Interaction of Hypocrellin B or Mono-cysteine Substituted Hypocrellin B with CT-DNA by Spectral Methods

The interaction of the anticancer drug hypocrellin B (HB) or the mono-cysteine substituted hypocrellin B (MCHB) and calf thymus deoxyribonucleic acid (CT-DNA) has been investigated using spectral methods. The results of UV-visible spectra show that the HB and MCHB could intercalate into the base-stacking domain of the CT-DNA double helix. The studies of fluorescence spectra and circular dichroism(CD) spectra also support the interacalation mechanism.

Preparation of hypocrellin B nanoparticlesfor photodynamic therapy

OBJECTIVE To prepare hypocrellin B-loaded apoferritin nanoparticles(HB-AFT NPs)for photodynamic therapy on tumor.METHODS HB-AFT NPs were prepared by taking advantage of the reversibleunfolding and refolding character of apoferritin in different pH environments.The photophysical and photobiological properties of hypocrellin B-loaded apoferritin were measured.RESULETS HB molecules were successfully encapsulated within apoferritincavity.HB-AFT-NPs exhibited higher ROS productionthan free HB.Additionally,phototoxicity of HB-AFT NPs to MDA-MB-231 cells was significantly improved as compared to free HB.CONCLUSION Together these results demonstrate that hypocrellin B-loaded apoferritin might be a potential nanoscale photosensitizer.

Killing effect of the combined treatment of ultrasound and hypocrellin B on Candidaalbicans

OBJECTIVE To investigate the killing effect of the combined treatment of ultrasound and hypocrellin B,an active component isolated from a natural product Hypocrella bambuase,on Candida albicans.METHODS At first,Candida albicans are incubated with hypcrellin B and the uptake of hypocrellin B in Candida albicans was determined using fluorescence intensity analysis.And then the sensitized Candida albicans were exposed to low-intensity of ultrasound.After the combined treatment of ultrasound and hypocellin B,the growth of Candida albicans was evaluated using the colony counting method,and membrane integrity of Candida albicans was also analyzed by a flow cytometry with propidium iodide staining.RESULTS Hypocrellin B was fast absorbed by candida albicans.The growth of candida albicans was more significantly inhibited by the combined treatment of ultrasound and hypocrellin B than the controls(P<0.05).The more marked damages to membrane integrity were found in the combined treatment than the controls(P<0.05).CONCLUSION The combined treatment of ultrasound and hypocrellin B had significant killing effect on Candida albicans,indicating sonodynamic therapy with hypocrellin B from natural product might be a potential approach for combating fungal infections.

Effect of sonodynamic action of hypocrellin B on biofilm-producing Enterococcus faecalis

OBJECTIVE To investigate the effect of sonodynamic action on biofilm-producing Enterococcus faecalis using hypocrellin B from a natural product Hypocrella bambuase as a sensitizer.METHODS The uptake of hypocrellin B in biofilm-producing Enterococcus faecalis was measured using the fluorescent analysis method.After the combined treatment of hypocrellin B and ultrasound,the growth of biofilm-producing Enterococcus faecalis was measured using the colony counting method,the membrane integrity was detected using a flow cytometric analysis with propidium iodide staining.Chromosomal DNA of bacteria was analysed using apulsed-field gel electrophoresis(PFGE).RESULTS The uptake of hypocrellin B in biofilm-producing Enterocuccus faecalis reached a high peak at the 20 min incubation.After the combined treatment of hypocrellin B,the growth of biofilm-producing Enterocuccus faecalis significantly descreased and membrane integrity was remarkably damaged.However,no remarkable change in bacterial DNA was found.CONCLUSION Sonodynamic action of hypocrellin B had significant killing activity on Enterocuccus faecalis.

Fluorescence response of hypocrellin B to the environmental changes in a mimic biological membrane——liposome

Liposome is well known as not only a drug-delivery system but also a simple model for biological membranes. It was reported that fluorescence properties of hypocrellins were changeable over some extreme pH values. In the current work, the effects of the microenviron-ments on the fluorescence properties of HB in liposome, including approximately physiological range of pH values pH = 6.0—8.0, concentration of cholesterols and ionic strength of the solution, were studied. It was found that the fluorescence intensity of HB was sensitive to and also regulated by the microenvironments. When concentration of cholesterols and ionic strength keep invariable in PBS solution, there exists the maximum for the fluorescence of HB-liposome at pH 7.4 while the minimum for that of HB at pH 7.0. In addition, when pH value keeps constant (7.2), there exists the maximum at the ionic strength of 0.12 mol/kg while that at the concentra-tion of 6?0-4 mol/L for cholesterols. On the other hand, in PBS solution, the lower the ionic strength is, the higher the fluorescence intensity is. The environment-sensitive fluorescence may be potentially applicable to probe some specific environmental features in cells or tissues.

Photoinduced charge injection from excited triplet hypocrellin B into TiO_2 colloid in ethanol

Photosensitization of TiO2 colloid by hypocrellin B (HB),a natural photodynamic pigment with extremely high photosta-bility,has been studied by surface enhanced Raman spec-troscopy (SERS),laser flash photolysis and electron paramagnetic resonance (EPR) techniques.The photoseiisitization of TiO2 occurred practically from the excited triplet dye and the electron injection rate constant is 1.3×106 s-1.The influences of donor and acceptor on the electron injection were investigated.

Quenching of fluorescence in membrane protein by hypocrellin B

The hypocrellin B (HB) was used as a fluorescence quencher to study the basic physical characteris-tics of HB in membrane systems, including the diffusion speed of quencher from aqueous phase into membrane phase, the partition coefficient (P) of quencher between membrane and water, and the fluorescence quenching constant of protein (Ksv; Kq). The experimental results show that the quenching of fluorescence in membrane protein by HB can be determined by the principle of dynamic quenching. The experimental process of fluorescence quenching was ob-served in detail by using the ESR technique. The signal of HB" was found to arise from an electron transfer from ex-cited trytophan to HB.

Raman spectroscopic study of space structure of membrane proteins and membrane lipids in photodamaged human erythrocyte sensitized by hypocrellin B

Laser Raman spectroscopy was used to investigate the photodamage characteristics of human erythrocyte membranes sensitized by hypocrellin B (HB) at the molecular level. It brought to light that the essence of the changes of erythrocyte membranes’ functions caused by membrane protein cross linking and membrane lipid peroxidation, including increase of fluidity and ion permeability of membranes, etc., was that the orderly structure of erythrocyte membranes had been damaged by the active oxygen ( 1O 2, O 2 .- and .OH) generated by HB, including the decrease of α helix, β sheet and the increase of random coil in the main chain of membrane proteins, the decrease of mercapto groups, indole rings, p hydroxy phenyl rings, monosubstituted phenyl rings, etc. in the side chain, and the changes of the conformations of membrane lipids as well. With the increase of the irradiation time, the trans conformation of membrane lipids increased first, then decreased. On the contrary, the gauche conformation decreased first, then increased. In addition, the decrease of the intensities of the lines assigned to bending vibration of the conformation insensitive CH 2 and CH 3 of membrane proteins and lipids suggested that break of their chains had occurred.

Hypocrellin B doped and pH-responsive silica nanoparticles for photodynamic therapy

pH-responsive 1O2 photosensitizing systems may serve as selective photodynamic therapy(PDT) agents by targeting the acidic interstitial fluid of many kinds of tumors.In this work,a natural and clinically used photosensitizer(Hypocrellin B,HB) and a pH indicator(Bromocresol Purple,BCP) were co-encapsulated in organically modified silica nanoparticles.BCP successfully regulated the 1O2 generation efficiency of HB through the "inner filter" effect,which shows much stronger 1O2 generation ability in an acidic than in a basic environment.In vitro experiments also demonstrated that HB-doped nanoparticles are effective in killing tumor cells by PDT.

SEPARATION AND IDENTIFICATION OF HYPOCRELLIN B AND FATTY ACIDS AS INGREDIENTS IN Hypocrella bambusae (B. et Br.) Sacc.

Hypocrella bambusae (B. et Br.) Sacc. is a kind of parasitic fungi which grows most abundantly in Yunnan Province in China. Both the Institute of Microbiology of Yunnan Province and the First People’s Hospital of the same province were for the first time to apply the extract of the fungus to skin and then to irradiate it with visible light for the treatment of white lesions of vulva and keloid, and

Abnormal behavior of fluorescence quenching of gramicidin A inphase transition of lipid vesicles by hypocrellin B——Does anelectron transfer inverted region exist?

The fluorescence of gramicidin A(GA) in lipid bilayer may be quenched by Hypocre-Ilin B. When the phospholipids undergo a phase transition from gel to liquid crystalline phase, the reaction rate decreases unusually. This phenomenon has been analyzed by Marcus’ pho-toinduced electron theory, and an electron transfer inverted region hypothesis is proposed,

REACTIONS OF HYPOCRELLIN B ON MERCAPTO COMPOUNDS Ⅱ: REACTIONS OF HYPOCRELLIN B ON CYSTEINE OR CYSTEAMINE

Ⅰ. INTRODUCTIONThe target of the photodynamic action of the new Chinese photothrapeutic agent- hypocrellins is the cell membrane. This photodynamic action causes the reduction in quantity of mercapto groups in membrane proteins. But the mechanism of

PHOTOOXYGENATION OF CAFFEINE SENSITIZED BY HYPOCRELLIN B

The photooxygenation of caffeine sensitized by Hypocrellin B in alcohol solvents hasbeen investigated in this paper. The products have been isolated and identified. The mainproduct is 8--alkoxyl substituted caffeine derivatives. Deuterium. oxygen partial pressure andNaN3-quenching experiments indicate that the reaction proceeds on singlet oxygen mechanism.

Synthesis,characterization and photodynamic activity of ethanolamino-substituted hypocrellin B(EAHB2)

The limitations of currently used clinical phototherapeutic agent, Photofrin, have prompted a search for more ideal photodynamic sensitizer. The hypocrellins, have been paid the

Raman spectroscopic study of DNA photodamage sensitized by hypocrellin B and 5-brominated-hypocrellin B

Hypocrellin B (HB) is a highly effective photosensitizer. One of its derivatives, 5_brominated_hypocrellin B (5_Br_HB) has better photosensitive characteristics than it. Using Raman spectroscopy, the microcosmic photodamage to DNA sensitized by HB and 5_Br_HB was studied at molecular level. The results showed that when HB and 5_Br_HB were added to the solution of DNA and irradiated, the characteristic Raman frequencies and intensities of DNA changed to various degrees. The photodamage occurred on the whole DNA molecule, including phosphate backbone,deoxyribose and four bases. Not only the conformation but also the configuration of DNA was photodamaged: breakage of some H_bonds, disappearance of B_form conformation , scission of double or single strand and serious damage of four bases. The damage to A_T pairs was stronger than that to C_G pairs and DNA became polynucleotides finally. The 5_Br_HB_photosensitized damage to DNA was stronger than HB , which suggested the better photosensitive characteristics of 5_Br_HB in bioactive environment. The molecular mechanisms of photodamage to DNA sensitized by 5_Br_HB and HB were also elucidated.

竹红菌乙素光诱导A549细胞凋亡的机制研究

竹红菌乙素(HB)在特定波长照射下可有效杀伤多种癌细胞,但其光诱导细胞死亡的机制尚未完全阐明。为了探索竹红菌乙素(HB)光诱导人肺腺癌细胞A549细胞死亡的机制,本研究运用激光扫描共聚焦显微镜、MTT染色法、流式细胞技术及蛋白质印迹(Western blot)等技术,针对HB在A549中细胞摄取、亚细胞定位、细胞内活性氧的生成、细胞毒性以及细胞死亡机制,进行了详细评估。研究结果显示,HB能够选择性地定位在线粒体,对A549细胞具有较低的暗毒性和较高的光毒性。HB能够光诱导线粒体损伤、线粒体膜电位改变、线粒体内细胞色素c释放和半胱天冬酶的激活,最终引发A549细胞凋亡。由此可见,天然产物HB作为一种靶向线粒体的潜在光敏剂,具有优异的抗肿瘤活性,可通过线粒体介导的内源途径信号通路诱导细胞凋亡。通过该研究,为HB光动力治疗非小细胞肺癌的临床应用提供参考和理论依据。

竹红菌素B的两种剂型用于鲜红斑痣光动力治疗的动物实验研究

目的:观察竹红菌素B的脂肪乳剂型和脂质体剂型对鲜红斑痣动物模型的光动力作用是否有差异,并观察其光动力效应及副作用。方法:莱亨鸡32只,分为对照组;HMME组;脂质体0.5 mg/kg组和1.0 mg/kg组;脂肪乳0.5 mg/kg组和1.0 mg/kg组。莱亨鸡静脉注入光敏剂后,立即用532 nm的激光照射鸡冠直径1 cm的圆形区域,激光剂量为功率密度100 mW/cm2,能量密度120 J/cm2。PDT后每天进行观察照像,14 d后取材进行病理观察。结果:HMME组6例皆为中度改变,真皮浅层血管网明显减少,结痂轻。脂肪乳0.5 mg/kg组6例中5例为重度改变、1例为中度改变,脂质体0.5 mg/kg组6例皆为重度改变,病理见表皮增生,真皮浅层血管少,结中等厚度的黒痂。脂肪乳1.0 mg/kg组6例皆为极重度,脂质体1.0 mg/kg组5例为极重度改变、1例为重度改变,病理为痂下坏死灶,部分修复的表皮增生,真皮浅层几乎无血管,结黑色厚痂。结论:HB的脂肪乳剂型和脂质体剂型对鸡冠的光动力效应基本一致,都具有较好的血管破坏作用,但对正常表皮和真皮的损伤较重。

竹红菌素B的两种剂型对小鼠S180肉瘤的光动力作用观察

目的观察竹红菌素B(HB)微乳剂型和脂质体剂型对荷瘤小鼠的光动力效应,并比较两者作用是否相同。方法昆明小鼠双侧胸皮下接种S180肉瘤腹水瘤液制成肿瘤模型。实验分为6组,每组6只小鼠。对照组(不作PDT处理);HMME组(10 mg／kg,给药1 h后照光);脂质体-1组(给药1 h后照光)和脂质体-6组(给药6 h后照光);脂肪乳-1组(给药1 h后照光)和脂肪乳-6组(给药6 h后照光),后4组HB剂量皆为1．5 mg／kg,尾静脉给药。激光波长532 nm,功率密度为100 mW／cm2,能量密度100 J／cm2。测量治疗前后瘤体大小,7 d后取材进行病理组织学检查。结果:PDT治疗后,肿瘤体积无缩小。HMME组肿瘤表面坏死轻,镜下皮肤和肿瘤浅层出现坏死,坏死灶周围有大量炎性细胞。两种HB剂型1 h组全部出现较重的肿瘤坏死,呈黑色,范围较肿瘤小。镜下皮肤及肿瘤的坏死,坏死灶周围有大量炎性细胞浸润,部分炎性细胞侵入未受破坏的肿瘤组织。两种HB剂型6 h组8只小鼠中有6只肿瘤表面无坏死,镜下在正常皮肤下、肿瘤深部有明显的坏死,呈椭圆形,坏死灶周围及皮下有大量炎性细胞浸润,并侵入未受破坏的肿瘤组织。结论HB的微乳和脂质体剂型都有一定的光动力效应,作用相近,HB是一种有开发潜力的光敏剂。

竹红菌乙素(HB)在C_(60)与三乙胺分子间电子转移反应中的光催化作用

用ＥＳＲ 方法探讨了在Ｃ６０ 与三乙胺（Ｅｔ３ Ｎ） 的分子间电子转移反应中竹红菌乙素（ＨＢ） 的光催化作用．通过对Ｅｔ３Ｎ／Ｃ６０／ＨＢ 电子转移反应体系及其中间体的研究得知：在ＨＢ存在的条件下，可通过光催化电子转移反应机理，实现室温下由Ｅｔ３Ｎ 到基态Ｃ６０

HB-PDT对经顺铂诱导耐药及非耐药肺癌细胞系杀伤效应的比较

目的:对比研究耐药及非耐药肺癌细胞株对竹红菌乙素-光动力疗法(HB-PDT)的反应性,以及耐药肿瘤对HB-PDT及化疗药物顺铂的反应性之间是否存在差别。方法:以不同浓度的竹红菌乙素(HB)分别孵育人肺腺癌细胞系A549及经顺铂(DDP)诱导耐药的多药耐药细胞系A549/DDP,然后分别在铜蒸汽激光混合光饱和光剂量条件下进行照光处理,照光后继续孵育24 h,MTT法分别测定不同HB浓度下2种细胞的存活率,分别绘制HB对2种细胞存活率曲线并拟合曲线方程,根据方程求出HB对2种细胞的半数杀伤浓度(IC50)。结果:HB-PDT对经顺铂诱导耐药及非耐药细胞系均具有很强的杀伤效应,HB-PDT对A549及A549/DDP的IC50分别为33.82 ng/ml和34.19 ng/ml,两者之间差异不显著(P>0.05);顺铂对A549及A549/DDP的IC50分别为1.06μg/ml和8.06μg/ml,两者之间差异显著(P<0.01);HB-PDT和化疗药物顺铂对耐药肿瘤细胞杀伤效应间差异显著(P<0.01)。结论:HB-PDT对于耐药及非耐药细胞的光毒效应无显著差别。HB-PDT对耐药肿瘤细胞具有明显的光毒效应,其杀伤经顺铂耐药肿瘤细胞的效果明显优于已产生耐药的化疗药物。HB-PDT有可能发展为对顺铂耐药肿瘤的有效治疗手段。