- 學位論文
天然抗氧化物prenylflavonoids對減少紫外線皮膚細胞傷害及抑制攝護腺癌細胞生長之研究
Natural Antioxidant Prenylflavonoids Attenuate UVA-induced Damage in Human Kerationcytes and Fibroblasts, and Enhance Growth Inhibition in Human Prostate Cancer Cells
摘要
Cycloheterophyllin（AH-C）和Heterophyllin（AH-H）是從菠蘿蜜根部分離出來帶有prenyl基團的黃酮類化合物(prenylflavonoids)。在這次抗氧化活性研究中顯示AH-C和AH-H對xanthine oxidase（XO）具有很強的抑制作用，IC50值分別為29.4±0.6和10.9±1.8 ?嵱；對2,2'-azinobis(3-ethylbenzthiazoline-6- sulphonic acid)（ABTS）陽離子自由基具有強烈性的清除活性，IC50值分別為25.9±0.6和44.1±0.9 ?嵱；對1,1- diphenyl-2-picrylhydrazyl（DPPH）自由基亦具有顯著的清除活性，IC 50值分別為16.8±0.9和53.6±8.7 ?嵱。這些結果顯示AH-C和AH-H是具有潛力的天然抗氧化劑。 曝露於紫外線UVA或UVB照射下會引發自由基的產生，進一步導致多種皮膚疾病。AH-C和AH-H是一種強效的多酚類抗氧化劑，我們假設可能對於紫外線照射引起之皮膚傷害的具有保護效果。為了驗證這一假說，我們進一步研究AH-C和AH-H對於在紫外線UVA或UVB照射下的皮膚角質細胞（HaCaT細胞株）或纖維細胞（Hs68細胞株）是否具有保護效果。結果發現AH-C和AH-H具有顯著的保護作用，可減少紫外線UVA對皮膚纖維細胞（Hs68細胞株）的輻射傷害。 以往研究顯示COX-1和COX-2抑制劑，對於膀胱癌和前列腺癌細胞的抑制有療效。 AH-C是一個強效的COX-1抑制劑，同時具有抗氧化活性。在這次研究中我們發現AH-C可顯著抑制PC3細胞的增殖，其作用48小時和72小時的IC50值分別為1.1±1.9和1.7±0.5 ?嵱；曝露於AH-C的前列腺癌（PC3細胞株）顯著表現出增加細胞內活性氧物質（ROS）的生成；經細胞儀分析顯示AH-C對PC3細胞作用72小時後，PC3會出現細胞週期阻滯，及伴隨著細胞凋亡增加的現象；這些數據顯示AH-C對PC3細胞作用是透過增加細胞內活性氧物質（ROS）的量來引發細胞週期S和G2 / M期阻滯和細胞凋亡。這些結果指示出AH-C可能是一種有潛力的抗前列腺癌藥物。
並列摘要
■ ABSTRACT The antioxidant properties of prenylflavonoids, cycloheterophyllin (AH-C) and heterophyllin (AH-H), isolated from Artocarpus heterophyllus Lamk, was evaluated. AH-C and AH-H displayed a strong inhibitory effect on xanthine oxidase (XO) activity with an IC50 values of 29.4 ± 0.6 and 10.9 ± 1.8 μM, respectively, potent 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) radical cation scavenging activity with an IC50 values of 25.9 ± 0.6 and 44.1 ± 0.9 μM, and significantly 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity with an IC50 values of 16.8 ± 0.9 and 53.6 ± 8.7 μM, respectively. These findings indicate that AH-C and AH-H are promising antioxidants. Exposure of UVA or UVB radiation induced the production of free radicals or inflammation that lead to a wide array of skin disease. AH-C and AH-H, a kind of polyphenols with strong antioxidant, may significantly contribute to its properties. To test this hypothesis, we found that AH-C and AH-H exhibited significant protective effect against UVA irradiation damage on human fibroblasts, Hs68 cell line. The combination of COX-1 and COX-2 inhibitors indicated a highly effective treatment modality for carcinoma of both the bladder and prostate cancers. We found that AH-C, a potent COX-1 inhibitor, significantly inhibited cell proliferation in PC3 cells with a IC50 value of 1.1 ± 1.9 and 1.7 ± 0.5 μM after treating cells for 48 and 72 hours, respectively. Exposure of PC3 to AH-C significantly increased the generation of reactive oxygen species (ROS) in cells. Flow cytometric analysis exhibited that treatment of PC3 with AH-C led to the cell cycle arrest, accompanied by an increase in apoptotic cells death after 72 h. These data suggest that the presentation of S and G2/M phases arrest and apoptosis in AH-C treated PC3 for 72 h mediated through increased amount of ROS in cells exposed to AH-C. These findings indicated that AH-C could be a promising anticancer agent for treatment of prostate cancer.