Chemical Composition and Biological Activities of Essential Oils from Peels of Three Species.

Background: Fruit peels are generally underutilized byproducts of the food industry, although they are valuable sources of bioactive compounds. The aim of this study is to evaluate a new application for three peel EOs as bio-herbicides.

Methods: After a micro-morphological evaluation of peels by SEM analysis, the phytochemical composition of the EOs of Risso & Poit., Raf., and (L.) Osbeck was characterized by GC/FID and GC/MS analyses. The in vitro phytotoxicity against germination and initial radical elongation of several crop and weed species was evaluated. Furthermore, the eco-compatibility of these EOs has been assessed by the brine shrimp () lethality assay.

Results: SEM analysis highlighted the morphometric differences of the schizolysigenous pockets among the peels of the three species. Oxygenated monoterpenes are the main constituents in (51.09%), whereas monoterpene hydrocarbons represent the most abundant compounds in (82.15%) and (80.33%) EOs. They showed marked and selective phytotoxic activity in vitro, often at very low concentration (0.1 μg/mL) against all plant species investigated, without showing any toxicity on , opening the perspective of their use as safe bio-herbicides.