Antimicrobial metabolite profiling of Nigrospora sphaerica from Adiantum philippense L.

Abstract

Background Endophyte bestows beneficial aspects to its inhabiting host, along with a contribution to diverse structural attributes with biological potential. In this regard, antimicrobial profiling of fungal endophytes from medicinal plant Adiantum philippense revealed bioactive Nigrospora sphaerica from the leaf segment. Chemical and biological profiling through TLC–bioautography and hyphenated spectroscopic techniques confirmed the presence of phomalactone as an antimicrobial metabolite. Results The chemical investigation of the broth extract by bioassay-guided fractionation confirmed phomalactone as a bioactive antimicrobial secondary metabolite. The antimicrobial activity of phomalactone was found to be highest against Escherichia coli by disc diffusion assay. The MIC was found to be significant against both Escherichia coli and Xanthomonas campestris in the case of bacteria and dermatophyte Candida albicans at 150 μg/ml, respectively. Conclusions Overall, the results highlighted the antimicrobial potential of phomalactone from the endophyte Nigrospora sphaerica exhibiting a broad spectrum of antimicrobial activity against human and phytopathogenic bacteria and fungi. This work is the first report regarding the antibacterial activity of phomalactone.

Phenolic and flavonoid contents and antioxidant activity of an endophytic fungus Nigrospora sphaerica (EHL2), inhabiting the medicinal plant Euphorbia hirta (dudhi) L.

“…Several antimicrobial bioactive compounds, such as nigrosporins, nigrosporolides and lactones, have previously been reported from Nigrospora sp. (Ramesha et al 2020). However, information available on the antioxidant compounds of the species is scanty.…”

“…Such substitute sources of endophytic fungi may reduce the overexploitation of host medicinal plants and the cost of host mimetic natural compounds (Verma et al 2009 ; Su et al 2012 ). Recently, an antimicrobial compound “phomalactone” has been reported from a fungal endophyte, Nigrospora sphaerica isolated from Adiantum philippense (Ramesha et al 2020 ). There are several reports that Nigrospora sp produces antimicrobial compounds, such as nigrosporins, nigrosporolides and lactones.…”

Epigenetic Modifiers Revamp Secondary Metabolite Production in Endophytic Nigrospora sphaerica

“…From the above bioprospection we identified N. sphaerica from Adiantum philippense L. in the Western Ghats region near Virajpete in prior antimicrobial profiling attempts for bioactive endophyte. N. sphaerica (GenBank Accession number: MF400860 ) was found to biosynthesize phomalactone ( Ramesha et al, 2020 ). In this regard, we have investigated to understand the probable changes caused by epigenetic modulations.…”

“…Later inoculated with N. sphaerica and incubated at 27 ± 2°C under shaking conditions. Following fermentation and crude ethyl extracts were profiled using TLC in solvent system of ethyl acetate and hexane (1:1) ( Ramesha et al, 2020 ).…”

Chemical and Bioactive Metabolites of Humicola and Nigrospora Secondary Metabolites

“…New powerful antibiotics have been discovered and commercialized in recent years and others are in clinical testing [20]. Natural products from endophytes have gained wide attention from the research community due to their wide structural diversities with potential biological applications [21,22].…”