruit peels using ecofriendly method steps. The characterization of the particles obtained was determined by using a UV-visible spectrophotometer (UV-Vis.), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction diffractometer (XRD), Fourier scanning electron microscope (FESEM), and transmission electron microscopy (TEM). The nanoparticles showed maximum absorbance at 463 nm, measuring 11.61 in crystal nanosize, and presented spherical in appearance. An antimicrobial activity test was determined with the minimum inhibition concentration (MIC) method. The nanoparticles showed promising inhibitory activity on the Gram-positive and Gram-negative pathogen microorganisms (Escherichia coli ATCC25922, Staphylococcus aureus ATCC29213, Bacillus subtilis ATCC11774, Pseudomonas aeruginosa ATCC27833 bacteria, and Candida albicans yeast) at low concentrations. The cytotoxic and growth inhibitory effects of silver nanoparticles on different cancer cell lines were examined via the MTT assay.

LncRNA SNHG6 knockdown inhibits cisplatin resistance and progression of gastric cancer through miR-1297/BCL-2 axis

Cisplatin (DDP) resistance is a huge obstacle to gastric cancer (GC) treatment. Long non-coding RNAs (lncRNAs) have been manifested to exert pivotal functions in GC development. Herein, we aimed to explore the functional impact of lncRNA small nucleolar RNA host gene 6 (SNHG6) on DDP resistance and progression of GC. Quantitative real-time PCR (qRT-PCR) assay or Western blotting was performed to detect the expression of SNHG6, microRNA(miR)-1297, and epithelia-mesenchymal transition (EMT)-related factors and B-Cell Lymphoma 2 (Bcl-2) in DDP-resistant GC cells. Half inhibition concentration (IC50) to DDP, clonogenicity, apoptosis and invasion were examined via CCK-8 assay, colony formation assay, flow cytometry and Transwell assay, respectively. Target association between miR-1297 and SNHG6 or BCL-2 was demonstrated via dual-luciferase reporter assay or RIP assay. Xenograft models in nude mice were formed to investigate role of SNHG6 in vivo. We found that SNHG6 and BCL-2 were upregulated, while miR-1297 expression was declined in GC tissues and DDP-resistant cells. Moreover, depletion of SNHG6 or gain of miR-1297 could repress DDP resistance, proliferation and metastasis of DDP-resistant cells, which was weakened by miR-1297 inhibition or BCL-2 overexpression. Besides, SNHG6 positively regulated BCL-2 expression by sponging miR-1297. Furthermore, SNHG6 knockdown repressed GC tumor growth in vivo. In a word, lncRNA SNHG6 knockdown had inhibitory effects on DDP resistance and progression of GC by sponging miR-1297, highlighting its potential in GC treatment.  Keywords: Gastric cancer, cisplatin resistance, lncRNA SNHG6, miR-1297, BCL-2