Pullularins E and F, two new peptides from the endophytic fungus Bionectria ochroleuca isolated from the mangrove plant Sonneratia caseolaris

Acknowledgements This project was supported by grants of the BMBF (to P.P.) and MOST (to W.L.). We wish to thank W.E.G. Müller (Johannes-Gutenberg-University, Mainz, Germany) for carrying out the cytotoxicity assay. A scholarship (Grant No. 10/6/117) granted and financed by the Egyptian Government (Ministry of High Education) to W.E. is gratefully acknowledged.Peer reviewedPublisher PD

Induced secondary metabolites from the endophytic fungus Aspergillus versicolor through bacterial co-culture and OSMAC approaches

LBK

Xanthones and sesquiterpene derivatives from a marine-derived fungus Scopulariopsis sp.

K

Pullularins E and F, Two New Peptides from the Endophytic Fungus Bionectria ochroleuca Isolated from the Mangrove Plant Sonneratia caseolaris

Chemical investigation of the EtOAc extract of the endophytic fungus Bionectria ochroleuca, isolated from the inner leaf tissues of the plant Sonneratia caseolaris (Sonneratiaceae) from Hainan island (China), yielded two new peptides, pullularins E and F (1 and 2) together with three known compounds (3–5). The structures of the new compounds were unambiguously determined on the basis of one- and two-dimensional NMR spectroscopy as well as by high-resolution mass spectrometry. The absolute configurations of amino acids were determined by HPLC analysis of acid hydrolysates using Marfey’s method. The isolated compounds exhibited pronounced to moderate cytotoxic activity against the mouse lymphoma cells (L5178Y) with EC50 values ranging between 0.1 and 6.7 µg/mL

Aspergillus Carneus metabolite Averufanin induced cell cycle arrest and apoptotic cell death on cancer cell lines via inducing DNA damage

Abstract Cancer is one of the leading causes of death worldwide, accounting for nearly 10 million deaths in 2020. Current treatment methods include hormone therapy, γ-radiation, immunotherapy, and chemotherapy. Although chemotherapy is the most effective treatment, there are major obstacles posed by resistance mechanisms of cancer cells and side-effects of the drugs, thus the search for novel anti-cancer compounds, especially from natural sources, is crucial for cancer pharmaceutics research. One natural source worthy of investigation is fungal species. In this study, the cytotoxicity of 5 metabolic compounds isolated from filamentous fungus Aspergillus Carneus. Arugosin C, Averufin, Averufanin, Nidurifin and Versicolorin C were analyzed using NCI-SRB assay on 10 different cell lines of breast cancer, ovarian cancer, glioblastoma and non-tumorigenic cell lines. Averufanin showed highest cytotoxicity with lowest IC50 concentrations especially on breast cancer cells. Therefore, Averufanin was further investigated to enlighten cell death and molecular mechanisms of action involved. Cell cycle analysis showed increase in SubG1 phase suggesting apoptosis induction which was further confirmed by Annexin V and Caspase 3/7 Assays. H2A.X staining revealed accumulation of DNA damage in cells treated with Averufanin and finally western blot analysis validated DNA damage response and downstream effects of Averufanin treatment in various signaling pathways. Consequently, this study shows that Averufanin compound induces cell cycle arrest and cell death via apoptosis through causing DNA damage and can be contemplated and further explored as a new therapeutic strategy in breast cancer

In Vitro Phytobiological Investigation of Bioactive Secondary Metabolites from the <i>Malus domestica</i>-Derived Endophytic Fungus <i>Aspergillus tubingensis</i> Strain AN103

Endophytic fungi including black aspergilli have the potential to synthesize multiple bioactive secondary metabolites. Therefore, the search for active metabolites from endophytic fungi against pathogenic microbes has become a necessity for alternative and promising strategies. In this study, 25 endophytic fungal isolates associated with Malus domestica were isolated, grown, and fermented on a solid rice medium. Subsequently, their ethyl acetate crude extracts were pretested for biological activity. One endophytic fungal isolate demonstrated the highest activity and was chosen for further investigation. Based on its phenotypic, ITS ribosomal gene sequences, and phylogenetic characterization, this isolate was identified as Aspergillus tubingensis strain AN103 with the accession number (KR184138). Chemical investigations of its fermented cultures yielded four compounds: Pyranonigrin A (1), Fonsecin (2), TMC 256 A1 (3), and Asperazine (4). Furthermore, 1H-NMR, HPLC, and LC-MS were performed for the identification and structure elucidation of these metabolites. The isolated pure compounds showed moderate-to-potent antibacterial activities against Pseudomonas aeruginosa and Escherichia coli (MIC value ranged from 31 and 121 to 14.5 and 58.3 μg/mL), respectively; in addition, the time–kill kinetics for the highly sensitive bacteria against isolated compounds was also investigated. The antifungal activity results show that (3) and (4) had the maximum effect against Fusarium solani and A. niger with inhibition zones of 16.40 ± 0.55 and 16.20 ± 0.20 mm, respectively, and (2) had the best effect against Candida albicans, with an inhibition zone of 17.8 ± 1.35 mm. Moreover, in a cytotoxicity assay against mouse lymphoma cell line L5178Y, (4) exhibited moderate cytotoxicity (49% inhibition), whereas (1–3) reported weak cytotoxicity (15, 26, and 19% inhibition), respectively. Our results reveal that these compounds might be useful to develop potential cytotoxic and antimicrobial drugs and an alternative source for various medical and pharmaceutical fields