Cytotoxicity Screening Research Articles

Antibacterial and Antibiofilm potential of Thuja orientalis L. extract targeting cariogenic Enterococcus faecalis ATCC 29212: A combined in-vitro, in-silico study, and cytotoxicity screening

ObjectivesIn this study, we explored the efficacy of methanolic extract of Thuja orientalis (TOME) as a novel antibacterial and antibiofilm agent against a cariogenic bacterium, Enterococcus faecalis ATCC 29212. DesignAntibacterial susceptibility studies were conducted and surface morphology analysis was performed using field emission scanning electron microscopy (FESEM). Antibiofilm activity was evaluated through both qualitative and quantitative biofilm inhibition assays and validated by microscopic analysis. In-silico molecular docking studies were conducted using the EDock server. The effectiveness of TOME was substantiated by biofilm model on dentin discs and cytotoxicity towards the HaCaT cell line was assessed using the MTT assay. ResultsTOME exhibited significant bactericidal activity with minimum inhibitory concentration of 12.5mg/mL and additionally, it effectively compromised bacterial cell wall integrity. Qualitative, quantitative and microscopic studies depicted the inhibition of biofilm formation. TOME significantly impacted the production of extracellular polymeric substance and extracellular DNA. Molecular docking studies identified beta-caryophyllene as a potent inhibitor of the Enterococcal surface protein (Esp). Biofilm model depicted the reduction of bacterial load on dentin discs. Additionally, TOME showed reduced cytotoxicity on HaCaT cells, indicating its potential as a safe therapeutic agent. ConclusionThese findings highlight TOME's promise for developing novel treatments for dental infections and biofilm-associated diseases. Further research should focus on isolating and characterizing the active compounds within TOME, particularly beta-caryophyllene, to elucidate their precise mechanisms of action.

LC-MS and GC-MS Analyses on Green Algae Penicillus Capitatus: Cytotoxic, Antimicrobial and Anticholinesterase Activity Screening Enhanced by Molecular Docking & Dynamics and ADME Studies.

In this comprehensive screening study, the chemical composition, and cytotoxic, antimicrobial, and anticholinergic activities of the green algae Penicillus capitatus, collected from Antalya-Türkiye, were determined as in vitro and in silico. GC-MS analysis of the hexane extract revealed a high content of fatty acids, with hexadecanoic acid constituting half of the total fatty acid content. LC-HRMS analysis of the DCM:MeOH extract identified ascorbic acid as the most abundant compound, followed by (-)-epigallocatechin and salicylic acid. The DCM:MeOH extract exhibited potent cytotoxicity against MDA-MB-231 and MCF7 breast cancer cell lines, outperforming doxorubicin with lower IC50 values and a higher selectivity index. Additionally, the extract demonstrated significant antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, along with selective inhibition of acetylcholinesterase (hAChE) over butyrylcholinesterase (hBChE). Molecular docking and dynamics studies revealed that apigenin-7-O-glucoside and epigallocatechin form stable interactions with estrogen receptor alpha (ERα) and hAChE, suggesting their potential as inhibitors. In silico ADME studies indicated favorable pharmacokinetic profiles for the detected compounds, supporting their potential as drug candidates. The promising cytotoxic activity of the P. capitatus extracts, coupled with significant antimicrobial properties and selective hAChE inhibition, highlights their therapeutic potential for breast cancer treatment, infection management, and neurodegenerative disease intervention.

Design, Synthesis and In-Vitro Antimicrobial and Cytotoxic Activity Screening of 5-Carboxamide Substituted 3, 4-Dihydropyrimidine-2 (1H) Ones

This paper describes the synthesis and in vitro biological evaluation of new compounds designated as 5(a-h) and 8(a-f). These compounds were synthesized by the reaction of thiazole derivative (3) or thiadiazole derivative (7) with urea and various aromatic aldehydes 4(a-h) in ethanol. The structures of the synthesized compounds were checked by IR,1H,13C NMR, and Mass spectroscopy. The antibacterial and antifungal activities of the compounds were evaluated against Escherichia coli (Gram-negative), Staphylococcus aureus (Gram-positive), and Candida albicans (fungus) using agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal/fungicidal concentration methods. The cytotoxic activities of these compounds against HT-29 and A-549 cancer cell lines were assessed in vitro by the MTT method. Our studies showed compounds 8c and 8f to have the most expressed antibacterial activity against S. aureus, while compounds 8c and 8d were the most potent against E. coli. Compounds 5h and 8e showed the highest antifungal activity against C. albicans, and compound 5f showed the most potent activity against the tested cancer cell lines.

Cytotoxicity and genotoxic impacts of LAPONITE® on murine adipose stem cells

This study comprehensively characterized LAPONITE® and evaluated its cytotoxic and genotoxic effects on rat adipose-derived stem cells (ADSCs). Chemical analyses included Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Cytotoxic screening using the Artemia salina lethality test indicated low toxicity. ADSCs exhibited mesenchymal stem cell chracteristics. LAPONITE® demonstrated osteogenic induction capability. MTT assays revealed increased cell viability across concentrations and exposure times. The comet assay for genotoxicity showed no significant differences in damage index between experimental groups, except for a distinction in the frequency of damage between LAPONITE® concentrations at the longest exposure time. This comprehensive assessment provides valuable insights into the safety and potential applications of LAPONITE® in regenerative medicine.

Screening of Lipid-Reducing Activity and Cytotoxicity of the Exometabolome from Cyanobacteria.

Cyanobacteria are rich producers of secondary metabolites, excreting some of these to the culture media. However, the exometabolome of cyanobacteria has been poorly studied, and few studies have dwelled on its characterization and bioactivity assessment. In this work, exometabolomes of 56 cyanobacterial strains were characterized by HR-ESI-LC-MS/MS. Cytotoxicity was assessed on two carcinoma cell lines, HepG2 and HCT116, while the reduction in lipids was tested in zebrafish larvae and in a steatosis model with fatty acid-overloaded human liver cells. The exometabolome analysis using GNPS revealed many complex clusters of unique compounds in several strains, with no identifications in public databases. Three strains reduced viability in HCT116 cells, namely Tolypotrichaceae BACA0428 (30.45%), Aphanizomenonaceae BACA0025 (40.84%), and Microchaetaceae BACA0110 (46.61%). Lipid reduction in zebrafish larvae was only observed by exposure to Dulcicalothrix sp. BACA0344 (60%). The feature-based molecular network shows that this bioactivity was highly correlated with two flavanones, a compound class described in the literature to have lipid reduction activity. The exometabolome characterization of cyanobacteria strains revealed a high chemodiversity, which supports it as a source for novel bioactive compounds, despite most of the time being overlooked.

Undescribed Amaryllidaceae Alkaloids from Zephyranthes citrina and Their Cytotoxicity.

This phytochemical study presents the isolation of eight alkaloids from Zephyranthes citrina Baker. The structures of the new alkaloids, zephycitrine (1) and 6-oxonarcissidine (2), were established by analysis of spectroscopic and spectrometric data. Processing the EtOH extract under acid-base conditions yielded the unreported isolation artifacts 3 and 4. This work also provides analytical data for alkaloids not properly described in the literature (5 and 6). The hippeastidine/zephyranine scaffolds in derivatives 3, 4, and 8-10 are also thoroughly discussed. Furthermore, a cytotoxicity screening of 25 Amaryllidaceae alkaloids isolated from Z. citrina was performed. Only the known alkaloids haemanthamine (12), haemanthidine (13), and lycorine (27) showed significant cell growth inhibition.

Cytotoxic and Anti-HSV-1 Effects of Caulerpin Derivatives.

Marine organisms represent a potential source of secondary metabolites with various therapeutic properties. However, the pharmaceutical industry still needs to explore the algological resource. The species Caulerpa lamouroux Forssk presents confirmed biological activities associated with its major compound caulerpin, such as antinociceptive, spasmolytic, antiviral, antimicrobial, insecticidal, and cytotoxic. Considering that caulerpin is still limited, such as low solubility or chemical instability, it was subjected to a structural modifications test to establish which molecular regions could accept structural modification and to elucidate the cytotoxic bioactive structure in Vero cells (African green monkey kidney cells, Cercopithecus aethiops; ATCC, Manassas, VA, USA) and antiviral to Herpes simplex virus type 1. Substitution reactions in the N-indolic position with mono- and di-substituted alkyl, benzyl, allyl, propargyl, and ethyl acetate groups were performed, in addition to conversion to their acidic derivatives. The obtained analogs were submitted to cytotoxicity and antiviral activity screening against Herpes simplex virus type 1 by the tetrazolium microculture method. From the semi-synthesis, 14 analogs were obtained, and 12 are new. The cytotoxicity assay showed that caulerpin acid and N-ethyl-substituted acid presented cytotoxic concentrations referring to 50% of the maximum effect of 1035.0 µM and 1004.0 µM, respectively, values significantly higher than caulerpin. The antiviral screening of the analogs revealed that the N-substituted acids with methyl and ethyl groups inhibited Herpes simplex virus type 1-induced cytotoxicity by levels similar to the positive control acyclovir.

Synthesis, cytotoxicity, anti-inflammatory, anti-metastatic and anti-oxidant activities of novel chalcones incorporating 2-phenoxy-N-arylacetamide and thiophene moieties: induction of apoptosis in MCF7 and HEP2 cells.

Eight Novel chalcones were synthesized and their structures were confirmed by different spectral tools. All the prepared compounds were subjected to SRB cytotoxic screening against several cancer cell lines. Compound 5c exerted the most promising effect against MCF7 and HEP2 cells with IC50 values of 9.5 and 12 µg/mL, respectively. Real-time PCR demonstrated the inhibitory effect of compound 5c on the expression level of Antigen kiel 67 (KI-67), Survivin, Interleukin-1beta (IL-1B), Interleukin-6 (IL-6), Cyclooxygenase-2 (COX-2) and Protein kinase B (AKT1) genes. Flow-cytometric analysis of the cell cycle indicated that compound 5c stopped the cell cycle at the G0/G1 and G2/M phases in MCF7 and HEP2 treated cells, respectively. ELISA assay showed that Caspase 8, Caspase 9, P53, BAX, and Glutathione (GSH) were extremely activated and Matrix metalloproteinase 2 (MMP2), Matrix metalloproteinase 9 (MMP9), BCL2, Malondialdehyde (MDA), and IL-6 were deactivated in 5c treated MCF7 and HEP2 cells. Wound healing revealed that chalcone 5c reduced the ability to close the scrape wound and decreased the number of migrating MCF7 and HEP2 cells compared to the untreated cells after 48 h. Theoretical molecular modeling against P53 cancer mutant Y220C and Bcl2 showed binding energies of -22.8 and -24.2 Kcal/mole, respectively, which confirmed our ELISA results.

Phytochemical Screening, GC-MS Analysis, and Evaluation of Antioxidants, Cytotoxicity, Analgesic, and Anti-Diarrheal Activity of the Extracts of the Leaves of Syzygium reticulatum Wight Walp

Syzygium genus is extensively used in managing different diseases such as antimicrobial, anti-diarrheal, antidiabetic, analgesic, anti-inflammatory, antioxidant, and anticancer activities. The present study aims to investigate phytochemicals by screening tests and GC-MS analysis and evaluate the antioxidants, cytotoxicity, analgesic, and anti-diarrheal activity of the extracts of the leaves of Syzygium reticulatum. The leaves of the S. reticulatum were extracted with hexane and methanol by the maceration process successively, denoted as SRH and SRM. The extract’s phytochemical analyses found flavonoids, alkaloids, saponins, tannins, glycosides, and carbohydrates. The GC-MS analysis of the methanol extract identified 8 compounds. The major components were identified as Diisooctyl phthalate (96.903 %), 2-methyltetracosane (1.094 %), and others with fewer amounts. The result of the antioxidant study of the extracts as total phenolic content of SRH 8.92 ± 0.62 and SRM 340.107 ± 11.11 mg/g, respectively, total flavonoids content of SRH 7.85 ± 0.71 and SRM 105.16 ± 0.93 mg/g, IC50 values of the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay of SRM was 14.67 µg/mL, SRH was 41.26 µg/mL and ascorbic acid 14.08 µg/mL; the total antioxidant capacity of SRH was 21.33 ± 2.52 mg/g, whereas SRM was 353.71 ± 4.59 mg/g. The results of these studies suggest that methanol extract has a more potent antioxidant capacity than hexane extract. The methanol extract also exhibited higher toxicity (LC50 value 49.99 µg/mL) compared to hexane extract (LC50 value 370.348 µg/mL), as revealed by the Brine shrimp nauplii cytotoxic study. An analgesic study of the methanol extract found that a lower dose (250 mg/kg) has more significant analgesic activity than the higher dose and standard drug aspirin. At 90 min, the hot plate’s highest percentage of latency elongation was 110.32, while the acetic acid-induced writhing inhibition was 63.04 %. At a dose of 500 mg/kg, the methanol extract also shown good efficacy in mice suffering from castor oil and magnesium sulfate-induced diarrhea. The findings from the study of the leaves of the S. reticulatum exhibited that methanol extracts have significant antioxidant, cytotoxic, analgesic, and anti-diarrheal activity. HIGHLIGHTS The extract’s phytochemical analyses found flavonoids, alkaloids, saponins, tannins, glycosides, and carbohydrates The GC-MS analysis of the methanol extract identified 8 compounds. The major components were identified as Diisooctyl phthalate (96.903 %), 2-methyltetracosane (1.094 %) The antioxidant and cytotoxicity studies suggest that methanol extract has a more potent antioxidant and cytotoxic capacity than hexane extract The findings from in-vivo study of the leaves of the reticulatum also exhibited that methanol extracts have significant analgesic, and anti-diarrheal activity GRAPHICAL ABSTRACT

Fully automated viability and toxicity screening—A reliable all‐in‐one attempt

AbstractBackgroundThe CRISPR/Cas9 technology is nowadays a common tool for genome editing to achieve new insights into, for example, diagnostics and therapeutics in cancer and genetic disorders. Cell proliferation and anticancer drug response studies are widely used to evaluate the impact of editing. However, these assays are often time‐consuming, expensive, and reproducibility is an issue. To overcome this, we developed a fast and cheap assay that combines a fully automated multispectral fluorescence microscopy platform with a nuclei staining and open‐source software analysis.MethodsHere, we generated different LEDGF/p75 model cell lines to validate the effect on proliferation and chemosensitivity. Therefore, a fast protocol for an optimized all‐in‐one attempt for cytotoxicity screenings and proliferation analysis of adherent cells in a 96‐well plate format was established using differential staining with two fluorescent dyes (Hoechst 33342 and propidium iodide) for live/dead cell discrimination. Subsequently, an automated cell nuclei count and analysis were performed using bioimage informatics.ResultsWith the new established assay technology, up to 50,000 cells/well can be detected and analyzed in a 96‐well plate, resulting in a fast and accurate verification of viability and proliferation with consistency of 98% compared to manual counting. Our screening revealed that LEDGF depletion using CRISPR/Cas9 showed a diminished proliferation and chemosensitivity independent of cell line origin. Moreover, LEDGF depletion caused a significant increase in 𝛾H2AX foci, indicating a substantial increase in DNA double strand breaks. LEDGF/p75 overexpression enhanced proliferation and chemoresistance underlining the role of LEDGF in DNA damage response.ConclusionIndependent of cancer cell type, LEDGF/p75 is a central player in DNA damage repair and is implicated in chemoresistance. Moreover, our automated fluorescence biosensor technology allowed fast and reliable data acquisition without any fixation or additional washing steps. Additionally, data analysis was implemented using the modular open‐source software that can be adapted as needed.

2-Aryl-1H-imidazo[4,5-f][1,10]phenanthroline-Based Binuclear Ru(II)/Ir(III)/Re(I) Complexes as Mitochondria Targeting Cancer Stem Cell Therapeutic Agents.

A series of novel Ru(II)/Ir(III)/Re(I)-based organometallic complexes [Ru2L1, Ru2L2, Ir2L1, Ir2L2, Re2L1, and Re2L2] have been synthesized to assess their potency and selectivity against multiple cancer cells A549, HCT-116, and HCT-116 colon CSCs. The cytotoxic screening of the synthesized complexes has revealed that complex Ru2L1 and Ir2L2 are two proficient complexes among all, but Ru2L1 is the most potent complex. A significant binding constant value was observed for DNA and BSA in all complexes. Significant lipophilic properties allow them to penetrate cancer cell membranes, and substantial quantum yield (ϕf) values support bioimaging potential. Again, these complexes are particular for mitochondrial localization and produce a profuse amount of ROS to damage the mitochondrial DNA and then G1 phase cell-cycle arrest. Protein expression analysis unveiled that pro-apoptotic Bax protein overexpressed in Ru2L1-treated cells, whereas antiapoptotic Bcl-2 protein was expressed twofold in Ir2L2-treated cells, which correlated with autophagy reticence.

In vitro cytotoxicity screening of some 3-substituted-4-oxo-imidazolidin-2-(1H)-thione derivatives as anticancer drug.

Aim: This study aimed to investigate the in vitro antitumor activity of new series of 2-thiohydanotin derivatives (7 and 9) against two cancer cell lines.Materials & methods: A new series of 2-thioxoimidazolidine derivatives (3-9) were synthesized and investigated for its structure through spectral analysis and also tested against (HepG-2) and (HCT-116) cell line.Results: Among the synthesized compounds, compound 7 halted liver cancer cells at the G0/G1 phase and triggered apoptosis of liver cancer. Contrarily, compound 9 caused colon cancer cells to be arrested at the S phase and trigger apoptosis. Also, they had a good inhibitory effect on (Nrf2).Conclusion: Both compounds had attractive lead molecules for the creation of colon and liver cancer medications.

Exploring chalcone-sulfonyl piperazine hybrids as anti-diabetes candidates: design, synthesis, biological evaluation, and molecular docking study.

To address the escalating rates of diabetes mellitus worldwide, there is a growing need for novel compounds. The demand for more affordable and efficient methods of managing diabetes is increasing due to the inevitable side effects associated with existing antidiabetic medications. In this present research, various chalcone-sulfonyl piperazine hybrid compounds (5a-k) were designed and synthesized to develop inhibitors against alpha-glucosidase and alpha-amylase. In addition, several spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR, and HRMS, were employed to confirm the exact structures of the synthesized derivatives. All synthesized compounds were evaluated for their ability to inhibit alpha-glucosidase and alpha-amylase in vitro using acarbose as the reference standard and they showed excellent to good inhibitory potentials. Compound 5k exhibited excellent inhibitory activity against alpha-glucosidase (IC50 = 0.31 ± 0.01 µM) and alpha-amylase (IC50 = 4.51 ± 1.15 µM), which is 27-fold more active against alpha-glucosidase and 7-fold more active against alpha-amylase compared to acarbose, which had IC50 values of 8.62 ± 1.66 µM for alpha-glucosidase and 30.97 ± 2.91 µM for alpha-amylase. It was discovered from the Lineweaver-Burk plot that 5k exhibited competitive inhibition against alpha-glucosidase. Furthermore, cytotoxicity screening assay results against human fibroblast HT1080 cells showed that all compounds had a good level of safety profile. To explore the binding interactions of the most potent compound (5k) with the active site of enzymes, molecular docking research was conducted, and the results obtained supported the experimental data.

Discovery of new 13(17)-epoxymyrsinane diterpenes from aerial flowering parts of euphorbia spinidens Bornm. ex Prokh. with proapoptotic activities against human bladder cancer EJ138 cells

Phytochemical analysis of aerial flowering parts of Euphorbia spinidens Bornm. ex Prokh. from Euphorbiaceae family (local name: Farfion-e-dandaneh-khari) led to the isolation of five diterpenes based on myrsinane backbone. Using HRESI-MS, 1D, and 2D NMR, they were identified as two previously unreported: 33,7,14,15(β)-tetraacetyl-5(α)-butanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (1), 7,14,15(β)-triacetyl-3(β),5(α)-dibutanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (2), and three known diterpenes: 3,7,14,15(β)-tetraacetyl-5(α)-propanoyl-13(17)-epoxy-8,10(18)-myrsinadiene (3), and 3,7,10,14,15(β)-Pentaacetyl-5(α)-butanoyl-13,17-epoxy-8-myrsinene (4), 3,7,10,14,15(β)-pentaacetyl-5(α)-propanoyl-13,17-epoxy-8-myrsinene (5). Compound 5 was previously reported in the roots of the same plant but without NMR data. Therefore, its mass pattern,1H-, and 13C-NMR data are reported. The cytotoxicity and proapoptotic properties of 1-3 were evaluated against EJ-138 bladder carcinoma cells through standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay for cytotoxicity screening and annexin V-FITC/PI apoptosis detection kit. In the cytotoxicity assay, the IC50 values found against EJ-138 were: (1) 41.6 ± 3.54 μM; (2) 38.4 ± 2.54 μM; (3) 57.3 ± 5.4 μM, whilst the IC50 value of doxorubicin was 1.7 ± 0.3 μM, respectively. In apoptosis assay, total apoptosis of compounds 1-3 at higher concentrations (100 μM) were 57.6 ± 3.54, 46.3 ± 2.82, and 57.2 ± 4.35%, respectively.

Mutational Analysis of RIP Type I Dianthin-30 Suggests a Role for Arg24 in Endocytosis.

Saponin-mediated endosomal escape is a mechanism that increases the cytotoxicity of type I ribosome-inactivating proteins (type I RIPs). In order to actualize their cytotoxicity, type I RIPs must be released into the cytosol after endocytosis. Without release from the endosomes, type I RIPs are largely degraded and cannot exert their cytotoxic effects. Certain triterpene saponins are able to induce the endosomal escape of these type I RIPs, thus increasing their cytotoxicity. However, the molecular mechanism underlying the endosomal escape enhancement of type I RIPs by triterpene saponins has not been fully elucidated. In this report, we investigate the involvement of the basic amino acid residues of dianthin-30, a type I RIP isolated from the plant Dianthus caryophyllus L., in endosomal escape enhancement using alanine scanning. Therefore, we designed 19 alanine mutants of dianthin-30. Each mutant was combined with SO1861, a triterpene saponin isolated from the roots of Saponaria officinalis L., and subjected to a cytotoxicity screening in Neuro-2A cells. Cytotoxic screening revealed that dianthin-30 mutants with lysine substitutions did not impair the endosomal escape enhancement. There was one particular mutant dianthin, Arg24Ala, that exhibited significantly reduced synergistic cytotoxicity in three mammalian cell lines. However, this reduction was not based on an altered interaction with SO1861. It was, rather, due to the impaired endocytosis of dianthin Arg24Ala into the cells.

Aminoquinoline-based ruthenium(II) and iridium(III) polypyridyl complexes: Investigating potential photosensitisers for cancer treatment via photodynamic therapy

Cancer is a devastating noncommunicable disease that remains one of the most pressing health challenges of the twenty-first century. Chemotherapy stands as one of the most common and effective cancer treatment methods. However, severe side effects and acquired drug resistance in many cancers have significantly diminished the efficacy of current chemotherapeutic agents. The urgent demand for novel treatment modalities has led to the development of photodynamic therapy (PDT) for the treatment of various cancer types. In this work, the synthesis of aminoquinoline-based transition metal complexes containing two PGMs (Ir(III) and Ru(II)) as potential photosensitisers is described. Mononuclear N,N-chelated Ru(II) and Ir(III) transition metal complexes were synthesized by reacting 4-aminoquinoline Schiff base ligands, which contain either a pyridyl or a quinolyl entity. The photostable Ru(II) and Ir(III) polypyridyl complexes were investigated for their potential use as PDT agents. In vitro cytotoxicity screenings conducted against a melanoma cell line (501mel) both in the absence and presence of light confirmed that all complexes demonstrated increased biological activity when exposed to visible light at 455 nm. Overall, the Ru(II) complexes are superior phototoxic agents in comparison with their Ir(III) congenors.

A proposed in vitro cytotoxicity test battery to detect and predict hepatotoxicity via multiple mechanisms and pathways: a minireview.

The 21st-century toxicity testing program recommends the use of cytotoxicity data from human cells in culture for rapid in vitro screening focusing on biological pathways of potential toxicants to predict in vivo toxicity. Liver is the major organ for both endogenous and exogenous chemical metabolism of xenobiotics. Therefore, this review was undertaken to evaluate side by side five different currently used commercial cytotoxicity assay kits for purpose of rapid predictive screening of potential hepatotoxicants. The test compounds for this review were selected from the NIH LiverTox and FDA Liver Toxicity Knowledge Base (LTKB) databases. Human liver HepG2, HepaRG, and rat liver Clone 9 cell cultures were used as the in vitro liver models. Five commercial assay kits representing different biomarkers or pathways were selected for this review. These kits are Vita-Orange Cell Viability Assay Kit (Sigma-Aldrich), CellTiter-Glo Cell Viability Assay Kit (Promega), CytoTox-ONE Homogeneous Membrane Integrity Assay Kit (Promega), DNA Quantitation Fluorescence Assay Kit (Sigma-Aldrich), and Neutral Red Based In Vitro Toxicology Assay Kit (Sigma-Aldrich). This review found that these kits can all be used for rapid predictive cytotoxicity screening of potential hepatotoxicants in human liver HepG2 and rat liver Clone 9 cells in culture as in vitro liver models without compromising quality and accuracy of endpoint measurements as well as the length of toxicity screening time. Unraveling the structure-activity relationship of potential hepatotoxins would help to classify their hepatotoxic effects. Therefore, in addition to the current regulatory hepatotoxicity testing strategies, development and regulatory approval of hepatotoxins need to be discussed in order to identify potential gaps in the safety assessment. The overall results of our study support the hypothesis that a battery of rapid, simple, and reliable assays is an excellent tool for predicting in vivo effects of suspected liver toxins. The human liver HepaRG cells do not appear to be an ideal in vitro liver model for this purpose.

Engineered Biosynthesis and Anticancer Studies of Ring-Expanded Antimycin-Type Depsipeptides.

Respirantins are 18-membered antimycin-type depsipeptides produced by Streptomyces sp. and Kitasatospora sp. These compounds have shown extraordinary anticancer activities against a panel of cancer cell lines with nanomolar levels of IC50 values. However, further investigation has been impeded by the low titers of the natural producers and the challenging chemical synthesis due to their structural complexity. The biosynthetic gene cluster (BGC) of respirantin was previously proposed based on a bioinformatic comparison of the four members of antimycin-type depsipeptides. In this study, we report the first successful reconstitution of respirantin in Streptomyces albus using a synthetic BGC. This heterologous system serves as an accessible platform for the production and diversification of respirantins. Through polyketide synthase pathway engineering, biocatalysis, and chemical derivatization, we generated nine respirantin compounds, including six new derivatives. Cytotoxicity screening against human MCF-7 and Hela cancer cell lines revealed a unique biphasic dose-response profile of respirantin. Furthermore, a structure-activity relationship study has elucidated the essential functional groups that contribute to its remarkable cytotoxicity. This work paves the way for respirantin-based anticancer drug discovery and development.

Phenazine Cations as Anticancer Theranostics†.

The biological properties of two water-soluble organic cations based on polypyridyl structures commonly used as ligands for photoactive transition metal complexes designed to interact with biomolecules are investigated. A cytotoxicity screen employing a small panel of cell lines reveals that both cations show cytotoxicity toward cancer cells but show reduced cytotoxicity to noncancerous HEK293 cells with the more extended system being notably more active. Although it is not a singlet oxygen sensitizer, the more active cation also displayed enhanced potency on irradiation with visible light, making it active at nanomolar concentrations. Using the intrinsic luminescence of the cations, their cellular uptake was investigated in more detail, revealing that the active compound is more readily internalized than its less lipophilic analogue. Colocalization studies with established cell probes reveal that the active cation predominantly localizes within lysosomes and that irradiation leads to the disruption of mitochondrial structure and function. Stimulated emission depletion (STED) nanoscopy and transmission electron microscopy (TEM) imaging reveal that treatment results in distinct lysosomal swelling and extensive cellular vacuolization. Further imaging-based studies confirm that treatment with the active cation induces lysosomal membrane permeabilization, which triggers lysosome-dependent cell-death due to both necrosis and caspase-dependent apoptosis. A preliminary toxicity screen in the Galleria melonella animal model was carried out on both cations and revealed no detectable toxicity up to concentrations of 80 mg/kg. Taken together, these studies indicate that this class of synthetically easy-to-access photoactive compounds offers potential as novel therapeutic leads.

Antioxidant and cytotoxicity screenings of ethyl acetate extract from Annona muricata leaves and its fractions.

Leaves of Annona muricata have medicinal potential which has gained attention from researchers around the world. This study has an objective to screen the antioxidant and cytotoxicity of ethyl acetate extract from A. muricata leaves and its fraction. The fine powder of A. muricata was macerated in methanol and further partitioned using two different solvents, namely n-hexane and ethyl acetate. In this article, we reported the screening results for ethyl acetate extract. Fractionation was then performed on the extract by means of column chromatography by gradient elution resulting in five combined fractions. Brine shrimp lethality test and 1-diphenyl-2-pycrilhidrazil (DPPH) assays were employed to evaluate the cytotoxicity and antioxidant of the extract, respectively. Characterization using gas chromatography-mass spectroscopy (GC-MS) was then conducted. The cytotoxicity of the samples was indicated by median lethal concentration50 values ranging from 28.84 to 1023.3 ppm. As for the antioxidant activity, the DPPH median inhibitory concentration50 values ranged from 4.12 to 180.66 ppm. GC-MS analysis on the most bioactive fraction revealed the predominating phytochemical contents of neophytadiene, palmitic acid, and phytol. In conclusion, the fraction of ethyl acetate extract from A. muricata leaves could potentially act as a strong antioxidant and moderate cytotoxic agent.