In-vitro investigation on the biological activities of squalene derived from the soil fungus Talaromyces pinophilus

Abstract

The consistent increase in multidrug resistance among pathogens and increased cancer incidence are serious public health concerns and threaten humans by killing countless lives. In the present study, Talaromyces pinophilus CJ15 was characterized and evaluated for its antibacterial, candidicidal and cytotoxic activities. The selected isolate Talaromyces pinophilus CJ15 with 18S rRNA gene sequence of 1021 base pairs exhibited antifungal activity on plant pathogens via dual culture. The GC-MS profiling of crude extract illustrated the existence of many bioactive macromolecules which include squalene belonging to the terpenoids family. The biological macromolecules in the bioactive fraction of CJ15 exhibited increasing antibacterial activity with an increase in concentration such that the highest activity was recorded against Shigella flexneri with 15, 18, 20, and 24 mm inhibition zones at 25, 50, 75 and 100 μl concentrations, respectively. The squalene, having a molecular weight of 410.718 g/mol, displayed candidicidal activity with a right-side shifted log phase in the growth curve of all the treated Candida species, indicating delayed exponential growth. In cytotoxic activity, the extracted squalene exhibited an IC₅₀ concentration of 26.22 μg/ml against JURKAT cells and induced apoptosis-induced cell death. This study's outcomes encourage the researchers to explore further the development of new and improved bioactive macromolecules that could help to prevent infections and human blood cancer.

Keywords: Antibacterial activity; Anticancer activity; Candidicidal activity; Human blood cancer; Squalene; Talaromyces pinophilus.

Fig. 1

Antagonistic activity of Talaromyces pinophilus CJ15; A)Sclerotium rolfsii and Fusarium sambucinum, B)Fusarium oxysporum and Colletotrichum capsici, and C)Alternaria alternata and Cercospora sp.

Fig. 2

Morphological features of Talaromyces pinophilus CJ15; A) Colony on PDB media, B) Microscopic image at 40× magnification, C) Morphology of CJ15 in SEM micrograph, and D) SEM image showing spore arrangement.

Fig. 3

Phylogenetic relationship of Talaromyces pinophilus CJ15 with closely related Talaromyces species.

Fig. 4

FTIR spectrum of Talaromyces pinophilus CJ15 crude extract showing presence for various biological macromolecules.

Fig. 5

GC-MS spectrum of Talaromyces pinophilus CJ15 crude ethyl acetate extract.

Fig. 6

Antibacterial activity of Talaromyces pinophilus CJ15 bioactive fraction against pathogens; A)S. aureus, B)B. subtilis, C)E. coli, and D)S. flexneri, and E) Graph showing concentration-dependent antibacterial activity of CJ15 bioactive fraction.

Fig. 7

TLC based bio-autography of Talaromyces pinophilus CJ15 derived bioactive fraction; A) TLC plate showing band pattern, and B) Bio-autography plate showing activity of fraction 1 against C. glabrata.

Fig. 8

Fragmentation mass spectrum of squalene derived from Talaromyces pinophilus CJ15.

Fig. 9

Candidicidal activity of Talaromyces pinophilus CJ15 derived squalene against selected Candida species; A)C. albicans, B)C. glabrata, C)C. tropicalis, D)C. haemulonii, and E) Graph showing concentration-dependent candidicidal activity of squalene.

Fig. 10

Growth curve assay against Candida species; A) Control sample, and B) Sample treated with squalene.

Fig. 11

Anticancer activity of Talaromyces pinophilus CJ15 extracted squalene on JURKAT cell line; A) Untreated cells, B) Std. doxorubicin treated cells, C) 12.5 μg/ml squalene treated cells, D) 25 μg/ml squalene treated cells, E) 50 μg/ml squalene treated cells, F) 100 μg/ml squalene treated cells, and G) 200 μg/ml squalene treated cells, and H) Graph showing dose-dependent activity of squalene against JURKAT cell line.