Efficacy of Penicillium limosum Strain AK-7 Derived Bioactive Metabolites on Antimicrobial, Antioxidant, and Anticancer Activity against Human Ovarian Teratocarcinoma (PA-1) Cell Line

Abstract

Natural metabolites from beneficial fungi were recognized for their potential to inhibit multidrug-resistant human and plant fungal pathogens. The present study describes the isolation, metabolite profiling, antibacterial, and antifungal, antioxidant, and anticancer activities of soil fungi. Among the 17 isolates, the AK-7 isolate was selected based on the primary screening. Further, the identification of isolate AK-7 was performed by 18S rRNA sequencing and identified as Penicillium limosum (with 99.90% similarity). Additionally, the ethyl acetate extract of the Penicillium limosum strain AK-7 (AK-7 extract) was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and a Gas Chromatography-Mass Spectroscopy (GC-MS) analysis, and the results showed different functional groups and bioactive metabolites. Consequently, a secondary screening of antibacterial activity by the agar well diffusion method showed significant antibacterial activity against Gram-negative and Gram-positive bacterial pathogens. The AK-7 extract exhibited notable antifungal activity by a food poisoning method and showed maximum inhibition of 77.84 ± 1.62%, 56.42 ± 1.27%, and 37.96 ± 1.84% against Cercospora canescens, Fusarium sambucinum and Sclerotium rolfsii phytopathogens. Consequently, the AK-7 extract showed significant antioxidant activity against DPPH and ABTS^•+ free radicals with IC₅₀ values of 59.084 μg/mL and 73.36 μg/mL. Further, the anticancer activity of the AK-7 extract against the human ovarian teratocarcinoma (PA-1) cell line was tested by MTT and Annexin V flow cytometry. The results showed a dose-dependent reduction in cell viability and exhibited apoptosis with an IC₅₀ value of 82.04 μg/mL. The study highlights the potential of the Penicillium limosum strain AK-7 as a source of active metabolites and natural antibacterial, antifungal, antioxidant, and anticancer agent, and it could be an excellent alternative for pharmaceutical and agricultural sectors.

Keywords: GC-MS analysis; Penicillium limosum; anticancer; apoptosis; biological activity.

Figure 1

Antifungal activity of isolate AK-7 against phytopathogens: (A) C. canescens; (B) F. sambucinum; and (C) S. rolfsii.

Figure 2

Morphological characterization of isolate AK-7: (A) Aerial mycelia; (B) Substrate mycelia; (C) Microscopic visualization of mycelia and sporulation; and (D) SEM image showing conidiophores and conidia.

Figure 3

Dendrogram showing phylogenetic relationship of Penicillium limosum strain AK-7.

Figure 4

FTIR analysis of AK-7 extract showing different functional groups.

Figure 5

GC-MS chromatogram of AK-7 extract.

Figure 6

Antimicrobial activity of AK-7 extract by agar well diffusion method: (A) P. aeruginosa; (B) S. flexneri; (C) E. coli; (D) S. aureus; (E) B. subtilis; and (F) B. cereus.

Figure 7

Graphical representation of antibacterial activity of AK-7 extract. (The inhibition zones represent the mean of triplicates trials and expressed as ± standard deviation).

Figure 8

Antifungal activity of AK-7 extract by food poison method: (A) Control and treated agar plates with AK-7 extract; and (B) Graphical representation of antifungal activity of AK-7 extract. (The percentage of inhibition rate represent mean of the triplicate trials and expressed as ± standard deviation).

Figure 9

Antioxidant activities of AK-7 extract: (A) DPPH free radical scavenging assay and (B) ABTS^•+ free radical scavenging assay. (The percentage of scavenging activity represent mean of the triplicate trials and expressed as ± standard deviation).

Figure 10

Anticancer activity (MTT assay) of AK-7 extract against PA-1 cell line: (A) Untreated control; (B) Standard Doxorubicin; (C) 12.5 μg/mL; (D) 25 μg/mL; (E) 50 μg/mL; (F) 100 μg/mL; (G) 200 μg/mL; and (H) Comparative graphical representation on cell viability of different concentration of AK-7 extract. (The cell viability percentage of each treatment represents mean of the triplicates trials and expressed as ± standard deviation).

Figure 11

Flow cytometric analysis of PA-1 cell line treated with AK-7 extract. The quadrangular plots indicate Annexin V/PI expression on PA-1 cell line: (A) Untreated cell line; (B) Standard treated cell line; and (C) AK-7 extract treated cell line. Cell cycle analysis of PA-1 cell line; (D) Untreated cell line; (E) Standard treated cell line; and (F) AK-7 extract treated cell line.