Temporal dynamics of essential oil production in Piper divaricatum leaves: monthly seasonal variation in a brazilian Cerrado-Amazon Transition Zone

The production of essential oils (EOs) in aromatic plants can be influenced by seasonal variations, as abiotic factors directly affect the biosynthetic pathways and accumulation of secondary metabolites. This study aimed to evaluate the influence of seasonality on the content and yield of EO extracted from leaves of Piper divaricatum Jacq. (Piperaceae). Leaf samples were collected monthly between October 2020 and September 2021 from native individuals located near the Salú Stream, in the municipality of Tangará da Serra, Mato Grosso, Brazil. The EO was extracted by hydrodistillation using a modified Clevenger apparatus, with a 4-hour distillation period per sample. The highest EO contents were recorded in January (1.29%), March (1.06%), April (1.22%), and September (1.12%) of 2021. The highest yield was obtained in January (253.18 µL/100 g of fresh plant material). Correlation analyses revealed positive associations between EO content/yield and temperature (r = 0.11), precipitation (r = 0.17), solar radiation (r = 0.41), and relative humidity (r = 0.53). However, only relative humidity showed statistically significant correlations with both EO content (r = 0.53) and yield (r = 0.60). These findings demonstrate that seasonality significantly affects EO production in P. divaricatum, highlighting January, March, April, and September as the most favorable months for obtaining higher volumes of essential oil under tropical conditions.