Essential Oil Variability of Azorean Cryptomeriajaponica Leaves under Different Distillation Methods, Part 1: Color, Yield and Chemical Composition Analysis

Abstract

This study mainly deals with the effect of hydrodistillation (HD) and water-steam distillation (WSD) methods on the color, yield, and chemical profile of the essential oil (EO) from Cryptomeria japonica fresh leaves from São Miguel Island (Azores Archipelago, Portugal). The yields of EO–HD (pale-yellowish) and EO–WSD (colorless) samples were 1.21% and 0.45% (v/w), respectively. The GC–FID, GC–MS, and 13C-NMR analyses of EO–HD vs. EO–WSD revealed (i) a high-content of monoterpenes (72.8% vs. 86.7%), mainly α-pinene (34.5% vs. 46.4%) and sabinene (20.2% vs. 11.6%), and oxygenated mono- and sesquiterpenes (20.2% vs. 9.6%); (ii) similar sesquiterpene (1.6% vs. 1.6%), β-myrcene (5.9% vs. 5.8%), and camphene (3.5% vs. 3.8%) contents; and (iii) significant differences in other classes/components: EO–HD is richer in oxygenated sesquiterpenes (17.1%, mainly elemol (10.4%) and α-eudesmol (3.4%)) and diterpenes (3%; mostly phyllocladene), while EO–WSD is richer in oxygenated monoterpenes (7.2%, mainly terpinen-4-ol (5.4%)), p-cymene (4.4%), and limonene (3.2%). Overall, the color, yield, and quantitative composition of the EO samples studied are strongly influenced by the distillation method. Nonetheless, this C. japonica leaf EO displayed a consistent α-pinene- and sabinene-rich composition. The same chemotype was found in a commercial Azorean C. japonica leaf EO sample, obtained by industrial steam distillation (SD), as well as in Corsica C. japonica leaf EO–HD. Furthermore, the bioactive composition of our EO samples revealed the potential to be used in green plant protection and in the medical, food, cosmetic, and household industries.

Variations in Essential Oil Biological Activities of Female Cones at Different Developmental Stages from Azorean Cryptomeria japonica (Thunb. ex L.f.) D. Don (Cupressaceae)

“…In the Azores, C. japonica is the most important forestry tree, not only because of its economic value, but also because its stands are a determinant element of the Azorean landscape (Figure 1A). Nowadays, about 12,500 hectares of C. japonica plantations are established in the Azores, representing 60% of the total wood-producing forest area [8,9], 66% of which is on São Miguel Island. This conifer species is a very large, conical, evergreen monoecious tree that can reach up to 70 m in height, with a trunk diameter of up to 4 m. Their leaves (needle-shaped), measuring 0.5-1 cm long, are densely spirally arranged, and their male cones (ovoid or ellipsoid) form axillary aggregations on branches near female cones (FC), which are globular, with a terminal distribution on down-curved branchlets with normal leaves, and often arranged in either an aggregated or solitary form (Figure 1B).…”

“…Currently, the main source of biomass for C. japonica EO production in the Azores is the foliage (CJF), which constitutes the bulk of the biomass waste generated by the timber industry and forestry operations. However, it should be noted that the yield, chemical composition, and biological activities of C. japonica EO and, consequently, its specific commercial applications and price, can be significantly influenced by both exogenous and endogenous factors, such as species variety; the geographical region of the plant; environmental abiotic and biotic stresses; plant age; plant parts and their developmental stages; management practices (e.g., harvest period); the post-harvest processing of plant material (e.g., drying); and the extraction process (method and protocol used), among other factors [9,[13][14][15][16]. It should also be highlighted that comparisons of data between different studies are very difficult when different raw materials, processing conditions, extraction protocols, analytical methods, and/or units of measurement were used, among other factors (e.g., experimental conditions of bioassays) [15].…”

“…Nevertheless, all these CJF EO chemotypes present antimicrobial activities (which are mostly related to the individual susceptibility of the tested microorganisms) and/or other biocidal activities (including mosquito larvicidal, acaricidal, termiticidal, molluscicidal, insect repellent properties, and toxicity against brine shrimp nauplii) [13,15] with potential application in IPMP and/or human and other animals' health areas. Many other pharmacological properties of CJF EO samples from several countries have been reported, such as: antimelanogenesis, skin whitening, antitussive, antiulcer, anxiolytic, anti-inflammatory, and antioxidant, among other important bioactivities, namely, neuropharmacological and cancer chemopreventive [9].…”

Bioprospecting essential oils of exotic species as potential mitigations of ruminant enteric methanogenesis

“…The PU and HG are invasive plants introduced in the archipelago in the mid-19th century, for different purposes, originating in Australia and the Himalayas, respectively [ 11 ]). CJ is a tree originally from Japan, introduced in the Azores at the same time, but to wood producing, currently representing 60% of the forest area of the archipelago [ 12 ], being these plants have been the subject of several studies over the last years.…”

“…Previous investigations have already determined the chemical composition and antimicrobial activity of the EO of the invasive species, HG and PU [ 11 ] and more recently in the species C. Japonica [ 12 , 13 ] (, revealing that all these EO have potential as natural biocides, also possessing antimicrobial properties.…”