Chemical constituents and biological activities of endophytic fungi from Fagopyrum dibotrys

PeerJ. 2024 Nov 18:12:e18529. doi: 10.7717/peerj.18529. eCollection 2024.

Abstract

Background: Fagopyrum dibotrys is an important wild food and feed germplasm resource. It has high nutritional and medicinal value and is rich in natural products, including flavonoids, phenolic acids, coumarins, and alkaloids. Endophytic fungi in F. dibotrys have emerged as valuable sources of natural products. However, studies on the biological activity and chemical composition of these endophytic fungi remain limited.

Methods: In this paper, a new method to obtain natural active ingredients by fermentation of endophytic fungi from medicinal plants was proposed. Then the antioxidant and pathogenic activities of the endophytic fungi extracts were determined in vitro. In addition, secondary metabolites produced by endophytic fungi with medicinal activity were analyzed by high performance liquid chromatography-tandem mass spectrometry (LC-MS).

Results: Among the 95 endophytic fungal strains in F. dibotrys, four strains with high phenol yields were selected by reaction: Alternaria alstroemeriae (J2), Fusarium oxysporum (J15), Colletotrichum karsti (J74), and Colletotrichum boninense (J61). Compared with those of various extracts, the ethyl acetate fractions of A. alstroemeriae (J2), F. oxysporum (J15), and C. boninense (J61) exhibited superior antioxidant and antibacterial properties. The results indicated that the fungal extract was an excellent natural antioxidant and might be a potential antibacterial agent. The DPPH free radical clearance of A. alstroemeriae was 94.96 ± 0.004%. These findings indicated that A. alstroemeriae had strong antioxidant activity. In addition, the extract of A. alstroemeriae had good antibacterial activity against Escherichia coli and Staphylococcus aureus, with MICs of 0.5 and 0.05 mg/mL, respectively. The chemical constituents of the ethyl acetate extract from A. alstroemeriae were further analyzed by liquid chromatography-mass spectrometry (LC-MS). We noted that A. alstroemeriae can create a variety of medicinal substances that have high value in medicine, such as caffeic acid (884.75 ng/mL), 3-phenyllactic acid (240.72 ng/mL) and norlichexanthone (74.36 ng/mL).

Discussion: In summary, many valuable active substances and medicinal substances can be obtained through the study of endophytic fungi of F. dibotrys.

Keywords: Antibacterial activity; Antioxidant; Chemicalcomposition; Endophytic fungi; F. dibotrys; Microbe.

MeSH terms

  • Alternaria / drug effects
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology
  • Antioxidants* / chemistry
  • Antioxidants* / pharmacology
  • Chromatography, High Pressure Liquid
  • Endophytes* / chemistry
  • Endophytes* / metabolism
  • Fagopyrum* / chemistry
  • Fagopyrum* / microbiology
  • Fermentation
  • Fungi* / drug effects
  • Fusarium / drug effects
  • Microbial Sensitivity Tests
  • Tandem Mass Spectrometry

Substances

  • Antioxidants
  • Anti-Bacterial Agents

Grants and funding

This study was supported by the Sichuan Sharing and Service Platform of Scientific and Technological Resource (Enzyme Resource) of China (Project No 2020JDPT0018) and the Technology Department of Sichuan Province International Cooperation Program of China (Project No 2023YFH0043). This work was also supported by the National Key R&D Program of China (2021YFD1200105). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.