Environmentally-safe scCO2 P. pinaster branches extracts: Composition and properties

Abstract

Considering the vast array of compounds that plants manufacture that help protect them against insects’ attacks, plant raw materials are a potential source of future insecticides/larvicides. In this work, volatiles from maritime pine (Pinus pinaster) branches, a pruning residue, were extracted by supercritical carbon dioxide (scCO2), and also by hydrodistillation for comparison purposes. The volatiles naturally emitted from the pine branches were identified as well. Experimental design results showed higher extraction yields (up to 6%), when scCO2 density and temperature increased, while the inverse occurred for total phenolic contents (1.2–3.3% GAE, gallic acid equivalents). Emitted volatiles from the branches were mainly α-pinene, β-pinene, β-myrcene, limonene, and β-caryophyllene. In general, the volatile profiles of the scCO2 and hydrodistillation extracts were quite similar, revealing abietadiene, the precursor of abietic acid, as the main compound. Oxidation inhibitions of ∼42 – 59% were obtained for the scCO2 extracts in the β-carotene assay. The acetylcholinesterase inhibitory activity assay revealed the potential of these extracts to have insecticidal/larvicidal activity, with IC50 values of 2.8–10.7 mg/mL. Overall, these extracts may be applied in environmentally-safe insect/larvae control strategies, in formulations that benefit from the presence of antioxidants.