Larvicidal Activity of Constituents Identified in Piper nigrum L. Fruit Against the Diamondback moth, Plutella xylostella

The larvicidal activities of Piper nigrum fruit methanol extracts and its constituents against larvae of the diamondback moth, Plutella xylostella, were investigated using the leaf dipping method. Administering the P. nigrum methanol extract resulted in 100 and 97% mortality against diamondback moth larvae at 5.0 and 2.5 mg/mL concentrations, respectively. Larvicidal activities of the P. nigrum fruit-derived piperidine alkaloids, piperine, and N-isobutylamide, as well as pellitorine, guineensine, pipercide, and retrofractamide A against P. xylostella varied according to test compound. Based on the 48 h $LC_{50}$ values, the most toxic compound to diamondback moth larvae was guineensine (0.013 mg/mL) followed by retrofractamide A (0.020mg/mL), pipercide (0.033mg/mL), and pellitorine (0.046 mg/mL). The $LC_{50}$ value of piperine was >0.5 mg/mL.

후추 열매 유래 화합물들의 배추좀나방 유충에 대한 살충 활성

잎침지법을 이용하여 후추 열매 메탄올 추출물 및 분리된 화합물들의 배추좀나방(Plutellaxylostella) 유충에 대한 살충 활성을 검정하였다. 후추 열매 메탄올 추출물은 배추좀나방 유충에 대해 5.0과 2.5 mg/mL 농도에서 각각 100%와 97%의 살충 활성을 보였다. 후추 열매에서 유래된 화합물들의 배추좀나방에 대한 살충 활성을 조사한 결과, guineensine ($LC_{50}$=0.013 mg/mL)의 살충 활성이 가장 높았으며, 다음으로 retrofractamide A (0.020 mg/mL), pipercide (0.033 mg/mL) 그리고 pellitorine (0.046 mg/mL) 순이었다. Piperine의 반수치사농도는 0.5 mg/mL 이상이었다.