scholarly journals Anti-trypanosomal activity of pentacyclic triterpenes isolated from Austroplenckia populnea (Celastraceae)

2002 ◽  
Vol 44 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Lucienir Pains DUARTE ◽  
Sidney Augusto VIEIRA FILHO ◽  
Grácia Divina de Fátima SILVA ◽  
José Rego de SOUSA ◽  
Artur da Silveira PINTO
Keyword(s):  
Growth Inhibition ◽  
High Activity ◽  
Incubation Time ◽  
Inhibitory Effect ◽  
Suitable Model ◽  
Pentacyclic Triterpenes ◽  
Total Growth ◽  
Dose Dependent

Four pentacyclic triterpenes isolated from Austroplenckia populnea and four compounds of known anti T. cruzi or anti-malarial activity were tested. Of those triterpenes tested 20alpha-hydroxy-tingenone showed high activity, epikatonic acid was less active, while populnilic and populninic acids were inactive against the trypanosome of the subgenus Schizotrypanum tested. Benzonidazole, nifurtimox, ketoconazole and primaquine presented a remarkable dose-dependent inhibitory effect reaching practically to a total growth inhibition of the parasite at the end of incubation time. The trypanosome tested appear to be a suitable model for preliminary screen for anti T. (S.) cruzi compounds.

scholarly journals Zebrafish as a model for haloperidol-induced catalepsy-like immobilization

2021 ◽  
Author(s):  
Akihiro Hasumi ◽  
Hideyuki Maeda ◽  
Ken-ichi Yoshida
Keyword(s):  
Drug Exposure ◽  
Inhibitory Effect ◽  
Suitable Model ◽  
Typical Antipsychotic ◽  
Activity Levels ◽  
Treatment Groups ◽  
Abnormal Movements ◽  
Bar Test ◽  
Dose Dependent ◽  
Increased Activity

Abstract This study investigated the validity of screening for antipsychotic-induced catalepsy-like immobilization in zebrafish (Danio rerio), as an alternative to the standard rodent model. To induce the desired symptoms, we used haloperidol, a typical antipsychotic that disturbs dopamine D2-receptors. In addition to observing swimming behaviors generally, we used the light and dark test to assess how drug exposure influences locomotive responses to those stimuli. We selected this test instead of the commonly used bar test for catalepsy in rodents, because fish cannot perform the necessary motions to participate in the latter. Normally, light attenuated activity and decreased locomotion, whereas darkness greatly increased activity levels in zebrafish. We confirmed that haloperidol had a dose-dependent inhibitory effect on activity; the highest dose of 10 mg/L almost stopped fish activity even in darkness. We did not observe any significant differences in heart rate or morphology across the control and treatment groups, whereas abnormal movements like rigid and erratic behaviors occurred in haloperidol-treated groups. Therefore, we found that immobilization and abnormal movements qualify as haloperidol-induced catalepsy. In conclusion, zebrafish appear to be a suitable model for antipsychotic-induced catalepsy-like immobilization.

Inhibitory Effect of Lactobacillus bulgaricus on Psychrotrophic Bacteria in Associative Cultures and in Refrigerated Foods

1984 ◽  
Vol 47 (1) ◽  
pp. 61-64 ◽  
Author(s):  
NADIA M. ABDEL-BAR ◽  
NATHOLYN D. HARRIS
Keyword(s):  
Growth Inhibition ◽  
Inhibitory Effect ◽  
Lactobacillus Bulgaricus ◽  
Pseudomonas Fragi ◽  
Psychrotrophic Bacteria ◽  
The Third ◽  
Control Growth ◽  
Natural Flora ◽  
Test Organisms ◽  
Total Growth

The purposes of this study were two-fold: (a) to determine growth inhibition of Pseudomonas fragi, Achromobacter liquefaciens and Staphylococcus aureus due to Lactobacillus bulgaricus in associative cultures, and (b) to evaluate use of L. bulgaricus to control growth of natural flora in refrigerated tuna and potato salads and ground beef. The antagonistic effects of three concentrations of L. bulgaricus were studied after storage for 5 d at 6°C. Data were analyzed using a Student t Test. Pronounced inhibition was observed toward test organisms. Total growth inhibition of P. fragi and A. liquefaciens was attained due to the third level of L. bulgaricus (1.4 × 106 − 5.7 × 106 cells/ml). Natural flora in test foods were also greatly inhibited. Total growth inhibition of bacteria was attained in potato salad due to the third level of L. bulgaricus (3.9 × 106 cells/g). It was suggested that organic acids and hydrogen peroxide were partially responsible for the inhibition.

Synthesis and Assessment of Novel Anti-chlamydial Benzylidene Acylhydrazides Derivatives

2018 ◽  
Vol 15 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Xiaofeng Bao ◽  
Ying Xue ◽  
Chao Xia ◽  
Yin Lu ◽  
Ningjing Yang ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Dependent Manner ◽  
Iron Starvation ◽  
Hydrochloride Salt ◽  
Obligate Intracellular ◽  
Biphasic Life Cycle ◽  
Ic50 Value ◽  
Ic50 Values ◽  
Dose Dependent ◽  
Better Than

Background: Chlamydiae, characterized by a unique biphasic life cycle, are a group of Gram-negative obligate intracellular bacterial pathogens responsible for diseases in a range of hosts including humans. Benzylidene acylhydrazide CF0001 could inhibit chlamydiae independent of iron starvation and T3SS inhibition. This finding promoted us to design and synthesize more benzylidene acylhydrazides to find novel anti-chlamydial agents. Methods: The carboxylic acids 1a-1d were coupled with Boc-hydrazide inpresence of EDCI and DMAP to obtain the intermediate 2a-2d in 60-62% yields. N-Boc deprotections were performed to obtain hydrazide hydrochloride salt 3a-3d. Nextly, the hydrazides were subjected to condensation with aldehydes to obtain benzylidene acylhydrazides 4a-4g in 30-52% yields in two steps. Results: Compound 4d exhibited best inhibitory effect on the formation and growth of chlamydial inclusions. The IC50 value of compound 4d for infectious progenies was 3.55 µM, better than 7.30 µM of CF0001. Conclusion: To find novel anti-chlamydial agents, we have designed and synthesized benzylidene acylhydrazides 4a-4g. Compounds 4a, 4d, 4g showed inhibitory activity on C. muridarum with the IC50 values from 3.55-12 µM. The 3,5-dibromo-4-hydroxyl substitutes on ring B are critical to keep their anti-chlamydial activity. Compound 4d inhibited C. muridarum in a dose-dependent manner without apparent cytotoxicity.

scholarly journals Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Antimalarial Activity ◽  
Clinical Malaria ◽  
Inhibitory Effect ◽  
Parasite Development ◽  
And Control ◽  
Speed Of Onset

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

scholarly journals In Vitro Effects of Doxycycline on Replication of Feline Coronavirus

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 312
Author(s):  
Magdalena Dunowska ◽  
Sayani Ghosh
Keyword(s):  
Inhibitory Concentration ◽  
Infectious Virus ◽  
Treatment Options ◽  
Inhibitory Effect ◽  
Virus Titration ◽  
Reverse Transcription Quantitative Pcr ◽  
In Vitro Effects ◽  
Dose Dependent ◽  
Feline Coronavirus

Feline infectious peritonitis (FIP) is a sporadic fatal disease of cats caused by a virulent variant of feline coronavirus (FCoV), referred to as FIP virus (FIPV). Treatment options are limited, and most of the affected cats die or are euthanized. Anecdotally, doxycycline has been used to treat FIP-affected cats, but there are currently no data to support or discourage such treatment. The aim of this study was to establish whether doxycycline inhibits replication of FIPV in vitro. The virus was cultured in Crandell-Rees feline kidney cells with various concentrations of doxycycline (0 to 50 µg/mL). The level of FIPV in cultures was determined by virus titration and FCoV-specific reverse-transcription quantitative PCR. Cell viability was also monitored. There was no difference in the level of infectious virus or viral RNA between doxycycline-treated and untreated cultures at 3, 12- and 18-hours post-infection. However, at 24 h, the growth of FIPV was inhibited by approximately two logs in cultures with >10 µg/mL doxycycline. This inhibition was dose-dependent, with inhibitory concentration 50% (IC50) 4.1 µg/mL and IC90 5.4 µg/mL. Our data suggest that doxycycline has some inhibitory effect on FIPV replication in vitro, which supports future clinical trials of its use for the treatment of FIP-affected cats.

scholarly journals In vitro study on the effect of cornin on the activity of cytochrome P450 enzymes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qun Zhang ◽  
Zengqiang Qu ◽  
Yanqing Zhou ◽  
Jin Zhou ◽  
Junwei Yang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interaction ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Drug Drug Interaction ◽  
Dose Dependent

Abstract Background Cornin is a commonly used herb in cardiology for its cardioprotective effect. The effect of herbs on the activity of cytochrome P450 enzymes (CYP450s) can induce adverse drug-drug interaction even treatment failure. Therefore, it is necessary to investigate the effect of cornin on the activity of CYP450s, which can provide more guidance for the clinical application of cornin. Methods Cornin (100 μM) was incubated with eight isoforms of CYP450s, including CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1, in pooled human liver microsomes. The inhibition model and corresponding parameters were also investigated. Results Cornin exerted significant inhibitory effect on the activity of CYP3A4, 2C9, and 2E1 in a dose-dependent manner with the IC50 values of 9.20, 22.91, and 14.28 μM, respectively (p < 0.05). Cornin inhibited the activity of CYP3A4 non-competitively with the Ki value of 4.69 μM, while the inhibition of CYP2C9 and 2E1 by cornin was competitive with the Ki value of 11.31 and 6.54 μM, respectively. Additionally, the inhibition of CYP3A4 by cornin was found to be time-dependent with the KI/Kinact value of 6.40/0.055 min− 1·μM− 1. Conclusions The inhibitory effect of cornin on the activity of CYP3A4, 2C9, and 2E1 indicated the potential drug-drug interaction between cornin and drugs metabolized by these CYP450s, which needs further investigation and validation.

Immunomodulatory activities of whey fractions in efferent prefemoral lymph of sheep

1996 ◽  
Vol 63 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Chun W. Wong ◽  
Geoffrey O. Regester ◽  
Geoffrey L. Francis ◽  
Dennis L. Watson
Keyword(s):  
Immune Responses ◽  
Bovine Milk ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Milk Whey ◽  
Significant Difference ◽  
Lymphocyte Phenotypes ◽  
Dose Dependent

SummaryStudies on the immunomodulatory activities of ruminant milk and colostral whey fractions were undertaken. By comparing with boiled colostral whey in a preliminary experiment, a putative heat-labile immunostimulatory factor for antibody responses was found to be present in ovine colostral whey. Studies were then undertaken in sheep in which the efferent prefemoral lymphatic ducts were cannulated bilaterally, and immune responses in the node were measured following subcutaneous injection in the flank fold of whey protein preparations of various purities. A significant sustained decline of efferent lymphocyte output was observed following injection with autologous crude milk whey or colostral whey preparations, but no changes were observed in interferon-gamma levels in lymph plasma. Two bovine milk whey fractions (lactoperoxidase and lactoferrin) of high purity were compared in bilaterally cannulated sheep. A transient decline over the first 6 h was seen in the efferent lymphocyte output and lymph flow rate after injection of both fractions. A significant difference was seen between the two fractions in interferongamma levels in lymph at 6 h after injection. However, no significant changes in the proportion of the various efferent lymphocyte phenotypes were seen following either treatment. Whereas both fractions showed a significant inhibitory effect in a dose-dependent manner on the proliferative response of T lymphocytes, but not B lymphocytes, to mitogenic stimulation in vitro, no similar changes were seen following in vivo stimulation with these two fractions.

Reversible arrest of Artemia development by cadmium

1986 ◽  
Vol 64 (8) ◽  
pp. 1633-1641 ◽  
Author(s):  
Parvaneh Rafiee ◽  
Christopher O. Matthews ◽  
Joseph C. Bagshaw ◽  
Thomas H. MacRae
Keyword(s):  
Normal Development ◽  
Developmental Process ◽  
Inhibitory Effect ◽  
Microtubule Assembly ◽  
Abnormal Development ◽  
Dependent Manner ◽  
Physiological Changes ◽  
Molecular Aspects ◽  
Reduced Rate ◽  
Dose Dependent

Under normal conditions, an encysted Artemia embryo undergoes a developmental process that culminates in the gradual, uninterrupted emergence of the prenauplius from the cyst. The hatching membrane surrounding the emerged organism is then ruptured, usually beginning at the posterior end, and a motile nauplius is released. We have observed this process microscopically in the presence and absence of cadmium and report that cadmium disrupts Artemia development in a dose–dependent manner. At 0.1 μM, cadmium slows emergence but nauplii eventually resume rellatively normal development. Emergence and hatching are either delayed considerably or almost entirely prevented at 1 μM cadmium. Cadmium at 10 μM, completely arrests emergence but development continues at a reduced rate, eventually resulting in hatching of some organisms without need for complete emergence. If organisms exposed to 10 μM cadmium are washed, abnormally shaped emerged forms are released and many of these eventually hatch, although in an unusual manner. Cadmium at 10 μM causes complete, rapid precipitation of purified Artemia tubulin at 0 °C but cadmium at the lower concentrations tested has no apparent inhibitory effect on microtubule assembly. Although we do not know the actual cadmium–induced physiological changes that result in abnormal development of Artemia, our results indicate that we can now examine the interdependence of morphological and molecular aspects of Artemia development in a way not previously possible.

scholarly journals Biochemical characterisation of α-glucosidase and β-glucosidase in the alimentary canal of larval Leptinotarsa decemlineata SAY, 1824 (Coleoptera: Chrysomelidae)

2014 ◽  
Vol 83 (4) ◽  
pp. 281-294 ◽  
Author(s):  
Majid Kazzazi ◽  
Fahimeh Dehghanikhah ◽  
Hossein Madadi ◽  
Vahid Hossseininaveh
Keyword(s):  
Incubation Time ◽  
Leptinotarsa Decemlineata ◽  
Digestive Enzymes ◽  
Specific Activity ◽  
Inhibitory Effect ◽  
Maximum Activity ◽  
Pest Population ◽  
Biochemical Characterisation ◽  
Leptinotarsa Decemlineata Say ◽  
Environmentally Safe

ABSTRACT Host plant resistance is an environmentally safe method used for reducing a pest population. Basically, when developing resistant cultivars one needs to study the biochemical characteristics of the digestive enzymes in the insect’s midgut. In this study, the activities of α- and β-glucosidase were determined from Leptinotarsa decemlineata midgut using p-nitrophenyl-α-Dglucopyranoside and p-nitrophenyl-β-D-glucopyranoside as substrates respectively. The results showed that the specific activity of α- and β-glucosidase from 4th instar larvae midguts of L. decemlineata were 5.14 and 5.48 Umg-1 protein respectively. The activity of α-glucosidase was optimal at pH 4, whereas the maximum activity of β-glucosidase in the midgut of L. decemlineata occurred at pH 4-5.5. Both enzymes were stable at pH 3-8 over an incubation time of 8 hours. The respective activities of α- and β-glucosidase were at their highest at 45 °C and 50 °C, but they were not stable at 50 °C during an incubation time of 8 days. Furthermore, our data showed that MgCl2, Tris and urea have a moderate but SDS a severe inhibitory effect on enzyme activity. Biochemical characterisation revealed one and three bands of α- and β-glucosidase activities in the midgut of L. decemlineata respectively.

Inhibitory Effects of Indomethacin on Implantation and its Related Phenomena

1996 ◽  
Vol 24 (4) ◽  
pp. 358-362 ◽  
Author(s):  
K Kanayama ◽  
H Osada ◽  
K Nariai ◽  
T Endo
Keyword(s):  
Birth Rate ◽  
Inhibitory Effect ◽  
High Rate ◽  
Control Group ◽  
Corpora Lutea ◽  
Response Relationship ◽  
Inhibitory Effects ◽  
Dose Response Relationship ◽  
Dose Dependent ◽  
Implantation Period

The dose-response relationship for the inhibitory effect of indomethacin on implantation and continuance of pregnancy was examined in four groups of rabbits administered with indomethacin (2.5, 5.0, 7.5 and 10.0 mg/kg) during the implantation period and compared with a control group. Implanted fetuses and corpora lutea were counted by laparotomy, and the number of offspring born was noted. The inhibitory effect of indomethacin on implantation was found to be dose–dependent, and the birth rate decreased in the indomethacin groups compared with the control group. As a result, even where implantation had been achieved, death of the implanted fetuses occurred at a high rate in rabbits administered with indomethacin during the implantation period.

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