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1.
Rosypal AC Hall JE Bakunova S Patrick DA Bakunov S Stephens CE Kumar A Boykin DW Tidwell RR 《Veterinary parasitology》2007,145(3-4):207-216
Canine leishmaniasis caused by Leishmania infantum is enzootic in the North American foxhound population. Currently available chemotherapy for canine leishmaniasis is not completely effective and relapses are common in treated dogs. Pentamidine and related aromatic diamidines possess broad spectrum antiprotozoal activity. The in vitro antileishmanial activities of 35 aromatic cationic molecules were determined, using pentamidine as the reference drug. The compounds were examined for activity against promastigotes of L. infantum isolated from a foxhound from Virginia. The compounds most active against Leishmania parasites were reversed amidines. Compound 9, a reversed amidine, exhibited the highest activity against L. infantum, with a 50% inhibitory concentration (IC(50)) of 0.0042 microM compared with 14.2 microM for pentamidine. Antileishmanial activities of nine compounds were at least 1000-fold higher relative to the reference drug. Results from this study indicate that several pentamidine-related compounds warrant further investigation as possible new agents for the treatment of canine leishmaniasis. 相似文献
2.
Hossain MA Yamato O Yamasaki M Maede Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(4):389-395
The present study was conducted to determine the cause of low parasitemia and simultaneous reticulocytosis in canine babesiosis. The parasitemia was significantly decreased in in vitro cultures of Babesia gibsoni by the pretreatment of host canine erythrocytes with lead acetate, which is a specific inhibitor of pyrimidine 5'-nucleotidase subclass I (P5N-I). The serum from dogs chronically infected with B. gibsoni did not decrease the activities of hexokinase, glucose-6-phosphate dehydrogenase or 6-phosphogluconate dehydrogenase in canine reticulocytes, although it was previously reported that this serum had inhibitory effects on both the maturation of reticulocytes and the canine P5N-I and purine-specific 5'-nucleotidase activities. Furthermore, the in vitro multiplication of B. gibsoni was significantly inhibited by pyrimidine nucleotides such as cytidine 5'-monophosphate (5'-CMP), which is preferentially catalyzed by P5N-I and also inhibits the morphological maturation of canine reticulocytes. Purine nucleotides such as inosine 5'-monophosphate (5'-IMP) also had an inhibitory effect on the multiplication of this parasite. These results suggest that nucleotides such as 5'-CMP and 5'-IMP might accumulate in young erythrocytes and/or serum in dogs infected with B. gibsoni as a result of the decreased activity of erythrocyte 5'-nucleotidase, and the accumulation of these nucleotides might inhibit the multiplication of this parasite and simultaneously retard the maturation of reticulocytes. The results obtained from the in vitro examinations in the present study may partially clarify the relationship between low parasitemia and simultaneous reticulocytosis in vivo in canine babesiosis. 相似文献
3.
Hossain MA Yamato O Yamasaki M Jeong JR Chang HS Maede Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(12):1281-1286
Erythrocyte 5'-nucleotidase is thought to be involved in the maturation of erythrocytes. In the present study, in vitro incubation of canine erythrocytes demonstrated that significant inhibition of 5'-nucleotidase activity occurred in the presence of serum from dogs infected with Babesia gibsoni, when the enzyme was assayed with cytidine 5'-monophosphate (5'-CMP) and inosine 5'-monophosphate (5'-IMP) as substrates. The multiplication of B. gibsoni in in vitro culture also resulted in a significant decrease in the enzyme activity of erythrocytes in the culture. Furthermore, the infected serum and 5'-CMP retarded the maturation of canine reticulocytes in vitro. These results suggested that nucleotides such as 5'-CMP and 5'-IMP might accumulate in young erythrocytes and/or serum in dogs infected with B. gibsoni as a result of decreased activity of erythrocyte 5'-nucleotidase, resulting in the delayed maturation of reticulocytes. 相似文献
4.
Sunaga F Namikawa K Kanno Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(7):571-575
Babesia gibsoni infected erythrocytes were collected from the blood of an experimentally infected dog. The parasite isolated could be continuously cultivated in vitro, with an average parasitemia of 18.2 +/- 2.4% on day 3 of culture, in RPMI-1640 medium supplemented with 7.5% normal dog serum in a humidified atmosphere containing 5% CO(2) at 37 degrees C. The parasites in the original culture were morphologically similar to those found in the peripheral blood of dogs, however, on the 4th generation of subculture, the large oval parasites, erythrocytes including many parasites and extracellular parasites were frequently observed. The B. gibsoni isolate was injected to the dog to test its infectivity after maintained in vitro for 738 days at the 214th subculture. The cultivated parasite did not cause a severe clinical sign in the dog. 相似文献
5.
Yamasaki M Ishida M Nakamura K Sasaki N Murakami M Kumara WR Tamura Y Lim SY Ohta H Takiguchi M 《Veterinary parasitology》2011,180(3-4):215-225
Antibodies that recognized either Babesia gibsoni or canine red blood cell (RBC) 70-kilodalton (kDa) protein were detected in serum from acutely and chronically B. gibsoni-infected. In those sera, antibodies that reacted with recombinant B. gibsoni and canine heat shock protein 70 (rBgHsp70 and rcHsp70) were detected; therefore, B. gibsoni and canine RBC 70-kDa proteins seemed to be BgHsp70 and cHsp70, respectively. In infected dogs, the amounts of these antibodies increased after infection. Interestingly, polyclonal antibody raised against rBgHsp70 in two rabbits reacted not only with rBgHsp70 but also with rcHsp70 and native cHsp70 from canine RBCs. Because BgHsp70 showed high homology with cHsp70 (70.8%), anti-rBgHsp70 antibody might cross-react with cHsp70. Additionally, the localizations of both BgHsp70 and cHsp70 were observed by indirect fluorescence assay. As a result, cHsp70 was not found on the membrane surface of erythrocytes, suggesting that erythrocytes would not be targets of anti-cHsp70 antibody. Meanwhile, only exoerythrocytic parasites were stained by anti-rBgHsp70 antibody. This result showed that BgHsp70 would be expressed on the surface of parasites during the exoerythrocytic stage. These results indicated that BgHsp70 was a highly immunogenic protein in canine B. gibsoni infection, and that exoerythrocytic parasites might be targets of anti-BgHsp70 antibody. 相似文献
6.
Alonso-Villalobos P Martinez-Grueiro MM 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2000,47(1):1-8
The secretion of acetylcholinesterase (AChE) by female and male Heligmosomoides polygyrus was studied in different in vitro culture media. AChE secretion was increased in the presence of fetal calf serum or bovine serum albumin (BSA). In the absence of crowding effects, specific AChE activity in excretion/secretion products was higher for male (2.41 +/- 0.07 mumol min-1 l-1 mg-1) than for female (0.56 +/- 0.04 mumol min-1 mg-1) worms but on a per nematode basis both sexes showed comparable rates of secretion. Acetylthiocholine iodide was the favoured substrate of the enzyme. When the nematodes were incubated in vitro with albendazole (ABZ), ricobendazole (RBZ), mebendazole (MBZ), levamisole (LVM), morantel (MRT) or ivermectin (IVM), at concentrations from 1 mM to 10 nM, in RPMI medium for 2 or 6 h and then transferred to a drug-free medium (RPMI medium supplemented with 0.5% BSA) for 24 h or continuously exposed to the drugs in supplement-free medium (24 h), the concentration- and time-dependent inhibitory effects on AChE secretion were observed. The continued exposure to the drugs for all incubation periods (with a single exception for LVM 1 mM) produced the highest levels of inhibition. Under these conditions, the concentrations inhibiting the secretion of AChE by 50% (IC50) relative to drug-free controls were estimated. The IC50 values ranged from 0.012 microM (IVM) to 2.96 microM (MRT). The potential of this bioassay for the selective primary evaluation of new compounds with broad-spectrum anti-nematodal activity is discussed. 相似文献
7.
An atovaquone (ATV)-resistant Babesia gibsoni was developed by in vitro exposure of uncloned wild type (WT) B. gibsoni to 800 nM ATV for 6 days. Sequence analysis of mitochondrial genes showed a single-nucleotide polymorphism (SNP) at cytb nt363 (G to T) that resulted in the substitution of methionine with isoleucine (M121I), which is one of the SNPs reported in a previous in vivo study. 363T or 363G allele-specific real-time polymerase chain reaction (PCR) revealed that an M121I variant was present in over 99% of the ATV-resistant population. As neither ATV resistance nor gene polymorphisms appeared in the B. gibsoni WT sibling clones, the expression of ATV resistance in this study was suspected to be because of selective multiplication of the B. gibsoni M121I variant. This ATV-resistant B. gibsoni displayed the same sensitivity as the WT B. gibsoni against 5 other drugs, including diminazene aceturate, azithromycin, doxycycline, clindamycin, and proguanil. This is the first report on the in vitro establishment of an ATV-resistant B. gibsoni with gene polymorphisms. 相似文献
8.
为探究复方中草药对犬源葡萄球菌的体外抑制作用效果,将30种单味中草药配伍后得到20种复配物并制成水提物,采用二倍稀释法测定中草药复配物对犬源葡萄球菌的最低抑菌浓度(MIC),利用琼脂扩散法测定中草药复配物对犬源葡萄球菌的抑菌圈直径。结果表明,编号为15和16的中草药复配物对犬源葡萄球菌体外抑菌效果最好,最低抑菌浓度均为31.25mg/mL,抑菌圈直径分别为31.0mm和38.0mm,犬源葡萄球菌对这2个复方均表现为极敏;其他复方中草药对犬源葡萄球菌也呈现出不同程度的抑菌活性。研究结果为兽医临床筛选高效低毒的复方中草药制剂提供了科学依据。 相似文献
9.
Matsuu A Koshida Y Kawahara M Inoue K Ikadai H Hikasa Y Okano S Higuchi S 《Veterinary parasitology》2004,124(1-2):9-18
The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites. 相似文献
10.
常用抗菌药物对东北地区猪源链球菌的体外抗菌活性研究 总被引：3，自引：0，他引：3
采用微量稀释法(27种药物)和琼脂扩散法(7类药物)分别对临床分离的101株猪源链球菌进行了体外耐药性研究。以美国临床检验标准委员会(CLSI/NCCLS)的临界浓度和抑菌圈直径做为判断标准,判定了其对27种药物的耐药性和7类药物的耐药谱。结果表明,临床分离的菌株以耐药菌为主,且100%的菌株呈多重耐药;对头孢菌素类(100%)、磺胺类药物(96%～100%)、大环内酯类(97%～99%)、四环素类(98%)、青霉素类(94%～97%)耐药性最为严重,氟喹诺酮类药物(48%～91%)耐药性次之,共有25种不同的耐药谱型。结果表明,在东北地区分离到的猪源链球菌以多重耐药为主。 相似文献
11.
为了探讨中药与抗菌药物联用对大肠杆菌耐药性的作用效果，本研究对河南部分地区采集的样品（50份）进行分离鉴定、生化试验及致病性试验，对分离鉴定后的致病性猪大肠杆菌选用12种中药采用K-B法进行耐药性检测，将筛选出来的中药与抗生素进行中西联用对致病性大肠杆菌做体外抑菌试验，并分析中西药联用对大肠杆菌的抑制作用。结果显示，采集的50份样品有23株菌符合大肠杆菌的分离培养特性和生化特性，且23株菌均为致病性大肠杆菌；通过耐药性检测，23株试验菌株对测试的中药均有不同程度的耐药性，其中试验菌株对甘草耐药率最高（82.6%），其次为生地（78.2%），而对黄柏（17.3%）和白头翁（21.7%）耐药性较低，具有一定的敏感性；体外抑菌试验结果发现，中药与抗生素联用均有不同程度的抑菌效果，其中黄柏、白头翁与抗菌药物联用的抑菌效果最明显。以上结果说明中药与抗菌药物联用不仅可以抑制大肠杆菌的耐药性，还可以延缓大肠杆菌耐药性的产生。 相似文献
12.
Otávio V. Carvalho Giuliana L. Saraiva Caroline G.T. Ferreira Daniele M. Felix Juliana L.R. Fietto Gustavo C. Bressan Márcia R. Almeida Abelardo Silva Júnior 《Canadian journal of veterinary research》2014,78(4):283-289
Canine distemper is a highly contagious disease with high incidence and lethality in the canine population. The objective of this study was to evaluate the efficacy of antiviral action with ribavirin (RBV), interferon-alpha (IFNα), and combinations of RBV and IFNα against canine distemper virus (CDV). Vero cells inoculated with CDV were treated with RBV, IFNα, and combinations of these drugs. The efficacy to inhibit viral replication was evaluated by adding the compounds at different times to determine which step of the viral replicative process was affected. Both drugs were effective against CDV in vitro. The IFNα was the most active compound, with an average IC50 (50% inhibitory concentration) value lower than the IC50 of the RBV. Ribavirin (RBV) was more selective than IFNα, however, and neither drug showed extracellular antiviral activity. The combination of RBV and IFNα exhibited antiviral activity for the intra- and extracellular stages of the replicative cycle of CDV, although the intracellular viral inhibition was higher. Both RBV and IFNα showed high antiviral efficacy against CDV, and furthermore, RBV + IFNα combinations have shown greater interference range in viral infectivity. These compounds could potentially be used to treat clinical disease associated with CDV infection. 相似文献
13.
Yamasaki M Asano H Otsuka Y Yamato O Tajima M Maede Y 《American journal of veterinary research》2000,61(12):1520-1524
OBJECTIVE: To determine the usefulness of canine RBC with high concentrations of potassium, reduced glutathione (GSH), and amino acid(i.e., HK cells) for in vitro cultivation of Babesia gibsoni. ANIMALS: RBC were obtained from 3 dogs that had inherited HK cells and from 3 genetically unaffected dogs that, therefore, had RBC with lower potassium (LK) concentrations (i.e., LK cells). PROCEDURES: First, B. gibsoni were cultivated using HK or LK cells in alpha-modification of Eagle medium, consisting of Earle salts with glutamine and without ribosides, deoxyribosides, and sodium bicarbonate under a humidified atmosphere containing 5% CO2 at 37 C. Second, parasites were cultivated with LK- or HK-cell lysates. Finally, HK cells were separated into 3 fractions (bottom, middle, top layers) by density gradient centrifugation, and B. gibsoni were cultivated with each of the HK-cell fractions. In addition, the concentrations of free amino acids and reduced glutathione (GSH) in each HK-cell fraction were measured. RESULTS: B. gibsoni preferentially multiplied in HK-cell cultures rather than in LK-cell cultures. Furthermore, the addition of HK-cell lysate to the culture medium resulted in enhanced multiplication of the parasites. Higher multiplication of the parasites was observed in HK cells from the top layer, compared with HK cells from the middle and bottom layers. The HK cells from the top layer had higher concentrations of glutamate, aspartate, and GSH, compared with HK cells from the middle and bottom layer. CONCLUSIONS: Canine HK cells are useful host cells for in vitro cultivation of B. gibsoni, and the high concentrations of glutamate, aspartate, and GSH may result in enhancement of multiplication of the parasites in HK cells. 相似文献
14.
OBJECTIVE: To develop and validate in cats suitable in vitro assays for screening and ranking nonsteroidal antiinflammatory drugs (NSAIDs) on the basis of their inhibitory potencies for cyclooxygenase (COX)-1 and COX-2. ANIMALS: 10 cats. PROCEDURE: COX-1 and COX-2 activities in heparinized whole blood samples were induced with calcium ionophore and lipopolysaccharide, respectively. For the COX-2 assay, blood was pretreated with aspirin. The COX-1 and COX-2 assays were standardized, such that time courses of incubation with the test compounds and conditions of COX expression were as similar as possible in the 2 assays. Inhibition of thromboxane B2 production, measured by use of a radioimmunoassay, was taken as a marker of COX-1 and COX-2 activities. These assays were used to test 10 to 12 concentrations of a COX-1 selective drug (SC-560) and of 2 NSAIDs currently used in feline practice, meloxicam and carprofen. Selectivities of these drugs were compared by use of classic 50% and 80% inhibitory concentration (ie, IC50 and IC80) ratios but also with alternative indices that are more clinically relevant. RESULTS: These assay conditions provide a convenient and robust method for the determination of NSAID selectivity. The S(+) enantiomeric form of carprofen was found to be COX-2 selective in cats, but meloxicam was only slightly preferential for this isoenzyme. CONCLUSIONS AND CLINICAL RELEVANCE: In vitro pharmacodynamic and in vivo pharmacokinetic data predict that the COX-2 selectivity of both drugs for cats will be limited when used at the recommended doses. This study provides new approaches to the selection of COX inhibitors for subsequent clinical testing. 相似文献
15.
Yamasaki M Hwang SJ Ohta H Yamato O Maede Y Takiguchi M 《The Japanese journal of veterinary research》2008,55(4):129-136
In the present study, we employed flow cytometry to evaluate the level of parasitemia of Babesia gibsoni infecting canine erythrocytes in vivo and in vitro by using fluorescent nucleic acid staining. Peripheral blood samples from a B. gibsoni-infected dog and cultured B. gibsoni parasitizing in canine erythrocytes were stained with a membrane-permeable fluorescent nucleic acid stain, SYTO16. In this study, we utilized normal canine erythrocytes (LK erythrocytes) and canine erythrocytes containing high concentrations of potassium, reduced glutathione, and some free amino acids (HK erythrocytes) as host cells for culture. Parasitized cells in vive were discriminated completely from unparasitized cells and a correlation (r = 0.998) between the percentage of SYTO16-positive cells and parasitemia in vivo was observed. On the other hand, erythrocytes in vitro could not be divided clearly into parasitized and unparasitized cells. However, when LK erythrocytes were used as host cells, the percentage of SYTO16-positive cells was almost the same as, and was well correlated (r = 0.932) with, the level of parasitemia. When HK erythrocytes were used as host cells, the percentage of SYTO16-positive cells was almost half of, but was correlated (r = 0.982) with, the level of parasitemia. Therefore, we attempted to observe the changes in the percentage of parasitized cells after treatment with antiprotozoal drug or mitochondria inhibitors by using flow cytometry. The changes in the percentage of SYTO16-positive cells corresponded well with the changes of the level of parasitemia when the parasites in HK erythrocytes were cultured with each compound. The present results suggest that flow cytometric detection using SYTO16 is a rapid and reliable method for monitoring parasitemia both in vive and in vitro. 相似文献
16.
A total of 18 chlamydial isolates from various psittacine birds, one isolate from a domestic pigeon and one isolate from a Pekin duck were isolated in continuous Buffalo Green Monkey (BGM) kidney cell cultures. All 20 isolates were identified by nested multiplex polymerase chain reaction as Chlamydophila psittaci. These isolates were multiplied to high titres and subsequently tested for in vitro sensitivity against two tetracyclines (chlortetracycline and doxycycline) and two quinolones (enrofloxacin and difloxacin) at concentrations of 0.0, 0.25, 0.50, 1.00, and 10.00 microg/ml. Replication of chlamydia in BGM cell cultures is assayed on the basis of formation of intracytoplasmic inclusions that are visualized by Giménez staining. All isolates, although to variable degrees, are sensitive to all four drugs. The number of chlamydial inclusions decreases gradually over a broad range of increasing concentrations of the drugs. The variation in the number of inclusions between isolates is remarkably high for chlortetracycline less for doxycycline and minimal for both fluoroquinolones, the enrofloxacin and difloxacin. The decline in numbers of inclusions is highly dose-dependend and the observed reduction stretches over a wide range of drug dilutions. Therefore, it is proposed to calculate drug sensitivity values in terms of inhibitory concentration 50%, (IC5). Its calculation includes all tested drug dilutions instead of the hitherto more common minimal inhibitory concentration, MIC, which is based on results of serial dilution tests for cell-free growing bacteria. Using a logistic regression model for the calculation of the inhibitory concentration 50% of all 20 chlamydial isolates, the IC50 is 0.807 microg/ml for tetracycline, 0.497 microg/ml for doxycycline, 0.180 microg/ml for enrofloxacin and 0.168 microg/ml for difloxacin. Complete prevention of inclusion formation was already seen for enrofloxacin at a concentration of 1.0 microg/ml in 12 out of 20 and for difloxacin in 5 out of 20 isolates whereas more than 10 microg/mI chlortetracycline is needed in 15 out of 20 isolates and for doxycycline 9 out of 20 isolates yielded inclusions at 10 microg/ml. 相似文献
17.
A cDNA encoding the Babesia bovis 12D3 antigen homologue was obtained by immunoscreening the expression library prepared from Babesia gibsoni merozoite mRNA. The complete nucleotide sequence of the gene was 1406 bp. Computer analysis suggested that the sequence contains an open reading frame of 1052 bp encoding an expected protein with a molecular weight of 36kDa. Based on homology analysis, this putative protein was designated as the B. gibsoni 12D3 antigen (Bg12D3). The Bg12D3 gene was expressed in the Escherichia coli BL21 strain, and the chronically infected dog serum reacted with the recombinant protein. The antiserum against the recombinant Bg12D3 protein can recognize a 38-kDa native protein, which is consistent with its expected size. Moreover, the purified recombinant proteins were used as the antigen to detect the antibody response in an experimentally infected dog by the enzyme-linked immunosorbent assay (ELISA). Our results indicated that the Bg12D3 protein was recognized by the host immune system and that it induced an antibody response in chronic B. gibsoni infection. These results allowed us to identify a new member of the 12D3 antigens and its characteristic immune response in canine B. gibsoni infection. 相似文献
18.
Longhofer S Martin-Jimenez T Soni-Gupta J 《Veterinary therapeutics : research in applied veterinary medicine》2010,11(3):E1-E7
In the past 5 years, the incidence of canine skin infections caused by resistant strains of Staphylococcus (pseud)intermedius has increased. Many older antibiotics are used to treat these infections because the sensitivity can be demonstrated in vitro. Additionally, many of these older drugs are efficacious and unlikely to induce multidrug resistance. More than a decade ago, the antibiotic tylosin tartrate was reported to be efficacious in vitro and in vivo against Staphylococcus intermedius. The purpose of this study was to determine whether S. (pseud)intermedius isolated from untreated pyoderma cases at veterinary referral centers across the United States are sensitive in vitro to this antibiotic. Minimum inhibitory concentrations for tylosin tartrate and other commonly used antibiotics were determined for 103 isolates. Most (82.61%) of the isolates not exposed to antibiotics in the 3 months before submission were sensitive to tylosin tartrate. These findings suggest that tylosin tartrate warrants further study as a first-line option for the treatment of dogs initially presenting with pyoderma. 相似文献
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20.
Bawm S Matsuura H Elkhateeb A Nabeta K Subeki Nonaka N Oku Y Katakura K 《Veterinary parasitology》2008,158(4):288-294
The medicinal plant Brucea javanica (L.) Merr. (Simaroubaceae) is widely distributed throughout Asia where its bitter fruits have been used in traditional medicine for various ailments. Fifteen C-20 quassinoids were isolated from the fruits of B. javanica and examined for their in vitro antitrypanosomal activities against trypomastigotes of Trypanosoma evansi. Bruceine A, bruceantinol, bruceine C, brusatol, and bruceine B showed strong antitrypanosomal activities with IC(50) values in the range of 2.9-17.8nM, which compared well with the standard trypanocidal drugs diminazene aceturate (IC(50)=8.8nM) and suramin (IC(50)=43.2nM). However, dehydrobruceine A, dehydrobruceine B, and dehydrobrusatol were about 2100, 900, and 1200 times less active, respectively, than bruceine A, bruceine B, and brusatol. The relationship of the structure and antitrypanosomal activity of these quassinoid compounds suggested that the presence of a diosphenol moiety in ring A and the nature of the C-15 side chain are important for their activities against T. evansi. This is the first report on the antitrypanosomal activity of isolated quassinoids. 相似文献