Drying temperature affects the quantity and quality of the essential oil of Psidium species and contributes to phytotoxicity in model plants

Abstract

The genus Psidium is recognized for its economic value and the species that produce essential oils with notable biological activities. This study investigated the characteristics of the essential oil from the leaves of Psidium myrtoides and Psidium cattleyanum under different drying temperatures. We aimed to understand how drying temperatures affect the yield and composition of the essential oil, as well as its biological activity. The oils obtained from the leaves of P. myrtoides and P. cattleyanum dried in an oven at 40°C showed the highest yields (0.86% and 1.07%, respectively). β-caryophyllene was the major compound in all essential oils of P. myrtoides and P. cattleyanum, except in the oil extracted from P. myrtoides leaves dried at room temperature, where the major compound was α-bisabolol (14.46%). Different phytotoxic effects were observed using the emulsion of these oils in bioassays with Lactuca sativa and Sorghum bicolor, which were associated with the chemical composition and synergy of the identified compounds. The essential oil emulsion from leaves dried at room temperature of both species showed greater phytotoxic activity in the bioassays. Thus, optimizing drying conditions to maximize yield and synergy of compounds from the essential oils of P. myrtoides and P. cattleyanum is an important step in developing environmentally friendly natural agrochemicals.