Chemical Characterization and Bioactivity of Commercial Essential Oils and Hydrolates Obtained from Portuguese Forest Logging and Thinning

Abstract

Essential oils (EOs) and hydrolates (Hds) are natural sources of biologically active ingredients with broad applications in the cosmetic industry. In this study, nationally produced (mainland Portugal and Azores archipelago) EOs (11) and Hds (7) obtained from forest logging and thinning of Eucalyptus globulus, Pinus pinaster, Pinus pinea and Cryptomeria japonica, were chemically evaluated, and their bioactivity and sensorial properties were assessed. EOs and Hd volatiles (HdVs) were analyzed by GC-FID and GC-MS. 1,8-Cineole was dominant in E. globulus EOs and HdVs, and α- and β-pinene in P. pinaster EOs. Limonene and α-pinene led in P. pinea and C. japonica EOs, respectively. P. pinaster and C. japonica HVs were dominated by α-terpineol and terpinen-4-ol, respectively. The antioxidant activity was determined by DPPH, ORAC and ROS. C. japonica EO showed the highest antioxidant activity, whereas one of the E. globulus EOs showed the lowest. Antimicrobial activity results revealed different levels of efficacy for Eucalyptus and Pinus EOs while C. japonica EO showed no antimicrobial activity against the selected strains. The perception and applicability of emulsions with 0.5% of EOs were evaluated through an in vivo sensory study. C. japonica emulsion, which has a fresh and earthy odour, was chosen as the most pleasant fragrance (60%), followed by P. pinea emulsion (53%). In summary, some of the studied EOs and Hds showed antioxidant and antimicrobial activities and they are possible candidates to address the consumers demand for more sustainable and responsibly sourced ingredients.

Antioxidant Activity of Essential Oils from Pinaceae Species

“…A variety of positive controls were used: ascorbic acid [ 47 , 52 , 58 , 70 , 71 , 72 , 73 , 74 ], alpha-tocopherol [ 45 , 52 , 64 , 75 , 76 , 77 ], BHA [ 45 , 55 , 74 , 78 , 79 ], BHT [ 42 , 44 , 45 , 54 , 58 , 67 , 76 , 78 , 80 , 81 ], beta-caryophyllene [ 64 ], caryophyllene oxide [ 64 ], quercetin [ 42 ], tannic acid [ 82 ], gallic acid [ 60 , 83 ], thymol [ 84 ], and even Thymus vulgaris essential oil [ 62 ].…”

“…The following methods were used only once or in a small number of cases: The superoxide radical inhibition based on the autooxidation of pyrogallol [ 88 ]; The superoxide radical scavenging based on nitroblue tetrazolium reduction [ 70 , 111 ]; The method based on 3-morpholino-sydnonimine and 1-keto-4-methylthiobutyric acid (SIN-1—KMB) [ 112 ]; The Fenton system [ 113 ] proposed for use in the antioxidant assessment by Halliwell and Gutteridge (1985) [ 114 ]; The method based on 1-aminocyclopropane-1-carboxylic acid (ACC) fragmentation induced by HOCl (hypochlorous acid) [ 112 ]; The ferric–phenanthroline assay (Phen assay) based on the ability of ferric ions to form a complex with phenanthroline [ 115 ]; The Rancimat method, developed by Hadorn and Zurcher in the 1970s (in a publication in the German language [ 116 ]), established itself as one of the most widely utilized accelerated techniques for assessing the oxidative stability of fats and fat-containing foods [ 117 , 118 ]; A method based on the xanthine/xanthine oxidase system [ 112 ]; A method based on the NADH/diaphorase system [ 112 ]; Two methods based on the impact of the EO on catalase and glutathione reductase [ 119 ]; The phosphomolybdenum method (total antioxidant capacity (TAC) assay) [ 64 ]; The Folin–Ciocâlteu method of quantifying total phenolics [ 43 ]; The 20,70-dichlorofluorescein diacetate probe to estimate the intracellular antioxidant activity in the human keratinocytes HaCaT cell line [ 73 ]. …”

“…The 20,70-dichlorofluorescein diacetate probe to estimate the intracellular antioxidant activity in the human keratinocytes HaCaT cell line [ 73 ].…”

“…The results between different labs are often not negligible for the same comparator using the same endpoint. For ascorbic acid using the DPPH method, for instance, the following IC 50 values have been reported (we converted mg/mL to μg/mL): 1.75 ± 0.69 μg/mL [ 70 ], 2.0 ± 0.13 [ 85 ], 3.27 μg/mL [ 47 ], 5.0 ± 0.4 μg/mL [ 101 ], 6.25 μg/mL [ 71 ], 11.5 μg/mL [ 72 ], 19.0 ± 1.1 μg/mL [ 69 ], 22.61 ± 1.08 [ 97 ], 40 ± 110 μg/mL [ 73 ], 46.54 ± 3.64 μg/mL [ 52 ], 53.24 ± 3.25 [ 59 ], 54 μg/mL [ 74 ], and 84 ± 63 μg/mL [ 99 ]. How do we use such a variety of values spanning almost two orders of magnitude?…”

Natural Products: Therapeutic Properties and Beyond II

“…There has been a growing interest from different industries such as pharmaceuticals, cosmetics, and food, in using essential oils, mainly due to their biological properties, such as antifungal, antibacterial, and antioxidant activities. Ruas et al [ 15 ] studied nationally produced (mainland Portugal and the Azores archipelago) essential oils and hydrolates obtained from forest logging and the thinning of Eucalyptus globulus , Pinus pinaster , Pinus pinea , and Cryptomeria japonica . Some of the essential oils and hydrolates showed relevant antioxidant and antimicrobial properties.…”