Leaf extracts from Eugenia punicifolia are rich in pentacyclic triterpenic acids (PTAs), especially barbinervic acid (BA), which is an important biomarker of the species. Dichloromethane extracts of E. punicifolia leaf samples harvested in Amazonian summer and winter seasons were analysed by infrared spectroscopy using ATR-FTIR technique aiming to evaluate barbinervic acid (BA) and its PTAs equivalent contents. A validated HPLC-DAD quantification method was also performed to compare the relationship between BA and PTAs contents in E. punicifolia extracts with ATR-FTIR technique. The use of ATR-FTIR allowed a rapid, efficient and environment-friendly quantification method for total PTAs equivalent content, showing a significant statistical difference (p< 0.05) in the production of these metabolites (38.66 μg/mL, summer; 13.62 μg/mL, winter). A mathematical correction factor between the HPLC-DAD and ATR-FTIR quantification methods was established.
Keywords: Eugenia punicifolia; Pedra-ume caá; barbinervic acid; seasonality.