Aspergillus Species from the Sabkha Marsh: Potential Antimicrobial and Anticancer Agents Revealed Through Molecular and Pharmacological Analysis

Abstract

Introduction: This study aimed to investigate the fungal growth and diversity in the Sabkha marsh. The anti-bacterial properties of the isolated fungi were assessed using an agar disk diffusion assay, and the crude extracts were tested for their anticancer activities. Liquid chromatography-mass spectrometry was employed to identify the active compounds of the fungal secondary metabolites. In-silico studies were conducted to predict the toxicity, pharmacokinetic properties, and safety profiles of the identified compounds.

Results: The analysis revealed that the isolated fungi belonged to the Aspergillus species, specifically Aspergillus flavus and Aspergillus niger. The crude extract of A. flavus exhibited significant anticancer activity against various cancer cell lines, while the antifungal activities against pathogenic bacteria varied between the two fungi. Liquid chromatography-mass spectrometry analysis identified several compounds in the fungal isolates. In Aspergillus flavus, the compounds included Aflavinine, Dihydro-24-hydroxyaflavinine, Phomaligin A, Hydroxysydonic acid, Gregatin B, Pulvinulin A, Chrysogine, Aspergillic acid, Aflatoxin B1, and Aflatoxin G1. In Aspergillus niger, the compounds identified were atromentin, fonsecin B, firalenone, rubrofusarin, aurasperone E, aurasperone D, aurasperone C, nigerone, and αβ-dehydrocurvularin.

Conclusion: This study demonstrated promising fungal growth and diversity in the Sabkha marsh, with Aspergillus species being the most prevalent. The fungal crude extract showed anticancer activities against various cancer cell lines, while the antifungal activities against pathogenic bacteria varied between the two fungi. Future research should focus on investigating the antimicrobial activities of these fungi against multidrug-resistant bacteria and exploring the genetic changes in bacteria and cancer cells treated with these fungal extracts. Additionally, it is important to test the anticancer activity of the active compounds separately to determine which one is the active agent against cancer cells. This information can be used in drug development trials.

Keywords: Aspergillus genus; antimicrobial screening; biological activity; microbial isolation; saline environment.

Graphical abstract

Figure 1

Elector spray ionization total ion chromatogram positive mode. (A) Electro spray ionization total ion chromatogram (Positive Mode) of Aspergillus flavus extract) and negative mode. (B) Electro spray ionization total ion chromatogram (Negative Mode) of Aspergillus flavus extract) of Aspergillus flavus extract.

Figure 2

Elector spray ionization total ion chromatogram positive mode. (A) Electro spray ionization total ion chromatogram (Positive Mode) of Aspergillus Niger extract) and negative mode. (B) Electro spray ionization total ion chromatogram (Negative Mode) of Aspergillus Niger extract) of Aspergillus Niger extract.

Figure 3

The chemical Structures of Secondary Metabolites Identified in Aspergillus flavus.

Figure 4

The chemical Structures of Secondary Metabolites Identified in Aspergillus Niger.

Figure 5

Images of the study area of the Makkah region, Rabigh city (Sabkha).

Figure 6

SEM images showing characteristic features of Aspergillus conidia: line (A) Aspergillus flavus, line (B) Aspergillus Niger.

Figure 7

Phylogenetic tree showing the position of Aspergillus flavus strain WIS (acc. no. OR262346.1) and the closest related strains based on (ITS) region sequences.

Figure 8

Phylogenetic tree showing the position of Aspergillus Niger strain WIS (acc. no. OR262345.1) and the closest related strains based on (ITS) region sequences.

Figure 9

Antimicrobial activity against gram-positive bacteria (⁺ve) Staphylococcus aureus (S. aureus) and gram-negative bacteria (⁻ve) Escherichia coli (E. coli) of Aspergillus flavus on three different media, Sabouraud dextrose agar (SDA), nutrient agar (NA) and blood agar (BA). (A) (⁻ve on SDA); (B) (⁺ve on SDA); (C) (⁻ve on NA); (D) (⁺ve on SDA); (E) (⁻ve on BA) and (F) (⁺ve on BA).

Figure 10

Antimicrobial activity against gram-positive bacteria (⁺ve) Staphylococcus aureus (S. aureus) and gram-negative bacteria (⁻ve) Escherichia coli (E. coli) of Aspergillus Niger on three different media, Sabouraud dextrose agar (SDA), nutrient agar (NA) and blood agar (BA). (A) (⁻ve on SDA); (B) (⁺ve on SDA); (C) (⁻ve on NA); (D) (⁺ve on SDA); (E) (⁻ve on BA) and (F) (⁺ve on BA).

Figure 11

MTT assay on six cell lines. The extracts Aspergillus flavus (A) and Aspergillus Niger (B) along with Doxorubicin (C) and Mitoxantrone (D) were used. The X-axis shows the log of concentrations of the extracts in µg/mL, and the Y-axis shows normalized absorbance in %.

Figure 12

Pharmacokinetic Properties for the Identified Metabolites Using SwissADME Webserver.