Synthesis and Evaluation of Trypanocidal Activity of Chromane-Type Compounds and Acetophenones.

American trypanosomiasis (Chagas disease) caused by the Trypanosoma cruzi parasite, is a severe health problem in different regions of Latin America and is currently reported to be spreading to Europe, North America, Japan, and Australia, due to the migration of populations from South and Central America. At present, there is no vaccine available and chemotherapeutic options are reduced to nifurtimox and benznidazole. Therefore, the discovery of new molecules is urgently needed to initiate the drug development process. Some acetophenones and chalcones, as well as chromane-type substances, such as chromones and flavones, are natural products that have been studied as trypanocides, but the relationships between structure and activity are not yet fully understood. In this work, 26 compounds were synthesized to determine the effect of hydroxyl and isoprenyl substituents on trypanocide activity. One of the compounds showed interesting activity against a resistant strain of T. cruzi, with a half effective concentration of 18.3 µM ± 1.1 and an index of selectivity > 10.9.

Effect of substituents in the A and B rings of chalcones on antiparasite activity.

Chalcones are a group of natural products with many recognized biological activities, including antiparasitic activity. Although a lot of chalcones have been synthetized and assayed against parasites, the number of structural features known to be involved in this biological property is small. Thus, in the present study, 21 chalcones were synthesized to determine the effect of substituents in the A and B rings on the activity against Leishmania braziliensis, Trypanosoma cruzi, and Plasmodium falciparum. The compounds were active against L. braziliensis in a structure-dependent manner. Only one compound was very active against T. cruzi, but none of them had a significant antiplasmodial activity. The electron-donating substituents in ring B and the hydrogen bonds at C-2' with carbonyl affect the antiparasitic activity.

Antileishmanial activity and cytotoxicity of ent-beyerene diterpenoids.

We describe the in vitro activity of two natural isomeric ent-beyerene diterpenes, several derivatives and synthetic intermediates. Beyerenols 1 and 2 showed EC50 of 4.6 ±â€¯9.4 and 5.3 ±â€¯9.4 µg/mL against amastigotes of L. (V) brazilensis, with SI of 5.1 and 7.7, respectively. Beyerenol 1 was synthesized from stevioside. In vivo experiments with bereyenols showed cure in 50% of hamsters infected with L. (V) brazilensis topically applied as Cream I (beyerenol 1, 0.81%, w/w) and Cream III (beyerenol 2, 1.96%, w/w). These results suggest that beyerenols are potential candidates for cutaneous leishmaniasis chemotherapy by topical application. In vitro assays of amastigotes of L. (V) brazilensis showed EC50 of 1.1 ±â€¯0.1 and 1.3 ±â€¯0.04 µg/mL, with SI of 3.1 and 3.5 for hydrazone intermediates 10 and 11, respectively.

Isoflavonoid composition and biological activity of extracts from soybean seedlings treated by different elicitors.

Time-course and dose-response experiments were carried out to establish the ability for synthesizing isoflavonoids of soybean seedlings (cv. Soyica P34) treated with salicylic (SA) and isonicotinic acids (INA). Then, 25 structurally-related compounds were evaluated for their isoflavonoid-eliciting activity. Next, the antimicrobial and antioxidant activities of EtOAc-soluble fraction from soybean seedlings treated with some synthetic elicitors were determined. Results showed that the concentration of isoflavonoids in soybean seedlings was significantly increased by the application of SA and INA. The major isoflavonoids detected were the malonyl-glycosidic isoflavones, followed by genistin and daidzin. The isoflavone aglycones (genistein, daidzein, and formononetin), coumestrol and glyceollins were found in lower concentrations. Maximum accumulation of glyceollins was detected after 48 and 144 h in soybean seedlings treated with 1.6 mM INA and SA, respectively. EtOAc-extracts from soybean seedlings treated with two structurally-related compounds to INA displayed a significant antimicrobial and antioxidant activity. Therefore, INA, SA and structurally-related compounds can be used to increase the amounts of natural antioxidant or antimicrobial compounds in soybean, either to protect the plant directly against pathogens or as a natural source for subsequent isolation of isoflavonoids or bioactive extracts, which have potential application in functional foods or pharmaceutical and personal care products.

Lower placental growth factor and higher free ß-hCG and PAPP-A levels in the fetal circulation of near-term pregnancies complicated with severe preeclampsia.

BACKGROUND: An imbalance between anti- and angiogenic factors during early placentation is key for the development of preeclampsia. Nevertheless, the majority of studies addressing this issue relate to maternal blood and not the fetal circulation. OBJECTIVE: To measure placental growth factor (PlGF), free beta human chorionic gonadotropin (ß-hCG), and pregnancy-associated plasma protein-A (PAPP-A) levels in the fetal circulation of near-term pregnancies complicated with severe preeclampsia (n = 20), and their controls matched for parity, and maternal and gestational age. METHOD: Upon delivery, a blood sample was withdrawn from the umbilical artery and vein of each case and its control in order to measure the proposed analytes using direct fluoroimmunoassay. RESULTS: Preeclampsia cases showed significantly lower median PlGF levels in fetal circulation as compared to controls (25.2 versus 36.9 and 23.6 versus 33.9 pg/mL, artery and vein, respectively, p < 0.05). Contrarily, cases displayed higher concentrations of PAPP-A (1024.0 versus 720.9 [median] and 1027.0 ± 298.4 versus 690.3 ± 401.9 mIU/L, artery and vein, respectively, p < 0.05), and free ß-hCG (mean: 33.9 ± 4.3 versus 17.2 ± 4.0 and 30.1 ± 5.2 versus 13.7 ± 3.3 ng/mL, artery, and vein respectively, p < 0.05). CONCLUSION: Lower PlGF and higher PAPP-A and free ß-hCG levels were found in the fetal circulation of near-term severe preeclamptic pregnancies. There is a need for more research in this regard.

Increased mood symptoms in postmenopausal women related to the polymorphism rs743572 of the CYP17 A1 gene.

BACKGROUND: Menopausal and depressive symptoms are highly prevalent after the menopause; but may vary from one population to another and genetics play a key role. OBJECTIVE: To analyze the intensity of these symptoms in relation to the genetic variants of the rs743572 polymorphism of the CYP17 A1 gene in postmenopausal women. METHODS: DNA was extracted from the whole blood of 168 natural postmenopausal women (40-65 years) and tested for the rs743572 polymorphism of the CYP17 A1 gene. Intensity of menopausal (Menopause Rating Scale, MRS) and depressive symptoms (Hospital Anxiety and Depressive Scale, HADS) were correlated to polymorphism genotypes. RESULTS: Women with the GG genotype of the rs743572 polymorphism displayed significantly higher scores for the MRS (items 5 and 6 [irritability and anxiety] and the psychological subscale) and the HADS (total and subscales). CONCLUSION: The intensity of menopausal symptoms related to mood was found higher among postmenopausal women presenting the GG genotype of the rs743572 polymorphism of the CYP17 A1 gene. There is a need for more research in this regard.

Umbilical cord plasma interferon-induced protein 10 (IP-10) and interferon-induced T-cell alpha chemoattractant (ITAC) levels are lower in women with severe preeclampsia.

BACKGROUND: Higher 1st trimester maternal serum levels of interferon-induced protein 10 (IP-10) and interferon inducible T-cell alpha chemoattractant (ITAC) are reported in gestations complicated with preeclampsia. However, parallel results in the fetal circulation are lacking. OBJECTIVE: To compare IP-10 and ITAC levels in neonatal cord blood from gestations complicated by severe preeclampsia vs. gestational age-matched controls. METHOD: Umbilical cord vessels were sampled following delivery of women with severe preeclampsia (n=30) ≥36 weeks to measure plasma IP-10 and ITAC levels and compared to corresponding controls matched for parity as well as maternal and gestational age. Chemokines were measured by specific ELISAs and expressed as pg/mL. Rho Spearman's coefficients were calculated to establish correlations between chemokine values and various numeric variables. RESULTS: Preeclamptic cases displayed significantly lower median plasma umbilical artery and vein levels of both chemokines when compared to controls (IP-10: 23.4 vs. 31.4 and 2.0 vs. 24.6 pg/mL, P<0.05; and ITAC: 2.0 vs. 13.9 and 11.9 vs. 31.6 pg/mL, P<0.05, in artery and vein, respectively). There was a significant correlation between levels of both chemokines (r2=0.616, P=0.0001), but not with other variables. CONCLUSION: In contrast to elevated 1st trimester levels of IP-10 previously found in the maternal serum of women who later developed preeclampsia, this study found lower umbilical cord IP-10 and ITAC plasma levels in near-term gestations with established severe preeclampsia.

Polymorphisms of the methylenetetrahydrofolate reductase gene (C677T and A1298C) in the placenta of pregnancies complicated with preeclampsia.

BACKGROUND: Preeclampsia has been related to single-nucleotide polymorphisms (SNPs) of the methylenetetrahydrofolate reductase (MTHFR) gene; however, data regarding the placenta are still lacking. OBJECTIVE: To determine the frequency of C677T and A1298C SNPs of the MTHFR gene in the placenta of preeclamptic pregnancies and healthy controls. METHODS: Genotyping of C677T and A1298C polymorphisms of the MTHFR gene using RFLP-PCR was performed to the placenta of 100 gestations (n = 50 complicated with preeclampsia and n = 50 normal controls matched for parity and maternal age). RESULTS: Gestational age at birth and neonatal and placental weight were significantly lower in women with preeclampsia as compared to controls. The TT genotype of the C677T polymorphism was threefold more prevalent in preeclamptic placentas as compared to the placenta of controls (24.0% versus 8.0%, p = 0.001). Upon pooled analysis (n = 100), placental and neonatal weights were significantly lower in placentas displaying this genotype (TT, C677T) as compared with the CC genotype. CONCLUSION: This study found that the frequency of the TT mutant genotype of the C677T polymorphism was higher in the placenta of pregnancies complicated with preeclampsia. There is a need for further research in this matter.

In vivo Antimalarial Activity of α-Mangostin and the New Xanthone δ-Mangostin.

Based on the previously reported in vitro antiplasmodial activity of several xanthones from Garcinia mangostana, two xanthones, α-mangostin and a new compound, δ-mangostin, were isolated from mangosteen husk, and the in vitro antiplasmodial and cytotoxic effects were determined. α-Mangostin was more active against the resistant Plasmodium falciparum chloroquine-resistant (FCR3) strain (IC50 = 0.2 ± 0.01 µM) than δ-mangostin (IC50 = 121.2 ± 1.0 µM). Furthermore, the therapeutic response according to the administration route was evaluated in a Plasmodium berghei malarial murine model. The greatest therapeutic response was obtained with intraperitoneal administration; these xanthones reduced parasitemia by approximately 80% with a daily dose of 100 mg/kg administered twice a day for 7 days of treatment. Neither compound was effective by oral administration. Noticeable toxicological effects were not observed. In addition to the antimalarial effect of these xanthones isolated from G. mangostana husk, the availability of larger amounts of husk raw material to purify the bioactive xanthones is advantageous, permitting additional preclinical assays or chemical transformations to enhance the biological activity of these substances.

Polymorphisms of the methylenetetrahydrofolate reductase gene (C677T and A1298C) in nulliparous women complicated with preeclampsia.

OBJECTIVE: To determine the prevalence of C677T and A1298C Single-nucleotide polymorphisms (SNPs) of the MTHFR gene in nulliparous women complicated with preeclampsia (PE). METHODS: One hundred fifty gestations complicated with PE and their corresponding controls without the disease were recruited for the genotyping of C677T and A1298C polymorphisms of the MTHFR gene using restriction fragment length polymorphism polymerase chain reaction. Secondarily, homocysteine (HCy) plasma levels were measured in preeclamptic women displaying the CC genotype of the A1298C polymorphism (homozygous) and compared to HCy levels determined among controls with the normal AA genotype for the A1298C variant. RESULTS: Only the mutant CC genotype of the A1298C polymorphism was associated to higher risk of presenting PE, as frequency of this genotype was significantly higher among cases than controls (15.3% versus 0.7%, p < 0.05). All PE women with a neck circumference ≥32 cm presented the mutant CC A1298C polymorphism as compared to none among preeclamptics with a lower neck circumference (p = 0.0001). Women with the mutant CC A1298C SNP displayed higher plasma HCy levels as compared to controls with normal AA A1298C genotype (8.4 ± 2.6 versus 7.5 ± 2.7 mmoL/L p = 0.04). CONCLUSION: Prevalence of the CC mutant genotype of the A1298C polymorphism was higher among PE women. This mutation among PE women was related to increased neck circumference and higher HCy levels. Future research should aim at linking these gestational findings with obesity and cardiovascular risk.

Evaluation of the presence and severity of menopausal symptoms among postmenopausal women screened for the metabolic syndrome.

BACKGROUND: The prevalence of the metabolic syndrome (METS) increases after the menopause. Reports indicate that the METS and its components, especially obesity, enhance the intensity of menopausal symptoms. OBJECTIVE: Assess the frequency and severity of menopausal symptoms in postmenopausal women. Factors related to the symptom severity were also analyzed including depressive and metabolic status. METHODS: A total of 204 natural postmenopausal women (40-65 years) participating in a METS screening program were asked to fill out the Menopause Rating Scale (MRS), the Hospital Anxiety and Depression Scale (HADS), and a general socio-demographic questionnaire containing personal and partner data. Criteria of the American Heart Association were used to define the METS. RESULTS: Median age of the whole sample was 56 years. A 52.9% presented the METS, with 37.3% presenting hyperglycemia, 51.5% hypertension, 58.3% abdominal obesity, 45.6% high triglyceride and 56.4% low HDL-C levels. Total and subscale MRS scores did not differ in accordance to the presence or not of the METS. The three top prevalent menopausal symptoms were muscle and joint problems (87.2%), physical and mental exhaustion (72%) and depressive mood (64.7%). A 19.6% of women presented total MRS scores above 16 defined as severe. Multivariate linear regression analysis determined that anxiety (higher HADS anxiety subscale scores) was significantly and positively correlated with all components of the MRS (Total and subscale scores). Higher total MRS scores correlated positively with abdominal perimeter and higher parity. Somatic scores correlated inversely with female education and positively with psychotropic drug use; and psychological MRS scores positively correlated depressed mood (higher HADS depressive subscale scores) and abdominal perimeter. CONCLUSION: In this postmenopausal sample, severity of menopausal symptoms correlated to abdominal obesity, mood and other personal aspects.

Easy access to a cyclic key intermediate for the synthesis of trisporic acids and related compounds.

The synthesis of a cyclohexane skeleton possessing different oxygenated functional groups at C-3, C-8 and C-9, and a D1,6-double bond has been accomplished in 10 steps with an overall 17% yield. This compound is a key intermediate for access to a wide range of compounds of the bioactive trisporoid family. The synthetic sequence consists of the preparation of a properly functionalized epoxygeraniol derivative, and its subsequent stereoselective cyclization mediated by Ti(III). This last step implies a domino process that starts with a homolytic epoxide opening followed by a radical cyclization and regioselective elimination. This concerted process gives access to the cyclohexane moiety with stereochemical control of five of its six carbon atoms.

Preparation of rotenone derivatives and in vitro analysis of their antimalarial, antileishmanial and selective cytotoxic activities.

Six derivatives of the known biopesticide rotenone were prepared by several chemical transformations. Rotenone and its derivatives showed differential in vitro antiparasitic activity and selective cytotoxicity. In general, compounds were more active against Plasmodium falciparum than Leishmania panamensis. Rotenone had an EC50 of 19.0 µM against P. falciparum, and 127.2 µM against L. panamensis. Although chemical transformation does not improve its biological profile against P. falciparum, three of its derivatives showed a significant level of action within an adequate range of activity with EC50 values < 50.0 µM. This antiplasmodial activity was not due to red blood cell hemolysis, since LC50 was >>400 µM. On the other hand, all derivatives displayed a non-specific cytotoxicity on several cell lines and primary human cell cultures.

The metabolic syndrome and its components in postmenopausal women.

BACKGROUND: Prevalence of the metabolic syndrome (METS) increases significantly after the menopause. OBJECTIVE: To assess the prevalence of the METS and its components in postmenopausal women. Factors relating to each of the composing items of the METS were also analyzed. METHODS: Natural postmenopausal women (40-65 years) were invited to participate in this cross-sectional study in order to assess the presence of the METS using modified Adult Treatment Panel III (ATP-III) criteria. Participants were also requested to fill out a general socio-demographic questionnaire. RESULTS: A total of 204 women were surveyed with a median age of 56 years. A 52.9% presented the METS according to modified ATP-III criteria, with 37.3% presenting hyperglycemia, 51.5% hypertension, 58.3% abdominal obesity, 45.6% high triglyceride levels and 56.4% low HDL-C levels. Women with the METS presented a higher rate of dyslipidemia (high triglyceride and low HDL-C levels), hyperglycemia, hypertension and abdominal obesity than those without the syndrome. Those with abdominal obesity and hyperglycemia significantly displayed higher rates of low HDL-C levels (bivariate analysis). Multiple linear regression analysis found a positive correlation between glucose and triglyceride levels. Systolic blood pressure significantly and positively correlated to age and abdominal circumference. Abdominal circumference displayed an inverse correlation with educational level. CONCLUSION: Prevalence of the METS in this postmenopausal female sample was high and associated to metabolic and lipid derangements. As abdominal obesity was significantly associated to lower education, there is an urgent need of implementing educational programs directed to high-risk populations in order to increase awareness of the problem.

Effect of salicylic acid and structurally related compounds in the accumulation of phytoalexins in cotyledons of common bean (Phaseolus vulgaris L.) cultivars.

In the present work, isoflavonoid phytoalexin production in response to the application of salicylic acid in cotyledons of four common bean (Phaseolus vulgaris) cultivars (SA) was evaluated. The time-course and dose-response profiles of the induction process were established by quantifying the isoflavonoids by HPLC. Cotyledons of anthracnose-resistant cultivars induced by SA produced substantially higher phytoalexin contents as compared to the susceptible ones. In addition, maximum levels of phytoalexins (50-100 fold increases) were reached between 96 and 144 h, and when a concentration of SA from 3.62 to 14.50 mM was used. The observations also indicate that there was a relatively good correlation between the phytoalexin contents and the inhibitory effect against C. lindemuthianum; the higher antifungal activity was observed during the first 48 hours for extracts from cotyledons treated with SA at 1.45 and 3.62 mM, and between 96 and 144 h after induction. Finally, compounds structurally related to SA (dihydro-quinazolinones and some imines) showed a strong elicitor effect. Moreover, induced extracts from cotyledons treated with these potential elicitors, besides the properly elicitors, displayed a weak to moderated antifungal activity. These compounds may be considered good candidates for developing of new phytoprotectants. Furthermore, phytoalexin-eliciting substances may contribute for selecting disease resistant cultivars.

Diosgenone synthesis, anti-malarial activity and QSAR of analogues of this natural product.

Solanum nudum Dunal steroids have been reported as being antimalarial compounds; however, their concentration in plants is low, meaning that the species could be threatened by over-harvesting for this purpose. Swern oxidation was used for hemisynthesis of diosgenone (one of the most active steroidal sapogenin diosgenin compounds). Eighteen structural analogues were prepared; three of them were found to be more active than diosgenone (IC50 27.9 µM vs. 10.1 µM, 2.9 µM and 11.3 µM). The presence of a 4-en-3-one grouping in the A-ring of the compounds seems to be indispensable for antiplasmodial activity; progesterone (having the same functional group in the steroid A-ring) has also displayed antiplasmodial activity. Quantitative correlations between molecular structure and bioactivity were thus explored in diosgenone and several derivatives using well-established 3D-QSAR techniques. The models showed that combining electrostatic (70%) and steric (30%) fields can explain most variance regarding compound activity. Malarial parasitemia in mice became reduced by oral administration of two diosgenone derivatives.

Nitric oxide and pro-inflammatory cytokine serum levels in postmenopausal women with the metabolic syndrome.

BACKGROUND: The metabolic syndrome (METS) increases after the menopause which may enhance cardiovascular risk in part explained by a pro-inflammatory state. OBJECTIVE: Measure nitric oxide (NO), tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) serum levels in postmenopausal women with and without the METS (Adult Treatment Panel III criteria). METHODS: Analyte levels were compared among those with and without the syndrome and each of its diagnostic components. Rho Spearman coefficients were also calculated to determine correlations between analyte levels and various numeric variables. RESULTS: Median age of all studied women (n = 88) was 54.4 years, 62.5% had abdominal obesity, 14.8% hyperglycemia, 59.1% high triglycerides (TG) and 44.3% hypertension. Women with the METS (n = 44) displayed higher body mass index values and higher rates of abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension and low HDL-C levels. Median NO and IL-6 levels were significantly higher in women with the METS as compared to controls (p < 0.05). Independent of presenting the METS, analytes were higher in those displaying abdominal obesity (IL-6), hypertension (IL-6 and TNF-α) and more METS diagnostic criteria and abnormal HDL-C, TG and glucose levels (NO). Both cytokines positively correlated with the number of METS criteria, age and time since menopause, IL-6 positively with waist circumference and TNF-α positively with blood pressure levels. NO levels inversely correlated with HDL-C values and positively with the number of METS criteria, glucose, and TG levels; correlation with the latter being the highest (r² = 0.65, p = 0.0001). CONCLUSION: Postmenopausal women with the METS displayed higher IL-6 and NO levels, with significant correlations found between studied analytes and some of the components of the syndrome.

Elicitation of isoflavonoids in Colombian edible legume plants with jasmonates and structurally related compounds.

Common bean (Phaseolus vulgaris L.), soybean (Glycine max L.) and mung bean (Vigna radiata L. Wilczek) seedlings were treated with methyl jasmonate (MeJA); then, dose-response and time-course experiments were carried out. Isoflavonoid composition was evaluated by high performance liquid chromatography. As a result of MeJA induction, all leguminous plants increase the amount of isoflavonoids, at levels that depend on the concentration of the elicitor and the time after induction. However, the application of MeJA in concentrations higher than 2.22 mM showed deleterious effects on seedlings and strong decreases in the concentration of isoflavonoids. In addition, a series of compounds structurally related to MeJA, such as jasmonic acid, cis-jasmone, coronatine, and indanoyl derivatives, were evaluated as elicitors. The results show that coronatine and the indanoyl-amino acids conjugates displayed a significant elicitor effect of isoflavonoids in common bean (cvs. Cargamanto Mocho and Corpoica LAS 106) and soybean (cv. Soyica P-34) seedlings, even higher than that found with the recognized elicitors, benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (acibenzolar S-methyl) and benzo-(1,2,3) thiadiazole-7-carbothioic acid (acibenzolar acid). Leguminous plants can be treated with jasmonates and indanoyl derivatives to increase levels of bioactive isoflavonoids and consequently improve biological and functional properties and resistance against pests.

Pro-inflammatory cytokine levels in postmenopausal women with the metabolic syndrome.

BACKGROUND: Prevalence of the metabolic syndrome (METS) and its components significantly increase after the menopause. Related increased cardiovascular risk may partially be explained by a pro-inflammatory state. OBJECTIVE: To assess pro-inflammatory cytokine serum levels in postmenopausal women with and without the METS. METHODS: Serum of 90 postmenopausal women who previously participated in a METS screening programme was analysed for tumour necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). Cytokine levels were compared among those with and without the syndrome, and for each of its components. Linear relationships were also assessed between cytokine levels and several continuous variables including each diagnostic METS criteria and menopausal symptoms assessed with the Menopause Specific Quality of Life tool (MENQOL). RESULTS: For all studied women mean age was 55.1 ± 7.3 years with 63.3% having abdominal obesity, 15.6% hyperglycaemia, 58.9% high triglycerides, 44.4% hypertension and 25.6% high total cholesterol levels. Women with the METS (n = 45) significantly had higher body mass index values, and higher rates of abdominal obesity, hyperglycaemia, hypertriglyceridemia, hypertension and lower HDL-C levels. Cytokine levels did not differ among women with or without the METS; however, independent of METS diagnosis those with abdominal obesity displayed significantly higher IL-6 levels and those with hypertension higher levels of both cytokines. Levels of both cytokines positively correlated with age and time since menopause, IL-6 positively correlating with waist circumference values and TNF-α positively with both systolic and diastolic blood pressure levels. A significant positive correlation was also found between the number of positive METS criteria (0-5) and both cytokine levels. Cytokine levels did not correlate with vasomotor and psycho-social MENQOL scores. CONCLUSION: Pro-inflammatory cytokine levels in this postmenopausal series positively correlated with age, time since the menopause, abdominal circumference, blood pressures levels and the number of positive METS diagnostic criteria. There is a need for more research in this regard.

Mode of action of a formulation containing hydrazones and saponins against leishmania spp. Role in mitochondria, proteases and reinfection process.

Toxicity and poor adherence to treatment that favors the generation of resistance in the Leishmania parasites highlight the need to develop better alternatives. Here, we evaluated the in vitro effectiveness of hydrazone derived from chromanes 2-(2,3-dihydro-4H-1-benzothiopyran-4-ylidene) hydrazide (TC1) and 2-(2,3-dihydro-4H-1-benzopyran-4-ylidene) hydrazide (TC2) and the mixture of triterpene saponin hederagenin-3-O-(3,4-O-diacetyl-ß-D-xylopyranosyl-(1à3)-a-L- rhamnopyranosyl-(1à2)-a-L-arabinofuranoside, hederagenin-3-O-(3,4-O-diacetyl-a-L- arabinopyranosyl-(1à3)-a-L-rhamnopyranosyl-(1à2)-a-L-arabinofuranoside and, hederagenin-3-O-(4-O-acetyl-ß-D-xylopyranosyl-(1à3)-a-L-rhamnopyranosyl-(1à2)-a-L-arabinofuranoside from Sapindus saponaria (SS) on L. braziliensis and L. pifanoi. Mixtures of TC1 or TC2 with saponin were formulated for topical application and the therapeutic effectiveness was evaluated in the model for cutaneous leishmaniasis (CL) in golden hamster. The mode of action of these compounds was tested on various parasite processes and ultrastructural parasite modifications. TC1, TC2 and SS showed moderate cytotoxicity when tested independently but toxicity was improved when tested in combination. The compounds were more active against intracellular Leishmania amastigotes. In vivo studies showed that combinations of TC1 or TC2 with SS in 1:1 ratio (w/w) cured 100% of hamsters with no signs associated with toxicity. The compounds did cause changes in the mitochondrial activity of the parasite with a decrease in ATP levels and depolarization of membrane potential and overproduction of reactive oxygen species; nevertheless, these effects were not related to alterations in membrane permeability. The phagolysosome ultrastructure was also affected impacting the survival of Leishmania but the function of the lysosome nor the pH inside the phagolysosome did not change. Lastly, there was a protease inhibition which was directly related to the decrease in the ability of Leishmania to infect and multiply inside the macrophage. The results suggest that the combination of TC1 and TC2 with SS in a 1:1 ratio is capable of curing CL in hamsters. This effect may be due to the ability of these compounds to affect parasite survival and the ability to infect new cells.