Arruda Filipe, Lima Ana, Wortham Tanner, Janeiro Alexandre, Rodrigues Tânia, Baptista José, Rosa José S, Lima Elisabete
Institute of Agricultural and Environmental Research and Technology (IITAA), University of the Azores, 9700-042 Angra do Heroísmo, Portugal.
Department of Biology (DB), Faculty of Science and Technology, University of the Azores, 9500-321 Ponta Delgada, Portugal.
Plants (Basel). 2024 Jun 22;13(13):1729. doi: 10.3390/plants13131729.
wood industry generates large amounts of foliage biomass residues. Due to the increasing applications and markets for essential oils (EOs), fresh Azorean foliage (Az-CJF) residues are used for local EO production. Hydrodistillation (HD), a common process for obtaining EOs, also provides the possibility to fractionate them. Thus, this study evaluated the in vitro antimicrobial and antioxidant activities of six Az-CJF 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), in comparison to the crude EO, obtained from a non-fractionated HD (0-240 min HDT). Antimicrobial activities were assessed via disc diffusion method against seven bacteria (foodborne and/or human pathogens) and two spp. (phytopathogenic fungi), and antioxidant activity was estimated using DPPH and ABTS assays. Concerning the antibacterial activity, all the EO samples were effective only toward Gram-positive bacteria. Fractions 1-3 (<30 min HDT) were the most active, with growth inhibition zones (GIZ) of 7.0-23.3 mm (1.4-2.2 times higher than those of the crude EO), being spp. ( and ) the most sensitive, followed by and Regarding the antifungal activity, Frs. 1-3 also displayed the best activities, but only against (GIZ around 9.0 mm), while the crude EO showed no antifungal activity. Overall, the best antimicrobial properties of Frs. 1-3 could be attributed, at least in part, to their highest content in α-pinene and bornyl acetate. On the other hand, Frs. 4-6 (>30 min HDT) exhibited the strongest antioxidant activities (EC values: 1.5-2.3 and 1.0-1.7 mg mL for DPPH and ABTS, respectively), being at least 1.3-fold higher than those of the crude EO. The presence of nezukol, elemol, and eudesmol isomers could strongly contribute to the best free radical scavenging properties of Frs. 4-6. In conclusion, HD was found to be an efficient process for obtaining new Az-CJF EO fractions with variable and enhanced bioactivities due to their differential composition, as assessed using GC-MS. Hence, these findings could contribute to increasing the commercial potential of the EO industry, namely, the Fr2 and Fr6, which presented the most significant activities and can have potential applications in the food, medical, and agriculture sectors.
木材工业产生大量的树叶生物质残渣。由于香精油（EOs）的应用和市场不断增加，新鲜的亚速尔群岛树叶（Az-CJF）残渣被用于当地的香精油生产。水蒸馏法（HD）是获取香精油的常用方法，也提供了对其进行分馏的可能性。因此，本研究评估了在连续水蒸馏时间段（HDTs：0-2、2-10、10-30、30-60、60-120和120-240分钟）收集的六种Az-CJF香精油馏分（馏分1-6）的体外抗菌和抗氧化活性，并与从未分馏的水蒸馏（0-240分钟HDT）中获得的粗制香精油进行比较。通过纸片扩散法评估了对七种细菌（食源性病原体和/或人类病原体）和两种真菌（植物致病真菌）的抗菌活性，并使用DPPH和ABTS测定法估计了抗氧化活性。关于抗菌活性，所有香精油样品仅对革兰氏阳性菌有效。馏分1-3（<30分钟HDT）活性最强，生长抑制圈（GIZ）为7.0-23.3毫米（比粗制香精油高1.4-2.2倍），其中[具体菌种1]和[具体菌种2]最敏感，其次是[具体菌种3]和[具体菌种4]。关于抗真菌活性，馏分1-3也表现出最佳活性，但仅对[具体真菌]有效（GIZ约为9.0毫米），而粗制香精油没有抗真菌活性。总体而言，馏分1-3的最佳抗菌性能至少部分可归因于其α-蒎烯和乙酸龙脑酯的含量最高。另一方面，馏分4-6（>30分钟HDT）表现出最强的抗氧化活性（DPPH和ABTS的EC值分别为1.5-2.3和1.0-1.7毫克/毫升）），比粗制香精油至少高1.3倍。nezukol、榄香醇和桉叶油醇异构体的存在可能极大地促进了馏分4-6最佳的自由基清除性能。总之，水蒸馏法被发现是一种有效的方法，可以获得具有不同且增强的生物活性的新Az-CJF香精油馏分，这是由于它们通过气相色谱-质谱法评估的不同组成。因此，这些发现有助于提高香精油产业的商业潜力，特别是馏分2和馏分6，它们表现出最显著的活性，并且在食品、医疗和农业领域可能具有潜在应用。
