Abstract
This study aimed to increase the therapeutic potential of medicinal plants through inoculation with endophytic fungi. As endophytes influence medicinal plants’ biological properties, twenty fungal strains were isolated from the medicinal plant
Ocimum tenuiflorum.
Among all fungal isolates, the R2 strain showed the highest antagonistic activity towards plant pathogenic fungi
Rosellinia necatrix
and
Fusarium oxysporum
. The partial ITS region of the R2 strain was deposited in the GenBank nucleotide sequence databases under accession number ON652311 as
Fusarium fujikuroi
isolate R2 OS. To ascertain the impact of an endophytic fungus on the biological functions of medicinal plants,
Stevia rebaudiana
seeds were inoculated with
Fusarium fujikuroi
(ON652311). In the DPPH assay, the IC
50
value of the inoculated
Stevia
plant extracts (methanol, chloroform, and positive control) was 72.082 µg/mL, 85.78 µg/mL, and 18.86 µg/mL, respectively. In the FRAP assay, the IC
50
value of the inoculated
Stevia
extracts (methanol, chloroform extract, and positive control) was 97.064 µM Fe
2+
equivalents, 117.662 µM Fe
2+
equivalents, and 53.384 µM Fe
2+
equivalents, respectively. In the extracts of the plant inoculated with endophytic fungus, rutin and syringic acid (polyphenols) concentrations were 20.8793 mg/L and 5.4389 mg/L, respectively, which were higher than in the control plant extracts. This approach can be further utilized for other medicinal plants to increase their phytochemical content and hence medicinal potential in a sustainable way.