Effect of Marine Basidiomycetes Fulvifomes sp.-Derived Ergosterol Peroxide on Cytotoxicity and Apoptosis Induction in MCF-7 Cell Line

Antimicrobial, antiproliferative activities and molecular docking of metabolites from Alternaria alternata

Endophytic fungi allied to plants have sparked substantial promise in discovering new bioactive compounds. In this study, propagation of the endophytic fungus Alternaria alternata HE11 obtained from Colocasia esculanta leaves led to the isolation of Ergosterol (1), β-Sitosterol (2), Ergosterol peroxide (3), in addition to three dimeric naphtho-γ-pyrones, namely Fonsecinone A (4), Asperpyrone C (5), and Asperpyrone B (6), which were isolated from genus Alternaria for the first time. Structures of the isolated compounds were established on the basis of extensive 1D and 2D NMR and, MS measurements. The ethyl acetate extract, as well as compounds 1, 3, 4 and 6 were evaluated for their antimicrobial activity using agar well-diffusion and broth microdilution assays. Molecular docking study was carried out to explore the pharmacophoric moieties that governed the binding orientation of antibacterial active compounds to multidrug efflux transporter AcrB and the ATP binding site to E. coli DNA gyrase using MOE software. Results revealed that the most active antibacterial compounds 4 and 6 bind with high affinity in the phenylalanine-rich cage and are surrounded with other hydrophobic residues. The antiproliferative activity of all isolated compounds was in vitro evaluated using the human prostatic adenocarcinoma cell lines DU-145, PC-3, PC-3 M, 22Rv1 and CWR-R1ca adopting MTT assay. Compound 4 was the most active against almost all tested cell lines, with IC₅₀ values 28.6, 21.6, 17.1 and 13.3 against PC-3, PC-3 M, 22Rv1 and CWR-R1ca cell lines, respectively.

On-chip mixing of cancer cells and drug using LED enabled 2D opto-wetting droplet platforms

Droplets of microliter size serve as miniaturized reaction chambers for practical lab on a chip (LoC) applications. The transportation and coalescence of droplets are indispensable for realizing microfluidic mixing. Light can be used as an effective tool for droplet manipulation. We report a novel platform for LED-based transport and mixing of cell-encapsulated microdroplets for evaluating dose response of cancer drugs. Microcontroller enabled LEDs (Light-emitting diodes) were used to actuate droplet movement on Azobenzene coated planar silicon substrates. Droplet transport was initiated by the spatial gradient in solid-liquid interfacial tension developed through LED triggered photoisomerization of Azobenzene substrate. Detailed UV-Visible characterization of Azobenzene molecule was performed for different LED light intensities and wavelengths. A complete standalone opto-wetting toolbox was developed by integrating various components such as a microcontroller, UV LED (385 nm), blue LED (465 nm), and Azobenzene coated photoresponsive substrate. 2D transport of DI water droplets (10-30μl) along simple trajectories was demonstrated using this device. Subsequently, the proposed opto-wetting platform was used for performing drug evaluation through on-chip mixing of droplets containing cancer cells (A549-Lung cancer cells) and cancer drug (paclitaxel). Separate cell viability analysis was performed using MTT assays, where the cytocompatibility of Azobenzene and UV light (385 nm) on A549 cells were studied. The dosage response of paclitaxel drug was studied using both MTT (3-(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) and live-dead cell assays. The results obtained indicate the potential use of our device as a cost-effective, reliable opto-wetting microfluidic platform for drug screening experiments.

Structure and Biological Activity of Ergostane-Type Steroids from Fungi

Mushrooms are known not only for their taste but also for beneficial effects on health attributed to plethora of constituents. All mushrooms belong to the kingdom of fungi, which also includes yeasts and molds. Each year, hundreds of new metabolites of the main fungal sterol, ergosterol, are isolated from fungal sources. As a rule, further testing is carried out for their biological effects, and many of the isolated compounds exhibit one or another activity. This study aims to review recent literature (mainly over the past 10 years, selected older works are discussed for consistency purposes) on the structures and bioactivities of fungal metabolites of ergosterol. The review is not exhaustive in its coverage of structures found in fungi. Rather, it focuses solely on discussing compounds that have shown some biological activity with potential pharmacological utility.

Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity

Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with a confidence level of 90 to 99.6%. Interestingly, artemisinin and its analogs show strong antiprotozoal activity with 79 to 99.6% confidence against obligate intracellular parasites which belong to the genera Plasmodium, Toxoplasma, Leishmania, and Coccidia. In addition to antiprotozoal activities, polycyclic endoperoxides show antitumor activity in the proportion: 4.6% show weak activity with a reliability of up to 70%, 65.6% show an average activity with a reliability of 70 to 90%, and 29.8% show strong activity with a reliability of 90 to 98.3%. It should also be noted that some polycyclic endoperoxides, in addition to antiprotozoal and antitumor properties, show other strong activities with a confidence level of 90 to 97%. These include antifungal activity against the genera Aspergillus, Candida, and Cryptococcus, as well as anti-inflammatory activity. This review provides insights on further utilization of polycyclic endoperoxides by medicinal chemists, pharmacologists, and the pharmaceutical industry.

A sensitive, precise and rapid LC-MS/MS method for determination of ergosterol peroxide in Paecilomyces cicadae mycelium

Ergosterol peroxide (EP) has considerable potential effect against the proliferation of tumor cells. Here, we established a new approach for EP content detection through liquid chromatography-tandem mass spectrometry. The specificity, limit of detection (LOD)/quantitative (LOQ), linearity and range, accuracy, repeatability, and intermediate precision were tested. The EP retention time was 7.18 min. The linear relationship between the mass concentration of nonylphenol and the chromatographic peak area was good within the EP concentration range of 0.1-2.0 μg/mL. The correlation coefficient was 0.994, the regression equation was Y = 27 409.8 × X - 1114.67, the average recovery rate was 82.77%, the relative standard deviation was 11.1%, the LOQ was 50 ng/mL, and the LOD was 20 ng/mL. The detection technique was convenient, accurate, reproducible, and rapid. Therefore, this method could be used for deep liquid fermentation, providing a basis for EP to serve as a quality standard for the fermentation of Paecilomyces cicadae.

High glucose causes apoptosis of rabbit corneal epithelial cells involving activation of PERK-eIF2α-CHOP-caspase-12 signaling pathway

AIM

To investigate the effect of high concentration of glucose (HCG) on double stranded RNA-activated protein kinase-like ER kinase (PERK)-eukaryotic initiation factor-2α (eIF2α)-transcription factor C/EBP homologous protein (CHOP)-cysteine aspartate specific proteinase (caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells (RCECs).

METHODS

RCECs were treated by different concentrations of glucose for 0-48h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 kDa glucose-regulated protein 78 (GRP78), CHOP, B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-2-associated X protein (Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eIF2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414.

RESULTS

HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs (P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12 (P<0.05), and the alterations caused by glucose were in concentration- and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups (P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group (P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits (P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eIF2α in the HCG group (P<0.05), while still did not affect the expression of PERK and eIF2α among groups (P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose (P<0.05).

CONCLUSION

HCG activates PERK-eIF2α-CHOP-caspase-12 signaling pathway and promotes apoptosis of RCECs.