Date Palm Trees Root-Derived Endophytes as Fungal Cell Factories for Diverse Bioactive Metabolites.

Endophytic fungi of healthy and brittle leaf diseased (BLD) date palm trees ( L.) represent a promising source of bioactive compounds with biomedical, industrial, and pharmaceutical applications. The fungal endophytes isolate TDPEF34, and isolate TDPEF20 from healthy and BLD date palm trees, respectively, proved very effective in confrontation assays against three pathogenic bacteria, including two Gram-positive bacteria () and (), and one Gram-negative bacterium (). They also inhibited the growth of three fungi sp. (), (), sp. (). Additionally, their volatile organic compounds (VOCs) were shown to be in part responsible for the inhibition of and and could account for the full inhibition of Fs. Therefore, we have explored their potential as fungal cell factories for bioactive metabolites production. Four extracts of each endophyte were prepared using different solvent polarities, ethanol (EtOH), ethyl acetate (EtOAc), hexane (Hex), and methanol (MetOH). Both endophyte species showed varying degrees of inhibition of the bacterial and fungal pathogens according to the solvent used. These results suggest a good relationship between fungal bioactivities and their produced secondary metabolites. Targeting the discovery of potential anti-diabetic, anti-hemolysis, anti-inflammatory, anti-obesity, and cytotoxic activities, endophytic extracts showed promising results. The EtOAc extract of displayed IC value comparable to the positive control diclofenac sodium in the anti-inflammatory assays. Antioxidant activity was evaluated using α,α-diphenyl-β-picrylhydrazyl (DPPH), β-carotene bleaching, reducing power (RP), and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonique) (ABTS) radical scavenging assays. The findings revealed strong anti-oxidant power with an IC of 177.55 µg/mL for EtOAc extract using DPPH assay, probably due to high polyphenol and flavonoid content in both fungal extracts. Finally, LC-HRMS (Liquid Chromatography–High Resolution Mass Spectrometry) and GC-MS (Gas Chromatography–Mass Spectrometry) analysis of and extracts revealed an impressive arsenal of compounds with previously reported biological activities, partly explaining the obtained results. Finally, LC-HRMS analysis indicated the presence of new fungal metabolites that have never been reported, which represent good candidates to follow for the discovery of new bioactive molecules.