Azorean Cryptomeria japonica immature female cones essential oil: Effect of hydrodistillation fractionation on the chemical composition and in vitro antifungal activity against Thielaviopsis paradoxa

ABSTRACT: Cryptomeria japonica’s wood production in Azores generates large amounts of underutilized biomass residues, such as immature female cones (Az–CJIFC), that can be used to produce essential oils (EOs). Hydrodistillation (HD) can be used both to obtain and to fractionate EOs. In this study, EOs from Az–CJIFC, grinded (GR) and non grinded (NGr) fresh samples, were obtained via HD over 4 h, yielding 1.0 % and 0.5 %, w/w, respectively. Thus, GR Az–CJIFC was chosen to obtain six EO fractions (Frs. 1–6), collected at sequential HD timeframes (HDTs: 0–2, 2–10, 10–30, 30–60, 60–120, and 120–240 min). The obtained EO samples (crude EOs and fractions) were evaluated for their chemical composition (GC–FID/GC–MS analyses) and antifungal activity (micro-atmosphere method) against phytopathogenic fungi (Penicillium italicum, P. digitatum and Thielaviopsis paradoxa). Results indicated that all samples were active only towards T. paradoxa, however, with a differential efficacy, due to their specific composition. Fraction 4 vapor treatment displayed the strongest activity, but lower than that of (–)-terpinen-4-ol, a key oxygen-containing monoterpene (OCM) of Az–CJIFC EO, peaking its concentration in Fr3 (14.5 %) and Fr4 (13.8 %). This latter fraction was the richest in the OCM α-terpineol (a minor Az–CJIFC EOs’ component). On the other hand, Frs.1–3 and EOs were dominated by monoterpene hydrocarbons (65.0–96.5 %), mainly α-pinene (19.0–28.4 %) and sabinene (19.9–50.5 %), while Frs.5 and 6 were the richest in oxygen containing sesquiterpenes (47.1–70.8 %; chiefly elemol plus α-, β- and γ-eudesmol) and diterpene hydrocar bons (5.2–6.4 %; mostly phyllocladene). In conclusion, new high value-added products can now be targeted in Az–CJIFC EO by adjusting the HDT, with potential importance in pineapple fruit black rot disease management caused by T. paradoxa on Ananas comosus in the Azores, and also contributing for the local C. japonica’s EO industry development and sustainable circular bio-economy