Neuroprotective effects of quercetin produced by an endophytic fungus Nigrospora oryzae isolated from Tinospora cordifolia

Abstract

Aims Alzheimer’s disease is considered one of the most prevalent neurodegenerative disorders and dementia is the core symptom of this disease. This study was aimed to test the bioactive compounds produced by endophytic fungus for the inhibition of acetylcholinesterase (AChE) activity and to identify the compound responsible for this activity. Methods and Results Endophytic fungi were isolated from the medicinal plant Tinospora cordifolia and screened for AChE inhibition and antioxidant activity. The extract of one of the isolates Nigrospora oryzae (GL15) showed maximum AChE inhibition as well as antioxidant activity. The compound responsible for AChE inhibition (fraction 3) was identified as quercetin based on UV, FTIR spectra, HPLC and ESI‐MS analyses. Furthermore, the identification of quercetin in the extract of fraction 3 was confirmed by 1H NMR analysis. This extract showed anti‐dementia‐like activity in scopolamine (SCO) model. The minimal effective dose of the extract of fraction 3 modulated the SCO‐provoked cognitive deficits such as impairments in spatial recognition memory and latency period in Y‐maze test and passive avoidance test, respectively. The SCO‐induced modulation in cholinergic pathway was ameliorated by the extract of N. oryzae in hippocampus, resulting in decrease in AChE activity and restoration of cytoarchitecture of hippocampus. Conclusions The bioactive compound quercetin produced by N. oryzae may cure the learning and memory shortfalls via AChE‐mediated mechanism in experimental mice. Significance and Impact of the Study The endophytic fungus N. oryzae serves as a potential source for the bioactive compound quercetin, which plays an important role in the management of Alzheimer’s disease.

Bioactive compounds and biomedical applications of endophytic fungi: a recent review

“…Furthermore, endophytic Diaporthe have been reported for antioxidant activity [ 263 ]. Epicoccum and Nigrospora genera have potential antioxidant activity as E. nigrum [ 240 ], N. sphaerica [ 237 ] and N. oryzae [ 238 ]. Moreover, endophytic Colletotrichum sp.…”

First Natural Yeast Strain Trichosporon asahii HZ10 with Robust Flavonoid Productivity and Its Potential Biosynthetic Pathway

“…Therefore, HZ10 was subjected to subsequent further analysis given its good growth performance and the highest productivity of flavonoids. This is the first reported natural flavonoid-producing yeast strain worldwide for only endophytic fungi isolated from medicinal plants − ,, , and a few Streptomyces species , have so far been found to naturally produce flavonoids.…”

“…Therefore, finding natural flavonoid-producing microorganisms represents a feasible approach to resolving the current problems faced during the industrial production of flavonoids by microbial fermentation. Currently, numerous flavonoid-producing endophytic fungi have been successfully isolated, such as Chaetomium cruentum from Conyza blinii H. Lév, Epicoccum sorghinum from Annona senegalensis, Alternaria alternata AE1 from Azadirachta indica A. Juss, and Nigrospora oryzae from Tinospora cordifolia. − Recently, a unique flavonoid biosynthetic system of endophytic fungi has been identified in Pestalotiopsis fici and Aspergillus candidus, which is quite distinct from that in plants. , These findings indicate that a more diverse flavonoid biosynthesis pathway possibly exists naturally.…”

The Neuroprotective Potential of Endophytic Fungi and Proposed Molecular Mechanism: A Current Update

“…Recently, bioactive compounds present in endophytic fungi Nigrospora oryzae were screened for their acetylcholinesterase (AChE) and antioxidant activity [ 71 ]. Also, one of the isolates from the study, Nigrospora oryzae (GL15) showed maximum AChE as well as antioxidant activity, and the compound (fraction 3) accountable for these activities was identified as quercetin based on analyses using ultra-violet spectrophotometers (UV), fourier-transform infrared spectroscopy (FTIR), electrospray ionisation mass spectrometry (ESI-MS), high-performance liquid chromatography, (HPLC) and proton nuclear magnetic resonance ( 1 H NMR).…”

“…Additionally, the extract exhibited antidementia-like activity which led to learning and memory shortfalls through the AChE-mediated mechanism in the scopolamine model. The extract also enhanced the scopolamine-induced modulation in the cholinergic pathway and as well as triggered decrease in the activity of AChE and restoration of cyto-architecture of hippocampus [ 71 ]. While in another study by Hou and group [ 72 ], a total of seven dibenzopyrone phenolic derivatives including alternariol, alternariol 5-O-methyl ether, altenusin B, altenuene, altenusin, alterlactone, and dehydroaltenusin were extracted and identified using different spectroscopic methods from the endophytic fungi, Alternaria alternate .…”