Ammar Rebai Ben, Bouhlel Ines, Valenti Kita, Sghaier Mohamed Ben, Kilani Soumaya, Mariotte Anne-Marie, Dijoux-Franca Marie-Geneviève, Laporte François, Ghedira Kamel, Chekir-Ghedira Leila
Unité de Pharmacognosie/Biologie Moléculaire 99/UR/07-03, Faculté de Pharmacie/Médecine Dentaire de Monastir, Rue Avicenne 5000 Monastir, Tunisie.
Chem Biol Interact. 2007 Jul 20;168(3):171-83. doi: 10.1016/j.cbi.2007.04.002. Epub 2007 Apr 13.
The ability of three Rhamnus alaternus leaves extracts on antigenotoxic and gene expression level effects was respectively investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37 and in human K562 lymphoblast cell line. Total oligomers flavonoids (TOF) enriched, methanol and ethyl acetate extracts were prepared from powdered R. alaternus leaves and characterized quantitatively for the presence of polyphenolic compounds. We explored the response to oxidative stress using the transcriptional profile of genes in K562 cells stressed with H2O2 after incubation with plant extracts. For this purpose, we used a cDNA microarrays containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair genes. Analysis revealed that SOD1, AOE 372, TXN genes involved in the antioxidant defense system and XPC, LIG4, POLD2, PCNA genes implied in the DNA repair system were among the most expressed ones in the presence of the tested extracts. These results were in accordance with those obtained when we tested the antigenotoxic and antioxidant effects of the same extracts with, respectively the SOS chromotest and the xanthine/xanthine oxidase enzymatic assay system. The effect of the tested extracts on SOS response induced by both Aflatoxin B1 (AFB1: 10 microg/assay) and nifuroxazide (20 microg/assay) showed that the TOF extract exhibited the highest antimutagenic level towards the indirect mutagen AFB1. Whereas ethyl acetate extract showed the highest antimutagenic effect towards the direct mutagen, nifuroxazide. None of the tested extracts induced mutagenic activity. However all the tested extracts exhibited xanthine oxidase inhibiting and superoxide anions scavenging effects. R. alaternus extracts contain compounds with significant antioxidant and antigenotoxic activities. These compounds modulate gene expression as detected by using cDNA arrays.
分别在细菌检测系统（即大肠杆菌PQ37的SOS显色试验）和人K562淋巴母细胞系中研究了三种鼠李叶提取物在抗基因毒性和基因表达水平方面的作用。从鼠李叶粉末中制备了富含总寡聚体黄酮类化合物（TOF）的提取物、甲醇提取物和乙酸乙酯提取物，并对其中多酚类化合物的含量进行了定量表征。在用植物提取物孵育后，我们利用H2O2应激的K562细胞中基因的转录谱来探究其对氧化应激的反应。为此，我们使用了一个包含82个与细胞防御相关基因的cDNA微阵列，这些基因主要由抗氧化和DNA修复基因组成。分析表明，参与抗氧化防御系统的SOD1、AOE 372、TXN基因以及参与DNA修复系统的XPC、LIG4、POLD2、PCNA基因是在受试提取物存在时表达量最高的基因之一。这些结果与我们分别用SOS显色试验和黄嘌呤/黄嘌呤氧化酶酶促试验系统检测相同提取物的抗基因毒性和抗氧化作用时所获得的结果一致。受试提取物对黄曲霉毒素B1（AFB1：10微克/试验）和硝呋恶唑（20微克/试验）诱导的SOS反应的影响表明，TOF提取物对间接诱变剂AFB1表现出最高的抗诱变水平。而乙酸乙酯提取物对直接诱变剂硝呋恶唑表现出最高的抗诱变作用。所有受试提取物均未诱导诱变活性。然而，所有受试提取物均表现出黄嘌呤氧化酶抑制和超氧阴离子清除作用。鼠李提取物含有具有显著抗氧化和抗基因毒性活性的化合物。如通过cDNA阵列检测所示，这些化合物可调节基因表达。
