The aromatic ginger Kaempferia galanga L. (Zingiberaceae) essential oil and its main compounds are effective larvicidal agents against Aedes vittatus and Anopheles maculatus without toxicity on the non-target aquatic fauna

Kaempferia galangal L. (Zingiberaceae), also known as aromatic ginger, is used in the food and cosmetics, pharmaceuticals and maquillage materials, as well as in the traditional Indian medicine. The essential oil (EO) obtained from its rhizome by hydrodistillation is of economic interest and contains ethyl p-methoxycinnamate as the main component, which is used as an anticancer, antimicrobial, skin protector and whiteneing and nema- ticidal agent. To our knowledge, the mosquitocidal properties of the aromatic ginger EO have hitherto been poorly investigated. Therefore, in the present work, we tested this EO and its major chemical constituents (MCCs), namely ethyl p-methoxycinnamate, trans-ethyl cinnamate and trans-cinnamaldehyde for their larval toxicity on Aedes vittatus and Anopheles maculatus. The EO chemical composition, studied by GC-MS analysis, was made up of 39 compounds, with ethyl p-methoxycinnamate (30.6%), trans-ethyl cinnamate (26.8%) and trans- cinnamaldehyde (11.5%) as the major constituents. The EO and its MCCs showed LC50 values of 39.22, 10.36, 28.26 and 36.35 μg/ml on Ae. vittatus, and of 41.36, 12.56, 30.23 and 38.47 μg/ml on An. maculatus third instar larvae, respectively. The ecofriendliness of EO and MCCs on the aquatic fauna was demonstrated as they were safe to Anisops bouvieri, Acilius sulcatus and Gambusia affinis. Our findings showed that the K. galanga rhizome EO and its MCCs are promising larvicidal agents without affecting non-target organisms (NTOs). They also give news insights into the potential economic exploitation of this EO and its MCCs in the fabrication of effective and eco- friendly mosquitocidal formulations.