Seasonal and geographical variation in the chemical composition of essential oil from Allophylus edulis leaves

Abstract

Allophylus edulis (Sapindaceae), also known as “chal-chal”, “vacuum” or “cocu”, is a tree widely found in Brazil whose leaves are still used in folk medicine and are rich in essential oil. The focus of this research was to investigate the chemical composition profiles of the essential oil from A. edulis leaves collected seasonally (the four seasons) in two cities. The A. edulis leaves were collected in winter (July) and spring (November) 2018 and summer (January) and autumn (May) 2019, in the cities of Bonito and Dourados, in the state of Mato Grosso do Sul, Brazil. The essential oils were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS). The essential oil yield in this seasonal variation study consistently ranged between 0.07% and 0.6% (wet wt.) for all samples, increasing considerably with higher temperature and during the inflorescence stage. In the oil samples obtained from Dourados, the major components present were α-pinene, caryophyllene oxide, and viridiflorol with yields of 3.04–29.81% across all four seasons, being caryophyllene oxide the most abundant (20.1–29.81%). The major compound identified in the oil samples obtained from Bonito was α-zingiberene for all four seasons, though its concentrations were highest in summer (46.90%) and spring (45.05%). The chemical composition profiles of both cities’ oil samples were similar, in that they shared four sesquiterpene compounds, caryophyllene oxide, germacrene D, E-caryophyllene and viridiflorol. The study highlighted that both seasonal and geographical variation can influence the chemical composition of essential oil from A. edulis.