Effects of postharvest UV-C irradiation on essential oils from leaves of Piper aduncum L. for industrial and medicinal use

Piper aduncum L. is a species known for its medicinal and pharmacological properties, cultivated due to commercial and industrial interest, especially in the production of essential oils (EOs). To explore its potential, the present study aimed to evaluate the post-harvest impact of UV-C irradiation on the metabolic profile of EOs from fresh leaves of P. aduncum cultivated in Southeastern Brazil, during different storage periods. Fresh leaves were exposed to controlled UV-C light irradiation in a chamber for 60, 120, 240, and 360 min. Subsequently, the EOs were extracted by hydrodistillation in a modified Clevenger apparatus and analyzed using GC. A non-irradiated sample was included as a control for comparison. The results revealed alterations in the relative percentage of specific chemical constituents, including arylpropanoids and sesquiterpenes, after UV-C irradiation. Remarkably, the relative percentage of the arylpropanoid dillapiole, a compound of high commercial value, increased significantly by threefold after exposure to UV-C radiation, ranging from 26.81 % (not irradiated) to 95.60 % (360 min of irradiation). This study indicates that exposure to UV-C radiation in freshly harvested P. aduncum leaves may be a promising technique for enriching the dillapiole content in the EO, with potential commercial applications and large-scale industry use.