Evaluation of Antimicrobial and Antioxidant Activities of Endophytic Penicillium and Aspergillus Species Isolated from Curcuma caesia Roxb. (Zingiberaceae), a Medicinal Plant of Odisha, India

Abstract

In addition to being important sources of bioactive chemicals, medicinal plants are essential for the
development of new therapeutic medicines. The capacity of endophytic fungus linked to medicinal
plants to create a variety of secondary metabolites with important biological functions has drawn more
attention. The antibacterial and antioxidant properties of endophytic fungi isolated from the medicinal
plant Curcuma caesia Roxb. (family Zingiberaceae) were examined in this work. Based on
morphological traits, three endophytic fungal isolates from the plant's rhizomes were identified as
Aspergillus oryzae, Penicillium citrinum, and Aspergillus niger. This identification was verified by
18S rRNA sequencing using ITS markers. The isolates' antibacterial activity against four human
pathogenic bacteria Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Pseudomonas
aeruginosa was first assessed using the agar block method. P. citrinum produced inhibition zones up to
3.5 cm against the investigated pathogens, demonstrating the greatest antibacterial activity among the
isolates. The disc diffusion method was used for secondary screening with ethyl acetate extracts.
DPPH and DMPD radical scavenging tests were used to measure antioxidant activity. While A. oryzae
demonstrated the highest activity in the DMPD testing (59.56%), P. citrinum demonstrated the highest
DPPH antioxidant activity (78.61%). Additionally, all isolates showed enzymatic activity, such as
tyrosinase, protease, and amylase. These results suggest that C. caesia endophytic fungus could be
useful sources of bioactive compounds with possible medical uses.