Oxya chinensis sinuosa (rice field grasshopper) is an edible insect with numerous health beneficial properties, traditionally being used to treat many ailments in Korea and other countries. O. chinensis sinuosa has been used from centuries, however, a little is known about the chemical functionality of its bioactive compounds. Therefore, this study examined the anti-inflammatory and
cathepsin C inhibitory activities of
N-acetyldopamine dimer (2R, 3S)-2-(3',4'-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2″-aminoethyl)-1,4-benzodioxane (DAB1) isolated from O. chinensis sinuosa. Results showed that DAB1 reduced the expression of pro-inflammatory mediator (iNOS, COX-2) and
cytokines (TNF-α, IL-1β, and IL-6), and curtailed the nuclear translocation of NF-κB by inhibiting the phosphorylation of IκBα in
lipopolysaccharide stimulated macrophages. Additionally, DAB1 inhibited
cathepsin C activity at the cellular level, supported by in vitro assay (Ki, 71.56 ± 10.21 µM and Kis, 133.55 ± 18.2 µM). Moreover, combinatorial molecular simulation and binding free energy analysis suggested a significant stability and binding affinity of
cathepsin C-DAB1 complex via formation of hydrogen bond and hydrophobic interactions with the catalytic residues (Gln228, Thr379, Asn380, and Hie381). Also, essential dynamics analysis showed DAB1 induced non-functional motions in
cathepsin C structure. Collectively, DAB1 was concluded as anti-inflammatory and
cathepsin C inhibiting agent and could be used in the
drug development against respective diseases.