Isolation of anticancer and anti-trypanosome secondary metabolites from the endophytic fungus Aspergillus flocculus via bioactivity guided isolation and MS based metabolomics

Tawfike, Ahmed F. and Romli, Muhammad and Clements, Carol and Abbott, Gráinne and Young, Louise and Schumacher, Marc and Diederich, Marc and Farag, Mohamed and Edrada-Ebel, RuAngelie (2019) Isolation of anticancer and anti-trypanosome secondary metabolites from the endophytic fungus Aspergillus flocculus via bioactivity guided isolation and MS based metabolomics. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 1106-1107. pp. 71-83. ISSN 1570-0232 (https://doi.org/10.1016/j.jchromb.2018.12.032)

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Abstract

This study aims to identify bioactive anticancer and anti-trypanosome secondary metabolites from the fermentation culture of Aspergillus flocculus endophyte assisted by modern metabolomics technologies. The endophyte was isolated from the stem of the medicinal plant Markhamia platycalyx and identified using phylogenetics. Principle component analysis was employed to screen for the optimum growth endophyte culturing conditions and revealing that the 30-days rice culture (RC-30d) provided the highest levels of the bioactive agents. To pinpoint for active chemicals in endophyte crude extracts and successive fractions, a new application of molecular interaction network is implemented to correlate the chemical and biological profiles of the anti-trypanosome active fractions to highlight the metabolites mediating for bioactivity prior to purification trials. Multivariate data analysis (MVDA), with the aid of dereplication studies, efficiently annotated the putatively active anticancer molecules. The small-scale RC-30d fungal culture was purified using high-throughput chromatographic techniques to yield compound 1, a novel polyketide molecule though inactive. Whereas, active fractions revealed from the bioactivity guided fractionation of medium scale RC-30d culture were further purified to yield 7 metabolites, 5 of which namely cis-4-hydroxymellein, 5-hydroxymellein, diorcinol, botryoisocoumarin A and mellein, inhibited the growth of chronic myelogenous leukemia cell line K562 at 30 μM. 3-Hydroxymellein and diorcinol exhibited a respective inhibition of 56% and 97% to the sleeping sickness causing parasite Trypanosoma brucei brucei. More interestingly, the anti-trypanosomal activity of A. flocculus extract appeared to be mediated by the synergistic effect of the active steroidal compounds i.e. ergosterol peroxide, ergosterol and campesterol. The isolated structures were elucidated by using 1D, 2D NMR and HR-ESIMS.

ORCID iDs

Tawfike, Ahmed F. ORCID logoORCID: https://orcid.org/0000-0003-2061-3093, Romli, Muhammad, Clements, Carol, Abbott, Gráinne, Young, Louise, Schumacher, Marc, Diederich, Marc, Farag, Mohamed and Edrada-Ebel, RuAngelie;
CORE (COnnecting REpositories)