Isolation, identification, and characterization of antimicrobial and cytotoxic secondary metabolites from the marine sponge-derived fungus Aspergillus versicolor

Abstract Investigation of an antimicrobial and cytotoxic ethyl acetate and methanol extracts from the marine sponge-derived fungus Aspergillus versicolor QT21 led to the isolation of twelve metabolites, including 5α,6α-epoxy-ergosta-8(14),22-diene-3β,7α-diol ( 1 ); 5α,6α-epoxy-ergosta-8(9),22-diene-3β,7α-diol ( 2 ); 4,8-dihydroxy-3,4-dihydronaphthalen-1(2 H)-one (isosclerone) ( 3 ); 5-methylbenzene-1,3-diol (orcinol) ( 4 ); ergosterol ( 5 ); (22 E , 24 R )-24-methylcholesta-5,22-diene-3β,7β-diol ( 6 ); cyclo-(Pro-Gly) ( 7 ); cyclo-(Pro-Ala) ( 8 ); cyclo-(Tyr-Trp) ( 9 ); N-acetyltryptamine ( 10 ); uridine ( 11 ); adenosine ( 12 ). Of these, compound 3 was isolated for the first time from the species Aspergillus versicolor . Antimicrobial assays showed that most compounds exhibited selective antimicrobial activity against Gram-positive bacteria and yeast. Compound 5 demonstrated the most promising antimicrobial activity, with MIC values of 32 µg/mL against E. faecalis , 64 µg/mL against B. cereus , and 64 µg/mL against C. albicans . In addition, compounds 1 , 4 and 5 exhibited cytotoxicity against all tested cell lines A549, MCF7, and HepG2 with IC 50 values of 13.07 ± 1.6 to 83.02 ± 1.65 µg/mL, whereas compound 2 had selective cytotoxicity against the A549 and MCF7 cell lines with IC 50 of 11.34 ± 1.56 and 10.91 ± 1.61 µg/mL, respectively. The structure–activity relationships of the isolated compounds were also discussed. This study highlights A. versicolor as a promising source of biologically active natural compounds.