A nematicidal tannin from Punica granatum L. rind and its physiological effect on pine wood nematode (Bursaphelenchus xylophilus)

- The ethanol extract of Punica granatum L. rind had significant nematicidal activity against PWN, which was reported for the first time.
- Three tannins with different nematicidal activities were obtained by bioactivity-guided isolation and identified as punicalagin 1, punicalin 2, corilagin 3.
- Punicalagin 1 showed the strongest nematicidal activity.
- Punicalagin 1 could inhibit the activity of acetylcholinesterase, amylase and cellulase from PWN.
- The morphology of nematodes changed significantly after they were treated by punicalagin 1.

The ethanol extract of Punica granatum L. rind was tested to show significant nematicidal activity against pine wood nematode. Three nematicidal compounds were obtained from the ethanol extract by bioassay-guided fractionation and identified as punicalagin 1, punicalin 2, and corilagin 3 by mass and nuclear magnetic resonance spectral data analysis. Punicalagin 1 was most active against PWN among the purified compounds with the LC50 value of 307.08 μM in 72 h. According to the enzyme assays in vitro, punicalagin 1 could inhibit the activity of acetylcholinesterase, amylase and cellulase from PWN with IC50 value of 0.60 mM, 0.96 mM and 1.24 mM, respectively. The morphological structures of PWNs treated by punicalagin 1 were greatly changed. These physiological effects of punicalagin 1 on PWN may helpful to elucidate its nematicidal mechanism.

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