Acetylcholinesterase inhibitory activity and molecular docking study of 1-nitro-2-phenylethane, the main constituent of Aniba canelilla essential oil.

The odoriferous principle of Aniba canelilla (H.B.K.) Mez is due 1-nitro-2-phenylethane, the main constituent of its essential oil and also responsible for the plant's cinnamon scent. This nitroderivative was previously reported by their antioxidant, antinociception, cardiovascular, and vasorelaxant properties, and now it was tested as the inhibitor of acetylcholinesterase using bioautography on TLC plates. The oil and a purified fraction containing 1-nitro-2-phenylethane were analyzed by GC and GC-MS. The percentage content of 1-nitro-2-phenylethane in the oil and after fractionation was 70.2% and 98.0%, respectively. The results showed that the oil and 1-nitro-2-phenylethane are strong acetylcholinesterase inhibitors with the detection limit of 0.01 ng, equivalent to physostigmine used as the positive control. A molecular docking study was used to determine the position and conformation of the 1-nitro-2-phenylethane inhibitor in the receptor-binding pocket of the acetylcholinesterase enzyme. The nitrogroup of 1-nitro-2-phenylethane was positioned near of the catalytic serine residue of acetylcholinesterase, forming strong hydrogen bond with its hydroxyl group. Therefore, the electronegative character of 1-nitro-2-phenylethane may explain the interaction that occurs with the catalytic serine residue and its significant inhibitory activity of acetylcholinesterase.