Analysis by CPG (IR), CPG-SM, and mosquito repellent effect of essential oils from Ocimum basilicum (Lamiaceae) from Côte D’ivoire

Abstract

The present study aims to determine the chemical composition and antioxidant activity of the essential oil extracted from Ocimum basilicum leaves harvested in Bingerville, as well as to evaluate its repellent effect against Anopheles gambiae. To this end, the essential oil of O. basilicum was obtained by hydrodistillation using a Clevenger-type apparatus, and its chemical composition was analyzed by GC (IR) and GC-MS. The repellent test was conducted in accordance with the World Health Organization guidelines on laboratory testing of chemical repellents. In addition, the antioxidant activity of this essential oil was determined using the DPPH test. The yield obtained for O. basilicum essential oil was 0.5 ± 0.03%. Analysis of the chemical composition of O. basilicum essential oil identified 24 compounds, including three major ones: 1,8 cineole (32.1%), camphor (19.9%) and trans ?-bergamotene (7.8%). With regard to repellent tests on A. gambiae, only the ointment containing 10% essential oil has repellent properties according to WHO standards (average protection P ? 90%). The molecules responsible for the repellent effect that makes these plants so effective are camphor, eucalyptol, linalool, limonene, and myrcene for the essential oil studied. Furthermore, the evaluation of antioxidant activity showed that O. basilicum essential oil exhibits antioxidant power with a CR50 of 1.952 but is less antioxidant than vitamin C.