Effect of Leaf Drying and Collection Site on the Yield and Spectral Fingerprint of Cinnamomum zeylanicum Blume Leaf Essential Oil from Two Ecuadorian Localities

Introduction/Objective Essential oils from Cinnamomum zeylanicum Blume show relevant bioactive properties; however, their yield and chemical profile are sensitive to biomass conditioning and collection site. This study evaluated the effect of leaf state (fresh vs. dried) and collection site in Ecuador — Puyo (928 m a.s.l.) and Santo Domingo de los Tsáchilas (705 m a.s.l.) — on the yield and spectral fingerprint of hydrodistilled leaf essential oil. Methods A balanced 2 2 factorial design was applied (n = 3 independent distillations per cell). Essential oil was extracted by Clevenger-type hydrodistillation adapted from ISO 6571, with NaCl salting-out and Na 2 SO 4 dehydration. Yield was expressed both on an as-distilled basis and on a dry-matter basis, so that fresh and dried leaves could be compared on the same mass reference. FTIR (4000–550 cm -1 , 4 cm -1 resolution) and UV–Vis spectroscopy (200–400 nm) were used as qualitative fingerprinting tools. Yield data were analyzed by two-way ANOVA with interaction, followed by Tukey's HSD (α = 0.05). Results When expressed on an as-distilled basis, drying increased the apparent yield at both sites: Puyo from 1.01 ± 0.03% to 1.57 ± 0.05% and Santo Domingo from 1.20 ± 0.04% to 1.35 ± 0.04%. When yields were recalculated on a dry-matter basis (moisture loss on drying = 61.47%), the direction reversed: fresh leaves gave more oil per unit dry matter (Puyo 2.62 ± 0.08%; Santo Domingo 3.11 ± 0.10%) than dried leaves (1.57% and 1.35%, respectively). This shows that the apparent increase with drying reflects moisture concentration rather than a real gain in recoverable oil. In the as-distilled data, leaf state explained ~73% of the variability, with a significant site × condition interaction (~24%). FTIR and UV–Vis fingerprints differed qualitatively between fresh and dried leaves and between sites, mainly in the oxygenated and conjugated regions. Discussion Expressed on a dry-matter basis, oven drying at 60°C was associated with a net reduction in recoverable oil per unit of dry matter, consistent with the loss of volatile constituents during thermal conditioning. The site × condition interaction indicates that this reduction differed between provenances. FTIR and UV–Vis provided complementary fingerprints but do not identify or quantify individual constituents. Conclusion Leaf state is the main driver of the measured yield, while collection site modulates its magnitude. Reporting yield on a dry-matter basis is needed to avoid misreading the effect of drying, and both parameters should be stated when comparing extracts.