Enhanced antiproliferative and apoptotic response of HT-29 adenocarcinoma cells to combination of photoactivated hypericin and farnesyltransferase inhibitor manumycin A

Several photodynamically-active substances and farnesyltransferase inhibitors are currently being investigated as promising anticancer drugs. In this study, the combined effect of hypericin (the photodynamically-active pigment from Hypericum perforatum) and selective farnesyltransferase inhibitor manumycin (manumycin A; the selective farnesyltransferase inhibitor from Streptomyces parvulus) on HT-29 adenocarcinoma cells was examined. We found that the combination treatment of cells with photoactivated hypericin and manumycin resulted in enhanced antiproliferative and apoptotic response compared to the effect of single treatments. This was associated with increased suppression of clonogenic growth, S phase cell cycle arrest, elevated caspase-3/7 activity and time-dependent total cleavage of procaspase-3 and lamin B, cleavage of p21Bax into p18Bax and massive PARP cleavage. Moreover, we found that the apoptosis-inducing factor is implicated in signaling events triggered by photoactivated hypericin. Our results showed the relocalization of apoptosis-inducing factor (AIF) to the nuclei after hypericin treatment. In addition, we discovered that not only manumycin but also photoactivated hypericin induced the reduction of total Ras protein level. Manumycin decreased the amount of farnesylated Ras, and the combination treatment decreased the amount of both farnesylated and non-farnesylated Ras protein more dramatically. The present findings indicate that the inhibition of Ras processing may be the determining factor for enhancing the antiproliferative and apoptotic effects of combination treatment on HT-29 cells.     

超声提取贯叶连翘中总黄酮和金丝桃素的工艺研究

研究了从贯叶连翘中同时提取总黄酮和金丝桃素的最佳工艺条件,探讨了采用超声波辅助乙醇提取的方法来考查乙醇浓度、料液比、提取温度、提取时间、提取次数等因素对总黄酮和金丝桃素得率的影响,并结合正交试验确定最佳工艺.实验结果表明,最佳工艺参数为乙醇浓度70%、料液比1∶25、提取温度50℃、提取时间60min、提取2次,总黄酮和金丝桃素的得率分别为7.02%和0.178%,采用此工艺提取快速、简便,为贯叶连翘资源的开发利用奠定了基础.     

金丝桃素的研究进展

对金丝桃素的最新研究成果进行了综述。包括测定,药理作用,着重介绍了金丝桃素的制备,为金丝桃素的进一步研究开发提供了文献依据。     

Antiproliferative Effects of St. John’s Wort,Its Derivatives,and Other Hypericum Species in Hematologic Malignancies

Hypericum is a widely present plant, and extracts of its leaves, flowers, and aerial elements have been employed for many years as therapeutic cures for depression, skin wounds, and respiratory and inflammatory disorders. Hypericum also displays an ample variety of other biological actions, such as hypotensive, analgesic, anti-infective, anti-oxidant, and spasmolytic abilities. However, recent investigations highlighted that this species could be advantageous for the cure of other pathological situations, such as trigeminal neuralgia, as well as in the treatment of cancer. This review focuses on the in vitro and in vivo antitumor effects of St. John’s Wort (Hypericum perforatum), its derivatives, and other Hypericum species in hematologic malignancies. Hypericum induces apoptosis in both myeloid and lymphoid cells. Other Hypericum targets include matrix metalloproteinase-2, vascular endothelial growth factor, and matrix metalloproteinase-9, which are mediators of cell migration and angiogenesis. Hypericum also downregulates the expression of proteins that are involved in the resistance of leukemia cells to chemotherapeutic agents. Finally, Hypericum and its derivatives appear to have photodynamic effects and are candidates for applications in tumor photodynamic therapy. Although the in vitro studies appear promising, controlled in vivo studies are necessary before we can hypothesize the introduction of Hypericum and its derivatives into clinical practice for the treatment of hematologic malignancies.     

HZ8160大孔树脂吸附金丝桃素的热力学研究

研究了HZ8160大孔树脂吸附金丝桃素的热力学特性。研究表明,其等温吸附规律符合Freundlich等温方程,n〉1,吸附焓变△H〈0,吸附自由能变△G〈0,吸附熵变△S〈0,表明金丝桃素在HZ8160大孔树脂上的吸附为放热、自发的和优惠吸附过程,属于物理吸附。     

微波辅助合成金丝桃素四磺酸衍生物

利用微波辅助合成的方法,对金丝桃素四磺酸衍生物合成路线中的大黄素蒽酮缩合反应分别从微波加热温度、辐射时间和催化剂3个因素进行了优化,确定了最佳反应条件:温度150℃,反应时间1 h,不使用催化剂;该步反应的产率可达82.2%,整个合成路线经放大后的总产率为65.3%。与常规加热方法相比,微波辅助合成法提高了反应效率和产率,减少了副反应的发生,使合成工艺更加低碳环保。     

3,5-二甲氧基邻苯二甲酸酐的合成与表征

3,5-二甲氧基苯甲酸与水合氯醛进行烷基化和成环反应生成(4,6-二甲氧基-7-三氯甲基)-2-苯并[c]呋喃酮,然后经水解、脱羧、氧化、脱水反应合成了3,5-二甲氧基邻苯二甲酸酐,反应总得率78%。反应的中间物和目标产物用IR,1HNMR和MS等进行了表征。用该化合物合成取代蒽醌、金丝桃素及其衍生物的研究正在进行中。     

大孔树脂对贯叶连翘中金丝桃素的静态吸附

考察了18种不同类型的大孔树脂对贯叶连翘中金丝桃素的静态吸附和解吸效果,并对3种效果较好的树脂进行了吸附动力学研究;比较了上样液pH对吸附效果的影响;探讨了NKA-9树脂在25℃等温吸附过程,并应用Langmuir方程进行了拟合。结果表明,弱极性树脂NKA-9对金丝桃素吸附解吸作用最好,到达吸附平衡时间为1h左右,吸附量可达12.45mg/g干树脂。上样液最佳pH=4,上样液pH对树脂的吸附有很大影响。NKA-9树脂对金丝桃素的吸附为单分子吸附,符合Langmuir吸附理论。     

响应面法优化乌腺金丝桃超声提取工艺及其抗传染性支气管炎病毒作用

以金丝桃素提取量为响应值，采用响应面法对乌腺金丝桃中金丝桃素影响显著的因素进行研究和优化，获得最佳提取工艺。采用细胞病变效应（CPE）法检测乌腺金丝桃提取物体外抗传染性支气管炎病毒（IBV）作用。结果建立了超声提取乌腺金丝桃中金丝桃素的工艺数学模型。超声提取金丝桃素的最佳工艺条件为提取温度40.5℃，丙酮浓度为69.5%，提取时间43.5 min，液料比为15.3，此条件下金丝桃素提取率可达到4.70mg/g，与理论值相符。主效应关系为提取时间＞丙酮浓度＞提取温度＞液料比。乌腺金丝桃提取物在细胞感染IBV前、后及同时加入，都有明显抑制CPE的作用。说明乌腺金丝桃超声提取工艺条件可靠，金丝桃素提取量远高于常规提取方法，乌腺金丝桃提取物具有很好的抗IBV作用。     

金丝桃素光动力作用诱导人鼻咽癌细胞凋亡

为了观察中药金丝桃素光动力作用对鼻咽癌细胞凋亡的影响,应用膜联蛋白AnnexinV-PI双染结合流式细胞仪,分析了中药金丝桃素光动力作用后,人鼻咽癌细胞株CNE2细胞发生凋亡和继发性坏死的比率。中药金丝桃素光动力作用实验组人鼻咽癌细胞株CNE2细胞发生凋亡和继发性坏死的比率分别增加到53.08%和6.77%,且均显著高于单纯光照射组、单纯金丝桃素光敏剂处理组和假照射组(P< 0.01),而单纯光照组、单纯金丝桃素光敏剂处理组和假照射组三对照组间无明显差异(P> 0.05)。中药金丝桃素光动力作用能有效诱导人鼻咽癌细胞株CNE2细胞凋亡的发生,这也可能是金丝桃素光动力作用杀伤鼻咽癌的重要机制之一。