Storage of Piper umbellatum L. Leaves Interferes with the Quality of the Essential Oil

Resumo

During storage, medicinal plants can undergo undesirable chemical reactions that affect their quality and
effectiveness. In this study, Piper umbellatum leaves were dried and stored for 12 months. The essential oils
(EOs) were extracted and analysed by Gas Chromatography-Mass Spectrometry. During storage, significant
variation was observed in EOs content (0.98-0.10%) and major components, mainly, (E)-caryophyllene
(21.77-8.07%) and germacrene D (26.33-23.45%). The EO lethality test for Artemia salina was used to
evaluate the influence of storage on this biological activity. The lethal concentration (LC50) of the EOs
ranged from 49.73-1100.0 µg mL-1. Multivariate analysis, correlating the EOs contents with chemical
components, proved significant variation of (E)-caryophyllene. From the third month of storage, it was
observed a progressive reduction of essential oil content reaching 89.8% in the twelfth month. In parallel
there was also observed a loss EO lethality for A. salina