Inhibition of acetylcholinesterase and glutathione S-transferase of the pinewood nematode (Bursaphelenchus xylophilus) by aliphatic compounds

To determine the nematicidal mode of action of aliphatic compounds against the pinewood nematode (Bursaphelenchus xylophilus), we evaluated the inhibition activity of 63 aliphatic compounds on B. xylophilus acetylcholinesterases (BxACEs) and glutathione S-transferase. In the primary inhibition assay using B. xylophilus crude proteins, more than 65% of BxACE inhibition activity was observed for C6, C9, C10, and C12 2E-alkenals. Other compounds showed moderate or weak inhibition activity. The inhibition activity against 3 recombinant BxACEs was subsequently evaluated using active compounds in a primary inhibition assay. C12 2E-alkenal showed the strongest inhibition activity against BxACE-1, followed by C9, C6, and C10 2E-alkenals. The IC50 values of C12, C6, C10, and C9 2E-alkenal against BxACE-2 were 0.0059, 0.57, 0.86, and 0.99 mg/ml, respectively. C12 2E-alkenal showed the strongest inhibition activity against BxACE-3 followed by C6 2E-alkenal. In an inhibition activity test using glutathione S-transferase from the pinewood nematode, C10, C9, and C6 2E-alkenals and C12 alkanoic acid showed >45% inhibition activity.

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► 2E-alkenals showed strong BxACE and BxGST inhibition activity.
► C6 and C12 2E-alkenals showed strong inhibition activity against BxACE-1, -2 and -3.
► C9 and C10 2E-alkenals exhibited strong inhibition activity against BxACE-1 and -2.
► C10 2E-alkenal showed the strongest BxGST inhibition activity.