Discovery Of Bioactive Compounds Research Articles

Comparative metabolite analysis of Piper sarmentosum organs approached by LC–MS-based metabolic profiling

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal and food plant widely distributed in the tropical and subtropical regions of Asia, offering both health and culinary benefits. In this study the secondary metabolites in different organs of P. sarmentosum were identified and their relative abundances were characterized. The metabolic profiles of leaves, roots, stems and fruits were comprehensively investigated by liquid chromatography high-resolution mass spectrometry (LC-HR-MS) and the data subsequently analyzed using multivariate statistical methods. Manual interpretation of the tandem mass spectrometric (MS/MS) fragmentation patterns revealed the presence of 154 tentatively identified metabolites, mostly represented by alkaloids and flavonoids. Principle component analysis and hierarchical clustering indicated the predominant occurrence of flavonoids, lignans and phenyl propanoids in leaves, aporphines in stems, piperamides in fruits and lignan-amides in roots. Overall, this study provides extensive data on the metabolite composition of P. sarmentosum, supplying useful information for bioactive compounds discovery and patterns of their preferential biosynthesis or storage in specific organs. This can be used to optimize production and harvesting as well as to maximize the plant’s economic value as herbal medicine or in food applications.Graphical

Marine Microalgae Schizochytrium sp. S31: Potential Source for New Antimicrobial and Antibiofilm Agent.

The rise of antibiotic-resistant bacteria necessitates the discovery of new, safe, and bioactive antimicrobial compounds. The antibacterial and antibiofilm activity of microalgae makes them a potential candidate for developing natural antibiotics to limit microbial infection in various fields. This study aimed to analyze the antibacterial effect of the methanolic extract of Schizochytrium sp. S31 microalgae by broth microdilution and spot plate assays. The antibacterial effects of Schizochytrium sp. S31 extract was studied on gramnegative pathogens, Pseudomonas aeruginosa, Escherichia coli 35218, Klebsiella pneumonia, which cause many different human infections, and the gram-positive pathogen Streptococcus mutans. At the same time, the antibiofilm activity of the Schizochytrium sp. S31 extract on Pseudomonas aeruginosa and Escherichia coli 35218 bacteria were investigated by crystal violet staining method. Schizochytrium sp. S31 extract at a 60% concentration for 8 hours displayed the highest antibacterial activity against P. aeruginosa, E. coli 35218, and K. pneumonia, with a decrease of 87%, 92%, and 98% in cell viability, respectively. The experiment with Streptococcus mutans revealed a remarkable antibacterial effect at a 60% extract concentration for 24 hours, leading to a notable 93% reduction in cell viability. Furthermore, the extract exhibited a dose-dependent inhibition of biofilm formation in P. aeruginosa and E. coli 35218. The concentration of 60% extract was identified as the most effective dosage in terms of inhibition. This research emphasizes the potential of Schizochytrium sp. S31 as a natural antibacterial and antibiofilm agent with promising applications in the pharmaceutical sectors. This is the first study to examine the antibacterial activity of Schizochytrium sp. S31 microalgae using broth microdilution, spot plate assays, and the antibiofilm activity by a crystal staining method. The findings of this study show that Schizochytrium sp. S31 has antibacterial and antibiofilm activities against critical bacterial pathogens.

ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF ETHYL ACETATE EXTRACT OF ACTINOMYCETES ISOLATED FROM TERMITE NESTS

Actinomycetes are an important source for the discovery of bioactive secondary metabolite compounds. Over 10,000 bioactive metabolite compounds have been isolated from terrestrial actinomycetes with various biological activities, such as antibiotic, antiviral, anti-inflammatory, antitumor, anticancer, and antioxidant. One source of origin for actinomycetes is soil, including termite nests. Utilization of natural sources such as actinomycetes from termite nests as antioxidants and antibacterials can be an alternative source of production of new secondary metabolite compounds. This research aims to evaluate the antioxidant and antibacterial activities of actinomycete extracts from termite nests. Antioxidant activity using the DPPH free radical scavenging method, and antibacterial activity against S. aureus. Antioxidant and antibacterial activity were performed by using the TLC dot-blot, TLC bioautography, and microdilution methods to determine the inhibitory concentration of 50% (IC50), antioxidant activity index (AAI), and minimum inhibitory concentration (MIC). From the 33 extracts tested, 16 extracts showed antioxidant activity with IC50 values range of 76.64-126.22 µg/mL or AAI value > 0.05 (moderate), and 8 extracts had moderate antibacterial activity against S. aureus (MIC values range of 256-512 µg/mL). Future research for scaling-up of actinomycete culture, isolating of active compounds, determining of the chemical structure of active compounds, and further testing as antioxidants and antibacterials still need to be carried out.

Rapid identifying of COX-2 inhibitors from turmeric (Curcuma longa) by bioaffinity ultrafiltration coupled with UPLC-Q Exactive-Orbitrap-MS and zebrafish-based in vivo validation

Turmeric (Curcuma longa), a typical source with recognized anti-inflammatory activity, is one such medicine-food homology source, yet its anti-inflammatory mechanisms and specific component combinations remain unclear. In this study, a net fishing method combining bio-affinity ultrafiltration and ultra-high performance liquid chromatography-mass spectrometry (AUF-LC/MS) was employed and 13 potential COX-2 inhibitors were screened out from C. longa. 5 of them (C1, 17, 20, 22, 25) were accurately isolated and identified. Initially, their IC50 values were measured (IC50 of C1, 17, 20, 22 and 25 is 55.08, 48.26, 29.13, 111.28 and 150.48 μM, respectively), and their downregulation of COX-2 under safe concentrations (400, 40, 120, 50 and 400 μM for C1, 17, 20, 22 and 25, respectively) was confirmed on RAW 264.7 cells. Further, in transgenic zebrafish (Danio rerio), significant anti-inflammatory activity at safe concentrations (15, 3, 1.5, 1.5 and 3 μg/mL for C1, 17, 20, 22 and 25, respectively) were observed in a dose-dependent manner. More importantly, molecular docking analysis further revealed the mode of interaction between them and the key active site residues of COX-2. This study screened out and verified unreported COX-2 ligands, potentially accelerating the discovery of new bioactive compounds in other functional foods.

Purification of andibenin and a chromanone analogue from rhizospheric Aspergillus flavus and soil-borne Penicillium notatum exhibiting cytotoxic and antibacterial properties

ABSTRACT The discovery of bioactive compounds from fungal natural sources holds immense potential for the development of novel therapeutics. The present study investigates the extracts of soil-borne Penicillium notatum and rhizosphere-inhabiting Aspergillus flavus for their antibacterial, antifungal, and cytotoxic potential. Additionally, two compounds were purified using chromatographic and spectroscopic techniques. The results demonstrated that the ethyl acetate fraction of A. flavus exhibited prominent cytotoxic activity against Artemia salina, whereas the ethyl acetate fraction of P. notatum displayed promising antibacterial potential. At dose concentrations of 10, 100, and 1000 µg mL−1, the ethyl acetate fraction of A. flavus showed mortality percentages of 7.6%, 66.4%, and 90%, respectively. The ethyl acetate fraction of P. notatum extract exhibited significant antibacterial activity, forming inhibition zones measuring 41, 38, 34, 34, and 30 mm against B. subtilis, S. flexneri, E. coli, K. pneumoniae, and S. aureus, respectively, at 1000 µg mL−1. At this concentration, inhibition zones of 28, 27, and 15 mm were recorded for P. vulgaris, S. typhi, and X. oryzae. Using bioassay-guided approach, one compound each was purified from the fungal extracts. The initial purification involved mass spectroscopic analysis, followed by structural elucidation using 500 MHz nuclear magnetic resonance (NMR) spectroscopy. Compound 1, derived from A. flavus, was identified as ethyl 2-hydroxy-5,6-dimethyl-4-oxocyclohex-2-ene-1-carboxylate, with a mass of 212, whereas compound 2, isolated from P. notatum, was identified as 3-amino-2-(cyclopenta-2,4-dien-1-ylamino)-8-methoxy-4H-chromen-4-one, with an exact mass of 270. Based on bioassay results, compound 1 was subjected to brine shrimp lethality assay and compound 2 was tested for its antibacterial potential. Compound 1 exhibited 30% lethality against brine shrimp larvae at a concentration of 100 µg mL−1, whereas at 1000 µg mL−1 the mortality increased to 70%. Compound 2 displayed notable antibacterial potential, forming inhibition zones of 30, 24, 19, and 12 mm against S. aureus, E. coli, B. subtilis, and S. flexneri, respectively. In comparison, the standard antibiotic tetracycline produced inhibition zones of 18, 18, 15, and 10 mm against the respective bacterial strains at the same concentration.

Extract of Schinus terebinthifolius Raddi intensifies morphological alterations in the colon of diabetic rats

There are several challenges in the treatment of diabetes mellitus. Some of these challenges include the discovery of bioactive compounds with the potential to be adjuncts in the treatment of diabetes mellitus. In this study, the effects of hydroethanolic extract of Schinus terebinthifolius Raddi on physiological, morphological, and quantitative parameters of the colon of diabetic rats were investigated. For this purpose, 16 90-day-old rats were randomly divided into four groups: Normoglycemics (N); normoglycemics treated with (50 mg/kg) the hydroethanolic extract of S. terebinthifolius Raddi (NA); streptozotocin-induced diabetics (D); and streptozotocin-induced diabetics treated with the hydroethanolic extract of S. terebinthifolius Raddi (DA). The diabetic rats had diarrhea, weight loss, increased water and food intake, and high blood glucose levels. In addition, atrophy of the entire intestinal wall and submucosa, hypertrophy of the muscularis mucosae, and changes in the histoarchitecture of the intestinal crypts and enterocytes were observed in groups NA, D, and DA. In addition, changes in collagen remodeling and the ganglia of the enteric nervous system, as well as changes in goblet cells and intraepithelial lymphocytes, were observed only in groups D and DA. Our results show that treatment with S. terebinthifolius Raddi extract does not protect the colon from the damage caused by diabetes, nor does it reverse physiological parameters. Moreover, the treatment caused morphological and quantitative changes in the colon of normoglycemic rats and intensified the damage caused by diabetes.

In Silico Discovery of Green Tea and Green Coffee Bioactive Compounds Against IGF-1R, PPAR-α, and TLR4 as a Therapeutic Candidate for Metabolic Disorder

In Silico Discovery of Green Tea and Green Coffee Bioactive Compounds Against IGF-1R, PPAR-α, and TLR4 as a Therapeutic Candidate for Metabolic Disorder

Phytochemical characterisation of leaves and stems of Murraya koenigii (L.) Sprengel and Murraya paniculata (L.) Jack and their antibacterial activity against multidrug‐resistant Acinetobacter baumannii bacterial infection

SummaryAntibiotic resistance is now deemed a worldwide problem that puts public health at risk. The potential of Murraya (Murraya koenigii (L.) Spreng. and Murraya paniculata (L.) Jacq.) leaves and stems as antibacterial agents against multidrug‐resistant Acinetobacter baumannii (MDRAB) was assessed in our study. First, screening was performed by disc diffusion assay, and minimum inhibitory concentration values were then determined as compared to tigecycline. A. baumnii mouse model of infection was established to substantiate the antibacterial activity of Murraya species. Results revealed high antimicrobial activity for stem of both plants where leaves showed moderate to weak activity. Phytochemical characterisation revealed the identification of 129 metabolites belonging to different classes of compounds viz. coumarins, carbazole alkaloids, flavonoids, phenolic acids, and miscellaneous. In vivo data from the animal model supported the high efficiency of M. paniculata stems as promising extract for lead candidates against MDRAB pulmonary infections. Inhibition of its essential MurF (UDP‐N‐acetylmuramoyl‐tripeptide‐D‐alanyl‐d‐alanine ligase) protein has been reported as a potential target for broad‐spectrum drugs. In silico results after molecular docking to MurF from Acinetobacter baumannii (PDB ID: 4QF5) showed competitive binding mode to ATP ligand at the active site predicting antibacterial activity of the tested compounds. Furthermore, chlorogenic acid, caffeic acid, sinapic acid, feruloyl agmatine, and mahanimbidine were detected as the key discriminatory metabolites correlated with antibacterial activity. To our knowledge, this is the first in vivo anti‐MDRAB study for the investigated plant. Murraya plants have enormous possibility for the discovery of novel bioactive compounds which could combat against resistant microorganisms.

Bioassay-Guided Fractionation of Pittosporum angustifolium and Terminalia ferdinandiana with Liquid Chromatography Mass Spectroscopy and Gas Chromatography Mass Spectroscopy Exploratory Study

Bioprospecting native Australian plants offers the potential discovery of latent and novel bioactive compounds. The promising cytotoxic and antibacterial activity of methanolic extracts of Pittosporum angustifolium and Terminalia ferdinandiana led to further fractionation and isolation using our laboratory’s bioassay-guided fractionation protocol. Hence, the aim of this study was to further evaluate the bioactivity of the fractions and subfractions and characterize bioactive compounds using liquid chromatography mass spectroscopy (LC-MS/MS) and gas chromatography MS (GC-MS). Compounds tentatively identified in P. angustifolium Fraction 1 using LC-ESI-QTOF-MS/MS were chlorogenic acid and/or neochlorogenic acid, bergapten, berberine, 8′-epitanegool and rosmarinic acid. GC-MS analysis data showed the presence of around 100 compounds, mainly comprising carboxylic acids, sugars, sugar alcohols, amino acids and monoalkylglycerols. Furthermore, the fractions obtained from T. ferdinandiana flesh extracts showed no cytotoxicity, except against HT29 cell lines, and only Fraction 2 exhibited some antibacterial activity. The reduced bioactivity observed in the T. ferdinandiana fractions could be attributed to the potential loss of synergy as compounds become separated within the fractions. As a result, the further fractionation and separation of compounds in these samples was not pursued. However, additional dose-dependent studies are warranted to validate the bioactivity of T. ferdinandiana flesh fractions, particularly since this is an understudied species. Moreover, LC-MS/GC-MS studies confirm the presence of bioactive compounds in P. angustifolium Fraction 1/subfractions, which helps to explain the significant acute anticancer activity of this plant. The screening process designed in this study has the potential to pave the way for developing scientifically validated phytochemical/bioactivity information on ethnomedicinal plants, thereby facilitating further bioprospecting efforts and supporting the discovery of novel drugs in modern medicine.

Exploring Bioactive Potential of Streptomyces thinghirensis WAE1 from Wadi El-Natron, Egypt

AbstractThis study aimed to investigate the bioactive metabolites produced by Streptomyces thinghirensis WAE1, an actinomycete isolated from El-Hamara Lake in Egypt. The discovery of new bioactive compounds from natural sources is crucial for the advancement of therapeutic treatments, and this study aimed to contribute to this field by exploring the potential of Streptomyces thinghirensis WAE1 as a source of such compounds. Streptomyces thinghirensis WAE1 was screened for its ability to produce antimicrobial, antioxidant, and anti-inflammatory metabolites. The results revealed that S. thinghirensis WAE1 exhibited strong antimicrobial activity against Streptococcus pneumoniae and moderate activity against Listeria monocytogenes, Staphylococcus aureus, and Candida albicans. Streptomyces thinghirensis WAE1 also displayed antioxidant activity through scavenging free radicals and chelating iron, and moderate anti-inflammatory activity as determined by its IC50 value. The isolate's demonstration of L-asparaginase activity suggests that S. thinghirensis WAE1 is a promising source of bioactive compounds with potential therapeutic uses. The high salinity and alkalinity of El-Hamara Lake, which create favorable conditions for the production of bioactive metabolites, further add to its potential as a source of actinomycetes strains with bioactive properties. These findings make both S. thinghirensis WAE1 and El-Hamara Lake valuable subjects for further exploration in the field of bioactive compounds.

Effect of n-Hexane Extract from Tanacetum argenteum (Lam.) Willd. subsp. argenteum on the Secretion of Proinflammatory Cytokines in THP-1 Cell Line

Inflammation is an initial biological process that involves the activation of the immune system in response to injury, infection or exposure to toxic agents. During this process, cytokines, small proteins produced by immune cells, play a vital role in regulating the immune response. Inflammatory cytokines, including interleukins, tumor necrosis factor-α, nitric oxide, and interferon-gamma, initiate the immune response and promote inflammation. Natural products are frequently a source of potential anti-inflammatory compounds, and screening natural products can lead to the discovery of novel bioactive compounds. The present study aimed to investigate the effects of n-hexane extract from Tanacetum argenteum subsp. argenteum on the lipopolysaccharide-induced inflammatory response in human macrophages THP-1 cell. Cells were incubated with different concentrations of n-hexane extract, and the inhibitor effects of the extract exposure on various cytokine secretions were determined. The findings demonstrated that n-hexane extract dramatically decreased the levels of interleukin‑6, interleukin‑1β, and tumor necrosis factor‑α in differentiated THP-1 cells, indicating the remarkable anti-inflammatory potential of the extract. Furthermore, in silico analysis of toxicogenomic data revealed the interactions between the active component of the n-hexane extract and interleukin-6, interleukin-1β, and tumor necrosis factor.

Metabolomics-Guided Discovery of New Dimeric Xanthones from Co-Cultures of Mangrove Endophytic Fungi Phomopsis asparagi DHS-48 and Phomopsis sp. DHS-11.

The co-culture strategy, which mimics natural ecology by constructing an artificial microbial community, is a useful tool for the activation of biosynthetic gene clusters (BGCs) to generate new metabolites, as well as to increase the yield of respective target metabolites. As part of our project aiming at the discovery of structurally novel and biologically active natural products from mangrove endophytic fungi, we selected the co-culture of a strain of Phomopsis asparagi DHS-48 with another Phomopsis genus fungus DHS-11, both endophyted in mangrove Rhizophora mangle considering the impart of the taxonomic criteria and ecological data. The competition interaction of the two strains was investigated through morphology observation and scanning electron microscopy (SEM), and it was found that the mycelia of the DHS-48 and DHS-11 compacted and tangled with each other with an interwoven pattern in the co-culture system. A new approach that integrates HPLC chromatogram, 1HNMR spectroscopy, UPLC-MS-PCA, and molecular networking enabled the targeted isolation of the induced metabolites, including three new dimeric xanthones phomoxanthones L-N (1-3), along with six known analogs (4-9). Their planar structures were elucidated by an analysis of their HRMS, MS/MS, and NMR spectroscopic data and the absolute configurations based on ECD calculations. These metabolites showed broad cytotoxic activity against the cancer cells assessed, of which compounds 7-9 displayed significant cytotoxicity towards human liver cells HepG-2 with IC50 values ranging from 4.83 μM to 12.06 μM. Compounds 1-6 exhibited weak immunosuppressive activity against the proliferation of ConA-induced (T-cell) and LPS-induced (B-cell) murine splenic lymphocytes. Therefore, combining co-cultivation with a metabolomics-guided strategy as a discovery tool will be implemented as a systematic strategy for the quick discovery of target bioactive compounds.

A divergent intermediate strategy yields biologically diverse pseudo-natural products.

The efficient exploration of biologically relevant chemical space is essential for the discovery of bioactive compounds. A molecular design principle that possesses both biological relevance and structural diversity may more efficiently lead to compound collections that are enriched in diverse bioactivities. Here the diverse pseudo-natural product (PNP) strategy, which combines the biological relevance of the PNP concept with synthetic diversification strategies from diversity-oriented synthesis, is reported. A diverse PNP collection was synthesized from a common divergent intermediate through developed indole dearomatization methodologies to afford three-dimensional molecular frameworks that could be further diversified via intramolecular coupling and/or carbon monoxide insertion. In total, 154 PNPs were synthesized representing eight different classes. Cheminformatic analyses showed that the PNPs are structurally diverse between classes. Biological investigations revealed the extent of diverse bioactivity enrichment of the collection in which four inhibitors of Hedgehog signalling, DNA synthesis, de novo pyrimidine biosynthesis and tubulin polymerization were identified from four different PNP classes.

Development of target-based cell membrane affinity ultrafiltration technology for a simplified approach to discovering potential bioactive compounds in natural products.

Target-based drug discovery technology based on cell membrane targets has gained significant traction and has been steadily advancing. However, current methods still face certain limitations that need to be addressed. One of the challenges is the laborious preparation process of screening materials, which can be time-consuming and resource-intensive. Additionally, there is a potential issue of non-specific adsorption caused by carrier materials, which can result in false-positive results and compromise the accuracy of the screening process. To address these challenges, this paper proposes a target-based cell membrane affinity ultrafiltration technology for active ingredient discovery in natural products. In this technique, the cell membranes of human lung adenocarcinoma epithelial cells (A549) with a high expression of epidermal growth factor receptor (EGFR) were incubated with candidate drugs and then transferred to an ultrafiltration tube. Through centrifugation, components that interacted with EGFR were retained in the ultrafiltration tube as "EGFR-ligand" complex, while the components that did not interact with EGFR were separated. After thorough washing and eluting, the components interacting with EGFR were dissociated and further identified using LC-MS, enabling the discovery of bioactive compounds. Moreover, the target-based cell membrane affinity ultrafiltration technology exhibited commendable binding capacity and selectivity. Ultimately, this technology successfully screened and identified two major components from the Curcumae Rhizoma-Sparganii Rhizoma (CS) herb pair extracts, which were further validated for their potential anti-tumor activity through pharmacological experiments. By eliminating the need for laborious preparation of screening materials and the potential non-specific adsorption caused by carriers, the development of target-based cell membrane affinity ultrafiltration technology provides a simplified approach and method for bioactive compounds discovery in natural sources.

Unlocking the potential of bacterial endophytes from medicinal plants for drug discovery.

Among the plant-associated microorganisms, the so-called endophytes continue to attract much attention because of their ability not only to protect host plants from biotic and abiotic stress factors, but also the potential to produce bioactive secondary metabolites. The latter property can elicit growth-promoting effects on plants, as well as boost the production of plant-specific secondary metabolites with valuable pharmacological properties. In addition, endophyte-derived secondary metabolites may be a rich source for the discovery of drugs to treat various diseases, including infections and cancer. However, the full potential of endophytes to produce bioactive secondary metabolites is often not revealed upon conventional cultivation in the laboratory. New advances in genomics and metabolic engineering offer exciting opportunities for the exploration and exploitation of endophytes' biosynthetic potential. This review focuses on bacterial endophytes of medicinal plants, some of their secondary metabolites and recent advances in deciphering their biosynthesis. The latter may assist in genetic engineering efforts aimed at the discovery of novel bioactive compounds with the potential to be developed into drugs.

Unveiling the anti-proliferative and pro-thermogenic activity of Staurosirella pinnata (Bacillariophyta) bioproducts

Biorefinery co-products obtained from biomass of the field isolated diatom Staurosirella pinnata have been investigated for their bioactivity on selected human and murine cell lines. Biomass grown in indoor photobioreactor, collected at the stationary phase, was subjected to methanolic extraction to produce a crude extract, sequentially fractionated (hydrophilic-hydrophobic gradient) to obtain six fractions (A4, A5, A7; B4, B5, B6). Fractions' bioactivity was tested on BRAFwt and BRAFV600E human melanoma cell lines, compared to normal keratinocytes. All fractions showed cytotoxic activity, but only fraction A4 showed a remarkable cell-type selectivity, with cell death induction up to 70 % on melanoma cells. Further characterization allowed to identify and purify four apocarotenoids from fraction A4, representing the first report of such class of compound s in mass cultivated diatoms. In addition, fraction A5 resulted to be a mixture of oxylipins and fraction B4 of purine nucleosides, with adenosine as main component. Residual biomass was further processed to obtain an enriched lipidic extract, characterized by a high content of poly-unsaturated fatty acids. Anti-diabetic and anti-obesity activities were assessed by evaluating the expression levels of key proteins involved into thermogenesis (UCP1), lipolysis (Perilipin, HSL660), and mitochondrial dynamics (pDRP1, VDAC), on murine white adipocyte cell line. Overall, the data here reported confirmed S. pinnata as a platform for the discovery and purification of bioactive compounds with biomedical potential, and the biorefinery pipeline allow their combined isolation, thus advancing the sustainability of diatom exploitation for the discovery and production of bioactive molecules.

Apoptotic and Autophagic Cell Death Effects of the Hexane Extract of Tropical Marine Algae Halymenia durvillei against Human Glioblastoma Cells: In vitro and in silico Studies

Glioblastoma (GBM) considered as aggressive brain cancer with high mortality rate in patients even after surgical resection. Resistant to chemotherapy is the major problem in GBM therapy. Discovery of novel bioactive compounds from algae is being investigated as alternative sources for potential treatment as well as prevention in glioblastoma. This study revealed the effects of marine red algae extract from hexane solvent fraction of Halymenia durvillei (HDHE) on proliferation and cell death in A172 human GBM cells. HDHE decreased proliferation and promoted cell cycle arrest at G2/M phase. HDHE induced apoptotic cell death in A172 cells through mitochondrial membrane dysfunction, the decrease of anti-apoptotic Bcl-2 protein expression, and activation of caspase 3/7. Moreover, HDHE increased intracellular reactive oxygen species (ROS) production and accumulation of LC3-II, an autophagic marker. The docked conformation of palmitic acid, a major component of HDHE, showed a high affinity binding to TP53 and Beclin-1 as cell death-related target molecules. This research conclusively demonstrated that HDHE might serve as a potent anticancer agent against glioblastoma by promoting apoptotic and autophagic cell death in A172 human GBM cells. HIGHLIGHTS The palmitic acid-enriched extract of red alga Halymenia durvillei (HDHE) could inhibit proliferation of A172 human glioblastoma cells by arresting cell cycle at G2/M phase HDHE could induce both caspase-dependent apoptotic and autophagic death of A172 cells Palmitic acid, a major component of HDHE, showed a high affinity binding to TP53 and Beclin-1 The extract could be beneficial to develop as chemopreventive agents or food supplements against glioblastoma GRAPHICAL ABSTRACT

UTILIZATION OF MANGROVE ENDOPHYTIC FUNGI AS A SUSTAINABLE AND ENVIRONMENTALLY FRIENDLY SOURCE OF CHITOSAN

Chitosan is an important biopolymer that is used as a raw material in several industries, but the manufacturing process has the potential to harm the environment. This study aimed to exploit chitosan in mangrove endophytic fungi and to characterize it. The four fungi isolates used were 20BB0501, 20CB07, 20BA04, and 20BA0502. Fungi were obtained from mangrove plants and identified macroscopically and microscopically using the coverslip method. After performing fungal maintenance on MEA media, fungi cultivation was done on rice media for 14 days. A chitosan extract was made by isolating and extracting the chitosan from the fungal biomass. FTIR was used to characterize the isolated chitosan extract. Macroscopic examinations revealed that each of the four strains had a delicate structure and was white. According to the extraction results, the yield of chitosan from the fungal biomass was 7.5%, 16.7%, 1.6%, and 11%, respectively. According to the FTIR data, showed the degree of deacetylation reached 85.02%, 97.78%, 88.7%, and 85.02%. It can be concluded that mangrove endophytic fungi can be used in the manufacture of chitosan, which produces a high degree of deacetylation using a more environmentally friendly process. The results of this study indicate that marine fungal strains can be used as a source of chitosan. This basis can be developed for the production of bio surfactants, enzymes, and the discovery of new bioactive compounds has pharmacological and biotechnological potential.

Antibacterial activity of two actinomycetes species isolated from black sand in North Egypt

Increasingly high levels of multidrug-resistant (MDR) pathogens have necessitated the discovery of novel bioactive compounds. For this reason, two actinomycetes strains, Streptomyces griseorubens and Streptomyces rochei, were isolated for the first time from the black sand shores of Kafr El Sheikh in Egypt, which is home to several large fish farms. Isolates were identified via phenotypic, biochemical and 16S rRNA sequence protocols. Both strains exhibited powerful antimicrobial activity against three serious MDR pathogens: Bacillus subtilis, Salmonella enteritidis and Pseudomonas aeruginosa. The bioactive compounds of isolates’ filtrates were identified using gas chromatography–mass spectroscopy (GC-MS). For S. griseorubens, the detectable antibacterial compounds were hexanoic acid, 2-ethyl-, 2-ethylhexyl ester, n-Decane, hexadecanoic acid methyl ester, benzene acetic acid, ricinolic acid, and ethylparaben, while S. rochei secretes heptadecane, 2,6-dimethyl-, benzene acetic acid, dibutyl phthalate, octacosane, hexacosane, and vitamin A aldehyde. These results strongly encourage the use of these eco-friendly isolates as a biocontrol against MDR pathogens that attack fish farms. Significance: Streptomyces spp. act as strong weapons for fighting multidrug resistance in pathogenic bacteria – one of the most important current threats to public health. They are additionally regarded as eco-friendly organisms that can be used as a biocontrol agent against infections that endanger fish farms.

Genome Mining of a Novel Marine Sponge Symbiont Nocardia sp. BML-15-R-026U Reveals High Biosynthetic Potential for Secondary Metabolites, Including a Non-Ribosomal Peptide and a Polyketide of High Novelty

Antibiotic and drug resistance poses serious global public health threats, leading to substantial infections and fatalities annually. Addressing these issues requires the discovery of novel bioactive compounds and a faster and more cost-effective discovery process. However, traditional approaches, which require isolation and multi-step purification of compounds from organisms and running of initial assays, suffer from serious limitations such asthe need for substantial amounts of biological material and high rates of compound rediscoveries. Because the biosynthetic capabilities of organisms are encoded in their genomes, genome mining provides a promising solution that would complement traditional approaches. This study conducted long-read whole genome sequencing on a marine sponge symbiont, Nocardia sp. BML-15-R-026U, to explore its genomic repertoire of secondary metabolite-encoding Biosynthetic Gene Clusters (BGCs). A four-contig genome assembly was generated for this isolate with a high degree of completeness and an estimated genome size of 4.84 Mbp. Its genome displays remarkable biosynthetic potential by containing at least 34 distinct secondary metabolite BGCs, predominantly Non-Ribosomal Peptide Synthetase (NRPS) and Polyketide Synthase (PKS) systems capable of producing novel chemical structures. Further analysis was focused on two genomic regions. In region 3.10, the study predicted a BGC for a novel, serine-rich non-ribosomal peptide with a predicted molecular weight of 2754 g/mol. Region 3.12 contained an iterative type-I PKS BGC, suggesting the potential synthesis of a polyketide compound with oxidoreductase-inhibiting properties. This study highlights genome mining as a productive early-phase approach for identifying promising drug leads and has identified the most promising candidates among this isolate’s BGCs for experimental validation