Evaluation of Antiviral, Antibacterial and Antiproliferative Activities of the Endophytic Fungus Curvularia papendorfii, and Isolation of a New Polyhydroxyacid

Abstract

An endophytic fungus isolated from Vernonia amygdalina, a medicinal plant from Sudan, was taxonomically characterized as Curvularia papendorfii. Ethyl acetate crude extract of C. papendorfii revealed an important antiviral effect against two viral pathogens, the human coronavirus HCoV 229E and a norovirus surrogate, the feline coronavirus FCV F9. For the last one, 40% of the reduction of the virus-induced cytopathogenic effect at lower multiplicity of infection (MOI) 0.0001 was observed. Selective antibacterial activity was obtained against Staphylococcus sp. (312 µg/mL), and interesting antiproliferative activity with half maximal inhibitory concentration (IC50) value of 21.5 ± 5.9 µg/mL was observed against human breast carcinoma MCF7 cell line. Therefore, C. papendorfii crude extract was further investigated and fractionated. Twenty-two metabolites were identified by gas chromatography coupled to mass spectrometry (GC–MS), and two pure compounds, mannitol and a new polyhydroxyacid, called kheiric acid, were characterized. A combination of spectroscopic methods was used to elucidate the structure of the new aliphatic carboxylic acid: kheiric acid (3,7,11,15-tetrahydroxy-18-hydroxymethyl-14,16,20,22,24-pentamethyl-hexacosa-4E,8E,12E,16,18-pentaenoic acid). Kheiric acid showed an interesting result with a minimum inhibitory concentration (MIC) value of 62.5 µg/mL against meticillin-resistant Staphylococcus aureus (MRSA). Hence, endophytes associated with medicinal plants from Sudan merit more attention, as they could be a treasure of new bioactive compounds.

Biotransformation ability of endophytic fungi: from species evolution to industrial applications

“…JN180937.1 Exopolysaccharide (composed of glucose, mannose, arabinose, and galactose in the ratio of 78.29:8.99:8.64:4.08) Antioxidation and inhibition of cell proliferation Zhang et al ( 2017 ) 10 Duroia hirsuta Stelliosphaera formicum YU.101029 Stelliosphaerols A Anti- Staphylococcus aureus Forcina et al ( 2015 ) 11 Stelliosphaerols B 12 Vernonia amygdalina Curvularia papendorfii KR673909 Kheiric acid The anti-virus activities of human coronavirus 229E, feline coronavirus FCV F9, and Staphylococus sp. could inhibit the proliferation of human breast cancer MCF7 cells Khiralla et al ( 2020 ) 13 Markhamia platycalyx Aspergillus flocculus 5,9-Dihydroxy-2,4,6,8,10-pentamethyldodeca-2,6,10-trienal Anti-parasite activity of parasite Trypanosoma Bruce Tawfike et al ( 2019 ) 14 Extensive host plants Diaporthe vochysiae LGMF1583 Vochysiamides A Activity against gram-negative bacteria, Klebsiella pneumoniae Noriler et al ( 2019 ) 15 Paullinia cupana Trichoderma asperellum KU512700 1-Hydroxy-8-methoxyanthracene-9,10-dione Broad-spectrum antibacterial activity Silva et al ( 2018 ) 16 Diaporthe Phaseolorum KU512679 3,4-Bis(2-ethylhexyl)phthalic acid Antitumor activity 17 …”

Molecular Identification of Endophytic Bacteria in Leucojum aestivum In Vitro Culture, NMR-Based Metabolomics Study and LC-MS Analysis Leading to Potential Amaryllidaceae Alkaloid Production

“…Several endophytic microbes present in plants were also described to be able to synthesize such biomolecules alone or in close interaction with plants, [ 9 , 10 ]. It has been recently reported in our group that the Curvularia papendorfii endophytic fungus can produce both known and novel structures [ 11 ]. Some strains of endophytes could potentially modulate the level of production of metabolites of interest in the model plant.…”

The Inhibitory Effect of Endophyte-Infected Tall Fescue on White Clover Can Be Alleviated by Glomus mosseae Instead of Rhizobia

“…Mutual relationships have been found between endophytes and some important cultivated grasses such as tall fescue and perennial ryegrass [22][23][24]. The host plants can provide endophytic fungi with photosynthetic products, nutrients and habitats; moreover, secondary metabolites produced by endophytic fungi can promote the growth and development of host plants [25] and improve the host's resistance to biotic [26][27][28][29][30] and abiotic stresses [31][32][33] such as drought [34][35][36], nutrient deficiency [37], herbivory [38][39][40][41] and pathogens [25,42,43], Given the higher growth advantages of endophyte-infected (E+) over endophyte-free (E−) plants, E+ grasses are considered to be ideal plant species for artificial grasslands. However, endophyte infection could change the interspecific relationship between host grasses and neighboring plants [44].…”