Seasonal variation, yield composition and biological activities of essential oils from Lantana camara grown in Côte d’Ivoire

Lantana camara is a thorny shrub that goes from 2 to 5 m high. Its ripe fruits are blackish and its flowers are in various colors. It is used in traditional medicine to treat several diseases and has numerous properties that were chemically described such as antioxidant, antibacterial and cytotoxic activities.
The aim of this work was to study the variations in L. camara essential oils composition during the vegetative cycle. Leaves, flowers, fruits and stems of L. camara were harvested in Bingerville (East Côte d'Ivoire) each month from June 2015 to June 2017. The essential oil was produced by hydrodistillation and then analyzed by GC-MS and RMN. The antioxidant, anti-inflammatory and insecticidal activities of leaf and flowers essential oils were also determined.
Results showed that essential oils hydrodistillated from L. camara are dominated by sesquiterpenes such as β-caryophyllene and α-humulene. Some monoterpenes such as thymol, sabinene and α-pinene were also present. The oil yield was high during the flowering and fruiting period. According to the chemical composition of L. camara’s oil, there were no significant differences between both harvesting periods defined but there were significant differences from one organ to another. However, within one organ the chemical composition varies under the vegetative cycle. It was found that the proportion of thymol was higher during flowering and fruiting months. The essential oil of stems, flowers, and fruits were more concentrated in thymol than leaf’s oil. E-β-caryophyllene and α-humulene were found in all essential oils. However, their quantity and the thymol content were strictly inverted throughout the harvest period or vegetative cycle. In addition, the essential oil extracted from leaves and flowers of L. camara showed good antioxidant, anti-inflammatory and insecticidal activities.