The Fungal EndophyteNigrospora oryzaeProduces Quercetin Monoglycosides Previously Known Only from Plants

Abstract

Three quercetin‐3‐O‐glycosides (1–3) were obtained from the endophytic fungus Nigrospora oryzae isolated from leaves of the Nigerian mistletoe Loranthus micranthus. The compounds were unequivocally identified based on their one and two dimensional NMR spectra and on their mass spectra. A fourth flavonoid glycoside (4) was tentatively identified as a luteolin monoglycoside. Comparative HPLC analyses of extracts of the endophyte and of the host plant indicated that compounds (1–3) were present as minor constituents in the extract of the host plant Loranthus micranthus whereas the latter was dominated by different gallic acid and by catechin derivatives that were missing in the endophyte extract. The presence of flavonoid glycosides in a fungal endophyte is remarkable and is unequivocally confirmed here for the first time. So far, compounds (1–3) were only known as commonly occurring plant secondary metabolites. This study adds further evidence to the remarkable plasticity of fungal secondary metabolism which has repeatedly been shown to produce the same compounds as present in plants.

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

“…These compounds can be classified as antibiotics, antioxidants, anticancer agents, volatile antimicrobial agents, immunosuppressive compounds, plant growth promoting agents, and insecticides (1). It has been reported that endophytes possess the ability to produce the same or similar chemicals as those originating from their host plants (2,3). This presents endophytic microorganisms as potential alternatives to plants in the search for biologically active molecules.…”

Antimicrobial Activity of Metabolites of an Endophytic Fungus Isolated from the Leaves of Citrus jambhiri (Rutaceae)

“…Tel: +2348063809147 bioactive molecules. [7][8][9][10][11][12][13][14][15] Only a few studies on the presence of endophytes in citrus plants have been performed and little is known about the microbial endophytic community of the citrus plants. [16][17][18][19] Several endophytic bacterial species have however been isolated from Citrus jambhiri.…”

Biotransformation of Host Plant Flavonoids by the Fungal Endophyte Epicoccum nigrum

“…Hence, compound 1 was established as kaempferol 3‐ O ‐[ α ‐rhamnopyranosyl‐(1→6)‐3‐ O ‐acetyl‐ β ‐galactopyranoside] and named 3′′‐ O ‐acetyl biorobin. Remarkably, glycosylation reactions by adding galactose vs. glucose to precursors are rare for fungi . Galactose, however, is also found as a structural moiety of the pyrenopolyene C ‐glycoside epipyrone A which is present in all extracts of E. nigrum analyzed in this study (Figures –) indicating the capacity of the fungus to use galactose for glycosylation reactions …”