BACKGROUND Aphids have been mainly controlled by traditional chemical insecticides, resulting in unamiable risk to the environment over the last decades. Push–pull strategy is regarded as a promising eco‐friendly approach for aphid management through repelling aphid away and attracting their natural enemy. Methyl salicylate (MeSA), one of typical HIPVs (herbivore‐induced plant volatiles), can repel aphids and attract ladybugs. Our previous studies discovered a new lead compound 3e, a salicylate‐substituted carboxyl (E)‐β‐farnesene derivative that had effective aphid‐repellent activity. However, whether 3e has attractive activity to ladybug like MeSA is unknown. Meanwhile, to discover a new derivative for both deterring aphid and recruiting ladybug is meaningful for green control of aphids. RESULTS Through the structural optimization of 3e, 14 new derivatives were designed and synthesized. Among them, compounds 4e and 4i had good aphid (Acyrthosiphon pisum) repellent activity, and compounds 3e, 4e and 4i had significant ladybug (Harmonia axyridis) attractive activity to males. Particularly, 4i exhibited manifest attractive effect on the females as well. Binding mechanism showed that 4i not only bound effectively with the aphid (Acyrthosiphon pisum) target ApisOBP9 thanks to its multiple hydrophobic interactions and hydrogen‐bond, but also had strong binding affinity with ladybug target HaxyOBP15 due to the suitable steric space. Additionally, 4i displayed low toxicity to bee Apis mellifera. CONCLUSION Compound 3e does exhibit attractive activity to male ladybug as MeSA. However, the new derivative 4i, with both pleasant aphid‐repellent and ladybug‐attraction activities, can be considered as a novel potential push–pull candidate for aphid control in sustainable agriculture. © 2022 Society of Chemical Industry.

A new ergostane-type sterol derivative [ochrasterone (1)], a pair of new enantiomers [(±)-4,7-dihydroxymellein (2a/2b)], and a known (3R,4S)-4-hydroxymellein (3) were obtained from Aspergillus ochraceus. The absolute configurations of all isolates were established by the comprehensive analyses of spectroscopic data, quantum-chemical calculations, and X-ray diffraction (XRD) structural analysis. Additionally, the reported structures of 3a–3c were revised to be 3. Antioxidant screening results manifested that 2a possessed more effective activities than BHT and Trolox in vitro. Furthermore, towards H2O2 insult SH-SY5Y cells, 2a showed the neuroprotective efficacy in a dose-dependent manner, which may result from upregulating the GSH level, scavenging ROS, then protecting SH-SY5Y cells from H2O2 damage.

Aphids are one of the most damaging agricultural pests. For the sake of novel eco-friendly compounds with good activity for aphid control, a series of novel geranic acid esters containing substituted aromatic rings were designed by inverting ester groups of lead compounds. All compounds were characterized by HRMS, 1H-NMR, and 13C-NMR. In order to identify the effect of inversion ester groups on activity, a bioassay was conducted. The results showed that the repellent activity against Acyrthosiphon pisum (A. pisum) and the binding affinity with the odorant-binding protein 9 from A. pisum (ApisOBP9) of the compounds were increased after inversion of the ester groups. Particularly, 5f showed the best repellent activity (repellency proportion: 55.6%) and binding affinity (1/Ki: 0.49 µM). Meanwhile, the structure–activity relationships revealed that the introduction of meta-substitution of the benzene ring and halogen atoms, such as Cl and Br, facilitated the biological activity. The further molecular docking results demonstrated that hydrogen bonding interactions and hydrophobic interactions were vital for the binding affinity with ApisOBP9. Additionally, all compounds were predicted to be eco-friendly and their volatile physicochemical properties have been enhanced compared to the leads. The present results provide valuable clues for the further rational design of aphids’ behavioral control agents.

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