Center for Pharmaceutical Sciences, Faculty of Life Science and Technology, Kunming University of Science and Technology, Chenggong Campus, Kunming, 650500, China.
State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China.
J Ethnopharmacol. 2023 Aug 10;312:116493. doi: 10.1016/j.jep.2023.116493. Epub 2023 Apr 11.
Lemon myrtle (Backhousia citriodora F.Muell.) leaves, whether fresh or dried, are used traditionally in folk medicine to treat wounds, cancers, skin infections, and other infectious conditions. However, the targets and mechanisms related to anti-cancer effect of lemon myrtle are unavailable. In our study, we found that the essential oil of lemon myrtle (LMEO) showed anti-cancer activity in vitro, and we initially explored its mechanism of action.
We analyzed the chemical compositions of LMEO by GC-MS. We tested the cytotoxicity of LMEO on various cancer cell lines using the MTT assay. Network pharmacology was used also to analyze the targets of LMEO. Moreover, the mechanisms of LMEO were investigated through scratch assay, flow cytometry analysis, and western blot in the HepG2 liver cancer cell line.
LMEO showed cytotoxicity on various cancer cell lines with values of IC 40.90 ± 2.23 (liver cancer HepG2 cell line), 58.60 ± 6.76 (human neuroblastoma SH-SY5Y cell line), 68.91 ± 4.62 (human colon cancer HT-29 cell line) and 57.57 ± 7.61 μg/mL (human non-small cell lung cancer A549 cell line), respectively. The major cytotoxic chemical constituent in LMEO was identified as citrals, which accounted for 74.9% of the content. Network pharmacological analysis suggested that apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1), androgen receptor (AR), cyclin-dependent kinases 1 (CDK1), nuclear factor erythroid 2-related factor 2 (Nrf-2), fatty acid synthase (FASN), epithelial growth factor receptor (EGFR), estrogen receptor 1 (ERα) and cyclin-dependent kinases 4 (CDK4) are potential cytotoxic targets of LMEO. These targets are closely related to cell migration, cycle and apoptosis. Notley, the p53 protein had the highest confidence to co-associate with the eight common targets, which was further confirmed by scratch assay, flow cytometry analysis, and western blot in the HepG2 liver cancer cell line. LMEO significantly inhibited the migration of HepG2 cells in time-dependent and dose-dependent manner. Moreover, LMEO caused a S-phase blocking on HepG2 cells and promoted apoptosis in the meanwhile. Western blot results indicated that p53 protein, Cyclin A2 and Bax proteins were up-regulated, while Cyclin E1 and Bcl-2 proteins were down-regulated.
LMEO showed cytotoxicity in various cancer cell lines in vitro. Pharmacological networks showed LMEO to have multi-component and multi-targeting effects that are related to inhibit migration of HepG2 cells, and affect cell cycle S-phase arrest and apoptosis through modulation of p53 protein.
柠檬桉（Backhousia citriodora F.Muell.）叶，无论是新鲜的还是干燥的，传统上都被用于民间医学来治疗伤口、癌症、皮肤感染和其他传染病。然而，柠檬桉的抗癌作用的相关靶点和机制尚不清楚。在我们的研究中，我们发现柠檬桉精油（LMEO）在体外具有抗癌活性，并且我们初步探索了其作用机制。
我们通过 GC-MS 分析了 LMEO 的化学成分。我们使用 MTT 测定法测试了 LMEO 对各种癌细胞系的细胞毒性。网络药理学也用于分析 LMEO 的靶点。此外，我们还通过划痕实验、流式细胞术分析和 Western blot 在 HepG2 肝癌细胞系中研究了 LMEO 的作用机制。
LMEO 对各种癌细胞系表现出细胞毒性，IC 50 值分别为 0.90 ± 2.23（肝癌 HepG2 细胞系）、58.60 ± 6.76（人神经母细胞瘤 SH-SY5Y 细胞系）、68.91 ± 4.62（人结肠癌细胞 HT-29 细胞系）和 57.57 ± 7.61μg/mL（人非小细胞肺癌 A549 细胞系）。LMEO 中的主要细胞毒性化学成分为柠檬醛，占含量的 74.9%。网络药理学分析表明，APEX1、雄激素受体（AR）、细胞周期蛋白依赖性激酶 1（CDK1）、核因子红细胞 2 相关因子 2（Nrf-2）、脂肪酸合酶（FASN）、表皮生长因子受体（EGFR）、雌激素受体 1（ERα）和细胞周期蛋白依赖性激酶 4（CDK4）是 LMEO 的潜在细胞毒性靶点。这些靶点与细胞迁移、周期和凋亡密切相关。p53 蛋白与八个共同靶点的关联置信度最高，这一点在 HepG2 肝癌细胞系中的划痕实验、流式细胞术分析和 Western blot 中得到了进一步证实。LMEO 以时间和剂量依赖的方式显著抑制 HepG2 细胞的迁移。此外，LMEO 导致 HepG2 细胞的 S 期阻滞并同时促进凋亡。Western blot 结果表明，p53 蛋白、Cyclin A2 和 Bax 蛋白上调，而 Cyclin E1 和 Bcl-2 蛋白下调。
LMEO 在体外对各种癌细胞系表现出细胞毒性。药物网络表明，LMEO 具有多成分、多靶点的作用，通过调节 p53 蛋白，抑制 HepG2 细胞的迁移，影响细胞周期 S 期阻滞和凋亡。
