番木瓜中异硫氰酸苄酯及其前体物质苄基硫代葡萄糖苷的含量分析

目的:建立番木瓜中抗癌活性物质异硫氰酸苄酯及其前体物质苄基硫代葡萄糖苷的含量测定方法,并测定它们在番木瓜各部位中的含量。方法:苄基硫代葡萄糖苷采用HPLC法,以依利特Hypersil BDS-C18(200 mm×4.6 mm,5μm)为分析柱,用含0.1%三氟乙酸的乙腈-水梯度洗脱,流速1.0 mL·min-1,检测波长214 nm。异硫氰酸苄酯采用GC法,色谱柱为SPB1701石英毛细管柱(30 m×0.32 mm×0.25μm),程序升温,载气为氮气。FID检测器温度280℃,进样口温度250℃。结果:苄基硫代葡萄糖苷在0.91～36.4μg范围内线性关系良好(r=0.9992),异硫氰酸苄酯在0.0174～0.556μg范围内线性关系良好(r=0.9992)。除成熟果肉外,苄基硫代葡萄糖苷在其他部位均能检测到,且以种子中含量最高为4.74 mg·g-1;而异硫氰酸苄酯只在花和种子中检测到,以种子中含量较高为0.605 mg·g-1。结论:所建方法可用于番木瓜中苄基硫代葡萄糖苷和异硫氰酸苄酯的含量测定。     

光果葶苈全草中硫代葡萄糖苷总量的测定

目的:测定光果葶苈全草中硫代葡萄糖苷的总含量,为进一步研究开发提供基础科学资料。方法:采用硫酸根离子沉淀法。结果:光果葶苈全草中硫代葡萄糖苷总含量为0.95%。结论:光果葶苈全草中硫代葡萄糖苷含量高,有较大的开发价值。     

科研技术简讯

S056 异硫氰酸芳酯的新合成PAK CS等〔Synthesis,(11):969～970 1982〕 N-芳香二硫代氨基甲酸甲酯(1)在较温和条件下,经碱催化裂解制得异硫氰酸芳酯(2)。收率佳,操作简便。     

新疆芜菁中硫代葡萄糖苷提取工艺条件的优化

目的研究从新疆芜菁中提取硫代葡萄糖苷的最佳工艺条件并对其含量进行测定。方法在单因素实验基础上,采用L9(34)正交实验设计安排实验,采用硫酸根离子沉淀法测定芜菁中硫代葡萄糖苷的含量。结果选用提取时间、料液比及提取次数作为研究因素,以提取液中硫代葡萄糖苷的含量为考察指标,各因素对芜菁硫代葡萄糖苷提取率的影响程度大小顺序为:提取时间>料液比>提取次数>D,D为误差项,提取时间、提取次数对硫代葡萄糖苷的提取的影响具有显著影响,而料液比的影响不显著。结论经L9(34)正交实验和方差分析,得到从芜菁中提取硫代葡萄糖苷最佳工艺条件为:提取次数为1次,提取时间为120min,料液比为1∶10。     

异硫氰酸酯化合物的抗癌作用及其机制研究进展

异硫氰酸酯化合物具有不同程度的防癌、抗癌作用,其作用机制既与抑制Ⅰ相代谢酶细胞色素氧化酶P450和(或)诱导Ⅱ相代谢酶相关,也与诱导肿瘤细胞周期阻滞及细胞凋亡密切相关。     

维药恰玛古中硫代葡萄糖苷的提取工艺研究

目的:优化维药恰玛古硫代葡萄糖苷的提取工艺。方法:采用乙醇回流法提取维药恰玛古中硫代葡萄糖苷,以硫代葡萄糖苷提取量和干膏得率的综合评分为指标,在单因素试验基础上采用L9(34)正交试验考察乙醇体积分数、提取时间、料液比对恰玛古硫代葡萄糖苷提取工艺的影响并进行验证试验。结果:优化的提取工艺为加8倍药材量的95%乙醇回流提取2次,每次1.0h;硫代葡萄糖苷提取量和干膏得率分别平均为7.36 mg/g、25.29%,综合评分的RSD为0.52%(n=3)。结论:优选的提取工艺稳定可行,可用于维药恰玛古中硫代葡萄糖苷的提取。     

新型α-葡萄糖苷酶抑制剂筛选及药理作用研究进展

α-葡萄糖苷酶抑制剂能有效降低餐后血糖,为临床一线降糖用药之一。近年来报道了大量新化合物作为α-葡萄糖苷酶抑制剂,不仅可以起到降糖的作用,而且还具有抗溶酶体堆积病、抗病毒、抗菌和抗癌的药效。α-葡萄糖苷酶抑制剂新型化合物按照产出途径主要有微生物代谢产物、天然产物与化学合成产物。就近年来开发的多种类型的α-葡萄糖苷酶抑制剂及其抗癌、抗病毒和抗溶酶体堆积病作用进行了综述,旨在为α-葡萄糖苷酶抑制剂或临床前候选药物提供更好的研究方向。     

异硫氰酸苄酯包合物胃漂浮片的药代动力学研究

目的 研究自制的异硫氰酸苄酯包合物胃漂浮片的药代动力学,观察其缓释效果.方法 本实验分体外和体内药代动力学研究,体外研究在模拟的人工胃液中的释放行为;体内药代动力学研究该胃漂浮片的血药浓度,拟合释药行为.结果 药物的稳定性增加,药物的达峰时间延迟.结论 制备的异硫氰酸苄酯包合物胃漂浮片的漂浮性能良好,且能达到缓释效果.     

番茄红素的生理学功能研究现状

番茄红素是人类血浆和组织中重要的类胡萝卜素,在类胡萝卜素中抗氧化能力最强,并且具有防癌和抗癌的保健作用。本文系统介绍了番茄红素生物学功能和作用机理。研究表明番茄红素具有优越的生理功能。番茄红素是很有开发价值的一种功能性天然食用色素。     

光果葶苈中硫代葡萄糖苷的提取工艺研究

目的：通过试验来优化光果葶苈中硫代葡萄糖苷的提取工艺。方法：在单因素试验基础上设计正交试验,对光果葶苈中硫代葡萄糖苷提取条件进行优化。结果：试验得出光果葶苈硫代葡萄糖苷提取最佳工艺条件为：提取温度80℃、提取时间20min、提取次数为1次,料液比1：7。结论：该工艺合理可行,可用于光果葶苈中硫代葡萄糖苷的大量提取。     

The isothiocyanate produced from glucomoringin inhibits NF-kB and reduces myeloma growth in nude mice in vivo

Glucosinolates (GLs), natural compounds extracted from Brassicaceae and precursors of isothiocyanates (ITCs), have been studied in the last decades mostly due to their chemopreventive activity and, more recently, for their potential use as novel chemotherapeutics. The aim of the present study was to investigate the in vitro and in vivo activity of glucomoringin (GMG), an uncommon member of the GLs family, and to compare it with glucoraphanin (GRA), one of the most studied GL. We have evaluated the potency of both compounds in inducing cell death, cell cycle perturbations, apoptosis, NF-kB inhibition and GST-π activity in human carcinoma cells with different GST-π contents as well as in human multiple myeloma and leukaemia cell lines. GMG-derived ITC (GMG-ITC) showed to be more effective compared to GRA-derived ITC (Sulforaphane), especially in inhibiting NF-kB activity and inducing apoptosis through a caspase-dependent pathway; these effects were more pronounced in myeloma cells, in which we could also observe a long lasting growth inhibitory effect, probably due to NF-kB inhibition, which is considered essential for myeloma cell survival. Both GLs were able to induce cell death in the μM range in all tested cell lines but caused cell cycle perturbations only in myeloma cells; they were also able to modulate the GST/GSH pathway by causing a 3-fold increase in GST-π activity in MCF7 cells. In vivo study showed that pure GMG-ITC was only slightly active in a carcinoma mice model, whereas it had significant antitumoral activity in a myeloma model, causing little toxicity.     

Isothiocyanates as cancer chemopreventive agents: their biological activities and metabolism in rodents and humans

Isothiocyanates (ITCs) are a group of naturally occurring compounds that occur as thioglucoside conjugates, termed glucosinolates, in plants and cruciferous vegetables such as watercress, Brussels sprouts, broccoli, cabbage, kai choi, kale, horseradish, radish and turnip. ITCs inhibit the development of tumors in many of the experimental models investigated, and are being investigated as possible chemopreventive agents for specific human cancers. The goal of this review is to provide a mechanistic understanding for the biological activities of ITCs and to relate the metabolism of ITCs to their action as chemopreventive agents. In vivo animal studies have been conducted to address issues of tissue disposition, pharmacokinetics, and metabolism of ITCs. Methods for analysis of ITCs and their metabolites in urine and plasma have been developed. The metabolism of several naturally occurring ITCs as constituents of foodstuffs or as drugs has also been investigated in human studies. Finally, based on recent epidemiological studies, the role of dietary consumption of vegetables containing ITCs in prevention of human cancers and human cancer susceptibility is discussed.     

Interaction of the isothiocyanate sulforaphane with drug disposition and metabolism: pharmacological and toxicological implications

Isothiocyanates (ITCs) are sulfur-containing compounds that are broadly distributed among cruciferous vegetables such as cabbages and broccoli. The consumption of ITCs is expected to rise due to the use of dietary supplements and public health initiatives promoting the consumption of more fruits and vegetables. Sulforaphane (SFN) is by far the most widely studied and characterized ITC. SFN is extensively metabolized and can therefore compete with other substrates of Phases I, II, III enzymes and transporters. In addition, it has an unusually high potency as an inducer of phase II enzymes and regulates the expression and function of different cytochrome P-450 genes. Such effects can be beneficial and may indicate a mechanism for the preventive role that SFN is believed to play against the degenerative events of aging and chronic diseases. Furthermore, these gene induction effects and the interaction with detoxification responses can modify bioavailability and in vivo bioactivity of drugs. This review will discuss 1) the metabolism of ITCs using SFN as an example, 2) inhibition of drug metabolism by SFN, and 3) induction of drug metabolizing enzymes by SFN. The potential pharmacological and toxicological implications of these effects on drug metabolism will also be discussed.     

Anti-angiogenic effects of dietary isothiocyanates: mechanisms of action and implications for human health

Isothiocyanates (ITCs) are electrophilic compounds derived from plants and are thought to play a major role in the potential chemopreventive effects associated with high intake of cruciferous vegetables. ITCs are also being evaluated for chemotherapeutic activity in early phase clinical trials. In addition to their effects on carcinogen metabolism and cancer cell survival and proliferation, ITCs have been shown to effectively interfere with angiogenesis in vitro and in vivo. Angiogenesis is the development of a new blood supply from existing vasculature and is required for tumours to develop beyond a small size limit determined by the diffusion limit for oxygen. Inhibition of angiogenesis may play a key role in the potential chemopreventive/chemotherapeutic activity of ITCs. In this review we highlight recent data demonstrating that ITCs have anti-angiogenic activity and identify potential molecular targets for these effects, including hypoxia-inducible factor (HIF), nuclear factor κB (NF-κB), activator protein 1 (AP1) and tubulin. We also discuss these findings in light of the potential chemopreventive/chemotherapeutic effects of ITCs.     

Isothiocyanates from Broccolini seeds induce apoptosis in human colon cancer cells: proteomic and bioinformatic analyses

Isothiocyanates (ITCs) have been shown to possess antitumor activity in colon cancer, however, the detailed mechanism is still unclear. The objective of this study was to investigate apoptosis-inducing activity of ITCs from Broccolini seeds and proteomic changes in SW480 cells, and to identify the molecular pathways responsible for the anticancer action of ITCs. We found that ITCs induces SW480 cells apoptosis in a dose-dependent manner by using MTT assay, phase contrast microscope and flow cytometry, and the IC50 was calculated to be 77.72 microg/ml, superior to the chemotherapeutical drug 5-flurouracil. Subsequently, 15 altered proteins in ITCs treated SW480 cells were identified. Further bioinformatics analysis predicted the potential pathways for ITCs to induce apoptosis of SW480 cells. In conclusion, this is the first report to investigate anticancer activity of ITCs from Broccolini seeds and its mechanism of action by proteomics analysis. Our observations provide potential therapeutic targets for colon cancer inhibitor intervention and implicate the development of novel anti-cancer therapeutic strategies.     

Effects of eleven isothiocyanates on P450 2A6- and 2A13-catalyzed coumarin 7-hydroxylation

Many isothiocyanates (ITCs), both naturally occurring and synthetic, are potent and selective inhibitors of carcinogenesis in animal models and are now viewed as a class of promising chemopreventive agents. We have investigated the ability of 11 ITCs to inhibit and/or inactivate P450 2A6- and 2A13-mediated coumarin 7-hydroxylation. Two of these 11 ITCs, phenylpropyl isothiocyanate (PPITC) and phenylhexyl isothiocyanate (PHITC), were potent inhibitors of P450 2A13. The K I values for the inhibition of P450 2A13-mediated coumarin 7-hydroxylation by PPITC and PHITC were approximately 0.14 and 1.1 microM, respectively. P450 2A6 was also inhibited by these two ITCs; however, the K I values indicated they were approximately 10-20-fold less potent for P450 2A6 than for P450 2A13. Most of the ITCs tested, including PPITC and PHITC, showed some degree of inactivation of both P450s; however, only one compound, tert-butyl isothiocyanate (tBITC), showed significant inactivation of P450 2A13 at a concentration of 10 microM. None of the ITCs caused significant inactivation of P450 2A6 at this concentration. tBITC inactivated P450 2A13 with an apparent K I of 4.3 microM and a k inact of 0.94 min (-1). Inactivation of P450 2A6 by tBITC was observed only at high concentrations and long incubation times. The observed differences in inhibition and/or inactivation of P450 2A6 and 2A13 by a few of the isothiocyanates suggest that these compounds may be useful for structure-function studies.     

Isothiocyanates in the chemoprevention of bladder cancer

Development of effective preventive strategies for bladder cancer is of critical importance. Bladder cancer is among the most common human malignancies and typically recurs after treatment. Many plant-derived isothiocyanates (ITCs) have shown cancer-preventive activity in a variety of rodent organs. They are known to inhibit carcinogen-activating enzymes, and to induce carcinogen-detoxifying enzymes, apoptosis, cell cycle arrest, and differentiation of cancer cells. More importantly, orally ingested ITCs are efficiently absorbed, rapidly and almost exclusively excreted and concentrated in the urine as N-acetylcysteine conjugates (NAC-ITC). NAC-ITCs also possess anticarcinogenic activity, perhaps due largely to their facile dissociation to free ITCs. Storage of urine in the bladder makes the bladder epithelium, which lines the inner surface of the bladder and gives rise to the majority of bladder cancers, the most exposed tissue to ITCs/NAC-ITCs upon their ingestion. Storage of urine in the bladder also will increase the release of ITCs from NAC-ITCs. Consequently, the amount of ITCs needed orally to achieve cancer prevention in the bladder may be much lower than that required for other organs. As a result, potential systemic adverse effects of ITCs may be minimized when using ITCs for chemoprevention of bladder carcinogenesis. Taken together, ITCs may be especially useful for the prevention of bladder cancer.     

Membrane transport of dietary phenethyl isothiocyanate by ABCG2 (breast cancer resistance protein)

Isothiocyanates (ITCs) are non-nutrient constituents abundant in cruciferous vegetables and are effective in blocking carcinogenesis in a variety of tissues. ITCs permeate into cells rapidly and accumulate in cells primarily as glutathione (GSH) conjugates. We have demonstrated recently that certain ITCs are inhibitors of ABCG2 (breast cancer resistance protein, BCRP), an ATP-binding cassette transporter that plays an important role in drug absorption and disposition as well as in the development of multidrug resistance in cancer cells. The purpose of this study was to investigate the mechanisms of interactions between ITCs and BCRP and elucidate the transport of phenethyl isothiocyanate (PEITC) by BCRP. Inside-out membrane vesicles were prepared from human breast cancer BCRP-overexpressing MCF-7/MX100 and the parental MCF-7/sensitive cells. The ATPase study using 100 muM ITCs showed that ITCs are potential inhibitors of BCRP ATPase activity. The transport of (14)C-PEITC into BCRP-overexpressing MCF-7/MX100 cell vesicles was ATP-dependent and inhibited by fumitremorgin C (FTC), a specific inhibitor of BCRP, indicating that PEITC is a substrate for BCRP. In the control MCF-7/sensitive cell vesicles, no ATP-dependent and FTC-inhibited transport of (14)C-PEITC was observed. Taken together, the results of this investigation provided evidence that ITCs are potential inhibitors of BCRP ATPase and PEITC, in its unchanged form, is transported by BCRP. These data may be important in elucidating the interaction of ITCs and cellular transporters and in understanding the potential food-drug interaction.