New Metabolites from the Marine Sponge Scopalina hapalia Collected in Mayotte Lagoon.

The biological screening of 44 marine sponge extracts for the research of bioactive molecules, with potential application in the treatment of age-related diseases (cancer and Alzheimer's disease) and skin aging, resulted in the selection of Scopalina hapalia extract for chemical study. As no reports of secondary metabolites of S. hapalia were found in the literature, we undertook this research to further extend current knowledge of Scopalina chemistry. The investigation of this species led to the discovery of four new compounds: two butenolides sinularone J (1) and sinularone K (2), one phospholipid 1-O-octadecyl-2-pentanoyl-sn-glycero-3-phosphocholine (3) and one lysophospholipid 1-O-(3-methoxy-tetradecanoyl)-sn-glycero-3-phosphocholine (4) alongside with known lysophospholipids (5 and 6), alkylglycerols (7-10), epidioxysterols (11 and 12) and diketopiperazines (13 and 14). The structure elucidation of the new metabolites (1-4) was determined by detailed spectroscopic analysis, including 1D and 2D NMR as well as mass spectrometry. Molecular networking was also explored to complement classical investigation and unravel the chemical classes within this species. GNPS analysis provided further information on potential metabolites with additional bioactive natural compounds predicted.

Neoechinulin A as a Promising SARS-CoV-2 Mpro Inhibitor: In Vitro and In Silico Study Showing the Ability of Simulations in Discerning Active from Inactive Enzyme Inhibitors.

The COVID-19 pandemic and its continuing emerging variants emphasize the need to discover appropriate treatment, where vaccines alone have failed to show complete protection against the new variants of the virus. Therefore, treatment of the infected cases is critical. This paper discusses the bio-guided isolation of three indole diketopiperazine alkaloids, neoechinulin A (1), echinulin (2), and eurocristatine (3), from the Red Sea-derived Aspergillus fumigatus MR2012. Neoechinulin A (1) exhibited a potent inhibitory effect against SARS-CoV-2 Mpro with IC50 value of 0.47 µM, which is comparable to the reference standard GC376. Despite the structural similarity between the three compounds, only 1 showed a promising effect. The mechanism of inhibition is discussed in light of a series of extensive molecular docking, classical and steered molecular dynamics simulation experiments. This paper sheds light on indole diketopiperazine alkaloids as a potential structural motif against SARS-CoV-2 Mpro. Additionally, it highlights the potential of different molecular docking and molecular dynamics simulation approaches in the discrimination between active and inactive structurally related Mpro inhibitors.

Neoechinulins: Molecular, cellular, and functional attributes as promising therapeutics against cancer and other human diseases.

Neoechinulins are fungal and plant-derived chemicals extracted from Microsporum sp., Eurotium rubrum, Aspergillus sp., etc. Two analogues of neoechinulin, i.e., A and B, exerted extensive pharmacological properties described in this review. Neoechinulin is an indole alkaloid and has a double bond between C8/C9, which tends to contribute to its cytoprotective nature. Neoechinulin A exhibits protection to PC12 cells against nitrosative stress via increasing NAD(P)H reserve capacity and decreasing cellular GSH levels. It also confers protection via rescuing PC12 cells from rotenone-induced stress by lowering LDH leakage. This compound has great positive potential against neurodegenerative diseases by inhibiting SIN-1 induced cell death in neuronal cells. Together with these, neoechinulin A tends to inhibit Aß42-induced microglial activation and confers protection against neuroinflammation. Alongside, it also inhibits cervical cancer cells by caspase-dependent apoptosis and via upregulation of apoptosis inducing genes like Bax, it suppresses LPS-induced inflammation in RAW264.7 macrophages and acts as an antidepressant. Whereas, another analogue, Neoechinulin B tends to interfere with the cellular mechanism thereby, inhibiting the entry of influenza A virus and it targets Liver X receptor (LXR) and decreases the infection rate of Hepatitis C. The present review describes the pharmaceutical properties of neoechinulins with notes on their molecular, cellular, and functional basis and their therapeutic properties.

iTRAQ-Based Proteomics Analysis of Response to Solanum tuberosum Leaves Treated with the Plant Phytotoxin Thaxtomin A.

Thaxtomin A (TA) is a phytotoxin secreted by Streptomyces scabies that causes common scab in potatoes. However, the mechanism of potato proteomic changes in response to TA is barely known. In this study, the proteomic changes in potato leaves treated with TA were determined using the Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technique. A total of 693 proteins were considered as differentially expressed proteins (DEPs) following a comparison of leaves treated with TA and sterile water (as a control). Among the identified DEPs, 460 and 233 were upregulated and downregulated, respectively. Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, many DEPs were found to be involved in defense and stress responses. Most DEPs were grouped in carbohydrate metabolism, amino acid metabolism, energy metabolism, and secondary metabolism including oxidation-reduction process, response to stress, plant-pathogen interaction, and plant hormone signal transduction. In this study, we analyzed the changes in proteins to elucidate the mechanism of potato response to TA, and we provided a molecular basis to further study the interaction between plant and TA. These results also offer the option for potato breeding through analysis of the resistant common scab.

Maculosin, a non-toxic antioxidant compound isolated from Streptomyces sp. KTM18.

CONTEXT: Streptomyces species are prolific sources of bioactive secondary metabolites known especially for their antimicrobial and anticancer activities. OBJECTIVE: This study sought to isolate and characterize antioxidant molecules biosynthesized by Streptomyces sp. KTM18. The antioxidant potential of an isolated compound and its toxicity were accessed. MATERIALS AND METHODS: The compound was purified using bioassay-guided chromatography techniques. Nuclear magnetic resonance (NMR) experiments were carried out for structure elucidation. The antioxidant potential of the isolated compound was determined using DPPH free radical scavenging assay. The toxicity of the isolated compound was measured using a brine shrimp lethality (BSL) assay. RESULTS: Ethyl acetate extract of Streptomyces sp. KTM18 showed more than 90% inhibition of DPPH free radical at 50 µg/mL of the test concentration. These data were the strongest among 13 Streptomyces isolates (KTM12-KTM24). The active molecule was isolated and characterized as maculosin (molecular formula, C14H16N2O3 as determined by the [M + H]+ peak at 261.1259). The DPPH free radical scavenging activity of pure maculosin was higher (IC50, 2.16 ± 0.05 µg/mL) than that of commercial butylated hydroxyanisole (BHA) (IC50, 4.8 ± 0.05 µg/mL). No toxicity was observed for maculosin (LD50, <128 µg/mL) in brine shrimp lethality assay (BSLA) up to the compound's antioxidant activity (IC50) concentration range. The commercial standard, berberine chloride, showed toxicity in BSLA with an LD50 value of 8.63 ± 0.15 µg/mL. CONCLUSIONS: Maculosin may be a leading drug candidate in various cosmetic and therapeutic applications owing to its strong antioxidant and non-toxic properties.

A novel antibacterial compound produced by Lactobacillus plantarum LJR13 isolated from rumen liquor of goat effectively controls multi-drug resistant human pathogens.

Probiotic lactobacilli have been implicated in the production of many low molecular weight bioactive molecules with tremendous potential to kill multidrug resistant human pathogens. The aim of the present study is to purify, characterise and evaluate a novel compound produced by a probiotic Lactobacillus plantarum LJR13 strain. The compound was purified employing silica gel column chromatography followed by RP-HPLC technique. The compound was identified as tert-butyl-4-(4-oxo-(2-((2-oxo-1- (p-tolyl) -2- (p-tolyloxy) ethyl) carbamoyl) pyrrolidin-1-yl) butanoyl) piperazine-carboxylate (BPBP) through various spectral techniques. Exhaustive literature search has revealed that the compound BPBP has not been reported from Lactobacillus species so far and ours is the first report describing its spectrum of activities against multidrug resistant human pathogens together with the morphological and physiological manifestations it brings about in the normal as well as human colon carcinoma cells. The MIC of BPBP for Listeria monocytogenes and Staphylococcus aureus was 15.62 µg/mL and 62.50 µg/mL respectively; however, for Acinetobacter baumannii the MIC was determined to be 31.25 µg/mL. Scanning electron microscopic studies of BPBP treated L. monocytogenes, S. aureus, and A. baumannii revealed the presence of blebs on the cell wall which represents the compromise in the cell wall integrity. While BPBP showed no significant cytotoxicity on mouse embryonic fibroblast cells, (NIH-3T3), marked discernible cytotoxic effect was observed on colorectal carcinoma cells, HCT-116, suggesting potential anti-cancer activity. Molecular docking studies displayed the interaction of BPBP with appropriate drug resistance associated proteins such as Penicillin binding proteins in gram positive L. monocytogenes and S. aureus and beta-lactamase in gram negative A. baumannii.

New Antibacterial Thiodiketopiperazines from the Deep Sea Sediment-Derived Fungus Epicoccum nigrum SD-388.

Two new antibacterial thiodiketopiperazine derivatives (TDKPs), 7-dehydroxyepicoccin H and 7-hydroxyeutypellazine F, along with seven known TDKP analogs, were isolated and identified from Epicoccum nigrum SD-388, a deep-sea-sediment-derived fungus. The structures of these compounds were elucidated on the basis of detailed spectroscopic analysis. The absolute configuration of 7-dehydroxyepicoccin H was established by X-ray crystallographic analysis, while 7-hydroxyeutypellazine F was determined by ECD experiment and TDDFT-ECD calculation. The antibacterial activities against human and aquatic pathogens were evaluated. 7-Dehydroxyepicoccin H and 7-hydroxyeutypellazine F displayed inhibitory activities against aquatic pathogens Vibrio vulnificus, V. alginolyticus, and Edwardsiella tarda, with MIC values ranging from 4.0 to 8.0 µg/mL.

Selective cytotoxicity of marine-derived fungal metabolite (3S,6S)-3,6-dibenzylpiperazine-2,5-dione against cancer cells adapted to nutrient starvation.

The cancer cells that are adapted to the hypoxic and nutrient-starved conditions of the tumor microenvironment have become a key target for anticancer therapies. In the course of search for selective cytotoxic substances against cancer cells adapted to nutrient starvation, (3S,6S)-3,6-dibenzylpiperazine-2,5-dione (1) was isolated from culture extract of marine-derived Paecilomyces formous 17D47-2. Compound 1 showed cytotoxic activity on the human pancreatic carcinoma PANC-1 cells adapted to glucose-starved conditions with IC50 value of 28 µM, whereas no effect was observed against PANC-1 cells under general culture conditions up to 1000 µM. Further studies on the mechanism of the selective cytotoxicity of 1 against the glucose-starved PANC-1 cells suggest that it may function via uncoupling of mitochondrial oxidative phosphorylation.

Preparation of a thiols ß-cyclodextrin/gold nanoparticles-coated open tubular column for capillary electrochromatography enantioseparations.

Inspired by the distinct chemical and physical properties of nanoparticles, here a novel open-tubular capillary electrochromatography column was prepared by electrostatic assembly of poly(diallydimethylammonium chloride) onto the inner surface of a fused-silica capillary, followed by self-adsorption of negatively charged SH-ß-cyclodextrin/gold nanoparticles. The formation of the SH-ß-cyclodextrin/gold nanoparticles coated capillary was confirmed and characterized by scanning electron microscopy and energy dispersive spectrometry. The results of scanning electron microscopy and energy dispersive spectrometry studies indicated that SH-ß-cyclodextrin/gold nanoparticles were successfully coated on the inner wall of the capillary column. The performance of the SH-ß-cyclodextrin/gold nanoparticles coated capillary was validated by the analysis of six pairs of chiral drugs, namely zopiclone, carvedilol, salbutamol, terbutaline sulfate, phenoxybenzamine hydrochloride, and ibuprofen. Satisfactory enantioseparation results were achieved, confirming the use of gold nanoparticles as the support could enhance the phase ratio of the open-tubular capillary column. Additionally, the stability and reproducibility of the SH-ß-cyclodextrin/gold nanoparticles coated capillary column were also investigated. Then, this proposed method was well validated with good linearity (≥0.999), recovery (90.0-93.5%) and repeatability, and was successfully used for enantioseparation of ibuprofen in spiked plasma samples, which indicated the new column's potential usage in biological analysis.

Chetocochliodins A-I, Epipoly(thiodioxopiperazines) from Chaetomium cochliodes.

Nine new epipoly(thiodioxopiperazine) (ETP) analogues, chetocochliodins A-I (1-9), along with two known ones, chetoseminudins E and C (10 and 11), were purified from the fungus Chaetomium cochliodes. The planar structures and absolute configurations of these new compounds were determined by extensive NMR spectroscopic analysis, CD spectra, and chemical reactions. Shielding effects from the indole on the 3-SCH3/3-OCH3/3-OCH2- groups facilitated the determination of relative configuration of the analogues. Compound 9 was cytotoxic, suggesting the importance of the sulfide bridge for the diketopiperazine bioactivities.

Amphiepicoccins A-J: Epipolythiodioxopiperazines from the Fish-Gill-Derived Fungus Epicoccum nigrum HDN17-88.

Ten new epipolythiodioxopiperazines (ETPs), namely, amphiepicoccins A-J (1-10), were isolated from the fish-gill-derived fungus Epicoccum nigrum HDN17-88. Their structures were deduced from extensive spectroscopic data and electronic circular dichroism (ECD) calculations. Amphiepicoccin A (1) which contains an aromatic indole motif is unprecedented among the epicoccin type of ETPs. Compounds 1, 3, and 6 displayed anti-HSV-2 activities, with IC50 values of 70, 64, and 29 µM, respectively (acyclovir as positive control with an IC50 value of 31 µM), while 5 and 6 also revealed inhibitory activity against Bacillus subtilis with minimum inhibitory concentration (MIC) values of 13 and 25 µM, respectively.

Bioactive xanthoquinodins and epipolythiodioxopiperazines from Chaetomium globosum 7s-1, an endophytic fungus isolated from Rhapis cochinchinensis (Lour.) Mart.

A new xanthoquinodin B9 (1), together with two known xanthoquinodins, xanthoquinodin A1 (2) and xanthoquinodin A3 (3), three epipolythiodioxopiperazines, chetomin (4), chaetocochin C (5) and dethio-tetra(methylthio)chetomin (6), and four other compounds, chrysophanol (7), emodin (8), alatinone (9), and ergosterol (10) were isolated from the endophytic fungus Chaetomium globosum 7s-1, isolated from Rhapis cochinchinensis (Lour.) Mart. All isolated structures were established based on their spectroscopic data analyses. Compounds 1-6 showed antibacterial activity against Gram positive bacteria with MICs ranging from 0.02 pM to 10.81 µM. Compounds 1-6 also exhibited cytotoxicity against KB, MCF-7 and NCI-H187 cancer cell lines (IC50 0.04-18.40 µM). However, they were cytotoxic towards a normal cell line (Vero cell) with IC50 values ranging from 0.04 to 3.86 µM.

A novel open-tubular capillary electrochromatography using carboxymethyl-ß-cyclodextrin functionalized gold nanoparticles as chiral stationary phase.

Enantioselective open tubular capillary electrochromatography with carboxymethyl-ß-cyclodextrin conjugated gold nanoparticles as stationary phase was developed. This novel open tubular column was fabricated through layer-by-layer self-assembly of gold nanoparticles on a 3-mercaptopropyl-trimethoxysilane-modified fused-silica capillary and subsequent surface functionalization of the gold nanoparticles through self-assembly of 6-mercapto-ß-cyclodextrin. The 6-mercapto-ß-cyclodextrin was firstly synthesized and determined by extensive spectroscopic data. Scanning electron microscopy, energy dispersive X-ray analysis spectroscopy, and electroosmotic flow experiments were carried out to characterize the prepared open tubular column. Then, the separation effectiveness of the open tubular column was verified by two pairs of ɑ-tetralones derivatives enantiomers and two pairs of basic drug enantiomers (tramadol hydrochloride and zopiclone) as mode analytes. Factors that influence the enantioseparation were optimized, and under the optimized conditions, satisfactory separation results were obtained for the four enantiomers: compound A, compound B, tramadol hydrochloride, and zopiclone with resolutions of 3.79, 1.56, 1.03, 1.60, respectively. For the combination of gold nanoparticles and negatively charged carboxymethyl-ß-cyclodextrin, the open tubular column exhibited wider separation range for neutral and basic drugs. Moreover, the repeatability and stability of the column were studied through the run-to-run and day-to-day investigations.

Chrysosporazines A-E: P-Glycoprotein Inhibitory Piperazines from an Australian Marine Fish Gastrointestinal Tract-Derived Fungus, Chrysosporium sp. CMB-F214.

Chemical analysis of Chrysosporium sp. CMB-F214, yielded five new piperazines, chrysosporazines A-E (1-5), with structures assigned by spectroscopic and X-ray analyses and biosynthetic considerations. The chrysosporazines 2-5 exist as an equilibrium of major and minor N-acyl rotamers, while 1-3 incorporate an unprecedented hexahydro-6H-pyrazino[1,2-b]isoquinolin-6-one scaffold. The noncytotoxic chrysosporazines reverse doxorubicin drug resistance in P-glycoprotein overexpressing colon carcinoma cells (SW620 Ad300), with 2 delivering a comparable gain in sensitivity to the positive control, verapamil.

A novel analytical method of TFMPP and mCPP in fluids of drug addicts using LLE-GC/NPD.

In recent years, drug-abuse problem is growing by leaps and bounds all over the world. The master minds spearheading its proliferation among the youth are difficult to identify, so drug-abuse case has become a hard nut to crack even with the help of best international experts in forensic science and criminology. Because most nations have tightened their controls on traditional drugs, the younger generation is now hooked onto new-type drugs: 1-(3- trifluoromethylphenyl) piperazine (TFMPP), 1-(3-chlorophenyl) piperazine (mCPP) and other new piperazine-drugs, acting as hallucinogens like 'ecstasy', are being consumed by vulnerable masses all over the world. However, only few research studies have focused on developing highly effective detection methods for TFMPP and mCPP in biological fluids; the number of detection methods for these new-type drugs is almost nil in China. Therefore, it is difficult to detect and prevent drug abuse cases related to piperazine drugs in China. There is an urgent need to develop some simple, fast, and reliable methods for detecting piperazine-drugs in vulnerable masses. Thus, the development of novel detection methods with high sensitivity and selectivity is a difficult task for the officials working in the department of forensic science in China. In this work, a new method was developed for the detection of piperazine derivatives: it was performed under the various specific conditions required for conducting chromatography and mass spectrometry analysis. With this novel method, TFMPP and mCPP was successfully detected with high accuracy in various biological samples. By comparing the purification effect of different solid-phase extraction columns for TFMPP and mCPP in biological fluids (urine and blood), we confirmed the validity of the novel method. In addition, this method has good linear relationship and a low detection line when GC/MS was performed for detecting TFMPP, mCPP in the biological fluids (urine and blood). It is a simple, reproducible method that is highly specific in the detection of piperazine-drugs. Thus, it is indeed a reliable method in forensic science.

Diketopiperazine-Type Alkaloids from a Deep-Sea-Derived Aspergillus puniceus Fungus and Their Effects on Liver X Receptor α.

Eight new diketopiperazine-type alkaloids including four oxepin-containing diketopiperazine-type alkaloids, oxepinamides H-K (1-4), and four 4-quinazolinone alkaloids, puniceloids A-D (5-8), together with two known analogues (9 and 10), were isolated from the culture broth extracts of the deep-sea-derived fungus Aspergillus puniceus SCSIO z021. Their structures were elucidated by spectroscopic analyses, and their absolute configurations were determined by Marfey's method along with comparison of their specific rotations and ECD spectra. The absolute configurations of 4 and 5 were further confirmed by a single-crystal X-ray diffraction analysis. Compounds 1-8 showed significant transcriptional activation of liver X receptor α with EC50 values of 1.7-50 µM, and 7 and 8 were the most potent agonists.

Investigation of deep eutectic solvents as additives to ß-CD for enantiomeric separations of Zopiclone, Salbutamol, and Amlodipine by CE.

The enantioseparation of chiral drugs via CE was first investigated using ß-CD as chiral additive and deep eutectic solvents (DESs) as auxiliary additive. The results showed that improved separation of tested chiral drugs was obtained in the presence of DESs and ß-CD compared to the single ß-CD separation system. With the optimized condition, resolutions of DESs applied ß-CD separation system for rac-Zopiclone, rac-Salbutamol, and rac-Amlodipine increased 3-4.2 times as single ß-CD separation system. The resolutions reached 4.74, 6.37, and 9.67, respectively. The results demonstrate that DESs are viable additives to CD system in CE for the separation of the chiral drugs.

Cristazine, a novel dioxopiperazine alkaloid, induces apoptosis via the death receptor pathway in A431 cells.

The fungus Chaetomium sp. is a causative agent of infections in humans and is ubiquitous in the natural environment. The secondary metabolites of this genus exhibit many biological activities, including antifungal activity and toxicity in mitochondria. In this study, we isolated cristazine from the fungus C. cristatum, which has the potential to inhibit the growth of human epidermoid carcinoma (A431) cells in a dose- and time-dependent manner. Its inhibitory activity was examined using a cell viability assay and cell death was elucidated by western blot analysis. Cristazine triggered apoptotic cell death via the Type I death receptor pathway including the activation of caspases and other target proteins. However, cristazine did not have any effect on mitochondrial apoptotic proteins such as Bid, cytochrome c, and apoptosis-inducing factor. Cristazine inhibited the cell cycle progression by arresting the G1 /S phase and up-regulating the inhibitory proteins of cyclin-dependent kinases. Thus, cristazine has great potential for inducing apoptosis in A431 cells via both cell cycle arrest and the inhibition of cell growth.

Hyalodendrins A and B, New Decalin-Type Tetramic Acid Larvicides from the Endophytic Fungus Hyalodendriella sp. Ponipodef12.

Two new decalin/tetramic acid hybrid metabolites, hyalodendrins A (1) and B (2) were isolated from plant endophytic fungus Hyalodendriella sp. Ponipodef12. The structures of the new compounds were elucidated by analysis of the spectroscopic data, including NMR, HRMS and ECD, and by chemical conversion. Compounds 1 and 2 were phomasetin analogues, and both showed potent larvicidal activity against the fourth-instar larvae of Aedes aegypti with the median lethal dose (LC50) values of 10.31 and 5.93 µg/mL, respectively.

Helvamide, a new inhibitor of sterol O-acyltransferase produced by the fungus Aspergillus nidulans BF-0142.

A new piperazine derivative designated helvamide was isolated as a pair of rotamers (1 and 2) from the culture broth of the fungus Aspergillus nidulans BF-0142 along with a known helvafuranone (3). The structures of 1 and 2 were elucidated based on spectroscopic analyses by the interpretation of one-dimensional and two-dimensional nuclear magnetic resonance data, ROESY (rotational Overhauser effect spectroscopy) correlations, and a chemical method. Helvamide existed as a rotameric mixture (1 and 2) in dimethyl sulfoxide. Helvamide inhibited sterol O-acyltransferases 1 and 2 (SOAT1 and SOAT2) in enzyme-based and cell-based assays using SOAT1-expressing and SOAT2-expressing Chinese hamster ovary (CHO) cells.