Graphical abstract

No abstract

No abstract

Fungal endophytes are considered promising sources of new bioactive natural products. In this study, a Mucor sp. has been isolated as an endophyte from the medicinal plant Centaurea stoebe. Through bioactivity-guided fractionation, the isolation of the new bioactive terezine E in addition to the previously reported 14-hydroxyterezine D was carried out. The isolated compounds were fully characterised by HRESIMS and 1D and 2D NMR analyses. Both compounds exhibited potent antiproliferative activity against K-562 and HUVEC cell lines and antifungal efficacy against the tested fungal strains.

Background Several plants have not been investigated for their endophytes, such as the medicinal plant Ficus carica for which anticancer activity has been confirmed. The endophyte Aspergillus neoniger was selected for investigation of its metabolites since it exerted anticancer activities in preliminary screening assays. Results Bioactivity-guided chromatographic fractionation was performed on the endophytic extract and resulted in the identification of asperazine and asperazine A through spectroscopic analysis. Moderate cytotoxicity against HeLa cell lines (CC50 = 18.4 µg mL−1) and moderate antiproliferative effects against HUVEC and K-562 cell lines (GI50 = 31.5 and 24.8 µg mL−1, respectively) were observed for asperazine. Asperazine A on the other hand showed weak cytotoxic activity against HeLa cell lines (CC50 = 34.6 µg mL−1) as well as weak cytostatic activities against HUVEC and K-562 cell lines (GI50 = 40.7 and 50.2 µg mL−1, respectively) while no antimicrobial activity was detected for both compounds. Conclusions These results suggest contribution of A. neoniger to the reported anticancer activity of the host plant and provides a new source of anticancer metabolites with therapeutic potential.

Objectives:The main aim of this study is to discover fungal endophytes associated with the Egyptian native olive tree Olea europaea as new sources for breast cancer control and investigate the chemistry and bioactivity of the fermentation metabolites of the identified active fungal species. Methods: Screening of multiple cultured Egyptian olive treeassociated fungal endophyte extracts identified Penicillium citrinum extract in breast cancer proliferation assays. Bioassay-guided isolation of the fungus P. citrinum extract identified four known metabolites 1-4. Their structure identity was established by different 1D and 2D NMR analyses. Compounds were tested for antiproliferative activity against the human breast cancer cell lines BT-474, MDA-MB-231 and MDA-MB-468using MTT assay and antimigratory activity against the human breast cancer cell lines MDA-MB-231 using wound healing assay. The antimicrobial activity of 1-3 was assessed using modified Kirby-Bauer disc diffusion method against multiple Gram positive and negative bacteria and fungi. Results: NMR analyses identified 1 as the known mycotoxin citrinin and the three different pyrrolidine alkaloids: 2-(hept-5-enyl)-3-methyl-4-oxo-6,7,8,8a-tetrahydro-4H-pyrrolo[2,1-b]-1,3-oxazine (2), scalusamide A (3) and perinadine A (4). Compounds 2-4 showed significant antiproliferative activity against the human triple negative breast cancer cell line MDA-MB-231 with IC 50 values of 10.6, 14.8 and 17.7 µM, respectively. Prerinadine (3) significantly suppressed the HGF-induced cell migration in a dose dependent manner with IC 50 9.7. Citrinin (1) exerted remarkable antibiotic activity against Gram (+) and Gram (-) bacteria and was even up to several-fold those of tetracycline standard. Conclusion: Egyptian olive tree endophytes are valuable sources for biologically active natural products.

Background The medicinal plant Ficus carica L., inhabiting southwest regions of Asia, is known for its wide ethnopharmacological applications. In traditional medicine, it has been applied as a treatment of respiratory, gastrointestinal and cardiovascular disorders, among others. Recent studies confirmed antimicrobial and anticancer activities for the plant extract. To find out whether endophytes of F. carica contribute to its biological activities, endophytes of the aerial parts of the plant were isolated and examined for anticancer and antimicrobial effects. Results The isolated species were identified as Chaetomium globosum, Penicillium oxalicum, Alternaria alternata, Fusarium proliferatum and Aspergillus neoniger. An anticancer assay was carried out on the extracts of fungal strains against human umbilical vein endothelial cells (HUVEC), human immortalized myelogenous leukemia cell line (K-562) and human immortal cervical cancer cell line (HeLa). Results revealed antiproliferative effects for all endophytic strains against HUVEC and K-562 with GI50 values ranging from 4.75 to 13.75 µg mL−1 as well as cytotoxicity against HeLa with CC50 ranging from 8.25 to 18.75 µg mL−1. The antimicrobial activity of the extracts was tested against several test strains in agar diffusion assay, and MIC values were determined by the broth microdilution method. All strain extracts exerted antibacterial and antifungal activities with highest antifungal effect observed for A. neoniger extract (MIC = 3.75 µg mL−1). Conclusions These results support the assumption that endophytes of F. carica contribute to the plant’s reported antimicrobial and anticancer activities and its corresponding applications in traditional medicine.

Objective: Endophytes are widely spread in the plant kingdom and represent a very promising source of biologically active natural products. The medicinal plant Bidens bipinnata Lin. (Asteraceae) which is known for its anti-inflammatory, antifungal and antitumor effects has been chosen for the investigation of its endophyte to search for bioactive metabolites. Methods: An endophytic Alternaria alternata species was isolated from the leaves of the plant B. bipinnata Lin. To investigate the metabolic profile of this endophytic fungus it was cultivated in several culture media as static and shaken culture. The antimicrobial and cytotoxic activities of the ethyl acetate extracts of the fungus were examined. Extracts exhibiting highest antimicrobial activities in agar diffusion assay and cytotoxicity against HeLa cancer cell line were subjected to activity-guided chromatographic fractionation for the identification of bioactive metabolites. A cytotoxic assay was performed on the isolated compounds against HeLa cancer cell lines as well as cytostatic activity tests against HUVEC and K-562 cell lines. Results: Chromatographic fractionation resulted in the isolation and identification of alternariol and tentoxin from the extract of the fungus cultivated in medium M5 while sterigmatocystin was isolated in addition to alternariol and tentoxin from the extract of the fungus grown in medium M25. Both alternariol and sterigmatocystin proved to be of moderate cytotoxicity and weak cytostatic activity with alternariol showing higher cytotoxic activity than sterigmatocystin. Highest cytotoxicity against HeLa cell lines was observed for tentoxin with a CC50 of 22.5 µg/ml. Conclusion: This study presents the isolation and identification of the bioactive metabolites alternariol, sterigmatocystin and tentoxin from the endophyte A. alternata in addition to the antifungal activity of the strain extract as well as the cytotoxic and cytostatic activities of the isolated metabolites against HeLa, HUVEC and K-562 cell lines, respectively.