Jagetia Ganesh Chandra, Venkatesha V A, Reddy Tiyyagura Koti
Department of Radiobiology, Kasturba Medical College, Manipal 576119, India.
Mutagenesis. 2003 Jul;18(4):337-43. doi: 10.1093/mutage/geg001.
Free radicals are responsible for the induction of damage to the cellular DNA that leads to the formation of chromosome aberrations. Antioxidants are known to scavenge free radicals, thereby decreasing the degree of such effects. Radiation is a well-known inducer of free radicals and compounds that can scavenge free radicals may reduce radiation-induced DNA damage. Naringin, a bioflavonoid predominant in grapefruit and other citrus fruits, has been found to scavenge free radicals, therefore it may also reduce radiation-induced damage. The aim of the present study was to evaluate the radioprotective action of 2 mg/kg naringin in the bone marrow of mice exposed to different doses of (60)Co gamma-radiation by scoring the frequency of asymmetrical chromosomal aberrations. The irradiation of mice resulted in a dose-dependent elevation in the frequency of aberrant cells, acentric fragments, chromatid and chromosome breaks, dicentrics and exchanges. All these aberrations were elevated with scoring time up to 24 h post-irradiation and declined thereafter, except chromatid breaks, which were maximum at 12 h post-irradiation. Treatment of mice with 2 mg/kg body wt naringin before exposure to various doses of gamma-radiation resulted in a significant reduction in the frequencies of aberrant cells and chromosomal aberrations like acentric fragments, chromatid and chromosome breaks, centric rings, dicentrics and exchanges. The evaluation of free radical scavenging activity of naringin revealed a dose-dependent scavenging of hydroxyl, superoxide and 2,2 equal to or precedes -diphenyl-1-picryl hydrazyl radical. Naringin at 5 microM scavenged the 2,2-azino-bis-3-ethyl benzothiazoline-6-sulphonic acid cation radical very efficiently, where a 90% scavenging was observed. Our study demonstrates that naringin can protect mouse bone marrow cells against radiation-induced chromosomal damage.
自由基会导致细胞DNA损伤，进而引发染色体畸变。已知抗氧化剂可清除自由基，从而降低此类影响的程度。辐射是一种众所周知的自由基诱导剂，能够清除自由基的化合物可能会减少辐射诱导的DNA损伤。柚皮苷是葡萄柚和其他柑橘类水果中主要的生物类黄酮，已被发现能够清除自由基，因此它也可能减少辐射诱导的损伤。本研究的目的是通过对不对称染色体畸变的频率进行评分，评估2 mg/kg柚皮苷对暴露于不同剂量（60）Coγ辐射的小鼠骨髓的辐射防护作用。对小鼠进行辐射导致异常细胞、无着丝粒片段、染色单体和染色体断裂、双着丝粒体和交换的频率呈剂量依赖性升高。所有这些畸变在照射后24小时内随评分时间升高，此后下降，但染色单体断裂除外，其在照射后12小时达到最大值。在暴露于各种剂量的γ辐射之前，用2 mg/kg体重的柚皮苷处理小鼠，可显著降低异常细胞和染色体畸变的频率，如无着丝粒片段、染色单体和染色体断裂、着丝粒环、双着丝粒体和交换。对柚皮苷清除自由基活性的评估显示，其对羟基、超氧阴离子和2,2 -二苯基-1-苦基肼自由基的清除呈剂量依赖性。5 microM的柚皮苷能非常有效地清除2,2-偶氮双（3-乙基苯并噻唑啉-6-磺酸）阳离子自由基，清除率达90%。我们的研究表明，柚皮苷可以保护小鼠骨髓细胞免受辐射诱导的染色体损伤。
