Restoration of the viability and bioactivity of endophytic fungi using epigenetic modification

Abstract

The growing threat of antibiotic resistance has prompted investigations into alternative sources of antibacterial agents. Endophytic fungi have emerged as a promising source of a variety of potent bioactive compounds. However, their bioactivity and viability often diminish with extended storage and cultivation. In this study, two endophytic fungi were screened for their viability and antibacterial potential through successive subculture and agar diffusion techniques. Epigenetic modification and combination therapy were adopted to reverse the anti bacterial potential. Aspergillus sp. isolate UILRZ5 became nonviable at the second generation, while Penicillium citrinum isolate UILRZ6 remained partially viable at the third generation. The first-generation activity ranged between 7.00 ± 0.00 mm to 13.50 ± 0.50 mm, while the minimum inhibitory concentration (MIC) ranged be tween 32 and 256 µg/mL. Nicotinamide was used as an epigenetic modifier to reactivate the lost antibacterial activity to a range of 3.70 ± 0.25 mm to 9.33 ± 0.21 mm and MIC between 32–256 µg/mL. The combination approach, with the inclusion of penicillin, had a zone of inhibition between 2.20 ± 0.20 mm and 19.23 ± 0.25 mm. The Gas chromatography-mass spectrometry analysis detected several chemical compounds of varying bioactive potential. Therefore, this study demonstrates the potential of epigenetic modification as an approach for enhancing the production of secondary metabolites from endophytic fungi. Furthermore, it high lights combinatorial strategies as promising approaches for stimulating the antibacterial potential of these fungi in the search for novel antimicrobial candidates.