Abstract
Nowadays, endophytic fungi represent a rich source of biological active compounds. In the current study, twelve endophytic fungal species were isolated from
Avicennia marina
leaves. From the isolates,
Aspergillus niger
,
Penicillium rubens
and
Alternaria alternata
recorded the highest isolation frequency (80%), relative density (12.5%) and antimicrobial activity. The antimicrobial and anticancer activities of
P. rubens
were more effective than those of
A. niger
and
A. alternata
; therefore, its identification was confirmed via the ITS rRNA gene. Filtrate extracts of
P. rubens
,
A. alternata
and
A. niger
were analyzed using GC-MS and showed different detected constituents, such as acetic acid ethyl ester,
N
-(4,6-Dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide, 1,2-benzenedicarboxylic acid, hexadecanoic acid and octadecanoic acid. Filtrate extract of
P. rubens
exhibited the presence of more compounds than
A. alternata
and
A. niger
.
Bacillus subtilis
,
Staphylococcus
aureus
,
Escherichia coli
,
Pseudomonas aeruginosa
,
Candida albicans
and
Aspergillus fumigatus
were more inhibited by
P. rubens
extract than
A. alternata
or
A. niger
, with inhibition zones of 27.2 mm, 22.21 mm, 26.26 mm, 27.33 mm, 28.25 mm and 8.5 mm, respectively. We observed negligible cytotoxicity of
P
. rubens
extract against normal cells of human lung fibroblasts (WI-38 cell line), unlike
A. alternata
and
A. niger
extracts. Proliferation of prostate cancer (PC-3) was inhibited using
P. rubens
extract, exhibiting mortality levels of 75.91% and 76.2% at 200 µg/mL and 400 µg/mL of the extract. Molecular docking studies against the crystal structures of
C. albicans
(6TZ6) and the cryo-EM structure of
B. subtilis
(7CKQ) showed significant interactions with benzenedicarboxylic acid and
N
-(4,6-dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide as a constituent of
P. rubens
extract.
N
-(4,6-dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide had the highest scores of −6.04905 kcal/mol and −6.590 kcal/mol towards (6tz6) and (7CKQ), respectively.