The present study aims to evaluate the antibacterial properties of natural products according to a pharmacodynamic approach in order to propose them as alternatives to synthetic products. Two essential oils (Cinnamomum cassia and Origanum compactum) were the subject of the chemical and biological study. First, we evaluated the sensitivity of the strains of avian Salmonella to the main antibiotics used and then to the chromatographic analysis of the composition of the two essential oils (EO); finally, we proceeded to the in vitro evaluation of the antibacterial activities of these EO (alone and in combination with antibiotics). The results obtained showed that carvacrol (35.2%), followed by γ-terpinene (20.1%), was the main constituent of the essential oil of O. compactum while cinnamaldehyde (69.1%) represents the major component of the essential oil of C. cassia. The antibioresistance profile of the Salmonella tested showed resistance to ampicillin (35%) and oxytetracycline (41.3%). Active products extracted from the essential oils studied showed antibacterial activity against Salmonella strains. C. cassia products were shown to be more active for Salmonella enteritidis (average inhibition diameter: 16.3 mm) and for Salmonella gallinarum (average inhibition diameter: 27.7 mm). The best synergistic activity with antibiotics has been obtained with the essential oil of C. cassia and its active product cinnamaldehyde. The minimum inhibitory concentration (MIC) of cinnamaldehyde is the lowest (0.05%). The results prove the presence of an antibacterial activity and a synergistic effect of two essential oils studied with the main antibiotics.

中文翻译：

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摩洛哥栽培的两种芳香植物（肉桂和牛至）精油的化学成分和抗菌活性

本研究旨在根据药效学方法评估天然产品的抗菌特性，以提出它们作为合成产品的替代品。两种精油（肉桂和牛至）是化学和生物研究的主题。首先，我们评估了禽沙门氏菌菌株对所用主要抗生素的敏感性，然后对两种精油 (EO) 的成分进行色谱分析；最后，我们继续对这些 EO（单独和与抗生素联合使用）的抗菌活性进行体外评估。所得结果表明香芹酚 (35.2%) 和 γ-萜品烯 (20.1%) 是 O. compactum 精油的主要成分，而肉桂醛 (69. 1%) 代表肉桂精油的主要成分。所测试沙门氏菌的抗生物性曲线显示对氨苄青霉素 (35%) 和土霉素 (41.3%) 具有抗性。从所研究的精油中提取的活性产品显示出对沙门氏菌菌株的抗菌活性。肉桂产品对肠炎沙门氏菌（平均抑制直径：16.3 毫米）和鸡沙门氏菌（平均抑制直径：27.7 毫米）的活性更高。使用肉桂精油及其活性产物肉桂醛获得了与抗生素的最佳协同活性。肉桂醛的最低抑菌浓度（MIC）最低（0.05%）。结果证明了抗菌活性的存在和两种精油与主要抗生素的协同作用。