Differential diagnosis of gallstones by using hypericin as a fluorescent optical imaging agent

AIM: To explore the feasibility of using hypericin as an optical imaging probe with affinity for cholesterol for differential fluorescent detection of human gallstones.METHODS: Cholesterol, mixed and pigment stones from cholecystectomy patients were incubated with hypericin or solvent. After 72 h, the stones were analysed for fluorescence(365 nm) and treated with 2-propanol/dimethyl sulfoxide for high performance liquid chromatography(HPLC) analysis. Rats with virtual gallbladder containing human cholesterol, mixed or pigment gallstones(VGHG) received 5 mg/kg hypericin or solvent and VGHG rats with cholesterol stones were given different hypericin doses(5-15 mg/kg). Twelve hours later, the stones were analysed at 365 nm. Biliary excretion and metabolites of hypericin were assessed in common bile duct(CBD) cannulated rats for 9 h using fluorospectrometry, HPLC and matrixassisted laser desorption/ionization-time-of-flight mass spectrometry(MALDI-TOF MS).RESULTS: Homogeneous high fluorescence was seen on cholesterol stones either pre-incubated with hypericin or extracted from VGHG rats receiving hypericin. Mixed stones showed a dotted fluorescent pattern, whereas pigment and solvent-treated ones lacked fluorescence. HPLC showed 7.68, 6.65 and 0.08 × 10^(-3) M of cholesterol in extracts from cholesterol, mixed, and pigment gallstones, respectively. Hypericin accounted for 2.0, 0.5 and 0.2 × 10-6 M in that order. On cholesterol stones from VGHG rats receiving different hypericin doses, a positive correlation was observed between dose and fluorescence. In the bile from CBD-cannulated rats, fluorescence represented 20% of the injected dose with two peaks in 9 h. HPLC analysis revealed that hypericin conjugates reached 60% of the peak area. By MALDI-TOF MS, hypericinglucuronide was detected. CONCLUSION: This study proves the potential use of hypericin for differential fluorescent detection of human gallstones regarding their chemical composition.

Evaluation of photodynamic efficiency of an endogenous enzyme-NQO1 activated hypericin

OBJECTIVE To investigate the therapeutic efficiency of an endogenous enzyme-NQO1 activated hypericin in photodynamic therapy.METHODS An endogenous enzyme-NQO1 responsive photo sensitizer was designed and synthesized by conjugating aquinonebased ligand to a natural photosensitizer derived from Chinese herb.The photophysical and photochemical properties were investigated through UV-visible and fluorescence spectrophotometer,and the photodynamic activity was evaluated with MTT assay.RESULTS An endogenous enzyme-NQO1 activated hypericin was prepared and fully characterized with various spectroscopic methods.The electronic absorption was almost the same with the free hypericin,indicating the introducing of the ligand to hypericin has little effect to its ground state,while there is almost no detected fluorescence and reactive oxygen species(ROS)generation in PBS solution indicating the introducing of the ligand can effectively quench the fluorescence emission and ROS generation.The in vitro study showed that both compounds have almost no dark toxicity,but they are highlyphotocytoxic with an IC50 less than 1μmol·L-1 against A549 cell lines indicating the modified compound can be activated in the intracellular environment.CONCLUSION A simple and efficient hypericin-based activated photosensitizer was prepared.The ROS generation was quenched in PBS solution and it would be activated inside A549 cell lines.It may be served as apromising tumor selective fluorescent probe and photosensitizer for targeted photodynamic therapy.

Topically applied hypericin exhibits skin penetrability on nude mice

OBJECTIVE Hypericin,a powerful naturally photosensitizer in photodynamic therapy(PDT),is suitable for treating skin diseases involving excess capillary proliferation.In the present study,we aimed to evaluate the skin penetrability of a topically applied hypericin,expecting reducing the risk of prolonged skin photosensitivity,which often occurs after systemic administration.METHODS The Franz diffusion cell assay was performed to evaluate different penetration enhancers.In vivo studies,fluorescence microscopy was performed to examine the distribution of hypericin in the skin,macroscopic and microscopic analyses were also carried out to detect pathological changes in the skin after topical hypericin-PDT treatment.Immunohistochemistry was used to determine the expression of PECAM-1 in the treated skin.RESULTS 5% menthol facilitated hypericin penetrate the skin of nude mice most.The results of in vivo assays revealed that hypericin penetrated nude mice skin,spread to the dermis,and resulted in obvious photosensitivity reaction on the dermal capillaries.Moreover,skin injured by the photosensitive reaction induced by hypericin was replaced by normal skin 7 d after hypericin-PDT treatment.CONCLUSION Topical hypericin could penetrate nude mouse skin well and be great potential in PDT treatment of skin diseases.

In vitro 3D malignant melanoma model for the evaluation of hypericin-loaded oil-in-water microemulsion in photodynamic therapy

Advances in biomimetic three-dimensional(3D) melanoma models have brought new prospects of drug screening and disease modeling, since their physiological relevancy for recapitulating in vivo tumor architectures is more accurate than traditional two-dimensional(2D) cell culture. Gelatin methacryloyl(GelMA) is widely used as a tissue-engineered scaffold hydrogel for 3D cell culture. In the present study, an in vitro 3D malignant melanoma model based on Gel MA was fabricated to evaluate the efficiency of hypericin(Hy)-loaded microemulsion(ME) in photodynamic therapy against melanoma. The ME was produced by the spontaneous emulsification method to enhance the bioavailability of Hy at tumor sites. Hy-loaded MEs were applied to a 3D malignant melanoma model made using 6% Gel MA and the co-culture of B16F10 and Balb/c 3T3 cells,followed by crosslinking using violet light(403 nm). The observation revealed excellent cell viability and the presence of F-actin cytoskeleton network. Hy-loaded MEs exhibited higher phototoxicity and cell accumulation(about threefold) than free Hy, and the cells cultured in the 3D system displayed lower susceptibility(about 2.5-fold) than those in 2D culture.These findings indicate that the developed MEs are potential delivery carriers for Hy;furthermore, Gel MA hydrogel-based modeling in polydimethylsiloxane(PDMS) molds is a user-friendly and cost-effective in vitro platform to investigate drug penetration and provide a basis for evaluating nanocarrier efficiency for skin cancer and other skin-related diseases.

Effects of Different Geographical Aspects and Ontogenetic Variability on Total Hypericin Content of Hypericum triquetrifolium Turra. and Hypericum scabrum L.

The present study was conducted to determine the total hypericin contents of Hypericum triquetrifolium Turra.and Hypericum scabrum L.species which are naturally distributed in the flora of Siirt province,Turkey.Hypericin contents of Hypericum species grown in different geographical aspects(North,South,East,and West),and it was measured at different harvest times(full bloom-ing and post blooming period).In the current study,it has been determined that total hypericin content varies considerably according to aspects,plant developmental stages(ontogenetic variance),and species.According to species x aspect interaction,the highest total hypericin content was recorded from the west aspect(3.13 mg/g)in Hypericum triquetrifolium,while,the lowest hypericin content was also obtained from the west aspect(1.22 mg/g)in Hypericum scabrum.When the highest total hypericin content was analyzed according to aspect x species x harvest time interaction,the highest total hypericin content was produced from Hypericum triquetrifolium at the harvest of west aspect with 5.28 mg/g,while the minimum amount of hypericin was obtained from the same aspect in Hypericum scabrum with 0.50 mg/g.In species x harvest time interaction,the highest total hypericin content was obtained from the full bloom(3.10 mg/g)harvest in Hypericum triquetrifolium,while the lowest hypericin was obtained from the full bloom(1.26 mg/g)harvest in Hypericum scabrum.The data suggest that the aver-age total hypericin content was 2.26 mg/g in Hypericum triquetrifolium and 1.28 mg/g in Hypericum scabrum.

Effect of Photoactivated Hypericin on Growth and Antibiotic Susceptibility of Hospital-Related Staphylococcus aureus and Enterococcus sp. Clinical Strains

Resistance against commonly used antibiotics is a serious clinical problem in recent medical practice. There exist several bacterial strains in which the possibilities of their inhibition are very limited due to multidrug resistance. Antimicrobial photodynamic therapy (aPDT) represents an option how to effectively suppress the growth of resistant pathogens. In this work we have studied interactions of potent photosensitizer hypericin (Hyp) with hospital-related gram positive (Gram+) and gram negative (Gram-) bacterial strains and the effects of photodynamic activated Hyp on bacterial susceptibility and/or resistance of these strains to antibiotics. We demonstrated a significant influence of photoactivated Hyp on growth of Staphylococcus aureus and Enterococcus sp. We have also shown that it is extremely important to use the effective concentrations of Hyp for aPDT, which completely inhibit the growth of microorganisms. Otherwise, there appears an increase in resistance, probably due to the activation of efflux mechanisms, which are involved in the efflux of Hyp and antibiotics as well.

Effect of Hypericin on Confocal Imaging of Ca^(2+) Signaling in Cultured Human Retinal Pigment Epithelium

Purpose: To investigate the mechanism of the Ca2 + signaling in cultured human retinal pigment epithelial(RPE) cells with the protein kinase C(PKC) specific inhibitor-hypericin stimulation.Methods: Cultured human RPE cells were analyzed using the fluorescence Ca2+ dye fluo-3 AM and laser scanning confocal microscope(LSCM) after stimulation with 100nM phorbol 12-myristate 13-acetate(PMA) and (or)5 concentrations of hypericin(1, 2, 3, 4 and 5 μM).Results: The normal fluorescence in RPE cells was strong and distributed throughout the cells. The nucleus appeared to be more fluorescent than the cytoplasm. After stimulation with PMA alone or 5 concentrations of hypericin, a rapid decrease in flurescence intensity was observed. There was no obvious difference in decreased curve among 5concentrations. However, after stimulation with a 24 hr preincubation of PMA and 5 concentrations of hypericin, a further decrease was not observed.Conclusion: Fluo-3 AM appears to be a good indicator of the change in Ca2+ occurring in RPE cells and hypericin is a strong inhibitor of Ca2 + influx channel. Hypericin has potential as a therapeutic drug for proliferative vitreoretinopathy(PVR), the inhibitory effect on PVR might be caused by blocking the PKC activity and inhibiting Ca2+ influxpathway.

金丝桃素-β-环糊精络合物的制备及其在小龙虾保鲜膜中的应用

目的探究魔芋葡甘露聚糖(konjac glucomannan,KGM)、海藻酸钠(sodium alginate,SA)、巴西棕榈蜡(carnaubawax,CW)与金丝桃素-β-环糊精络合物(hypericin-β-cyclodextrin complex,Hyp-β-cd)制备的光敏性保鲜膜在4℃储藏条件下对小龙虾的品质影响。方法将制备的Hyp-β-cd加入到KGM、SA与CW溶液中,采用流延法制备光动力杀菌保鲜膜(KGM/SA/CW/Hyp-β-cd膜),通过核磁共振光谱(nuclear magnetic resonance spectroscopy,NMR)与荧光猝灭法验证了Hyp-β-cd的形成和活性氧(reativ oxygen species,ROS)的生成能力,然后用正交实验法对复合膜的制备进行优化。通过扫描电子显微镜(scanning electron microscope,SEM)、傅里叶红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线衍射(X-ray diffrction,XRD)进行表征,最后,以pH、总挥发性盐基氮(total volatile basic nitrogen,TVB-N)、菌落总数及硫代巴比妥酸反应物(thiobarbituric acid reactants,TBARS)值做为指标对保鲜效果进行评估。结果NMR及荧光猝灭的结果表明Hyp-β-cd的形成和ROS的生成,通过正交实验法对复合膜的制备进行优化:KGM含量为0.7%(m/V,下同)、SA含量为1.2%、CW含量为0.6%、Hyp-β-cd含量为0.4%时,复合膜有最优机械性能,拉伸强度为51.84MPa,断裂伸长率为14.27%。SEM证明了各物质在复合膜中的均匀分布。FTIR与XRD结果表明,随着SA、CW与Hyp-β-cd的加入,KGM与SA之间形成氢键,提高了复合膜的物理性能,CW的加入减少了复合膜的微孔隙,其中水接触角从67.5°增加到88.7°,氧气透过率从32.96降低到22.37 m^(3)·μm/m^(2)·day·kPa。由KGM/SA/CW/Hyp-β-cd膜包裹且在黄色LED光源照射处理后的小龙虾,在第8d时TVB-N值为20.37mg/g,菌落总数为6.14lgCFU/g,TBARS值为0.85 mg/kg,pH超过7.6。结论KGM/SA/CW/Hyp-β-cd复合膜具有作为光敏性抗菌包装材料的潜在应用价值。

Raman spectroscopic study on structure of human immunodeficiency virus (HIV) and hypericin-induced photosen- sitive damage of HIV

The first Raman spectra of HIV1- HIV2 in human sera and hypericin-induced pho- tosensitive damage of the virus have been obtained. The prominent Raman lines in the spectra are assigned respectively to the carbohydrates of viral glycoprotein, RNA, protein and lipid. The spectra are dominated by Raman scattering of the carbohydrates. The lines of D-Mannose and N-acetylglucosamine in carbohydrates are obvious and there is a β-configuration in the anomeric C1 position in D-Mannose. The viral RNA duplexes bound assumes an A-form geometry. The lines of backbone phosphate group, bases (involving interbase hydrogen bonding) and ribose of the RNA are complete and distinct. The secondary structure of the viral protein maintains α-helix, β-sheet, β-turn and random coil. Its side chains are rich and vary from tryptophan, phenylalanine and “buried” tyrosine; the stable conformation of the S-S bond of gauche-gauche-gauche; the two forms of C-S bonds of gauche and trans ; to sulfhydrl group and ionized and unionized carboxyl groups. The viral lipid bilayer molecules are probably in the liquid ordered phase or the gel phase. It was observed that the hypericin-induced photosensitive damage of HIV1-HIV2 in human sera changed various components of HIV1-HIV2 in different degrees : The orderly A-form viral RNA would become a disordered viral RNA. There were a breakage of interbase hydrogen bonds and disruption of vertical base-base stacking interactions. In addition, the groups of ribos and four bases were damaged obviously. A decrease in ordered structure (α-helix and β-sheet) of viral protein is accompanied by an increase in random coil. The Tyr buried in the three-dimensional structure of protein was damaged, but it was still “buried” and the damage of C-S bond of trans form was stronger. The groups of carbohydrates, including D-Mannos and N-acetyl glucosamine, in viral envelope glycoprotein had also been changed. The hydrophilic C-N bond of choline in viral lipid was damaged, which was the possible binding site to hypericin, whereas the viral lipids bilayers were still probably in the liquid ordered phase or the gel phase. So the space structure of HIV1-HIV2 was damaged under the experimental conditions, which might block viral infection and inhibit its growth and breeding. It is apparent that the laser Raman spectra have provided certain direct evidence at the molecular level for photosensitive damage of HIV1-HIV2.

Signal interaction between nitric oxide and hydrogen peroxide in heat shock-induced hypericin production of Hypericum perforatum suspension cells

Heat shock(HS, 40℃, 10 min) induces hypericin production, nitric oxide(NO) generation, and hydrogen peroxide(H2O2) accumulation of Hypericum perforatum suspension cells.Catalase(CAT) and NO spe-cific scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(cPTIO) suppress not only the HS-induced H2O2 generation and NO burst, but also the HS-triggered hypericin produc-tion.Hypericin contents of the cells treated with both NO and H2O2 are significantly higher than those of the cells treated with NO alone, although H2O2 per se has no effects on hypericin production of the cells, which suggests the synergistic action between H2O2 and NO on hypericin production.NO treatment enhances H2O2 levels of H.perforatum cells, while external application of H2O2 induces NO generation of cells.Thus, the results reveal a mutually amplifying action between H2O2 and NO in H.perforatum cells.CAT treatment inhibits both HS-induced H2O2 accumulation and NO generation, while cPTIO can also suppress H2O2 levels of the heat shocked cells.The results imply that H2O2 and NO may enhance each other's levels by their mutually amplifying action in the heat shocked cells.Membrane NAD(P)H oxidase inhibitor diphenylene iodonium(DPI) and nitric oxide synthase(NOS) inhibitor S,S′-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea(PBITU) not only inhibit the mutually amplifying action between H2O2 and NO but also abolish the synergistic effects of H2O2 and NO on hypericin production, showing that the synergism of H2O2 and NO on secondary metabolite biosynthesis might be dependent on their mutual amplification.Taken together, data of the present work demonstrate that both H2O2 and NO are essential for HS-induced hypericin production of H.perforatum suspension cells.Furthermore, the results reveal a special interaction between the two signal molecules in mediating HS-triggered secondary metabolite biosynthesis of the cells.

兴安杜鹃3种主要成分的HPLC测定及其对大鼠气管平滑肌的舒张作用

[目的]建立同时测定兴安杜鹃中金丝桃苷、槲皮素和杜鹃素含量的高效液相色谱法(HPLC),并探讨兴安杜鹃提取物及3种主要成分对大鼠气管平滑肌舒张作用的影响及其作用机制。[方法]采用HPLC法测定兴安杜鹃中金丝桃苷、槲皮素和杜鹃素的含量并进行方法学考察。采用离体气管灌流法取大鼠气管环,将气管环固定于麦氏浴皿中,使用扑尔敏、吲哚美辛、格列苯脲、左旋硝基精氨酸甲酯(L-NAME)、硝苯地平和普萘洛尔进行预孵育,待气管环张力稳定后,加入60 mmol/L KCl溶液收缩气管环,进行兴安杜鹃对气管环的舒张试验,观察大鼠气管平滑肌张力变化。[结果]兴安杜鹃中3种主要成分HPLC测定方法考察结果显示,3种成分均在2~80μg/mL线性关系良好,平均回收率分别为金丝桃苷100.3%(RSD=2.63%)、槲皮素102.7%(RSD=2.89%)、杜鹃素102.1%(RSD=2.36%)。在吲哚美辛、格列本脲和普萘洛尔孵育组织中,兴安杜鹃提取物及3种单体成分的舒张作用与未孵育组相比没有显著差异;在扑尔敏、L-NAME和硝苯地平孵育的组织中,兴安杜鹃及金丝桃苷与未孵育的组织相比有显著差异,舒张作用有所降低。这种现象可能是通过抑制组胺H1受体、一氧化氮合酶途径和钙离子通道介导的钙离子内流实现的。[结论]该试验建立的方法简单、准确,能快速测定兴安杜鹃中金丝桃苷、槲皮素和杜鹃素的含量,为其质量评价和控制提供了有效的分析手段;并且这3种成分与兴安杜鹃舒张气管的作用有关,可作为支气管扩张剂开发的理论依据。

Hypericin: chemical synthesis and biosynthesis

Hypericin is one of the most important phenanthoperylene quinones extracted mainly from plants of the genus Hypericum belonging to the sections Euhypericum and Campylosporus of Keller's classification. Widespread attention to the antiviral and anti-tumor properties of hypericin has spurred investigations of the chemical synthesis and biosynthesis of this unique compound. However, the synthetic strategies are challenging for organic and biological chemists. In this review, specific significant advances in total synthesis, semi-synthesis, and biosynthesis in the past decades are summarized.

月季花饮片标准汤剂的制备与质量评价研究

目的建立月季花饮片标准汤剂的质量评价方法,为月季花标准汤剂的应用和质量控制提供参考。方法采收不同产地的月季花饮片共15批并制备成标准汤剂,将金丝桃苷和异槲皮苷选定为定量检测指标计算出膏率及转移率,建立高效液相色谱(HPLC)特征图谱,并采用中药色谱指纹图谱相似度评价系统(2012版)软件对特征图谱进行分析。结果15批月季花标准汤剂出膏率范围为16.32%~23.22%,金丝桃苷的转移率为27.57%~45.42%,异槲皮苷的转移率为34.38%~49.71%;11个共有特征峰被标定,其中4个色谱峰被指认,与对照图谱相比较,其相似度均>0.90。结论建立了简便、稳定、可行的月季花饮片标准汤剂的制备和质量评价方法,可为月季花饮片标准汤剂的制备和质量控制提供参考。

高效液相色谱法测定臻源胶囊中金丝桃苷和五味子醇甲含量

目的 提升臻源胶囊质量标准,完善其质量控制水平。方法 利用高效液相色谱法(HPLC)测定臻源胶囊中金丝桃苷和五味子醇甲含量。结果 臻源胶囊中金丝桃苷和五味子醇甲平均含量分别为0.27 mg/g和0.34 mg/g,平均加样回收率标准偏差值(RSD)分别为1.63%和1.69%,方法学考察符合规定。结论 在臻源胶囊现有质量标准的基础上,增加了金丝桃苷和五味子醇甲作为含量测定指标,方法简便可行,结果准确,重现性好,为更好控制臻源胶囊产品质量以及探究功效物质基础提供科学依据。

贯叶连翘中金丝桃素抗自由基活性研究

本文采用热回流提取法提取贯叶连翘中的活性成分,通过柱层析法分离纯化出9种化合物,首次从贯叶连翘植物中分离出二十六碳醇、金丝桃苷等化合物,以主要活性成分金丝桃素、槲皮苷和槲皮素为研究对象进行了抗自由基活性研究,结果发现三种物质对超氧阴离子自由基(O^(2-)·)、DPPH自由基(DPPH·)和脂质过氧自由基(RO_(2)·)均具有清除作用,其中槲皮素清除3种自由基能力最强,槲皮苷次之,金丝桃素最弱,通过分析三者的构效关系解释其清除自由基能力差异的原因。

山地虎耳草质量控制方法研究

目的建立山地虎耳草的质量控制方法。方法采用薄层色谱法对山地虎耳草中金丝桃苷进行定性鉴别;采用高效液相色谱法测定山地虎耳草中金丝桃苷和当药醇苷含量。结果金丝桃苷薄层色谱鉴别斑点清晰,特征明显,专属性强,可行性良好,12批样品均显示有金丝桃苷的斑点;高效液相色谱法测定金丝桃苷和当药醇苷2种成分分别在0.1246~1.4946μg(r=0.9999)、0.0453~0.5436μg(r=0.9999)范围内与其峰面积积分值均呈良好的线性关系。结论该文建立的质量控制方法简便、准确、可行,可用于山地虎耳草的质量控制。

金丝桃素与乙基金丝桃素的全合成及对人免疫缺陷病毒逆转录酶的抑制活性

金丝桃素与乙基金丝桃素的全合成及对人免疫缺陷病毒逆转录酶的抑制活性赵晶张致平陈鸿珊陈湘红（中国医学科学院医药生物技术研究所，北京１０００５０）近年发现由贯叶金丝桃（Ｈｙｐｅｒｉｃｕｍｐｅｒｚｏｒａｔｕｍ），三棱三叶金丝桃（Ｈ．ｔｒｉｑｕｅｔｒｉｆ...

金丝桃属植物研究进展

金丝桃属植物中许多种是传统草药,二蒽酮类、类黄酮类及间苯三酚类等次生代谢产物具有许多药理作用.因此近年来对该属植物的分泌结构、具药理作用的化学成分、快速繁殖以及分子水平的研究越来越多.本文就以上各方面的研究进展作一综述.

几种理化因子对贯叶金丝桃细胞培养中的细胞生长和总金丝桃素合成的影响研究

目的 :为了探讨几种理化因子对贯叶金丝桃愈伤组织中金丝桃素含量的影响。方法 :采用高效液相色谱法和植物组织培养的方法。结果与结论 :当硝态类氮和铵态类氮的比例 3∶1时贯叶金丝桃愈伤组织的生长量提高至 1.6倍 ,金丝桃素的合成量也略有提高 ;加入甘露 (0 .1～ 0 .2mol·L-1时 )金丝桃素的合成量有很大的提高 ;加入PVPP ,PVP等防褐化的物质能促进贯叶金丝桃愈伤组织的生长。

金丝桃素体外抗高致病性猪生殖与呼吸综合征病毒活性的研究

为研究金丝桃素体外对高致病性猪生殖与呼吸综合征病毒(PRRSV)活性的影响,以Marc-145细胞培养增殖的PRRSV为研究对象,通过噻唑蓝(MTT)比色法和观察细胞病变效应(CPE),测定吸光度值(D490nm)和半数细胞感染量(TCID50),以细胞存活率、病毒抑制率和TCID50为指标,评价不同剂量的金丝桃素体外抑制PRRSV活性的效应,并通过改变加药方式(同时、感染前、感染后给药),探讨其抗PRRSV的作用机制。结果表明,在PRRSV感染的同时加入金丝桃素,其细胞存活率和对PRRSV的抑制率略有升高,与PRRSV对照组和拉米夫定对照组相比,均有显著性差异(P<0.01)。在PRRSV感染前和感染后加入金丝桃素,其细胞存活率和对PRRSV的抑制率明显升高,且随药物浓度的增加而上升,与PRRSV对照组相比,有显著性差异(P<0.01),与拉米夫定对照组相比无统计学意义(P>0.05)。金丝桃素可使PRRSV的TCID50从6.1下降至4.15。证实,金丝桃素具有多环节体外抗PRRSV效应;不同浓度的金丝桃素表现出不同的抗PRRSV活性,并呈现剂量依赖关系。