請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/50824
標題: Antimutagenicity of Hsian-tsao extracts and its protective effect on DNA damage in human lymphocytes by single cell gel electrophoresis assay
仙草萃取物之抗致突變性及以單細胞電泳法探討其防止淋巴球細胞DNA損 傷之研究
作者: Hung, Yu-Ling
洪玉玲
關鍵字: DNA損傷
Hsian-tsao (Mesona procumbens Hemsl.)
antimutagenicity
health function
component analysis
DNA damage
仙草
抗致突變性
保健功能
成分分析
出版社: 食品科學系
摘要: The toxic, mutagenic, and antimutagenic effects of extracts (waters, methanol and ethyl acetate) from Hsian-tsao (Mesona procumbens Hemsl.) were investigated using the Ames test. The results showed that water extracts of Hsian-tsao (WEHT) had no toxicity toward Salmonella typhyimurium TA98 and TA100 either with or without S9 mix. All the extracts showed no mutagenicity to S. typhimurium TA98 and TA100. Methanolic and ethyl acetate extracts exhibited a similarly inhibitory effect on the mutagenicity of benzo[a]pyrene (B[a]P), which was stronger than that of water extracts. The inhibitory effect of WEHT on the mutagenicity of 2-amino-3-methylimidazo(4,5-f)quinoline (IQ) and B[a]P increased with an increase of the concentration; it showed a 90% inhibitory effect at a concentration of 2.5 mg/plate. The WEHT from three growing areas exhibited an inhibitory effect of over 90% on the mutagenicity of IQ toward TA98 at a concentration of 2.5-5.0 mg/plate. These three samples also showed no significant difference (P>0.05) in antimutagenicity toward IQ.The content of special components in Hsian-tsao and water extracts of Hsian-tsao in relation to their antimutagenicity was evaluated. The content of ascorbic acid in WEHT from Hua-lian, Jia-yih and Quan-shi was 6.63, 6.47 and 3.16 mg/g, respectively. The content of polyphenol in Hsian-tsao from different growing areas was in the order of Jia-yih>Quan- shi>Hua-lian. The content of polyphenol in WEHT from different growing areas was in the order of Hua-lian (238.7 mg/g)>Jia-yih (215.7 mg/g)>Quan-shi (144.3 mg/g). WEHT contained only a small amount of chlorophyll whereas Hsian-tsao contained a high amount of chlorophyll. Hsian-tsao contained a high amount of b- carotene and a trace level of a-tocopherol; however, these two components were not detected in WEHT. The WEHT from different growing areas showed an inhibitory effect of over 90% on the mutagenicity of IQ toward TA98 at a concentration of 2.5-5.0 mg/ plate. The inhibitory effect of WEHT on the mutagenicity of IQ correlated well (r2=0.76, P<0.05) with its polyphenol content. Some correlation was also found between the ascorbic acid content and antimutagenicity of WEHT. However, the antimutagenicity of WEHT was not significantly (P>0.05) correlated with its chlorophyll content.The protective effect of water extracts from Hsian-tsao (WEHT) on DNA damage in human lymphocytes induced by UV-C and/or H2O2 was evaluated using single cell electrophoresis (COMET assay). No toxicity was found in WEHT toward human lymphocytes. WEHT did not cause DNA damage at lower concentrations of 0.05 and 0.1 mg/mL while it did cause a slight DNA damage at a concentration of 0.5-2.5 mg/ mL when compared with the control group. When WEHT was mixed with H2O2 for reaction, it exhibited a slight inhibitory effect on DNA damage induced by H2O2. Moreover, when WEHT and lymphocytes were irradiated by UV-C and then repaired for 35 min, the DNA damage was reduced with an increase of the concentration of WEHT. Thus, WEHT could reduce the UV-C-induced DNA damage, and WEHT had a more protective effect on UV-C than on H2O2-induced DNA damage. The protective effect of WEHT on DNA damage might be due to the fact that it contains polyphenol compounds. However, WEHT showed different protective effects on DNA damage induced by different treatments.In conclusion, WEHT possessed a good antimutagenicity and protective effect on human lymphocytes. These results might be attributable to the polyphenols and/or active components in WEHT.
本研究以Ames test利用Salmonella typhimurium TA98和TA100測試仙草 水萃取物、甲醇萃取物及乙酸乙酯萃取物之毒性、致突變性及抗致突變性 。且進一步針對台灣數種仙草產地,探討不同產地之仙草水萃取物的抗致 突變效果,並分別測定其所含的特殊成分,及其與仙草抗致突變性之相關 性。另外以單細胞電泳法探討仙草水萃取物對於人類淋巴球細胞之DNA損 傷的防護效應。結果顯示,仙草水萃取物不論有無添加S-9混合物對TA98 和TA100均無毒性。各溶劑萃取物均無致突變性。甲醇萃取物及乙酸乙酯 萃取物於測試劑量內對需要S-9混合物活化之benzo[a]pyrene (B[a]P) 致 突變性抑制效果相近,均優於水萃取物。當水萃取物提高添加劑量對2- amino-3-methylimidazo(4,5-f)quinine (IQ)及B[a]P之抗致突變效果亦 隨之增加,添加劑量2.5 mg/plate時可達90%左右之抑制效果。各產地間 仙草水萃取物在高劑量(2.5-5.0 mg/plate) 下於TA98對IQ抗致突變效果 達90%以上,且無顯著差異 (p >0.05)。仙草水萃取物中特殊成分,分析 結果顯示,花蓮和嘉義仙草水萃取物中的抗壞血酸含量分別高達6.63 mg/ g和6.47 mg/g,關西仙草水萃取物其含量最低 (3.16 mg/g)。仙草中多酚 類化合物的含量高低依序為嘉義仙草>關西仙草>花蓮仙草。各產地仙草水 萃取物中多酚類化合物含量依序為花蓮仙草水萃取物 (238.7 mg/g) > 嘉 義仙草水萃取物 (215.7 mg/g) > 關西仙草水萃取物 (144.3 mg/g) 。仙 草水萃取物含有極少量的葉綠素,但是仙草中的葉綠素含量則相當高。仙 草中除了上述水溶性成分之外,亦含有豐富的β-胡蘿蔔素和少量的生育 醇 ; 但仙草水萃取物並未偵測到β-胡蘿蔔素和生育醇。仙草水萃取物對 於IQ致突變性的抑制效果與仙草水萃取物中的多酚類化合物含量有顯著的 正相關性 (r2=0.76, p <0.05)。而仙草水萃取物中的抗壞血酸含量與其 抗致突變性也有一些相關性,但並不如多酚化合物含量來得顯著。另外, 仙草水萃取物對IQ的抑制性則與葉綠素含量無顯著相關性 (p > 0.05) 。 加鹼處理的仙草水萃取物隨著鹼含量的提高,其中多酚類化合物含量則顯 著地減少 (p<0.05),且對IQ的抑制效果則呈現減弱趨勢,而仙草水萃取 物的pH值是影響其多酚類化合物含量的重要因子。在探討仙草水萃取物對 於人類淋巴球細胞之DNA損傷的防護效應方面。樣品對淋巴球細胞不具有 細胞毒性作用。添加樣品在低濃度0.05 和0.1 mg/ml時,對於細胞亦不會 造成DNA損傷;當樣品濃度提高至0.5 至2.5 mg/ml時,與控制組比較則會 對DNA造成一些DNA損傷的現象。當仙草水萃取物和H2O2一起反應,對於H2 O2的誘導DNA損傷則有些許抑制效果。此外,細胞懸浮液中添加仙草水萃 取物後,由UV-C照射之後35分鐘,具有良好的抑制DNA損傷效果,其顯示 仙草水萃取物具有減少由UV-C照射所引起的DNA損傷。且樣品對於UV-C照 射比H2O2有較好的防護作用,這可能是樣品中的多酚類化合物提供了細胞 這些防護效應。樣品本身對此兩種不同作用所引起的傷害會有不同的防護 作用差異,可能來自於兩種系統的不同,也有可能H2O2對細胞的作用比樣 品的防護作用速度較快,而UV-C照射對細胞的作用比樣品的防護作用速度 較慢,亦或為其他的可能機制。綜合以上結果可得知,仙草水萃取物具有 良好的抗致突變性及對於人類淋巴球細胞具有防護效應,其中多酚類化合 物對於這些特性扮演著重要的角色。此外,其仍存有其他活性成分,而共 同呈現出其具有的生理活性。
URI: http://hdl.handle.net/11455/50824
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