High Value-Added Application of Natural Plant Products in Crop Protection: Construction and Pesticidal Activities of Piperine-Type Ester Derivatives and Their Toxicology Study

Abstract

To discover new potential pesticide candidates, recently, structural modification of natural bioactive products has received much attention. In this work, a series of new piperine-type ester derivatives were regio-and stereoselectively synthesized based on a natural alkaloid piperine isolated from Piper nigrum. Their structures were characterized by IR, mp, 1 H NMR ( 13 C NMR), and high-resolution mass spectrometry (HRMS). Against Tetranychus cinnabarinus Boisduval (Acari: Tetranychidae), compounds 4e, 4f, 4u, and 4v displayed the most significant acaricidal activity with LC 50 values of 0.155, 0.117, 0.177, and 0.164 mg/mL, respectively. Particularly, compound 4f showed >120-fold higher acaricidal activity than piperine (LC 50 : 14.198 mg/mL). Notably, the acaricidal activity of 4f was equivalent to that of the commercial acaricide spirodiclofen (LC 50 : 0.115 mg/mL). Additionally, against Eriosoma lanigerum Hausmann (Hemiptera: Aphididae), compounds 4w and 4b′ showed 1.8-fold aphicidal activity of piperine. Furthermore, via the scanning electron microscope (SEM) imaging method, the obvious destruction of the construction of the cuticle layer of 4f-treated T. cinnabarinus was observed. Compound 4f could be further studied as a lead acaricidal agent.

Exploration of Synergistic Pesticidal Activities, Control Effects and Toxicology Study of a Monoterpene Essential Oil with Two Natural Alkaloids

“…There were lots of white spots destroyed by T. urticae on the seedling leaves in the CK-treated group, whereas in the MT/OMT (3/7)-and MT/OMT (3/7)/CN-treated groups, almost no small white spots were on the seedling leaves. These findings were the same as our previous report [58]. Photographs of control effects of those complexes against T. urticae are shown in Figures S4-S6.…”

“…Then, Petri dishes were placed in a light incubator (temperature: 26 ± 1 • C; RH: 60-80%; photoperiod: light/dark = 14/10 h). Finally, the dead mites were collected at 24, 48 and 72 h after treatment by the complex for scanning electron microscope (SEM) analysis [56,58].…”

Synthesis of Piperine-Based Ester Derivatives with Diverse Aromatic Rings and Their Agricultural Bioactivities against Tetranychus cinnabarinus Boisduval, Aphis citricola Van der Goot, and Eriosoma lanigerum Hausmann

“…Notably, their acaricidal activities were more potent than those of 7-oxycarbonylandrographolide, cholesterol, and osthole ester/amide derivatives [ 38 , 41 , 45 , 46 ]. When compared with our previous results [ 48 ], it suggested that introduction of the CH 2 between the phenyl/4-Fphenyl/4-Clphenyl and the carbonyl groups was very important for the acaricidal activity. Later, to obtain good acaricidal agents, R as the different substituted benzyl should be considered.…”

“…Obviously, it suggested that introduction of the furan-2-ylcarbonyloxymethylene group at the C-2 position of compound 1 was very important for aphicidal activity against E. lanigerum . Based on our previous results [ 48 ], it demonstrated that introduction of the CH 2 between the (un)substituted phenyl and the carbonyl groups was not necessary for aphicidal activity against E. lanigerum .…”

“…After 48 h ( Figure 5 E,H), the sectional cuticles of the 9 -treated group were assembled into masses; additionally, the crests of 11 -treated mites partially disappeared. After 72 h, the crests of mite cuticles of the 9 - and 11 -treated groups ( Figure 5 F,I) all appeared broken and rough and their surfaces were accompanied by the characteristics of collapsed and lacunal symptoms [ 48 , 49 ].…”