Search Results (342)

This review paper covers publications from 2013 to July 2025, and describes brominated and non-brominated indole alkaloids, ircinianins, terpenoids, and polyketide compound classes from the marine sponge of the genus Psammocinia. It provides an overview of the reported secondary metabolites, their source organisms, geographic origins, and associated biological activities. Also, the structure-activity relationship study and biosynthetic pathways of the reported compounds are illustrated. Herein, 15 new secondary metabolites, including 11 terpenoids and four akaloids, were identified in the Psammocinia sponge species during this period. Briefly, the biological activities of these secondary metabolites involve molecular, cellular, and microbial targets. Full article

Marine invertebrates produce a remarkable diversity of polyhydroxylated steroids and secosteroids whose structural features—particularly vicinal (1,2-)diols, 1,3-diols, and clustered hydroxyl arrays—make them well suited for coordination with boron species. In the marine environment, where boron is abundant, chemically stable, and predominantly present as borate under mildly alkaline conditions, such interactions are not only plausible but may be widespread. This review examines the chemistry of boron–steroid complexation in marine systems, emphasizing how rigid steroidal frameworks preorganize diol motifs to form reversible yet stable borate esters under environmentally relevant conditions. We discuss how polyhydroxy steroids may exist in dynamic equilibria between free and boron-bound forms, with speciation governed by pH, boron concentration, and local microenvironmental factors rather than enzymatic control. Boron complexation can modulate key physicochemical properties, including solubility, conformation, and membrane affinity, thereby influencing the biological activity of marine steroids without covalent modification of the carbon framework. By integrating examples from sponges, echinoderms, and corals together with well-characterized model polyols, this review highlights boron complexation as an underrecognized but potentially important factor influencing the structure, function, and bioactivity of marine steroid metabolites. Full article

Southeast Asia (SEA) harbors one of the world’s richest reservoirs of marine biodiversity, offering immense potential for natural product discovery. This review presents a comprehensive survey of sponge-derived marine natural products (MNPs), with notable activity, reported from SEA over the past two decades, highlighting their chemical diversity, biological activities and regional research trends. Analysis of the past two decades of MNPs data reveals that sponges (Phylum Porifera) remain the dominant source of new MNPs, representing nearly half of all discoveries in the region. Indonesia, Vietnam, and Thailand are leading contributors, with Indonesia exhibiting the highest productivity but limited local research leadership. The South China Sea and Indonesian archipelagos emerge as biodiversity and bioprospecting hotspots, yet large areas remain underexplored. Bioactive metabolites isolated from SEA sponges demonstrate potent anticancer, antimicrobial, anti-inflammatory, antiviral and enzyme-inhibitory properties, underscoring their value for pharmaceutical innovation. Despite this promise, uneven research capacity, infrastructure gaps and environmental degradation constrain sustainable exploitation. By consolidating recent advances in lead compound development and identifying key taxonomic as well as geographic priorities, this review strengthens the scientific foundation for marine drug discovery in SEA and supports integration of bioprospecting with regional Blue Economy and biodiversity conservation agendas and programs. Full article

Marine ecosystems have yielded a remarkable diversity of bioactive metabolites with relevance for antiviral drug discovery. This article reviews recent advances in marine-derived compounds investigated as anti-HIV agents. Metabolites, such as sulfated polysaccharides, lectins, alkaloids, and terpenoids, display inhibitory activity across multiple stages of the HIV life cycle, including viral entry, reverse transcription, integration, and maturation. From sponge-inspired development of AZT to the application of Griffithin in clinical trials for the prophylaxis of the HIV infection, recent discoveries showcase the chemical diversity of marine ecosystems and validate their utility as hit and compound sources in drug discovery. We highlight possible mechanisms of action, as well as translational hurdles from research to clinical trials. Overall, marine biodiversity represents a valuable and underexploited reservoir for the development of novel HIV therapeutics. Full article

Marine-derived fungi have become a vital resource for the discovery of novel secondary metabolites with diverse structures and significant biological activities. This study focuses on a systematic chemical investigation of the sponge-associated fungus Talaromyces stipitatus HF05001, leading to the isolation and identification of 20 compounds, including one new marine ketal natural product (Compound 17, Talarobispiral A). These compounds were structurally elucidated using comprehensive spectroscopic analyses, including 1D and 2D NMR, HRESIMS. All isolates were screened for their anti-inflammatory and anti-adipogenic properties. Among them, compound 4 (Secalonic acid D, SAD), 7 (Sch 725680) and 16 (bacillisporins C) demonstrated significant anti-inflammatory potential by markedly suppressing nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Notably, compound 4 showed superior inhibitory effect, with an IC₅₀ value of 0.22 μM. Additionally, compound 4 exhibited the strongest dose-dependent inhibition of lipid droplet accumulation in 3T3-L1 preadipocytes. These findings highlight the dual therapeutic potential of metabolites from Talaromyces stipitatus, identifying promising lead compounds for the development of novel treatments for inflammatory and metabolic disorders. Full article

Reliable taxonomy of biological producers is essential for finding new natural substances. A recent study morphologically re-examined 21 accessed vouchers to confirm multiple reported misidentifications and suggested marine sponges from the genus Rhabdastrella as the only known source of the isomalabaricane triterpenoids. The present study aimed to find isomalabaricane-containing sponges among the samples collected during seven marine expeditions to the Vietnam waters of the South China Sea, accompanied with their identification confirmed using morphological and molecular (18S rRNA and 28S rRNA) analyses. As a result, nine sponges identified as Rhabdastrella globostellata were found to contain isomalabaricanes in their extracts. A chemical investigation of the R. globostellata (PIBOC O63-136) specimen led to the isolation of nine isomalabaricane triterpenoids including the new compound 1, of which the chemical structure was elucidated based on HRESIMS and NMR data. Subsequently, a combination of LC–MS/MS, multivariate statistical analysis, and feature-based molecular networking was applied to detect, annotate, and characterize the isomalabaricane chemical diversity across the nine R. globostellata specimens. As a result, two primary chemotypes containing individual sets of annotated compounds were discovered within the Vietnamese population of this sponge. Moreover, obtained data showed a series of new extremely rare isomalabaricanes in R. globostellata extracts including nitrogen-containing metabolites and glycosides of this structural class. Full article

Alzheimer’s disease continues to be one of the most urgent neurodegenerative conditions, with acetylcholinesterase (AChE) inhibitors serving as a fundamental component of contemporary treatment approaches. Growing evidence underscores that marine ecosystems are a rich source of structurally varied and biologically active natural products exhibiting anticholinesterase properties. This review presents a thorough synthesis of marine-derived metabolites—including those sourced from bacteria, fungi, sponges, algae, and other marine life—that demonstrate inhibitory effects against AChE and butyrylcholinesterase (BuChE). Numerous compounds, such as meroterpenoids, alkaloids, peptides, and phlorotannins, not only show nanomolar to micromolar inhibitory activity but also reveal additional neuroprotective characteristics, including antioxidant effects, anti-amyloid properties, and modulation of neuronal survival pathways. Despite these encouraging findings, the transition to clinical applications is hindered by a lack of comprehensive pharmacokinetic, toxicity, and long-term efficacy studies. The structural variety of marine metabolites provides valuable frameworks for the development of next-generation cholinesterase inhibitors. Further interdisciplinary research is essential to enhance their therapeutic potential and facilitate their incorporation into strategies for addressing Alzheimer’s disease and related conditions. Full article

Background/Objectives: The growing threat of antimicrobial resistance has intensified the search for alternative therapeutic approaches. Quorum sensing (QS) inhibition, which disrupts bacterial communication and virulence, represents a promising approach to mitigating infection. Given the complexity of the sponge holobiont, sponge-associated microorganisms may demonstrate QS inhibitory properties and serve as potential sources of novel anti-virulence agents. This study aimed to investigate the QS inhibitory potential of sponge-associated Bacillus species against Pseudomonas aeruginosa, a multidrug-resistant pathogen that relies on QS for virulence regulation. Methods: Ninety-eight bacterial isolates were obtained from seven intertidal South African sponges. Biosensor-based sandwich assays using Chromobacterium violaceum identified 15 isolates with putative QS inhibition (QSI) activity, including five classified as Bacillus species via 16S rRNA gene sequencing. Crude extracts from these isolates, cultivated in medium Mannitol (Mann) and medium 5294, were screened for their ability to inhibit QS-regulated virulence factors in P. aeruginosa. Results: Extracts, particularly from medium 5294, exhibited significant QSI activity without cytotoxic effects. The five most potent extracts, i.e., Bacillus mobilis SP2-AB7 (5294), Bacillus wiedmannii SP5-AB7 (Mann), B. mobilis SP2-AB7 (Mann), and Bacillus cereus SP1-AB4 (Mann and 5294), inhibited both Las- and Rhl-regulated virulence factors, including pyocyanin, pyoverdine, elastase, protease, rhamnolipid production, motility, and initial adhesion, achieving inhibition rates of up to 93% (p < 0.05). Molecular analysis confirmed the presence of the aiiA lactonase gene in key isolates, while GC-MS and FTIR profiling revealed medium-specific differences in metabolite production. Conclusions: Sponge-associated Bacillus species from KwaZulu-Natal exhibit robust QSI activity against P. aeruginosa, highlighting their potential as sources of alternative anti-virulence agents. Further characterization and in vivo validation are needed to assess their therapeutic application in combatting resistant infections. Full article

In this study, three Antarctic sponges of the genus Latrunculia were investigated, leading to the isolation of five unreported pyrroloiminoquinone alkaloids along with the known metabolite (+)-debromodiscorhabdin A (3). Three of the new metabolites were brominated, while the other two were found to have a C-5/C-8 sulfur bridge and a C-2/N-18 bridge. Three of the metabolites were shown to have a phenyl ketone substituent on C-14, not previously reported for discorhabdin derivatives. The cytotoxicity against the A549 cell lines was studied and compounds 1–4 showed activity of 4.3, 1.8, 1.0, and 23.9 µM, respectively, while no inhibition was found for 5 and 6. Full article

Marine Aspergillus fungi, adapted to extreme marine environments (e.g., sediments, corals, mangroves), are prolific producers of structurally diverse secondary metabolites with significant bioactivities. This review comprehensively analyzes 340 novel natural products reported from 81 marine-derived Aspergillus strains over the past three years, classifying them into six major categories: alkaloids (31.2%), polyketides (29.4%), terpenoids, lignans, cyclopeptides, and others. Bioactivity assessments reveal broad therapeutic potential, including antitumor, antimicrobial, anti-inflammatory, and antiviral effects. Notably, marine sediments constitute the primary source (25.9% of strains), followed by sponges and corals. The predominance of alkaloids and polyketides underscores their pharmacological relevance. These findings highlight marine Aspergillus as a critical resource for drug discovery, offering promising scaffolds for developing treatments against human diseases and agricultural pathogens. Full article

The study of various microorganisms isolated from an Indian Ocean sponge, Scopalina hapalia ML-263, led to the selection of a promising Actinobacteria strain, Micromonospora sp. SH-82. Genomic analysis identified this strain as a new species, revealing the presence of 23 biosynthetic gene clusters (BGCs), some of which are associated with the synthesis of specialized metabolites such as polyketides deriving from polyketide synthases (PKSs). The strain was cultivated under favorable conditions for the production of bioactive molecules, resulting in the isolation and identification of seven microbial metabolites. Three of them are potentially novel, two erythronolides and one erythromycin, all characterized by a rare C10–C11 double bond. Some of these compounds also display atypical conformations, forming hemiacetals or spiroacetals. Their identification was achieved through detailed chemical analyses (NMR and ESI⁺-HRMS). A molecular networking approach was employed to assess the presence of potentially novel molecules in the microbial crude extract, supported by the identification of isolated molecules. Four molecules (1, 2, 3 and 5) were evaluated for their cytotoxic activities against cancer cell lines (HCT-116 and MDA-MB-231) and the immortalized retinal pigment epithelial RPE1 cells. No activity was observed in the latter, suggesting a lack of toxicity toward healthy cells. Moreover, megalomicin C1 (3), one of the isolated compounds, showed interesting antiplasmodial activity against Plasmodium falciparum 3D7, with an IC₅₀ of 6.37 ± 2.99 µM. Full article

The aim of this study was to investigate the metabolites in Aspergillus subramanianii 1901NT-1.40.2 extract using UPLC-MS, isolate and elucidate the structure of individual compounds, and study the antimicrobial and cytotoxic activities of the isolated compounds. The structures of two previously unreported ergostane triterpenoid aspersubrin A (1) and pyrazine alkaloid ochramide E (2) were established using NMR and HR ESI-MS. The absolute configuration of 1 was determined using quantum chemical calculations. Moreover, the known polyketides sclerolide (3) and sclerin (4); the indolediterpene alkaloid 10,23-dihydro-24,25-dehydroaflavinine (5); the bis-indolyl benzenoid alkaloids kumbicin D (6), asterriquinol D dimethyl ether (7), petromurin C (8); and the cyclopentenedione asterredione (9) were isolated. The effects of compounds 3-9 on the growth and biofilm formation of the yeast-like fungus Candida albicans and the bacteria Staphylococcus aureus and Escherichia coli were investigated. Compounds 5 and 6 inhibited C. albicans growth and biofilm formation at an IC₅₀ of 7–10 µM. Moreover, the effects of compounds 3-9 on non-cancerous H9c2 cardiomyocytes, HaCaT keratinocytes, MCF-10A breast epithelial cells, and breast cancer MCF-7 and MDA-MB-231 cells were also investigated. Compound 8 (10 µM) significantly decreased the viability of MCF-7 cells, inhibited colony formation, and arrested cell cycle progression and proliferation in monolayer culture. Moreover, 8 significantly decreased the area of MCF-7 3D spheroids by approximately 30%. A competitive test with 4-hydroxytamoxyfen and molecular docking showed that estrogen receptors (ERβ more than ERα) were involved in the anticancer effect of petromurin C (8). Full article

Nudibranchs have garnered increasing interest in biomedical research due to their complex chemical defense mechanisms, many of which are derived from their diet, including sponges, cnidarians, tunicates, and algae. Their remarkable ability to sequester dietary toxins and synthesize secondary metabolites positions them as a promising source of biologically active compounds with potential therapeutic applications, particularly in oncology. This study aimed to review and summarize the available literature on the bioactive potential of nudibranch-derived compounds, focusing mainly on their antitumor properties. Although research in this area is still limited, recent studies have identified alkaloids and terpenoids isolated from species such as Dolabella auricularia, Jorunna funebris, Dendrodoris fumata, and members of the genus Phyllidia. These compounds exhibit notable cytotoxic activity against human cancer cell lines, including those from colon (HCT-116, HT-29, SW-480), lung (A549), and breast (MCF7) cancer. These findings suggest that compounds derived from nudibranchs could serve as scaffolds for the development of more effective and selective anticancer therapies. In conclusion, nudibranchs represent a valuable yet underexplored resource for antitumor drug discovery, with significant potential to contribute to the development of novel cancer treatments. Full article

Combining biosynthetic gene cluster analysis with the OSMAC strategy, fractionation of the fermentation extract of Aspergillus templicola from the sponge Agelas sp. led to the isolation of four novel cytochalasins, colachalasins J–M (1–4), a novel cyclic pentapeptide, avellanin P (5), together with five known compounds (6–10). The structures of 1–9 were elucidated using spectroscopic data, single crystal X-ray diffraction, and Marfey’s analysis. Compound 2 exhibited potent anti-inflammatory activity in zebrafish assays. Additionally, Compounds 4 and 6 showed modest cytotoxicity against several human cancer cell lines with IC₅₀ values ranging from 2.6 to 11.2 μm. Full article

The Red Sea is rich in symbiotic microorganisms that have been identified as sources of bioactive compounds with antimicrobial, antifungal, and antioxidant properties. In this study, we aimed to explore the potential of marine sponge-associated bacteria as sources of antibacterial compounds, emphasizing their significance in combating antibiotic resistance (AMR). The crude extracts of Micrococcus, Bacillus, and Staphylococcus saprophyticus exhibited significant antibacterial activity, with inhibition zones measuring 12 mm and 14 mm against Escherichia coli, Staphylococcus aureus, Candida albicans, and other infectious strains. The DPPH assay showed that the bacterial isolates AN3 and AN6 exhibited notable antioxidant activity at a concentration of 100 mg/mL. To characterize the chemical constituents responsible for the observed bioactivity, a GC–MS analysis was performed on ethyl acetate extracts of the potent strains. The analysis identified a range of antimicrobial compounds, including straight-chain alkanes (e.g., Tetradecane), cyclic structures (e.g., Cyclopropane derivatives), and phenolic compounds, all of which are known to disrupt microbial membranes or interfere with metabolic pathways. The bioprospecting and large-scale production of these compounds are challenging. In conclusion, this study underscores the potential for marine bacteria associated with sponges from the Red Sea to be a source of bioactive compounds with therapeutic relevance. Full article