Chemical Stability of the Stem Bark Essential oil of Artabotrys jollyanus Pierre (Annonaceae) Throughout the Phenological Cycle in Côte d’Ivoire

Abstract

This study evaluated the temporal stability of the stem bark essential oil of Artabotrys jollyanus Pierre (Annonaceae) throughout a complete phenological cycle in Côte d’Ivoire. Stem bark was collected monthly for 12 months from the same individual plant, and essential oils were obtained by hydrodistillation using a Clevenger-type apparatus. The oils were analysed by gas chromatography, gas chromatography–mass spectrometry and carbon-13 nuclear magnetic resonance spectroscopy. Fifty-two constituents, comprising 19 monoterpenes and 33 sesquiterpenes, were identified and represented 88.0–92.3% of the total composition. Oil yields ranged from 0.04% to 0.13%. The samples were dominated by sesquiterpenes, particularly trans-calamenene (18.9–27.6%), 7-hydroxycalamenene (8.7–25.1%) and α-copaene (6.7–10.4%). Although the relative proportions of individual compounds varied among sampling months, the main qualitative profile remained broadly consistent across the annual cycle. Comparison with the previously characterised leaf oil indicated a shared sesquiterpene chemotype but organ-related differences in constituent abundance, with the stem bark oil containing higher mean proportions of trans-calamenene and 7-hydroxycalamenene and a lower extraction yield. These findings provide baseline information on the composition and month-to-month stability of A. jollyanus stem bark essential oil. Confirmation across multiple plants and locations is required before the observed stability can be generalised to the species level.