Citrus Research Institute, Southwest University, Chongqing, People's Republic of China.
National Citrus Engineering Research Center, Chongqing, People's Republic of China.
Drug Des Devel Ther. 2021 May 14;15:2047-2058. doi: 10.2147/DDDT.S304624. eCollection 2021.
Lemon peel, a traditional Chinese medicine, was tested in this study for its novel application in inhibiting cellular oxidative stress, and the effect of lemon peel extract (LPE) on protecting H9c2 rat heart cells from oxidative stress was investigated.
The scavenging effects of LPE on 1,1-diphenyl-2-picryhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radicals were measured in extracellular experiments. The 3-(4,5-dimethyl-2-thiazolinyl)-2,5-diphenyl-2-h-tetrazolylammonium bromide (MTT) assay was used to detect the cell survival rate. The cell supernatant and intracellular oxidation-related indicators were detected by a kit, and the mRNA expression in H9c2 cells was detected by quantitative polymerase chain reaction (qPCR). The chemical substances of LPE were analyzed by high-performance liquid chromatography (HPLC).
The results showed that LPE exhibited better DPPH and ABTS free radical scavenging abilities than vitamin C. Compared with the cells in the normal state (control group), the cell survival rate in the model group decreased, and the level of lactate dehydrogenase (LDH) increased, the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) decreased, and the content of malondialdehyde (MDA) increased. Compared with the control group, the expression of Bcl-2-related X protein (Bax), caspase-3, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in the model group was increased, and the expression of B-cell lymphoma-2 (Bcl-2) was reduced. Compared with the model group, LPE treatment improved the cell survival rate, reduced the levels of LDH and MDA, increased the levels of SOD, CAT, and GSH, downregulated the expression of Bax, caspase-3, Nrf2 and HO-1, and upregulated the expression of Bcl-2. The composition analysis showed that LPE contained catechin, rutin, naringin, quercetin, and hesperidin.
The results indicated that LPE could protect H9c2 cells from oxidative stress through five active components. LPE has the potential to be developed into natural medicine or health food for the inhibition of cell oxidative damage.
本研究旨在探索传统中药柠檬皮在抑制细胞氧化应激方面的新应用，考察柠檬皮提取物（LPE）对氧化应激状态下人 H9c2 心肌细胞的保护作用。
采用体外实验方法，测定 LPE 对 1,1-二苯基-2-苦基肼基（DPPH）自由基和 2,2'-联氮-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基的清除作用。采用 MTT 法检测细胞存活率。试剂盒检测细胞上清液和细胞内氧化相关指标，实时荧光定量聚合酶链式反应（qPCR）检测 H9c2 细胞中 mRNA 的表达。采用高效液相色谱法（HPLC）分析 LPE 的化学成分。
结果表明，LPE 对 DPPH 和 ABTS 自由基的清除能力优于维生素 C。与正常状态（对照组）下的细胞相比，模型组细胞存活率降低，乳酸脱氢酶（LDH）水平升高，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽（GSH）水平降低，丙二醛（MDA）含量增加。与对照组相比，模型组 B 细胞淋巴瘤-2 相关 X 蛋白（Bax）、半胱氨酸天冬氨酸蛋白酶-3（caspase-3）、核因子红细胞 2 相关因子 2（Nrf2）和血红素加氧酶-1（HO-1）的表达增加，B 细胞淋巴瘤-2（Bcl-2）的表达减少。与模型组相比，LPE 处理可提高细胞存活率，降低 LDH 和 MDA 水平，增加 SOD、CAT 和 GSH 水平，下调 Bax、caspase-3、Nrf2 和 HO-1 的表达，上调 Bcl-2 的表达。成分分析表明，LPE 含有儿茶素、芦丁、柚皮苷、槲皮素和橙皮苷。
结果表明，LPE 可通过 5 种活性成分保护 H9c2 细胞免受氧化应激，具有开发成为抑制细胞氧化损伤的天然药物或保健品的潜力。
