铂类络合物引起的DNA O6-AGT的耗竭及染色体损伤

本文测定了KB,CHL,HL-60和L1210细胞DNA鸟嘌呤O⁶-烷基转移酶(O⁶-AGT)活性。结果表明,KB细咆有较高的O⁶-AGT活性,系Mer⁺细胞。而CHL,HL-60和L1210细胞的O⁶-AGT活性低,属于Mer^-细胞。在此基础上我们观察了顺铂(DDP)、宁辛铂(樟脑胺氯乙酸铂,CCP)和碳铂(JM-8)对KB(Mer⁺)细胞O⁶-AGT的影响及Mer⁺和Mer^-细胞的杀伤及微核的诱发作用。结果表明,三种络合物在等毒性浓度下对O⁶-AGT耗竭程序是CCP>DDP>JM-8,但这种耗竭与杀细胞作用无明显相关性而与微核诱发作用相关。此结果提示铂类络合物对DNA鸟嘌呤O⁶的损伤可能是其致痛致突变的原因之一。     

人参二醇皂甙和三醇皂甙对兔纹状体ATP酶的影响

本文报道用体外给药法,观察了PDS和PTS对纹状体ATP酶(Na⁺、K⁺-ATP酶,Ca²⁺-ATP酶及M²⁺-ATP酶)的影响。结果发现PDS和PTS对Na⁺,K⁺-ATP酶都有明显的抑制作用,且随PDS和PTS浓度的高低,其抑制作用增强或减弱;对Ca²⁺-ATP酶,PDS在10^-5g/ml时有激活作用,当浓度增高到10^-3g/mL时则转为抑制,而PTS仅为抑制效应;对于Mg²⁺-ATP酶能被PDS所兴奋,而被PTS所抑制。此结果表明PDS和PTS对中枢神经系统的作用,可能与其影响脑内ATP酶有密切的内在联系。     

CD4+CD25+调节性T淋巴细胞在儿童传染性单核细胞增多症的变化及作用

目的 观察儿童传染性单核细胞增多症（IM）治疗前后外周血T淋巴细胞亚群和CD4⁺CD25⁺调节性T淋巴细胞（Treg细胞）比例变化,分析Treg对IM的影响。方法 选取2017年1月至2018年5月安徽医科大学第二附属医院儿科收治的IM患儿60例作为观察组,以同期于本院儿童保健门诊行体检的40例健康儿童作为对照组,采用流式细胞术检测观察组治疗前、后及对照组的外周血T细胞亚群（CD3⁺T细胞、CD3⁺CD4⁺T细胞、CD3⁺CD8⁺T细胞比例,CD4/CD8比值）、CD4⁺CD25⁺调节性T淋巴细胞比例,对比分析两组患者机体细胞免疫功能的变化。结果 观察组治疗前CD3⁺T细胞比例、CD3⁺CD8⁺T细胞比例显著高于对照组;CD3⁺CD4⁺T细胞比例、CD4/CD8比值低于对照组,差异均有统计学意义（P <0.05）。观察组治疗后CD3⁺T细胞比例、CD3⁺CD8⁺T细胞比例均低于观察组治疗前;CD3⁺CD4⁺T细胞比例、CD4/CD8比值高于治疗前,差异均有统计学意义（P <0.05）。观察组治疗前外周血Treg细胞比例低于正常对照组,差异有统计学意义（P <0.05）;而观察组治疗后外周血Treg细胞比例高于治疗前,差异有统计学意义（P <0.05）。结论 IM患儿存在T细胞亚群比例的变化,Treg细胞水平的降低,可能参与IM患儿疾病的发生发展过程。     

阿托伐他汀的肝毒性机制研究

目的 研究阿托伐他汀肝毒性损伤作用及机制。方法 将24只Wistar han雄鼠分为对照组和阿托伐他汀低（68.5mg/kg）、高剂量组（205.5 mg/kg）,按照10 mL/kg的药液体积给药,溶媒对照组ig等体积5% CMC-Na,连续ig 28 d。检测血清中天门冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、碱性磷酸酶（ALP）、尿素氮（BUN）和血肌酐（CRE）的含量,HE染色观察肝组织病理。在体外,HepG2细胞经传代培养后,给予阿托伐他汀干预24 h,检测细胞存活率,丙二醛（MDA）水平、Na⁺-K⁺-ATP酶和Ca²⁺-Mg²⁺-ATP酶活性及线粒体膜电位。结果 与对照组比较,阿托伐他汀高剂量组大鼠肝细胞弥漫性肿胀,核分裂多见,部分肝细胞极性消失,排列紊乱（P<0.05）。与对照组比较,阿托伐他汀高剂量组给药后血清中ALT和AST显著升高（P<0.05、0.01）。在体外,与对照组比较,阿托伐他汀125、250、500 μmol/L能明显抑制细胞存活率（P<0.05、0.001）。与对照组比较,阿托伐他汀500 μmol/L HepG2细胞MDA含量明显升高（P<0.01）。与对照组比较,阿托伐他汀125 μmol/L能使Na⁺-K⁺-ATP酶活性增强,500 μmol/L使Na⁺-K⁺-ATP酶活性降低（P<0.001）。与对照组比较,阿托伐他汀125、250、500 μmol/L均能使能使Ca²⁺-Mg²⁺-ATP酶活性降低（P<0.01,0.001）。与对照组比较,阿托伐他汀125、250、500 μmol/L均能降低线粒体膜电位（P<0.001）。结论 阿托伐他汀高剂量可导致肝组织损伤,其毒性作用通过破坏细胞的线粒体膜电位,抑制Na⁺-K⁺-ATP酶、Ca²⁺-Mg²⁺-ATP酶活性,细胞膜脂质过氧化,从而破坏细胞内微环境的平衡,导致细胞凋亡和坏死。     

蝙蝠葛苏林碱及异构体对PC12细胞缺血性损伤的保护作用

用细胞培养术,以NaCN加缺糖引起PC12细胞损伤作为细胞缺血性损伤的模型,观察蝙蝠葛苏林碱(DS)及其3个光学异构体对PC12细胞缺血性损伤的保护作用;以Fura-2/AM为Ca²⁺的荧光探针,用AR-CM-MIC阳离子测定系统观察DS及异构体对NaCN引起的Ca²⁺内流的抑制作用。结果表明DS及3个异构体在10^-8～10^-5mol·L^-1的浓度范围内对PC12细胞损伤有较明显的保护作用,其机制之一与抑制NaCN加缺糖诱发的细胞内游离Ca²⁺异常升高有关。     

肿瘤特异性CD8+T细胞分化及调控机制的研究进展

肿瘤特异性CD8⁺T细胞是抗肿瘤免疫应答的主要效应细胞之一，其分化状态与免疫应答强度、对免疫疗法的响应程度密切相关。在肿瘤病程中，CD8⁺T细胞往往呈现耗竭状态，主要表现为效应功能降低和增殖能力下降。近几年，耗竭CD8⁺T细胞的高度异质性特征备受关注，其中记忆、效应和终末耗竭表型是当下考察肿瘤特异性CD8⁺T细胞分化状态的3个重要维度。伴随肿瘤进展，肿瘤特异性CD8⁺T细胞的干性、效应表型逐渐丢失，最终分化为终末耗竭细胞，表观遗传学变化和代谢重编程参与调控这一过程，另外肿瘤微环境中复杂多样的免疫抑制性信号加速了这一过程的发生。本文综述了肿瘤特异性CD8⁺T细胞激活后的命运以及不同分化状态的分子标志物和转录调控分子、影响分化状态的因素、与免疫疗法响应相关的标志物、调控CD8⁺T细胞增强抗肿瘤作用的应用等方面近年来的研究进展，以期为更加精准地调控CD8⁺T细胞表型，增强抗肿瘤免疫应答等研究提供参考。     

丹酚酸B预处理对心肌缺血/再灌注损伤能量代谢的影响

目的 观察丹酚酸B预处理对大鼠心肌缺血/再灌注损伤（MI/RI）能量代谢的作用。方法 通过结扎冠状动脉30min再灌注2 h建立大鼠MI/RI模型,随机分为4组：假手术组、模型组及丹酚酸B高、低（20、10 mg/kg）组,于建立模型前7 d开始ip给药,每天1次;再灌注结束后,采用比色法测定血清乳酸脱氢酶（LDH）、肌酸激酶（CK）活力,染色法测定心肌梗死面积（MIA）,定磷法测定心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-Mg²⁺-ATP酶活性。结果 与模型组（42.60%）比较,丹酚酸B高、低剂量组的MIA分别缩小至35.93%和37.21%,差异显著（P<0.05）;与模型组比较,丹酚酸B高、低剂量组血清CK、LDH活力均显著降低（P<0.05、0.01）;与模型组比较,丹酚酸B高、低剂量组心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-Mg²⁺-ATP酶活性均显著升高（P<0.05、0.01）。结论 丹酚酸B预处理可保护MI/RI所致心肌损伤,作用途径可能与改善心肌组织的能量代谢相关。     

安替可胶囊联合TP方案治疗晚期食管鳞癌的临床研究

目的 探讨安替可胶囊联合TP方案（紫杉醇＋顺铂）治疗晚期食管鳞癌的临床疗效。方法 选取2019年1月—2022年1月河南省人民医院收治的100例术后复发转移、晚期转移无法手术治疗的晚期食管鳞癌患者,将所有患者随机分为对照组（50例）和治疗组（50例）。对照组第1天静脉滴注紫杉醇注射液135 mg/m²,第1～3天静脉滴注顺铂注射液75 mg/m²。治疗组于对照组基础上口服安替可胶囊,2粒/次,3次/d。3周为1个治疗周期,两组患者持续治疗3个周期。观察两组的临床疗效,比较两组肿瘤标志物[鳞状细胞癌抗原（SCC-Ag）、细胞角蛋白19片段（CYFRA21-1）、癌胚抗原（CEA）、糖类抗原125（CA125）]、细胞免疫功能淋巴细胞（CD3⁺、CD4⁺、CD8⁺、CD4⁺/CD8⁺）、生存质量（QLQ-C30评分、KPS评分）以及不良反应、随访1年的生存情况。结果 治疗后,治疗组客观缓解率（42.00%）、疾病控制率（74.00%）明显高于对照组（22.00%、52.00%）,组间比较差异有显著性（P＜0.05）。治疗后,两组QLQ-C30评分、KPS评分均显著升高（P＜0.05）,治疗组QLQ-C30评分、KPS评分显著高于对照组（P＜0.05）。治疗后,对照组CD3⁺、CD4⁺、CD4⁺/CD8⁺显著降低,CD8⁺显著升高（P＜0.05）;治疗组CD3⁺、CD4⁺、CD4⁺/CD8⁺明显高于对照组,CD8⁺低于对照组（P＜0.05）。治疗后,两组血清SCC-Ag、CYFRA21-1、CEA、CA125水平均显著降低（P＜0.05）,治疗组血清SCC-Ag、CYFRA21-1、CEA、CA125水平显著低于对照组（P＜0.05）。治疗组不良反应发生率为28.00%,明显低于对照组不良反应发生率48.00%,组间比较差异有显著性（P＜0.05）。随访1年后,治疗组中位生存期、肿瘤无进展时间均明显长于对照组（P＜0.05）。结论 安替可胶囊联合TP方案治疗晚期食管鳞癌能增强治疗效果,提高生活质量,减轻免疫功能抑制,降低肿瘤标志物水平,有助于延长患者生存期。     

中药大黄的生化学研究ⅩⅫ蒽醌衍生物对兔肾髓质Na+-K+-ATP酶活性的抑制和利尿作用

家兔实验表明:大黄素、大黄酸以30 mg/kg的剂量灌胃给药,2～4h后尿量、排Na⁺和K⁺量达最高峰,比对照组明显增多。而芦荟大黄素和大黄酚的作用较弱。大黄素、大黄酸和芦荟大黄素对免肾髓质Na⁺-K⁺-ATP酶活性有较强的竞争性抑制作用。     

毒毛旋花子苷元对豚鼠心室肌细胞内钙浓度的影响

观察毒毛旋花子苷元(strophanthidin, Str)对分离豚鼠心室肌细胞内游离钙浓度(［Ca²⁺］_i)的影响。酶解分离豚鼠心室肌细胞, 用Fluo 3-AM负载, 激光共聚焦显微镜法测定单个豚鼠心室肌细胞［Ca²⁺］_i的荧光密度。Str可浓度依赖性地升高［Ca²⁺］_i, Str (10 μmol·L^-1)在［Ca²⁺］_i升高达峰值时, 可使细胞挛缩, 而Str (1和10 nmol·L^-1)对细胞形态无影响。TTX、 尼索地平或升高细胞外钙可影响Str (1和100 nmol·L^-1)对［Ca²⁺］_i的升高作用,而对Str (10 μmol·L^-1)无明显影响。在外液中加入ryanodine或去除细胞外钙, 则3个检测浓度的Str升高［Ca²⁺］_i作用均被明显抑制。在无K⁺、 无Na⁺液中, 10 μmol·L^-1 Str升高［Ca²⁺］_i的作用减弱, 而Str (1和100 nmol·L^-1)升高［Ca²⁺］_i的作用无明显影响。加入TTX、 尼索地平或增加细胞外的钙离子浓度, 则3个检测浓度Str的作用均受到影响。提示低浓度Str对［Ca²⁺］_i的升高作用与抑制Na⁺、K⁺-ATP酶活性无关, 而与促进L-型钙通道和TTX敏感性钠通道的“slip-mode”钙电导有关; 高浓度Str升高［Ca²⁺］_i的作用则是抑制Na⁺、K⁺-ATP酶的结果。此外, Str对［Ca²⁺］_i的升高作用还与直接作用于ryanodine受体促进内钙释放有关。     

紫杉醇类似物的合成及抗肿瘤活性

Sinenxan A(SIA)为生物合成法得到的新紫杉烷化合物。为寻找有抗肿瘤活性的新型taxol类似物,对SIA进行结构修饰.设计合成了10个化合物,在母核中引入四氢呋喃环,在14β-位或10β-位连接taxol/taxotere侧链,部分化合物显示一定的抗肿瘤活性。并讨论了这类化合物的构效关系。     

Development of Novel Chitosan Derivatives as Micellar Carriers of Taxol

Purpose. To develop an intravenous injectable carrier composed of chitosan derivatives for taxol. Methods. A chitosan with lauryl groups attached to amino groups to provide the hydrophobic moieties and, carboxymethyl groups attached to hydroxy groups to provide the hydrophilic moieties (N-lauryl-carboxymethyl-chitosan = LCC), was newly synthesized. The solubility of taxol in LCC micelles in aqueous solution was examined. The hemolysis test of LCC and the growth inhibition experiment of taxol-loading micelle using KB cells were also performed as in vitro assay. Results. It was found that LCC solubilized taxol by forming micelles with particle sizes less than l00nm. This particle size was considered effective for passive targeting for tumors. The concentration of taxol in the micellar solution was very high, with a maximum of 2.37mg/ mL. This maximum was 1000 times above that in a saturated solution of taxol at pH 7.4. Hemolysis testing as an in vitro assay indicated that LCC was safer than Polysorbate 80 (TO-10M) as intravenous surfactant in terms of induction of membrane damage. As judged by cytostatic activity against KB cells, taxol retained activity even when included in LCC micelles. LCC-entrapped taxol was more effective in cytostatic activity than free taxol in low concentrations. Conclusions. The results of solubilization capacity examination, hemolysis testing, and cytostatic activity suggest that LCC may be useful as a carrier of taxol.     

新型14β-侧链紫杉醇衍生物的合成及构效关系研究

以生物合成得到的紫杉烷 sinenxan A为起始原料,合成一系列新的紫杉醇衍生物,以寻找高效低毒、抗瘤谱广、综合性能好的新一代紫杉醇类抗癌药,并进行构效关系研究。从半合成的紫杉烷中间体7出发,分别经5步和6步反应成功地合成了4位羟基和4位乙酸酯两类共8个新的14β 侧链紫杉醇衍生物,2位基团为苯甲酸酯、间氯苯甲酸酯、正戊酸酯和苯乙酸酯。将目标化合物连同已合成的2个14β-侧链紫杉醇衍生物进行了微管聚合试验和体外肿瘤细胞抑制试验。所有化合物在浓度为10μmol·L^-1时对微管无作用。在体外肿瘤细胞抑制试验中,大部分化合物显示边缘细胞毒活性。14β-侧链紫杉醇衍生物的构效关系与13α-侧链紫杉醇衍生物有所不同,2位脂肪酸酯与2位芳香酸酯活性相当,表明2位基团的改变对活性无明显影响。4位羟基衍生物的活性好于4位乙酸酯。     

云南红豆杉抗肿瘤活性成分的研究

云南红豆杉(Taxus yunnanensis Cheng et L.K.Fu)树皮的乙醇提取物显示较强的抗肿瘤活性,从中分离得到8个紫杉烷类二萜及其生物碱。经光谱分析和化学反应鉴定7个已知物为taxinine E(1),taxinine J(2),1-acetoxy-5-deacetvl baccatin Ⅰ(4),baccatin Ⅲ(5),taxol(6),cephalomannine(7)和7-xylosyl-10-deacetyl taxol(8)。化合物3命名为云南红豆杉甲素(ymlnanxane),为一新的紫杉烷二萜化合物,其结构为taxa-4(20),11-diene-2α,5α,10β,14β-tetraol-2α,5α,10β-triacetate-14β-αmethyl-β-hydroxyl butyrate,并通过X-射线单晶衍射予以证实.经体外筛迭化合物3具有抗肿瘤活性。     

Diethyl pyrocarbonate, a histidine-modifying agent, directly stimulates activity of ATP-sensitive potassium channels in pituitary GH(3) cells

The ATP-sensitive K(+) (K(ATP)) channels are composed of sulfonylurea receptor and inwardly rectifying K(+) channel (Kir6.2) subunit. These channels are regulated by intracellular ADP/ATP ratio and play a role in cellular metabolism. Diethyl pyrocarbonate (DEPC), a histidine-specific alkylating reagent, is known to modify the histidine residues of the structure of proteins. The objective of this study was to determine whether DEPC modifies K(ATP)-channel activity in pituitary GH(3) cells. Steady-state fluctuation analyses of macroscopic K(+) current at -120 mV produced power spectra that could be fitted with a single Lorentzian curve in these cells. The time constants in the presence of DEPC were increased. Consistent with fluctuation analyses, the mean open time of K(ATP)-channels was significantly increased during exposure to DEPC. However, DEPC produced no change in single-channel conductance, despite the ability of this compound to enhance K(ATP)-channel activity in a concentration-dependent manner with an EC(50) value of 16 microM. DEPC-stimulated K(ATP)-channel activity was attenuated by pretreatment with glibenclamide. In current-clamp configuration, DEPC decreased the firing of action potentials in GH(3) cells. A further application of glibenclamide reversed DEPC-induced inhibition of spontaneous action potentials. Intracellullar Ca(2+) measurements revealed the ability of DEPC to decrease Ca(2+) oscillations in GH(3) cells. Simulation studies also demonstrated that the increased conductance of K(ATP)-channels used to mimic DEPC actions reduced the frequency of spontaneous action potentials and fluctuation of intracellular Ca(2+). The results indicate that chemical modification with DEPC enhances K(ATP)-channel activity and influences functional activities of pituitary GH(3) cells.     

Stilbene 5c,a microtubule poison with vascular disrupting properties that induces multiple modes of growth arrest and cell death

The stilbene derivative, cis-3,4′,5-trimethoxy-3′-aminostilbene (stilbene 5c), is a potentially potent antitumor agent that acts via binding to the colchicine-binding site in tubulin. The current studies were designed to investigate the effectiveness of stilbene 5c against the HCT-116 human colon cancer cell line and B16/F10 melanoma cells as well as human endothelial cell tube formation and tumor perfusion. Stilbene 5c produced a time-dependent decrease in cell viability in both cell lines and the capacity of the cells to proliferate was not restored upon removal of the drug. Treatment with stilbene 5c also promoted both senescence and autophagy in both cell lines. TUNEL and annexin 5 staining indicated that apoptosis also occurs in stilbene 5c-treated HCT-116 cells, but not in B16/F10 melanoma cells. DAPI staining revealed morphological changes in the cell nuclei (binucleated and micronucleated cells) indicative of mitotic catastrophe in HCT-116 cells but not in the B16/F10 melanoma cells. p53-null HCT-116 cells demonstrated a similar growth arrest/cell death response to stilbene as p53-wild type HCT-116 cells. Stilbene 5c also completely inhibited human endothelial cell tube formation on Matrigel, consistent with potential anti-angiogenic actions. Using a new method developed for monitoring the pharmacodynamic effects of stilbene 5c in vivo, we found that a single injection of stilbene 5c reduced tumor perfusion by 65% at 4 h, returning to baseline by 24 h, while subsequent daily injections of stilbene 5c produced progressively larger reductions and smaller rebounds. This work indicates that stilbene 5c could potentially be effective against melanoma and colon cancer through the promotion of multiple modes of growth arrest and cell death coupled with anti-angiogenic and antivascular actions.     

Combination of oxaliplatin and irinotecan on human colon cancer cell lines: activity in vitro and in vivo

The in vitro and in vivo combination of oxaliplatin and irinotecan was investigated in a panel of four human colon cancer cell lines and their counterpart xenografts. In vitro and in vivo experiments demonstrated a synergistic or additive interaction in three cell lines (HCT-116, HCT-8 and HT-29) and an antagonism in SW-620 cells. Since there were clearly opposite interactions depending on the cell line, we further investigated cellular determinants possibly involved in the interaction between the two drugs in HCT-8 and SW-620 cells. Irinotecan slowed down the early platinum-DNA adducts repair (1 h after oxaliplatin exposure) in the presence of irinotecan only in HCT-8 cells (p=0.03, n=3). Moreover, a decrease of the expression of two proteins of the nucleotide excision repair (NER) system, ERCC1 and XPA, was observed. None of these effects was seen in SW-620 cells. Irinotecan induced apoptosis with an increase of poly(ADP-ribose) polymerase (PARP) cleavage in SW-620 cells (60 versus 7% basal level). Pretreatment of these cells with oxaliplatin abolished the increase in PARP cleavage induced by irinotecan (29%). In HCT-8 cells, a very little PARP cleavage was observed whatever the drug treatment. The persistence of platinum-DNA adducts in the presence of irinotecan could be due to a direct impact of irinotecan on NER gene expression or to an indirect effect on topoisomerase I activity. Complementary studies are required to determine if the cellular parameters identified in this study could be translated at the clinical level to predict clinical response after combined treatment with oxaliplatin and irinotecan in humans.     

Gene Expression Profiles of ABC Transporters and Cytochrome P450 3A in Caco-2 and Human Colorectal Cancer Cell Lines

Purpose. The mRNA levels of MDR1 (P-glycoprotein), multidrug resistance-associated proteins (MRP1, MRP2), cytochrome P450 3A (CYP3A) and villin in human colorectal cell lines (HCT-15, LoVo, DLD-1, HCT-116 and SW620) were quantitatively compared with those in Caco-2 cells. Methods. The mRNA levels were determined by real time quantitative polymerase chain reaction and expressed as the relative concentrations of MDR1 mRNA to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA. Results. MDR1 mRNA was expressed in HCT-15 LoVo and DLD-1 cells at similar or lower level to Caco-2. The expression of MRP1 mRNA in the cell lines tested was comparable with Caco-2. MRP2 mRNA was detected only in HCT-116 and SW620 at significantly lower level than Caco-2. CYP3A mRNA was detected in HCT-15, LoVo, DLD-1 and SW620 at similar level to Caco-2. Conclusions. HCT-15 LoVo and DLD-1 cells express proteins important for regulating the intestinal absorption of drugs, i.e., MDR1, MRP1 and CYP3A, whereas HCT-116 and SW620 cells were not acceptable for evaluation of absorption properties of drug candidates.     

The application of absolute quantitative 1H NMR spectroscopy in drug discovery and development

ABSTRACT

Introduction: The identification of a drug candidate and its structural determination is the most important step in the process of the drug discovery and for this, nuclear magnetic resonance (NMR) is one of the most selective analytical techniques.

Area covered: The present review illustrates the various perspectives of absolute quantitative ¹H NMR spectroscopy in drug discovery and development. It deals with the fundamentals of quantitative NMR (qNMR), the physiochemical properties affecting qNMR, and the latest referencing techniques used for quantification. The precise application of qNMR during various stages of drug discovery and development, namely natural product research, drug quantitation in dosage forms, drug metabolism studies, impurity profiling and solubility measurements is elaborated. To achieve this, the authors explore the literature of NMR in drug discovery and development between 1963 and 2015. It also takes into account several other reviews on the subject.

Expert opinion: qNMR experiments are used for drug discovery and development processes as it is a non-destructive, versatile and robust technique with high intra and interpersonal variability. However, there are several limitations also. qNMR of complex biological samples is incorporated with peak overlap and a low limit of quantification and this can be overcome by using hyphenated chromatographic techniques in addition to NMR.     

New cytotoxic cucurbitacins from Wilbrandia ebracteata Cogn

Chemical investigation of the roots of Wilbrandia ebracteata Cogn. (Cucurbitaceae) led to the isolation of two new (1- 2) and four known (3- 6) cucurbitacins. Their structures were elucidated by NMR and MS and compared with related compounds. The in vitro cytotoxicity of isolated compounds was evaluated against RD, KB, HCT-8, and A549 cell lines showing strong activity.