Synthesis of a natural quinoline alkaloid isolated from the deep-sea-derived fungus and its potential as a therapeutic for Parkinson’s disease

2-(Quinoline-8-carboxamido)benzoic acid (2-QBA; 1) is a natural quinoline alkaloid isolated from the deep-sea-derived fungus Aspergillus sp. SCSIO06786. Alkaloid 1 was synthesized by an amidation reaction of 8-quinolinecaroxylic acid with methyl anthranilate, followed by hydrolysis. The neuroprotective properties of 1 were evaluated using a Caenorhabditis elegans Parkinson's disease model, which revealed that 1 significantly ameliorated 1-methyl-4-phenylpyridinium (MPP+)-induced dopaminergic neurodegeneration in a dose-dependent manner. MPP+-induced behavioral defects in worms, including impaired locomotion and basal slowing ability, were restored by treatment with 1. We further demonstrated that treatment with 1 modulates the formation of neurotoxic α-synuclein oligomers by suppressing α-synuclein expressions and enhancing proteasome activity. These results suggest that 1 is a promising therapeutic candidate for the treatment of Parkinson’s disease.