Enhanced Antibacterial Potential of Fractionated Bioactive Compounds Isolated from Endophytic Nigrospora oryzae UILRZ1 in Ocimum gratissimum
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Date
2025
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Publisher
Universitas Gadjah Mada, Indonesia
Abstract
The recurring global health challenges due to antimicrobial resistance require an
impulsive response to search for alternative drugs with strong activities against
multidrug-resistant pathogens. This study evaluated and screened endophytic fungi
of strong antibacterial potential from Moringa oleifera and Ocimum gratissimum.
Primer pairs of ribosomal DNA's internally transcribed spacer regions (ITS1 and
ITS4) were used to determine their evolutionary relationships. A principal
component analysis (PCA) biplot was used to identify the most effective endophyte
at a 95 % confidence level (P˂0.05). Improved culture conditions for the production
of bioactive metabolites was done using the Taguchi design of experiment.
Considering PCA biplot analysis, Nigrospora oryzae UILRZ1 from Ocimum
gratissimum was most effective against selected pathogens. Production of
metabolites was optimum at pH 5, 0.3 % (w v-1) protein, 6-day inoculation time, and
4-plug inoculum, while variable of highest contribution was percentage of protein
used. The column and thin layer chromatography were used to fractionate the
extracts after optimization of production conditions while GCMS analysis was
adopted to identify the chemical compounds. The crude extract's minimum
inhibitory concentration (MIC) for chosen test microorganisms was 256 µg mL-1
prior optimization; while fractions of partially purified optimized extract of
Nigrospora oryzae UILRZ1 showed enhanced antibacterial activity against
Staphylococcus aureus with a MIC of 64 µg mL-1. Efficient synthesis of bioactive
metabolites was significant in the enhanced antibacterial activity against S. aureus.
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Keywords
Antibacterial resistance Bioactive compounds Endophytic fungi Nigrospora oryzae Ocimum grattisimum
Citation
Zakariyah et al., 2025