A simple, robust, and precise method for the absolute quantification of the terpenes α-pinene, camphene, β-pinene, 3-carene, limonene, bornyl acetate, β-caryophyllene, and borneol was developed using gas chromatography coupled to a flame ionization detector (GC-FID) and validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use. The GC-FID method shows high accuracy (91–105%) and low imprecision (< 7.6%) for all terpenes at quality control (QC) low, medium, and high level. The curves are linear with strong correlation (R 2 ≥ 0.999) for all terpenes. Additionally, the relative response factor (RRF) for each terpene is calculated. The method was validated in terms of specificity, linearity, accuracy, precision, LOD, LOQ, stability tests, and carry-over. The method was successfully applied to quantify the selected terpenes in conifer-derived essential oils (CEOs). The total amount of terpenes ranged from 6.3 to 11.8 mM. Additionally, the CEOs were screened in vitro for the antibacterial activity against E. coli and S. aureus using the broth microdilution method to determine the minimum inhibitory concentration (MIC). All the CEOs showed antibacterial activity in the concentration from 0.3 to 50 μg/mL ( S. aureus ) and 1.2 to 50 μg/mL ( E. coli ), respectively. CEO14 showed the most effective antibacterial activity of the entire tested CEOs (MIC values 0.3 μg/mL ( S. aureus ); 1.2 μg/mL ( E. coli )). Our results suggest that the terpenoid profile should be considered for a comprehensive evaluation of the antibacterial activity, as none of the single compounds seems to be fully responsible for antibacterial activity.

中文翻译：

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针叶树精油中萜烯的绝对定量及其抗菌活性

使用气相色谱与火焰电离联用开发了一种简单、可靠且精确的方法，用于对萜烯 α-蒎烯、蒎烯、β-蒎烯、3-蒎烯、苎烯、醋酸冰片、β-石竹烯和冰片进行绝对定量检测器 (GC-FID) 并根据国际人用药物技术要求协调委员会进行验证。GC-FID 方法在质量控制 (QC) 低、中和高水平的所有萜烯中均显示出高精度 (91–105%) 和低不精密度 (< 7.6%)。所有萜烯的曲线都是线性的，具有很强的相关性 (R 2 ≥ 0.999)。此外，还计算了每个萜烯的相对响应因子 (RRF)。该方法在特异性、线性、准确度、精密度、LOD、LOQ、稳定性测试和残留方面进行了验证。该方法已成功应用于量化针叶树衍生精油 (CEO) 中选定的萜烯。萜烯的总量在 6.3 到 11.8 mM 之间。此外，还使用肉汤微量稀释法对 CEO 进行了体外抗大肠杆菌和金黄色葡萄球菌的抗菌活性筛选，以确定最低抑菌浓度 (MIC)。所有CEO分别在0.3至50 μg/mL（金黄色葡萄球菌）和1.2至50 μg/mL（大肠杆菌）浓度范围内表现出抗菌活性。CEO14 在整个测试 CEO 中表现出最有效的抗菌活性（MIC 值 0.3 μg/mL（金黄色葡萄球菌）；1.2 μg/mL（大肠杆菌））。我们的结果表明，应考虑萜类化合物对抗菌活性的综合评价，