Fermentation enhances the neuroprotective effect of shogaol-enriched ginger extract via an increase in 6-paradol content

• Incubation of 6-shogaol with A. niger resulted in the conversion to 6-paradol.
• Optimal condition for 6-paradol produced by A. niger was 1.5 × 106 spores/mL with 240 µg/mL of shogaol for 60 h.
• FSE protects against neurotoxicity of hippocampal cells and inhibits AChE activity.

This study was designed to investigate the neuroprotective effect of fermented shogaol-enriched extract (FSE), which is converted to 6-paradol by Aspergillus niger. FSE was fermented for varying time points (FSE-0, FSE-30, and FSE-60). Optimal condition for 6-paradol produced by A. niger was determined as initial inoculated cell concentration (1.5 × 106 spores/mL) from shogaol-enriched extract (240 µg/mL) for 60 h. The ability of FSE to protect the rat primary hippocampal cells from beta-amyloid (Αβ) oligomer and Αβ plaque induced neurotoxicity and to inhibit acetylcholinesterase (AChE) activity was evaluated. Hippocampal cell viability was reduced to 70% when exposed to Αβ oligomer, and exposure to Αβ plaque for 18 h and 50 µg/mL of FSE-60 increased cell viability (92% and 95.3%, respectively). In addition AChE inhibitory activity of FSE-60 at 50 µg/mL was 53%, which was similar to 0.1 µM tacrine. Therefore, these results demonstrate that FSE-60 has potential as a neuroprotective agent.