Recovery of bioactive products from industrial hemp (Cannabis sativa L.) waste: CBD-rich essential oils and eco-friendly biopesticides

The essential oil from hemp (Cannabis sativa L.) byproducts represents a niche product for the pharmaceutical, nutraceutical, cosmetic and agrochemical industries. Its composition can be properly modulated on an industrial level by optimizing the extractive conditions and sample pretreatment. This allows to achieve high concentrations of bioactive compounds, such as cannabidiol (CBD) and (E)-caryophyllene which exert documented anti-inflammatory, anticancer, immunomodulatory and antinociceptive effects. In the present work, we evaluated the effects of type of distillation apparatus, status of conservation of the plant material, grinding and sample-pretreatment with microwave and heat, on the chemical profile of hemp essential oil obtained from cv. Felina 32. Furthermore, moving from the concept that hemp essential oil has evolved as a natural weapon against phytophagous insects, we assayed its potential as a botanical insecticide. The oil was tested against the filariasis vector Culex quinquefasciatus, the peach-potato aphid Myzus persicae, the housefly Musca domestica and the tobacco cutworm Spodoptera littoralis. To prove its harmlessness on non-target invertebrates, it was tested on the multicolored Asian lady beetle, Harmonia axyridis, and Eisenia foetida earthworms and compared with cypermethrin as the positive control. Overall, results give new insights into the exploitation of hemp essential oil in pharmaceuticals, nutraceuticals and cosmetics. Moreover, they shed light on the possible utilization of the crop residue of industrial hemp as a source of botanical insecticides.