Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice

Aim： To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice.
Methods： Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin （2, 4, or 6 mg/kg, ip） 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses.

Results： Plumbagin （2.5–20 μmol/L） concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro （the IC50 value of inhibition of cell viability was 14.7 μmol/L）. Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2–3 weeks and reduced the tumor volume by 44%–74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts.

Conclusion： Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells.     

Binding and Anticancer Properties of Plumbagin with Human Serum Albumin

Plumbagin has received extensive attention as a promising anticancer drug. Therefore, we investigated the binding and anticancer properties of plumbagin with human serum albumin. Fluorescence results demonstrated that plumbagin interacts with human serum albumin, although its binding affinity may be affected to various extents by different compounds. The human serum albumin–plumbagin complex structure revealed that plumbagin binds to the hydrophobic cavity in the IIA subdomain of human serum albumin through hydrogen bonding and hydrophobic interactions. The plumbagin–human serum albumin complex enhances cytotoxicity by 2‐ to 3‐fold particularly in cancer cells but has no effect on normal cells in vitro. Compared with the unbound drug, the human serum albumin–plumbagin complex promotes HeLa cell apoptosis and has a stronger capacity for cell cycle arrest at the G2/M phase of HeLa cells. In conclusion, this study contributes to the rational design and development of plumbagin‐based drugs and a drug–human serum albumin delivery system.     

紫金莲药材的质量控制方法的研究

目的：建立紫金莲药材的定性鉴别和定量检测方法。方法：采用TLC法，以紫金莲对照药材和白花丹醌对照品鉴别紫金莲药材；以HPLC测定白花丹醌含量。结果：采用C₁₈色谱柱，以甲醇-水(75∶25)为流动相，检测波长265 nm，供试品色谱中白花丹醌分离良好，白花丹醌进样量在33.6～313.6 ng线性关系良好，r=0.999 9，平均加样回收率100.3%，RSD 1.9%。结论：通过研究制定了紫金莲药材TLC和HPLC质量控制方法。     

HPLC法测定云南不同产地白花丹的不同部位中白花丹醌的含量

目的:建立白花丹药材中白花丹醌的反相高效液相色谱测定方法,以分别考察云南不同产地白花丹药材的不同部位中白花丹醌的含量。方法:色谱柱为 Kromasil C_(18)柱(250 mm×4.6 mm,5μm),流动相为甲醇-水(70:30),流速为1.0mL·min~(-1),检测波长为254 nm,柱温为25℃。结果:白花丹醌在25.3～253μg·mL~(-1)范围内,具有良好的线性关系,r=0.9998;平均回收率为99.0%,RSD=1.4%(n=6)。不同产地白花丹药材地上部分的白花丹醌含量分别为0.046%(嘎洒),0.079%(勐养),0.134%(嘎东),0.032%(曼东),0.047%(曼阁),0.057%(曼老);根部的白花丹醌含量分别为0.842%(嘎洒),1.04%(勐养),1.44%(嘎东),0.763%(曼东),0.639%(曼阁),1.97%(曼老)。结论:本法简便、准确,灵敏度高,重复性好,可用于控制白花丹药材质量。     

Quality Control Standards for the Roots of Three Plumbago Species

Physicochemical parameters of roots of three Plumbago species, Plumbago capensis, P. rosea and P. zeylanica belonging to Plumbaginaceae were analyzed. Microbial contamination, aflatoxins, pesticide residue and heavy metal content were also determined. Attempt has also been made to estimate the biologically active chemical plumbagin present in them and the data compared. The study ensures that the quality control parameters do help in the proper standardization of the crude drugs in drug development process for global acceptance.     

白花丹素的体外肾毒性及酸性成纤维细胞生长因子对白花丹素所致肾损伤的保护作用

目的：观察白花丹素在体外对人胚肾细胞293的毒性,以及酸性成纤维细胞生长因子（aFGF）对白花丹素所致肾损伤的保护作用。方法：采用四噻唑蓝（MTT）法检测不同浓度白花丹素对人胚肾细胞293的毒性,以及aFGF对白花丹素IC50值的影响,并测定培养上清液中超氧化物歧化酶（SOD）、丙二酰二醛（MDA）和乳酸脱氢酶（LDH）的活性。结果：白花丹素在体外对人胚肾细胞293的毒性呈现剂量依赖性,24、48和72 h的IC50值分别为（150.421±3.014）、（88.426±1.965）和（84.811±1.035）μg/mL。在aFGF作用下,24、48和72 h的IC50值分别升至（342.624±2.887）（、176.835±1.097）和（133.278±1.124）μg/mL。aFGF保护组与白花丹素损伤组的SOD、MDA和LDH测定结果有显著性差异（P〈0.05）。结论：白花丹素可抑制人胚肾细胞293的增殖,对肾脏有一定的毒性。aFGF对白花丹素所致肾损伤有明显的保护作用。     

白花丹炮制工艺考察

目的:优化白花丹炮制工艺,为该药材的临床安全应用提供参考。方法:以白花丹醌、香草酸含量的综合评分为指标,通过正交试验考察炮制时间、白酒用量、乙醇体积分数对白花丹炮制工艺的影响。采用HPLC测定白花丹醌及香草酸含量,流动相甲醇-0.15%磷酸梯度洗脱,检测波长260 nm。结果:最佳酒炙炮制工艺为白酒用量0.2 m L·g-1,炮制时间45 min,乙醇体积分数12%。白花丹醌、香草酸质量分数分别为0.013 0%,0.019 3%。结论:优选的工艺条件稳定可行、方法简便,可用于白花丹的质量控制与酒炙品制备。     

Perspectives on medicinal properties of plumbagin and its analogs

Plumbagin is one of the simplest plant secondary metabolite of three major phylogenic families viz. Plumbaginaceae, Droseraceae, and Ebenceae, and exhibits highly potent biological activities, including antioxidant, antiinflammatory, anticancer, antibacterial, and antifungal activities. Recent investigations indicate that these activities arise mainly out of its ability to undergo redox cycling, generating reactive oxygen species and chelating trace metals in biological system. The compound is endowed with a property to inhibit the drug efflux mechanism in drug‐resistant bacteria, thereby allowing intracellular accumulation of the potent drug molecules. An interesting bioactivity exhibited by this compound is the elimination of stringent, conjugative, multidrug‐resistant plasmids from several bacterial strains including opportunistic bacteria, such as Acinetobacter baumannii. Moreover, plumbagin effectively induces apoptosis and causes cell cycle arrest, which is, in part, due to the inactivation of NF‐κB in cancer cells. Therefore, it has been suggested that designing “hybrid drug molecules” of plumbagin by combining it with other appropriate anticancer agents may lead to the generation of novel and potent anticancer drugs with pleiotropic action against human cancers. This comprehensive review is an attempt to understand the chemistry of plumbagin and catalog its biological activities reported to date.     

白花丹醌通过CXCL8/PI3K/AKT糖酵解通路抑制结肠癌细胞增殖、促进凋亡

目的:观察白花丹醌对结肠癌细胞Caco-2增殖、凋亡的影响,探究其潜在的作用机制。方法:运用CCK8法、流式细胞术检测不同浓度白花丹醌（4、8、12 μmol/L）处理的Caco-2细胞的增殖抑制率、凋亡率。不做任何处理的Caco-2细胞设为Control;脂质体法将si-NC组（转染si-NC）、si-CXCL8组（转染si-CXCL8）转染至Caco-2细胞;8 μmol/L的白花丹醌与0.5%DMSO处理的Caco-2细胞设为8 μmol/L+DMSO组;8 μmol/L的白花丹醌分别与z-VAD-FMK、740Y-P处理的Caco-2细胞设为8 μmol/L+z-VAD-FMK组、8 μmol/L+740Y-P组。RT-qPCR、Western blot实验检测细胞中CXCL8的mRNA、蛋白表达,CXCL8、M2-型丙酮酸激酶（M2 pyruvate kinase, PKM2）、L-乳酸脱氢酶A（lactate dehydrogenase A,LDHA）、人α-烯醇化酶(apha-enolase,ENO1)、葡萄糖磷酸异构酶（glucose phosphate isomerase,GPI）、磷酸化磷脂酰肌醇3激酶（phosphorylated phosphatidylinositol 3 kinase,p-PI3K）、磷酸化蛋白激酶B（phosphorylated protein kinase B,p-AKT）的蛋白表达。结果:与Control组相比,白花丹醌（4、8、12 μmol/L）呈浓度依赖性促进Caco-2细胞增殖抑制率、凋亡率升高,抑制CXCL8的mRNA和蛋白表达。与8 μmol/L+DMSO组相比,8 μmol/L+z-VAD-FMK组细胞的增殖抑制率、凋亡率明显降低,CXCL8的mRNA和蛋白表达明显升高（P＜0.05）。白花丹醌（4、8、12 μmol/L）呈浓度依赖性抑制PKM2、LDHA、p-PI3K、p-AKT的蛋白表达。si-CXCL8组PKM2、LDHA、p-PI3K、p-AKT的蛋白表达明显低于si-NC组。740Y-P明显减弱白花丹醌对Caco-2细胞增殖抑制率和凋亡率的促进作用。结论:白花丹醌抑制结肠癌细胞增殖,促进凋亡,其潜在的作用机制与CXCL8/PI3K/AKT糖酵解通路有关。     

Fingerprinting of Plumbagin in lic>Drosera burmannii Vahl using High Performance Thin Layer Chromatography

HPTLC fingerprinting profile of the alcohol and aqueous extracts of Drosera burmannii is described. Seven components have been detected in the alcohol extract. Further, plumbagin, an useful antifertility agent, was also detected by comparison with the reference standard. The aqueous extract revealed two spots with no spot corresponding to plumbagin.