Optimization of Baccharis punctulata volatile oil isolation extraction for enhanced yield of trypanocidal compounds

This study examines how storage conditions affect the volatile oil composition of Baccharis punctulata, to enhance the yield of trypanocidal sesquiterpenes. Oils extracted from fresh leaves and inflorescences appear yellow, while those extracted from stored material turn green, primarily due to guaiazulene formation. Short drying periods enhance yields of shyobunone and verboccidentafuran (15.33% and 10.93%, respectively), while longer storage times reduce these compounds, and increase oxidation products such as caryophyllene oxide and spathulenol. Female plants in the flowering stage are the best source, with a 4-h hydrodistillation yielding optimal results. In biological assays of the isolated oil components, caryophyllene oxide showed the highest trypanocidal activity (IC₅₀ = 1.62 µg/mL, SI = 45.28), followed by spathulenol (IC₅₀ = 15.91 µg/mL), verboccidentafuran (IC₅₀ = 20.71 µg/mL) and shyobunone (IC₅₀ = 30.28 µg/mL). These findings emphasize the need to identify the best source and to refine isolation methods to obtain pure compounds that ensure reproducible trypanocidal activity.