Antimicrobial secondary metabolites and antioxidant activities of fungal endophytes associated with Ziziphus spina-christi (L.) Desf. (Nabq) leaves.

A total of 20 endophytic fungi were isolated (ZSEFL1-ZSEFL20) from Ziziphus spina-christi (L.) Desf. (Nabq) leaves. Four isolates A2/ZSEFL2, Alternaria alternata, D/ZSEFL14, Aspergillus niger, E/ZSEFL15, Epicoccum nigrum, and S/ZSEFL19, Penicillium crustosum were found to show the most promising antimicrobial activities either in plug or disc diffusion screening assays against Gram-positive, Gram-negative bacteria and pathogenic fungi. Antimicrobial activity was tested against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Serratia marcescens ATCC 14764, Klebsiella pneumoniae ATCC 700603, Candida albicans ATCC 10231, and Fusarium oxysporum ATCC417. In vitro antioxidant activity assay was conducted using the ABTS [2,2'-Azino-bis (3-Ethylbenzthiazoline-6-Sulfonic Acid)] free radical scavenging method. EtOAc extracts of all isolated endophytic fungi showed antioxidant activities. This study would be one of the first reports to measure the antioxidant activity of Z. spina-christi (L.) Desf. endophytic fungi. Therefore, these isolated endophytic fungi can provide additional information for medicinal sources of natural antioxidants and antimicrobial agents.

The anti-infective potential of the endophytic fungi associated with Allium cepa supported by metabolomics analysis and docking studies.

Endophytic fungi are known to be a rich source of anti-infective drugs. In our study, Allium cepa was investigated for fungal diversity using different media to give 11 isolates which were identified morphologically. Out of the isolated fungal strains, Penicillium sp. (LCEF10) revealed potential anti-infective activity against the tested microbes (Fusarium solani ATTC 25922, Pseudomonas aeruginosa (ATTC 29231), Staphylococcus aureus ATTC 27853, Candida albicans ATTC 10231), besides, their MICs were measured by well diffusion method, therefore, it was subjected to molecular identification in addition to phylogenetic analysis. Moreover, the ITS sequence of strain LCEF10 showed a consistent assignment with the highest sequence similarity (99.81%) to Penicillium oxalicum NRRL 787. The crude ethyl acetate extract of Penicillium sp. LCEF10 was investigated for metabolomic analysis using LC-HR-ESI-MS. The metabolic profiling revealed the presence of polyketides, macrolides, phenolics and terpenoids. Furthermore, in silico molecular docking study was carried out to predict which compounds most likely responsible for the anti-infective activity.