# Investigation of Essential Oil from Cumin (Cuminum cyminum) Seeds and Selected Terpenes as Repellents Against Adult Female Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) Sand Flies

## TL;DR

This study explores cumin seed essential oil and its compounds as natural, effective repellents against sand flies that transmit Leishmaniasis.

## Contribution

The study is the first to evaluate cumin seed essential oil and cumin aldehyde as potential sand fly repellents.

## Key findings

- Cumin seed essential oil and cumin aldehyde showed strong repellent effects comparable to transfluthrin.
- Repellency effects lasted up to 3 hours at concentrations as low as 0.07 μg/cm² for cumin aldehyde.
- Octanol also demonstrated significant repellent activity against Phlebotomus papatasi.

## Abstract

Leishmaniasis, a disease transmitted by sand flies, remains a major global health concern. While chemical repellents and insecticides are commonly used for protection, their prolonged use has led to reduced efficacy, resistance, and environmental concerns. This study analyzed the chemical composition of cumin seed essential oil (EO) from Greece and tested its repellent properties against the sand fly Phlebotomus papatasi. Gas chromatography–mass spectrometry (GC-MS) identified five major compounds, including cumin aldehyde, β-pinene, and γ-terpinene. The repellency of cumin seed EO, its major constituents, octanol, and 1-octen-3-ol was evaluated alongside the established repellents transfluthrin and DEET. Results showed that cumin seed EO, cumin aldehyde, and octanol demonstrated strong repellency, with effects lasting up to 3 h. Cumin aldehyde exhibited repellent activity comparable to transfluthrin, while knockdown effects were observed at higher concentrations. This study is the first to assess cumin seed EO and cumin aldehyde as potential alternatives to conventional repellents for sand flies.

Leishmaniasis, a parasitic disease transmitted by sand flies, poses a significant global health threat. Chemical repellents and insecticides are widely used for protection, but prolonged use has led to resistance, reduced efficacy, and environmental concerns, emphasizing the need for new repellent compounds, ideally from sustainable sources. This study investigated the chemical composition and repellent properties of cumin seed essential oil (EO) from Greece against Phlebotomus papatasi. Gas chromatography–mass spectrometry (GC-MS) identified five major constituents, including cumin aldehyde (27.0%), β-pinene (11.4%), and γ-terpinene (10.8%). In addition to cumin seed EO and its major constituents, octanol, and 1-octen-3-ol were tested for comparison, along with transfluthrin and DEET as standard repellents. Using a static air repellency bioassay, cumin seed EO, cumin aldehyde, and octanol exhibited strong spatial repellency (EC50 of 0.34, 0.07, and 0.60 μg/cm2 respectively) comparable to transfluthrin (EC50 of 0.04 μg/cm2) at 1 h, and contact repellency, both lasting up to 3 h. This is the first study to evaluate cumin seed EO and cumin aldehyde against sand flies, highlighting their potential as alternatives to conventional repellents. Further research is needed to explore their applicability in vector control strategies.