Essential oil of Daucus carota (L.) ssp. carota (Apiaceae) flower: chemical composition, antimicrobial potential, and insecticidal activity on Sitophilus oryzae (L.).

Abstract

In order to search for new chemotypes and to carry out a comparative study with the literature, the current study investigated the chemical composition of the essential oil of the flowers of Daucus carota (L.) ssp. carota using gas chromatography coupled with mass spectrometry (GC-MS). Moreover, the antimicrobial and insecticidal potentials of essential oil were studied. Hydrodistillation was used to extract the essential oil. Due to the immiscibility of essential oils in water and, therefore, in the culture medium, emulsification was carried out using a 0.2 % agar solution to promote germ/composite contact. Fumigation with the oil phase of the essential oil was carried out in airtight and transparent plastic boxes, with a capacity of 1 L as an exposure chamber to test the lightness of essential oils against adults of Sitophilus oryzae (L.). In each box, five Petri dishes were placed. Each replicate consisted of five adults of S. oryzae (L.). The essential oils were spread on Wathman filter paper and placed inside the exposure chamber. Mortality control was carried out by counting insect deaths from the first day of treatment until the death of all individuals. α-Pinene (22.2 %) was the major compound in the essential oil of the oil phase of D. carota (L.) ssp. carota followed by β-asarone (15.1 %), sabinene (12.4 %), and α-himachalene (10.1 %), as well as the crystallized phase containing β-asarone. In terms of antimicrobial activity, the essential oils showed significant inhibition of the six bacteria and seven molds studied at a concentration of 0.45 mg/mL. The essential oils were found to be highly effective against S. oryzae (L.). This approach can help reduce the amount of synthetic antibiotics applied and, therefore, decrease the negative impact of artificial agents, such as residues, resistance, and environmental pollution.