Abstract: The total alkaloids from Pinellia ternata and Sophora alopecuroides along with three main alkaloid monomers(i.e.,sophoridine,oxymatrine and oxysophocarpine) from S.alopecuroides were firstly screened for their antinematodal activity in this study.After 24 h of treatment,the total alkaloid of P.ternata showed antinematodal activity with the median inhibitory concentration(IC₅₀) values of 16.18,20.25,33.24 and 20.77 μg/mL on the nematodes Bursaphelenchus xylophilus, Meloidogyne incognita, Panagrellus redivivus and Caenorhabditis elegans, respectively.Similarly,the total alkaloid of S.alopecuroides showed antinematodal activity with IC₅₀ values of 0.622,0.383,1.476 and 1.224 μg/mL on B.xylophilus, M.incognita, P.redivivus and C.elegans, respectively.The total alkaloid of S.alopecuroides showed either stronger antinematodal activity than the positive control avermectin or similar activity to it.Three alkaloid monomers from S.alopecuroides all showed their obviously antinematodal activity.Among them,oxysorphocarpine exhibited the strongest activity.The results provided the support data for the development of plant-derived antinematodal agents.

Key words: alkaloids;oxysophocarpine;antinematodal activity;Pinellia ternata, Sophora alopecuroides, Bursaphelenchus xylophilus, Meloidogyne incognita