Fungal endophytes from leaves of Avicennia marina growing in semi‐arid environment as a promising source for bioactive compounds

• Published in: Letters in applied microbiology Vol. 72; no. 3; pp. 263 - 274
• Main Authors: Khalil, A.M.A., Abdelaziz, A.M., Khaleil, M.M., Hashem, A.H.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.03.2021
• Subjects: Alternaria - chemistry; Alternaria tenuissima; Antiinfectives and antibacterials; antimicrobial; antioxidant; antioxidant activity; Antioxidants; Antioxidants - pharmacology; Arid zones; Aridity; Aspergillus - chemistry; Aspergillus ochraceus; Aspergillus ochraceus - chemistry; Avicennia - microbiology; Avicennia marina; Bioactive compounds; Biocompatibility; Biological activity; Biological Products - pharmacology; Cell Extracts - pharmacology; cell lines; Chaetomium; Chaetomium - chemistry; Chaetomium globosum; Contaminants; Curvularia - chemistry; Curvularia lunata; Cytotoxicity; Desert Climate; Drug Discovery; drugs; ecosystems; Endophytes; Endophytes - chemistry; Endophytes - isolation & purification; endophytic fungi; Fungi; Fungi - chemistry; Fungi - drug effects; Fungi - isolation & purification; Gas chromatography; Gas Chromatography-Mass Spectrometry; GC‐MS; Gene banks; habitats; Heavy metals; Leaves; Mass spectrometry; Mass spectroscopy; Metabolites; Natural products; Phenolic compounds; Phenols; Plant Leaves - microbiology; Plant tissues; semiarid zones; Toxicity; GC-MS; antimicrobial; bioactive compounds; antioxidant; endophytic fungi; cytotoxicity
• ISSN: 0266-8254; 1472-765X; 1472-765X
• DOI: 10.1111/lam.13414

Endophytic fungi are broadly dispersed residing inside plant tissues and have been demonstrated as a treasure for bioactive natural products. Unexplored harsh and heavy metal contaminant habitat of Avicennia marina may have diverse and potential fungal association. Therefore, this work aimed to isolate the culturable fungal endophytes associated with leaves of A. marina and to evaluate their medical potentialities. Seventeen isolates of endophyte fungi were isolated from healthy leaves and their antimicrobial activities were evaluated. Results showed that isolates had activity against micro‐organisms in addition to their antioxidant activity produced a variety of phenolic compounds, besides exhibited a lowest cytotoxicity against ATCC‐CCL‐81 cell line. Consequently, selected endophytic fungal isolates were identified genetically as Chaetomium sp., Chaetomium madrasense, Chaetomium sp., Chaetomium globosum, Aspergillus hiratsukae, Aspergillus ochraceus, Alternaria tenuissima and Curvularia lunata with gene bank accession numbers MT089951, MT089952, MT089953, MT089954, MT089955, MT089956, MT089957 and MT089958 respectively. The most potent fungus extract was analysed using Gas chromatography–mass spectrometry which verified the presence of numerous bioactive compounds. These findings confirmed that new endophytic fungal strains derived from A. marina thrive in harsh ecosystem produce bioactive metabolites which can be recommended as a novel source for drug discovery. Significance and Impact of the Study: This work is the first report for isolating, characterizing and identifying the culturable fungi that colonize leaves of Avicennia marina residing in harsh and heavy metal–enriched habitat at Yanbu industrial city in an attempt to evaluate their activity against human pathogenic microbes and antioxidant potential with measuring the toxicity of its crude extracts. A further objective was to assess the preliminary qualitative phytochemical screening of secondary metabolites, total phenolics quantitatively and detecting the bioactive compounds using GC‐MS. This study might be offering a novel species with valuable bioactive metabolites, which provide a new source for drug discovery.