Phyto-inspired cyclic peptides derived from plant Pin-II type protease inhibitor reactive center loops for crop protection from insect pests.

•Cyclization of Pin-II Reactive center loop peptides mimics bi-domain plant PIs.•Bicyclic peptides show ten-fold enhanced inhibition potency compared to linear tripeptides.•Bicyclic peptides exhibit insect deterrent and antibiosis activity in bio-assay on leaves.•Bi-domain cyclic peptides interact with multiple sites on trypsin.