Essential Oil Composition From Cryptomeria japonica D.Don Grown in Azores: Biomass Valorization From Forest Management

Abstract

Cryptomeria japonica biomass was obtained monthly from forest lumbering operations at São Miguel, Terceira and Pico (Azores), between May 2018 and June 2020. C japonica stands with different ages (2 to ±50 years), grown in different soil types (lithosol and andosol) and at different altitudes (200 to >800 m) were used. The chemical composition of 118 C japonica essential oil (EO) samples, plus 1 sample from an EO solid deposit, were analyzed by gas chromatography and gas chromatography–mass spectrometry. Chemical composition cluster analysis showed 2 clusters, cluster I and II, with no chemical correlation. Cluster I grouped all 117 EO samples that resulted from extraction of branches and foliage with, or without, strobili, from strobili, and from the solid deposit sample. Cluster II grouped the 2 samples of EO isolated from wood, with a markedly different composition. Cluster I showed 5 subclusters (Ia-Ie). The degree of chemical correlation between the samples in these subclusters varied between moderate (subclusters Id and Ie), high (subclusters Ib and Ic), and very high (subcluster Ia). Of the 119 samples, 94 (79% of the total) were included in subcluster Ia, with 66 samples from São Miguel, 2 from Terceira, and 26 from Pico, showing a yield range from 0.1% to 0.4% (v/w). All these samples, with a high chemical correlation, were obtained by steam distillation from branches and foliage with, or without, female or male strobili, or both. This subcluster did not show any grouping pattern regarding the collection month, the altitude (200 to >800 m), the soil type (lithosol, andosol, or its subtypes), or the wood age (±30 to ±50 years). Subcluster Ia was characterized by the dominance of α-pinene (13%-43%), sabinene (5%-25%), phyllocladene (2%-22%), limonene (2%-16%), kaurene (traces-13%), elemol (1%-11%), and terpinen-4-ol (1%-7%). The determination of the concentration limits of the EOs representative components confirmed the homogeneity of C japonica EO, obtained from plant material collected in the 3 Azores islands, despite the variability in the range of some diterpenes that deserves further study. This study allowed for the determination of the concentration limits of the EOs representative components, with the purpose of adding value to C japonica EO, obtained from forest lumbering.