Investigation of biological activity of soil fungal extracts and LC/MS-QTOF based metabolite profiling

Afrah E Mohammed,Rasha Saad Suliman,Nouf Alothman,Hana Sonbol,Hanadi Talal Ahmedah,Sohailah Alotaibi,Modhi O Alotaibi,Rizwan Ali,Suaad Saleh Alwakeel

doi:10.1038/s41598-021-83556-8

Abstract

Soil is considered an extensively explored ecological niche for microorganisms that produce useful biologically active natural products suitable for pharmaceutical applications. The current study aimed at investigating biological activities and metabolic profiles of three fungal strains identified from different desert sites in Saudi Arabia. Soil fungal isolates were collected from AlQasab, Tabuk, and Almuzahimiyah in Saudi Arabia and identified. Furthermore, their antibacterial activity was investigated against Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumonia, and Escherichia coli in blood, nutrient, and Sabouraud dextrose agars. Moreover, fungal extracts were evaluated on cell viability/proliferation against human breast carcinoma and colorectal adenocarcinoma cells. To identify the biomolecules of the fungal extracts, High-performance liquid chromatography HPLC–DAD coupled to analytical LC–QTOF-MS method was employed for fungal ethyl acetate crude extract. Identified fungal isolates, Chaetomium sp. Bipolaris sp. and Fusarium venenatum showed varied inhibitory activity against tested microbes in relation to crude extract, microbial strain tested, and growth media. F. venenatum showed higher anticancer activity compared to Chaetomium sp. and Bipolaris sp. extracts against four of the tested cancer cell lines. Screening by HPLC and LC/MS-QTOF identified nine compounds from Chaetomium sp. and three from Bipolaris sp. however, for F. venenatum extracts compounds were not fully identified. In light of the present findings, some biological activities of fungal extracts were approved in vitro, suggesting that such extracts could be a useful starting point to find compounds that possess promising agents for medical applications. Further investigations to identify exact biomolecules from F. venenatum extracts are needed.

Highlights

Soil is a rich source of different microorganisms that tolerate the environmental changes via the synthesis of natural products as survival strategies to handle extreme habitat
A recent study by Gashgari et al.[11] showed the antimicrobial ability of fungal extracts isolated from medicinal plants in Saudi Arabia against important human pathogenic bacteria
Three culturable fungal isolates were collected from different desert soils in Saudi Arabia, including Cochliobolus sp. (Bipolaris sp.) and Chaetomium sp., were from AlQasab and Tabuk, respectively[24], and F. venenatum was isolated from Almuzahimiyah

Summary

Introduction

Soil is a rich source of different microorganisms that tolerate the environmental changes via the synthesis of natural products as survival strategies to handle extreme habitat. Microbes from harsh soil like deserts with exceptional environmental conditions could provide unique metabolites that serve as potential pharmaceutical products; some are d etrimental[1]. Fungi were the most abundant natural product producers, estimated at 42%2. Fungi inhabit harsh habitats and produce unique secondary metabolites, including cryoprotectant compounds such as sugars and polyols to sustain turgor pressure of the membranes. A recent study by Gashgari et al.[11] showed the antimicrobial ability of fungal extracts isolated from medicinal plants in Saudi Arabia against important human pathogenic bacteria. This study was undertaken to identify fungi from desert soils in Saudi Arabia and test their antimicrobial and anticancer activities, as well as to explore their molecular and chemical constituents. The current investigation is considered the first report for antibacterial and cytotoxic effects for fungal strains isolated from AlQasab, Tabuk and Almuzahimiyah region of Saudi Arabia

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Discussion

Conclusion