Cyclic Acetals as Novel Long-Lasting Mosquito Repellents

Discovery of novel skeletons of aphid repellents based on the key fragment of nepetalactone and plant volatiles

BACKGROUND

Aphids are significant agricultural pests, causing extensive crop damage and transmitting plant viruses. Conventional insecticide-based pest control faces challenges such as human and environmental toxicity and resistance. As alternative solutions, pheromone-based repellents have emerged as a promising approach. However, the instability of key compounds like (E)-β-Farnesene (EBF) has limited their effectiveness in field applications. To address these limitations, this study focuses on developing novel aphid repellent compounds based on plant volatiles and nepetalactone key fragments.

RESULTS

In this study, a series of derivatives were designed and synthesized from the lead compound (±)I by incorporating plant volatiles, leading to the discovery of two novel compounds with new skeletons, IV-13 and IV-4. Through further modifications of the ring size and the alkyl substitutions, two optimized structures, compounds IV-30 and IV-36, were identified, demonstrating promising aphid repellent activities. Bioassays indicated that IV-30 (RV = 85.2%) and IV-36 (RV = 70.3%) exhibited significantly enhanced repellent properties compared to their precursor compounds. Molecular docking studies revealed strong binding interactions of these compounds with aphid odorant-binding protein 3(OBP3), providing further evidence of their improved biological efficacy.

CONCLUSION

The introduction of novel structures such as compounds IV-30 and IV-36 based on nepetalactone and plant volatile fragments resulted in the discovery of novel promising para-pheromones for aphid control. These compounds exhibit stable and effective repellent activities, providing a solid foundation for further development of synthetic aphid repellents in integrated pest management strategies. © 2025 Society of Chemical Industry.

Association of N, N-diethyl-m-toluamide (DEET) with arthritis among adult participants

BACKGROUND

N, N-diethyl-m-toluamide (DEET), an active ingredient prevalent in insect repellents, has its effects on human health under ongoing debate and scrutiny.

OBJECTIVE

This study aimed to investigate the association between exposure to DEET and arthritis outcomes within the broader adult demographic, leveraging data obtained from the National Health and Nutrition Examination Survey (NHANES).

METHODS

3-diethyl-carbamoyl benzoic acid (DCBA) was used as a specific indicator of DEET exposure. Drawing on NHANES 2007-2016 data, our study incorporated 7065 adults to examine urinary DCBA impacts on arthritis risks using logistic regression and cubic spline analysis.

RESULTS

Our study included a total of 7065 patients, of which 1860 (26.33%) had arthritis. After adjusting for all covariates, the multivariate logistic regression analysis showed that high DCBA levels (>7.37 ug/L) were associated with an increased likelihood of arthritis (OR: 1.236, 95% CI: 1.037-1.474, p = 0.018). Nevertheless, participants in the highest quartile of DCBA levels (Q4) were associated with a 33.9% decreased risk of rheumatoid arthritis (OR: 0.661; 95% CI: 0.501-0.872; p = 0.003).

CONCLUSION

It was observed that increased levels of DCBA are positively associated with the prevalence of arthritis in the adult population. Conversely, high concentrations of DCBA showed a reverse correlation with the prevalence of rheumatoid arthritis.

Chemical Ecology and Management of Dengue Vectors

Dengue, caused by the dengue virus, is the most widespread arboviral infectious disease of public health significance globally. This review explores the communicative function of olfactory cues that mediate host-seeking, egg-laying, plant-feeding, and mating behaviors in Aedes aegypti and Aedes albopictus, two mosquito vectors that drive dengue virus transmission. Aedes aegypti has adapted to live in close association with humans, preferentially feeding on them and laying eggs in human-fabricated water containers and natural habitats. In contrast, Ae. albopictus is considered opportunistic in its feeding habits and tends to inhabit more vegetative areas. Additionally, the ability of both mosquito species to locate suitable host plants for sugars and find mates for reproduction contributes to their survival. Advances in chemical ecology, functional genomics, and behavioral analyses have improved our understanding of the underlying neural mechanisms and reveal novel and specific olfactory semiochemicals that these species use to locate and discriminate among resources in their environment. Physiological status; learning; and host- and habitat-associated factors, including microbial infection and abundance, shape olfactory responses of these vectors. Some of these semiochemicals can be integrated into the toolbox for dengue surveillance and control.