Abstract

Background: Endophytic fungi are largely underexplored in the discovery of natural bioactive products though being rich sources of novel compounds with promising pharmaceutical potential. In this study, Taxus wallichiana, which has huge medicinal value, was investigated for its endophytic diversity and capability to produce bioactive secondary metabolites by analyzing antioxidant, antimicrobial and cytotoxic properties.
Methods: The endophytes were identified by ITS-PCR using genomic DNA samples. The secondary metabolites were extracted by solvent extraction method using ethyl acetate. The antioxidant activity was analyzed by Thin Layer Chromatography, Total Phenol Content (TPC), Total Flavonoid Content (TFC) and DPPH assay, and the antimicrobial activity was analyzed by agar-well diffusion method. Brine shrimp lethality assay was used to analyze the cytotoxicity of the fungal extracts.
Results: Out of 16 different Taxus trees sampled from different locations of Dhorpatan, 13 distinctive endophytic fungi were isolated and grouped into 9 different genera: Bjerkandera, Trichoderma, Preussia, Botrytis, Arthrinium, Alternaria, Cladosporium, Sporormiella and Daldinia. The ethyl acetate extracts isolated from three endophytic fungi: Alternaria alternata, Cladosporium cladosporioides and Alternaria brassicae showed significant TPC values of 204±6.144, 312.3±2.147 and 152.7±4.958µg GAE/mg of dry extract, respectively, and TFC values of 177.9±2.911, 644.1±4.202 and 96.38±3.851µg RE/mg of dry extract, respectively. Furthermore, these three extracts showed a dose dependent radical scavenging activity with IC₅₀ concentration of 22.85, 22.15 and 23.001 µg/ml, respectively. The extracts of C. cladosporioides and A. brassicae also showed promising antimicrobial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis with a minimum inhibitory concentration of 250μg/ml for all bacteria. Both the samples showed cytotoxic property against shrimp nauplii with LC₅₀ of 104.2 and 125.9µg/ml, respectively.
Conclusions: The crude fungal extracts obtained from endophytes: A. alternata, C. cladosporioides and A. brassicae upon purification and further identification of the bioactive compounds can be a fascinating source for novel pharmaceutical agents.

Keywords

Taxus wallichiana; Endophytic; DPPH; GAE; RE; cytotoxic

Published in

F1000Research
2020, Volume: 9, article number: 379

SLU Authors

• Garcia Gil, Rosario

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Microbiology


Publication identifier

DOI: https://doi.org/10.12688/f1000research.23250.2

Permanent link to this page (URI)

https://res.slu.se/id/publ/111423