Sweet basil (Ocimum basilicum L.), a well-known medicinal and aromatic herb, rich in essential oils and antioxidants (contributed by phenolics), is widely used in traditional medicine. The biosynthesis of phytochemicals occurs via different biochemical pathways, and the expression of selected genes encoding enzymes involved in the formation of phenolic compounds is regulated in response to environmental factors. The synthesis of the compounds is closely interrelated: usually, the products formed in the first reaction steps are used as substrates for the next reactions. The current study attempted a comprehensive overview of the effect of aromatic amino acid composition (AAAs) in Ocimum basilicum in respect to the expression of genes related to the biosynthesis of phenolic compound and their content. The transcript expression levels of EOMT, PAL, CVOMT, HPPR, C4L, EGS, and FLS increased depending on the AAAs concentration compared to the control plants. The highest mRNA accumulation was obtained in EOMT, FLS, and HPPR in the leaves of sweet basil. The expression of the TAT gene in the leaves significantly reduced in response to all AAAs applications compared to untreated groups and it had the lowest transcript accumulation. Eleven individual phenolic compounds were determined in the basil leaves, and the contents of chicoric acid, methyl chavicol, caffeic acid, and vanillic acid increased depending on administered concentration to control (p < 0.05). Additionally, AAAs lead to an incremental change in the amount of chlorogenic acid at 50 and 100 mg kg⁻¹ compared to control plants (p < 0.05). Rutin and rosmarinic acid were detected as the main phenolic compounds in all experimental groups of sweet basil in terms of quantity. However, their amount significantly decreased as compared to control plants based on the increase in AAAs concentrations (p < 0.05). Also, the accumulation of cinnamic acid, eugenol, and quercetin did not significantly change in the leaves of AAAs treated plants compared to control (p < 0.05). When AAAs was applied, total flavonoid content increased in all treatments compared to the control plants, but total phenolic content did not change significantly (p < 0.05). To the best of our knowledge, our work is the first detailed work to evaluate in detail the impact of AAAs on individual phenolic compounds at the phytochemistry and transcriptional levels in the O. basilicum plant. For a detailed understanding of the whole mechanism of phenolic compound regulation, further research is required to fill in some gaps and to provide further clarification.

罗勒 ( Ocimum basilicum L.) 是一种著名的药用和芳香草本植物，富含精油和抗氧化剂（由酚类物质提供），广泛用于传统医学。植物化学物质的生物合成通过不同的生化途径发生，编码参与酚类化合物形成的酶的选定基因的表达受到环境因素的调节。化合物的合成密切相关：通常，在第一个反应步骤中形成的产物用作下一个反应的底物。目前的研究试图全面概述罗勒 中芳香族氨基酸组成（AAAs）的影响。关于酚类化合物生物合成相关基因的表达及其含量。与对照植物相比， EOMT、PAL、CVOMT、HPPR、C4L、EGS和FLS的转录物表达水平随 AAAs 浓度的增加而增加。在甜罗勒叶的EOMT、FLS和HPPR中获得了最高的mRNA积累。TAT的表达与未处理组相比，叶片中的基因在响应所有 AAAs 应用时显着降低，并且其转录物积累最低。罗勒叶中测定了 11 种单独的酚类化合物，菊苣酸、甲基菊苣酚、咖啡酸和香草酸的含量随给药浓度的增加而增加（p  < 0.05）。此外，与对照植物（^p < 0.05)。在甜罗勒的所有实验组中，从数量上都检测到芦丁和迷迭香酸是主要的酚类化合物。然而，基于 AAAs 浓度的增加，与对照植物相比，它们的数量显着减少 ( p  < 0.05)。此外，与对照相比，AAAs 处理的植物叶片中肉桂酸、丁子香酚和槲皮素的积累没有显着变化 ( p  < 0.05)。施用 AAAs 后，各处理总黄酮含量均高于对照，但总酚含量无显着变化 ( p < 0.05)。据我们所知，我们的工作是第一个详细评估 AAAs 在O. basilicum植物的植物化学和转录水平上对单个酚类化合物的影响的详细工作。为了详细了解酚类化合物调控的整个机制，需要进一步的研究来填补一些空白并提供进一步的澄清。