Issues in Biological Sciences and Pharmaceutical Research
Vol.7(1), pp. 7-15, January 2019
Available online at https://www.journalissues.org/IBSPR/
Author(s) retain the copyright of this article. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Antimicrobial activities of two secondary metabolites isolated from Aspergillus niger, endophytic fungus harbouring stems of Acanthus montanus
Isabelle Kamga Mawabo1,2, Celine Nkenfou*2,3,4,Augustin Notedji2,Jean Bosco Jouda5, Paul-Keilah Lunga6, Pierre Eke6, Valere Tsouh Fokou6 and Jules-Roger Kuiate1
1Department of Biochemistry, University of Dschang, Dschang, Cameroon.
2Molecular Biology Center, P.O. Box 14495, Yaounde, Cameroon.
3Higher Teachers’ Training College, University of Yaounde I, Cameroon.
4Chantal biya International reference entre, P O Box 3077, Messa, Yaounde, Cameroon.
5Department of Chemistry, University of Yaounde I, Yaounde, Cameroon.
6Department of Biochemistry, University of Yaounde I, Yaounde, Cameroon.
*Corresponding Author Email: nkenfou(at)yahoo.com
Emergence of multidrug-resistant pathogenic microorganisms has prompted a worldwide search for new antibiotics from various sources. Endophytic fungi from unique habitats that are much easier to grow are considered as potential sources of novel bioactive compounds including antimicrobials. The objective of this work was to isolate, identify and characterize compounds produced by endophytic fungi associated with Acanthus montanus stems. Aspergillus niger was isolated from the stems of Acanthus montanus and subjected to solid-state fermentation on rice medium. Its secondary metabolites were extracted using ethyl acetate. The obtained crude extract was sequentially fractionated by column chromatography. The structures of isolated compounds were identified based on their spectral studies using nuclear magnetic resonance and comparison with published data. The antimicrobial and cytotoxicity of these compounds were determined using broth microdilution method. Two compounds were isolated from Aspergillus niger and identified as Trypacidin A and Methylsulochrin. They showed different degrees of antibacterial activities against the tested pathogenic bacteria. Methylsulochrin was most active on Enterobacter cloacae and Enterobacter aerogenes with MIC between 7.8–31.2 μg/mL. Trypacidin A was inactive on all the tested microorganisms Methylsulochrin isolated from Aspergillus niger crude extract is a potential candidate for the development of anti- infectious diseases molecules.
Key words: Acanthus montanus, endophytic fungi, Aspergillus niger, Trypacidin A, Methylsulochrin, antibacterial activity.