Evaluation of Fractions 25-30 of Epigenetically Modified Lasiodiplodia Pseudotheobromae as a Potential Antimicrobial Agent Against Escherichia. Coli

The emergence of multidrug-resistant organisms poses a significant public health threat, which has necessitated the exploration of alternative antimicrobial sources, such as endophytic fungi, to combat rising resistance to synthetic drugs. This study aims to evaluate the potential of epigenetically modified endophytic Lasiodiplodia pseudotheobromae using DNA methyltansferase (Hydrazine) and histone deacetylase (azacytidine). Column chromatography was carried out to separate and purify the complex mixture of metabolites, followed by thin-layer chromatography (TLC) to pool fractions with similar profiles, 25-30 were used to identify fractions exhibiting antimicrobial activity against E. coli using bioautography method. The fractions were subsequently evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) by microdilution method. Time-kill assay (TKA) was performed to estimate the bactericidal rate of the fractions within 12-hour period. Chemical components detected in fraction 28 using Gas Chromatography-Mass Spectrometry (GCMS) were 15 compounds with Stigmast-4-en-3-one identified as the most abundant, accounting for 37.99% of the total area and major bioactive metabolite. This compound contributes to the observed antimicrobial activity of the fungal extract against E. coli, validating the potential of Ocimum gratissimum as a source of antimicrobial agent.