Peguy Flora Djuidje Kouomou¹*, Franklin Mepong Noboudem¹, Armel Herve Nwabo Kamdje⁴, Hervet Paulain Dongmo Fogang⁴, Gedeon Ngautala¹, Maurice Tagatsing Fotsing³ and Cecile Annie Ewane^1,2*

¹Biotechnology Centre of the University of Yaoundé I, Yaoundé, Cameroon, Laboratory of Phytoprotection and Valorization of Genetic Resources, P.O. Box 17 673, Etetak-Yaoundé, Cameroon
²Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon, P.O. Box 812, Yaoundé, Cameroon; Biotechnology Centre of the University of Yaoundé I, Yaoundé, Cameroon
³Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé Cameroon, Laboratory of Natural Substances and Valorization, P.O. Box 812, Yaoundé, Cameroon
⁴Department of Physiological Sciences and Biochemistry, Faculty of Medicine and Biomedical Sciences, University of Garoua, P.O. Box 317, Garoua, Cameroon

*Corresponding Author: Peguy Flora Djuidje Kouomou, Biotechnology Centre of the University of Yaoundé I, Yaoundé, Laboratory of Phytoprotection and Valorization of Genetic Resources, P.O. Box 17 673, Etetak-Yaoundé, Cameroon and Cecile Annie Ewane, Biotechnology Centre of the University of Yaoundé I, Yaoundé, Laboratory of Phytoprotection and Valorization of Genetic Resources, P.O. Box 17 673, Etetak-Yaoundé, Cameroon.

Received: September 10, 2025; Published: September 29, 2025

Abstract

Bacteria of the Streptomyces genus are a promising source of bioactive products, with several applications. This study aimed to evaluate the antimicrobial and antioxidant properties of the methanol crude extract of Streptomyces sp. PFK4, its modes of action, and bioactive metabolites. Zone of inhibition (ZI), minimum inhibition concentration (MIC), and minimum bactericidal concentration (MBC) were conducted to determine antibacterial activity. Bacterial cell and protein synthesis were assayed as potential modes of action of extract. The antioxidant properties were determined by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging and Ferric reducing assays (FRAP). The gas chromatography-mass spectrometry (GC-MS) was used to identify bioactive compounds. The mean ZI ranged from 11.00±0.33 to 20.60±0.88 mm with the highest ZI observed against Salmonella typhi and Staphylococcus aureus. The MIC ranged from 0.25 to 0.5 mg/mL and MBC from 0.25 to 2 mg/mL against bacterial pathogens. The crude methanol extract of Streptomyces sp. PFK4 showed the ability to inhibit Escherichia coli cell from 100 to 60.17% while protein synthesis was from 5.45 to 5.17 μg Eq BSA/g. It also exhibited DPPH and ABTS scavenging activities at concentrations of 50 μg/mL with the highest inhibition concentration of 83.74 ± 2.10% and 72.97 ± 2.67%, IC50 values of 100.8 μg/mL and 15.69 μg/mL respectively. The highest FRAP was 8.04 ± 0.85 μg/mL at a 200 μg/mL concentration. From the GC-MS analysis, twenty-three biological compounds primarily fatty acids or their esters were identified. This study demonstrates the methanol crude extract of Streptomyces sp. PFK4 possesses antibacterial and antioxidant activities; inhibits bacterial cell and protein synthesis ability; and contains mostly fatty acids and their derivatives recognized as therapeutic agents.

Keywords: Streptomyces sp. PFK4; Crude Methanol Extract; Antimicrobial; Modes of Action; Antioxidant Properties; GC-MS

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Citation

Citation: Peguy Flora Djuidje Kouomou, et al. “Methanol Crude Extract Derived from Streptomyces sp. PFK4: Antimicrobial, Antioxidant Properties, Potential Modes of Action, and Chemical Profile of Bioactive Compounds".Acta Scientific Microbiology 8.10 (2025): 29-43.

Copyright

Copyright: © 2025 Peguy Flora Djuidje Kouomou, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.