The scientific community is paying increasing attention to plant waste valorization, and also to “greener” practices in the agriculture, food and cosmetic sectors. In this context, unused forest biomass (e.g., leaves, seed cones, branches/twigs, bark and sapwood) of Cryptomeria japonica, a commercially important tree throughout Asia and the Azores Archipelago (Portugal), is currently waste/by-products of wood processing that can be converted into eco-friendly and high added-value products, such as essential oils (EOs), with social, environmental and economic impacts. Plant-derived EOs are complex mixtures of metabolites, mostly terpenes and terpenoids, with valuable bioactivities (e.g., antioxidant, anti-inflammatory, anticancer, neuroprotective, antidepressant, antimicrobial, antiviral and pesticide), which can find applications in several industries, such as pharmaceutical, medical, aromatherapy, food, cosmetic, perfumery, household and agrochemical (e.g., biopesticides), with manifold approaches. The EOs components are also of value for taxonomic investigations. It is known that the variation in EOs chemical composition and, consequently, in their biological activities and commercial use, is due to different exogenous and endogenous factors that can lead to ecotypes or chemotypes in the same plant species. The present paper aims to provide an overview of the chemical composition, biological properties and proposals of valorization of C. japonica EO from several countries, and also to indicate gaps in the current knowledge.

Azorean Cryptomeria japonica is widely used for local wood production, generating large amounts of aerial-part biomass residues that can be a sustainable source of value-added bioproducts. This comparative study aimed (i) to determine the yield and chemical profile of the essential oils (EOs) extracted by hydrodistillation from Azorean C. japonica foliage, leaves, male cones (MCs), and female cones (FCs), and (ii) to investigate the antimicrobial and brine shrimp lethality (BSL) effects of the obtained EOs and some major components. The EOs yield revealed a wide range (ca. 1–3%, w/d.w.) and their chemical composition, analysed by GC–MS and GC–FID, showed the presence of seventy-one components. Monoterpene hydrocarbons (38–71%) dominated in all the studied EOs, mainly α-pinene (17–45% of total EOs), decreasing as follows: cone EOs > leaf EOs > foliage EOs. Oxygen-containing monoterpenes (mainly terpinen-4-ol) also dominated in cone EOs. Contrariwise, oxygen-containing sesquiterpenes (mainly elemol) and diterpene hydrocarbons (mainly phyllocladene) dominated in foliage/leaf EOs. The studied EOs exhibited activity against Gram-positive bacteria but no activity against Gram-negative bacteria. A similar trend was displayed by α-pinene. Only the cone EOs showed antifungal activity against Penicillium chrysogenum, but this was significantly lower than those of α-pinene and terpinen-4-ol. Moreover, FC EO should also be considered for further investigation due to its high toxicity on BSL bioassay. In conclusion, this study demonstrated the variability of yield, chemical profile, and bioactivities in the EOs from different parts of the Azorean C. japonica, expanding the knowledge of the potentialities of C. japonica aerial-part EOs, particularly the ones from the cone samples.

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.

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This study reports on the in vivo molluscicidal activity and Artemia salina lethality of Azorean Cryptomeria japonica leaf (CJL) essential oils (EOs) obtained by hydrodistillation (HD) and water-steam distillation (WSD) techniques, especially in light of the recent focus on the use of forestry and wood industry residues in a sustainable world economy. Molluscicidal activity was performed during several life stages of Radix peregra by the immersion method, under laboratory conditions. A first screening through a single-dose bioassay revealed that both EOs were highly active towards eggs, juveniles and adult snails (ca. 100% mortality). Concentration- and time-toxicity assays were carried out only on adult snails to determine the lethal parameters (LC50;90 and LT50;90). The LC50 values were 33 and 62 µg/mL for EO–WSD and EO–HD, respectively, after 48 h. The LT50 of EO–WSD required only 21 h for both 16 h and continous exposure periods, while that of EO–HD was slighty superior (21.8–25.6 h). Although not significant, EO–WSD was also slightly more toxic against A. salina than EO–HD (LC50 = 98 and 115 µg/mL after 24 h, respectively). In conclusion, Azorean CJL EOs, which are rich in α-pinene (mostly EO–WSD), have huge potential to be used as safe raw materials for the development of natural molluscicide products to control snails responsible for transmitting fascioliasis.