During a screening program for new agrochemicals from Chinese medicinal herbs, the ethanol extract of Notopterygium incisum rhizomes is found to possess strong nematicidal activity against the two species of nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita . Based on bioactivity-guided fractionation, the four constituents are isolated from the ethanol extract and identified as Columbianetin, Falcarindiol, Falcarinol, and Isoimperatorin. Isoimperatorin also has LC ₅₀ values of 21.83 μg/mL against B. xylophilus . When using 15 min UV light treatment, falcarindiol, falcarinol, and isoimperatorin demonstrated almost five times more toxic to the southern root-knot nematodes than in dark treatment while columbianetin showed only two times more toxic. isoimperatorin has been demonstrated to possess insecticidal activity against several insects, such as the cabbage aphid ( Brevicoryne brassicae ). Isoimperatorin is identified in the active fraction of Angelica dahurica (AD) extract. Isoimperatorin is usually used as the internal standard (IS).