RESUMEN
Passiflora cincinnata is a Passifloraceae typical of the Caatinga, a biome unique to Brazil. It has various pharmacological properties associated with its high flavonoid content. Vitexin, isovitexin, orientin, isoorientin and derivatives are the main chemical and pharmacological markers for this plant. Although flavonoids enriched-extracts have been widely applied in phytocosmetics, especially in sunscreen formulations, the use of P. cincinnata as a photoprotective ingredient remains unexplored. Different hydro-alcoholic extracts were prepared and their antioxidant and photoprotective activities were evaluated by in vitro assays. The most promising extract (Pc-1) was analyzed by HPLC-DAD-ESI-MS/MS. Nine flavonoids were identified as major compounds: isovitexin-7-O-glucoside, isoorientin-2"O-hexoside, orientin, isoorientin, isovitexin-2"-O-glucoside, isovitexin-6"-O-glucoside, isoscoparin and isoquercitrin. Finally, Pc-1 (5 and 10%, v/v) was incorporated into gel formulations, alone or combined to commercial chemical filters (benzophenone-3 and octyl methoxycinnamate). Formulations containing Pc-1 showed high SPFspectrophotometric values. When combined to commercial filters, Pc-1 (5%) potentiated their photoprotective efficacy (p<0.05). A physicochemical characterization indicated no incompatibility or signs of instability after extract incorporation. Altogether, these findings encourage the use of Pc-1 as a photoprotective ingredient or co-adjuvant in sunscreens formulations.
RESUMEN
The chemical composition and inâ vitro antibacterial and cytotoxic activities of the essential oil (EO) of Chiliadenus antiatlanticus (Emb. & Maire) Gómiz, an asteraceous species endemic to the southwest of Morocco, were investigated. The EO yield was 1.07±0.28 %, twenty-seven metabolites were identified representing more than 96.4 % of the total composition. Camphor (35.7 %) and derivatives, borneol (4.9 %) and camphene (4.2 %) together with intermedeol (19.9 %), α-pinene (15.5 %) and (E)-pinocarveol (4.1 %) were the major constituents. An antibacterial activity was noticed against 24â strains (all Gram-positive) out of 71 at MICs values=100â µg/mL. The EO also showed significant toxicity towards liver HepG2 (55.8 % of cell viability) and melanoma B16 4A5 (41.6 % of cell viability) tumor cell lines at 100â µg/mL.
Asunto(s)
Antibacterianos/farmacología , Antineoplásicos Fitogénicos/farmacología , Asteraceae/química , Bacterias Grampositivas/efectos de los fármacos , Aceites Volátiles/farmacología , Animales , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Aceites Volátiles/química , Aceites Volátiles/aislamiento & purificaciónRESUMEN
The chemical composition and inâ vitro biological activities of the essential oil (EO) of Micromeria macrosiphon Coss. and M.â arganietorum (J. Emb.) R. Morales, two Lamiaceae endemic to south Morocco, were investigated. GC/MS analysis resulted in the identification of 36 metabolites from the EO of M.â macrosiphon, 45 from M.â arganietorum. Borneol was the major metabolite in both oils and together with related derivatives such as camphor, accounted for 2/3 of the EO of M.â macrosiphon, 1/3 of those of M.â arganietorum. Pinene and terpinene derivatives were also present in high proportions. From a chemotaxonomic point of view, the composition of the examined samples may be related to those of other species endemic to Macaronesia. Both EOs showed significant toxicity towards liver HepG2 and melanoma B16 4A5 tumor cell lines at 100â µg/mL; however, they were also cytotoxic towards S17 normal cell lines, with a selectivity index <1. No antibacterial activity was noticed against 52 strains at 100â µg/mL.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Lamiaceae/química , Aceites Volátiles/farmacología , Animales , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/aislamiento & purificación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ratones , Aceites Volátiles/química , Aceites Volátiles/aislamiento & purificaciónRESUMEN
The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C (1) and an original derivative of ochnaflavone, 7-O-methylochnaflavone (2), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone (3 - 5). The linkage site of the sub-units of 2 was confirmed by chemical correlation, after semi-synthesis of a trimethoxylated derivative of ochnaflavone (2a). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D- and 2D-NMR experiments, HR-ESI-MS and Electronic Circular Dichroism (ECD) calculations. A low-pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1. All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.
Asunto(s)
Biflavonoides/química , Glucósidos/química , Nitrilos/química , Ochnaceae/química , Animales , Antiprotozoarios/química , Antiprotozoarios/aislamiento & purificación , Antiprotozoarios/farmacología , Biflavonoides/aislamiento & purificación , Biflavonoides/farmacología , Línea Celular , Dicroismo Circular , Flavonoides/síntesis química , Flavonoides/química , Glucósidos/aislamiento & purificación , Leishmania/efectos de los fármacos , Leishmania/fisiología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/parasitología , Espectroscopía de Resonancia Magnética , Ratones , Conformación Molecular , Ochnaceae/metabolismo , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
Jungia sellowii (Asteraceae) is a shrub that grows in Southern Brazil and polar extract of its leaves presents anti-inflammatory properties. Cyperane, guaiane, nortrixane, and trixane sesquiterpene types were reported as the main metabolites in Jungia species. This work aims to describe the isolation and identification of sesquiterpenes in the leaves of J. sellowii using liquid-liquid partition and centrifugal partition chromatography. Thus, the crude extract of fresh leaves of J. sellowii was partitioned with hexane, dichloromethane, ethyl acetate and butanol, respectively. The butanol fraction was then subjected to a selected ternary system optimized for the CPC (centrifugal partition chromatography): ethyl acetate-ethanol-water (9:2:10, v/v/v). The separation was carried out isocratically at a flow rate of 25 mL/min at 1200 rpm, affording seven fractions A to G. TLC of fractions B, C and F displayed a single spot corresponding to three new glycosylated sesquiterpenoids. Their structures were established by using spectroscopic data in comparison to those reported in the literature. Furthermore, the isolates were evaluated for their leishmanicidal and cytotoxic effects. No cytotoxic effect was observed against the three cancer cell lines (HL60, JURKAT and REH), but compound 1 showed a weak antiprotozoal activity. Liquid-liquid partition and CPC turned to be a versatile technique of glycoside purification which is environmentally friendly and requires a limited amount of organic solvents.
RESUMEN
Two regioisomeric polycyclic xanthones, 3,16-oxyguttiferone A (2) and 1,16-oxyguttiferone A (3), which are polyprenylated acylphloroglucinol-derived analogues, were isolated from the seeds of Symphonia globulifera, together with their presumed o-dihydroxybenzoyl precursor, guttiferone A (1). Anodic oxidation of 1 into the corresponding o-quinone species proved to be an efficient biomimetic method to generate xanthones 2 and 3 in high overall yield and to confirm their structures. Both compounds displayed cytotoxicity against the HCT 116 colon carcinoma cell line with IC50 values of 8 and 3 µM, respectively.
Asunto(s)
Benzofenonas/aislamiento & purificación , Clusiaceae/química , Xantonas/aislamiento & purificación , Benzofenonas/química , Benzofenonas/farmacología , Guyana Francesa , Células HCT116 , Humanos , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Corteza de la Planta/química , Prenilación , Semillas/química , Estereoisomerismo , Xantonas/químicaRESUMEN
Symphonia globulifera has been widely used in traditional medicine and has therefore been subjected to several phytochemical studies in the American and African continents. Interestingly, some disparities have been observed concerning its metabolic profile. Several phytochemical studies of S. globulifera have led to the identification of more than 40 compounds, including several polycyclic polyprenylated acylphloroglucinols. Biological evaluations have pointed out the promising biological activities of these secondary metabolites, mostly as antiparasitic or antimicrobial, confirming the traditional use of this plant. The purpose of this review is to describe the natural occurrence, botanical aspects, ethnomedicinal use, structure, and biogenesis, as well as biological activities of compounds isolated from this species according to their provenance.
Asunto(s)
Antiinfecciosos/farmacología , Clusiaceae/química , Extractos Vegetales/farmacología , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Vías Biosintéticas , Medicina Tradicional , Metabolómica , Estructura Molecular , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Plantas Medicinales , Metabolismo SecundarioRESUMEN
The aim of this study was to investigate the species Symphonia globulifera, a source of polycyclic polyprenylated acyl phloroglucinols such as guttiferone A, which is known to exhibit a variety of biological activities including noticeable antileishmanial properties. Our goal was the identification and the quantification of guttiferone A in different renewable parts of S. globulifera and its preparative isolation. To the best of our knowledge, there is no data concerning its mechanism of action. Consequently, it is particularly interesting to isolate it in gram quantities in order to establish structure activity relationship studies. After performing high-performance liquid chromatography profiles detecting the presence of guttiferone A and proceeding to its quantification, a centrifugal partition chromatography methodology using a two-phase solvent system of cyclohexane/ethyl acetate/methanol/water (20 :â 1 :â 20 : 1, v/v/v/v) was applied to each extract. In conclusion, a centrifugal partition chromatography system has been developed to ensure a fast, reliable, and scalable way to isolate, with a high level of purity, guttiferone A from five renewable parts of S. globulifera. Moreover, this methodology can be extended to the isolation of other polycyclic polyprenylated acyl phloroglucinols such as guttiferones B, C, and D.
Asunto(s)
Benzofenonas/aislamiento & purificación , Centrifugación por Gradiente de Densidad/métodos , Clusiaceae/química , Benzofenonas/química , Cromatografía Líquida de Alta Presión , Estructura MolecularRESUMEN
Since the 1960s, fungal infections have become a major worldwide public health problem. Antifungal treatments have many limitations, such as toxicity and resistance. Matayba guianensis Aublet (Sapindaceae) was chemically investigated as part of our ongoing search for lead molecules against fungi in the Brazilian Cerrado biome. The ethanolic extract of M. guianensis root bark revealed the presence of two previously unreported ether diglycosides: matayoside E (1) and F (2) with anti Candida activity, along with two known compounds: cupanioside (3) and stigmasterol (4).
Asunto(s)
Antifúngicos/química , Glicósidos/química , Sapindaceae/química , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Candida/efectos de los fármacos , Glicósidos/aislamiento & purificación , Glicósidos/farmacología , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Conformación Molecular , Corteza de la Planta/química , Corteza de la Planta/metabolismo , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Sapindaceae/metabolismoRESUMEN
Fusarium graminearum causes destructive ear rot diseases in maize and wheat. New antifungals are essential to combat this pathogen, and aerial parts of Justicia species (Acanthaceae) are a potential source. We investigated the antifungal activity of extracts from stems and leaves of five Justicia species native to Northwest Argentina. The aerial parts were subjected to sequential extractions with dichloromethane, ethyl acetate, and methanol. The resulting extracts were tested by the disc diffusion method against F. graminearum strains. Only the leaf and stem extracts from J. xylosteoides displayed inhibitory effects, with the dichloromethane leaf extract as the most active. The compounds involved were identified as the lignans hinokinin, savinin, and isohibalactone. Both the dichloromethane extract and hinokinin synergised with tebuconazole, and inhibited deoxynivalenol biosynthesis. The identified compounds warrant further research as additives to azole fungicides for F. graminearum control.
RESUMEN
Twenty four extracts from Bignoniaceae plants of northwest Argentina were tested for antifungal activity against Aspergillus species responsible of the grape black rot. Stems and leaves of Amphilophium cynanchoides, Macfadyena cynanchoides, Tecoma stans and Jacaranda mimosifolia were separately extracted with solvents of increasing polarity to obtain the dichloromethane (fCH2Cl2), ethyl acetate (fEtOAc) and methanol extracts (fMeOH). The fCH2Cl2 from stem of M. cynanchoides had the lowest IC50 (1.0-1.2 mg/mL) and MID values (0.6-1.2 mg) and the highest ID values (5.0-6.8 mm) on A. niger and A. carbonarius. The main contributors of the antifungal activity of fCH2Cl2 were identified as lapachol (MIC = 0.25-1.00 mg/ml) and 1-hydroxy-4-methylanthraquinone (MIC = 0.0625-0.125 mg/mL). These compounds synergized the antifungal activity of sodium metabisulfite and showed an additive effect in mixtures with propiconazol. They might be used as additives of commercial antifungals to protect grapes against A. niger and A. carbonarius.
Asunto(s)
Antifúngicos/aislamiento & purificación , Aspergillus niger/efectos de los fármacos , Bignoniaceae/química , Antifúngicos/farmacología , Aspergillus/efectos de los fármacos , Bignoniaceae/microbiología , Ocratoxinas , Enfermedades de las Plantas/microbiología , Hojas de la Planta/química , Tallos de la Planta/química , Vitis/microbiologíaRESUMEN
Extracts from aerial parts of Prosopis ruscifolia, Bidens pilosa, Cercidium praecox and Phoradendron liga were assayed against toxigenic Aspergillus species. They were obtained by sequential extraction of the aerial parts with hexane (fHex), dichloromethane (fDCM), ethyl acetate (fEtOAc) and methanol (fMeOH). The fMeOH from P. ruscifolia showed the highest antifungal spectrum (MIC = 750-1500 µg mL-1; MID = 50-200 µg; DI = 1.7-3.0 mm). Indolizidine alkaloids (juliflorine and juliprosine) and tryptamine were identified with strong (MIC = 188 µg mL-1) and moderate antifungal activities (MIC = 750 µg mL-1), respectively, towards A. parasiticus and A. flavus. The fMeOH, the indolizidine alkaloids and tryptamine synergized the fungitoxic effect of potassium sorbate and propiconazole. They completely suppressed the biosynthesis of aflatoxins at concentrations of 47, 94 and 375 µg mL-1, respectively. Our results indicate that fMeOH and its identified alkaloids are promisory additives of commercial antifungals and are antiaflatoxigenic agents at concentrations below of those required for complete suppression of fungal growth.
Asunto(s)
Antifúngicos/farmacología , Aspergillus/efectos de los fármacos , Extractos Vegetales/farmacología , Plantas/química , Aflatoxinas/metabolismo , Alcaloides/química , Alcaloides/farmacología , Antifúngicos/química , Argentina , Aspergillus/metabolismo , Bidens/química , Evaluación Preclínica de Medicamentos , Microbiología de Alimentos , Fungicidas Industriales/química , Fungicidas Industriales/farmacología , Indolizinas/farmacología , Metanol/química , Pruebas de Sensibilidad Microbiana , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/metabolismo , Extractos Vegetales/química , Prosopis/química , Triptaminas/farmacologíaRESUMEN
Extracts from aerial parts of medicinal plants from northwest Argentina were screened for antibacterial activity against the phytopathogenic strains namely CECT 124 (Pseudomonas corrugata), CECT 126 (P. syringae pv. tomato), CECT 225 (Erwinia carotovora var. carotovora), CECT 472 (Agrobacterium tumefaciens) and CECT 792 (Xanthomonas campestres pv. vesicatoria). Leaves and stems of Aspidosperma quebracho-blanco, Schinus fasciculatus, S. gracilipes, Amphilophium cynanchoides and Tecoma stans were separately extracted with solvents of increasing polarity to obtain the dichloromethane (fCH2Cl2), ethyl acetate (fEtAc) and methanol extracts (fMeOH), respectively. Among the thirty extracts tested, only fEtAc from leaves and stems of S. fasciculatus reached the IC50 against the five bacterial strains tested (IC50 = 0.9 mg/ml). The fEtAc from the leaves contained kaempferol, quercetin and agathisflavone which had moderate to strong antibacterial activity. This extract and its identified flavonoids showed synergic (CECT 124,126 and 792) or additive effects (CECT 472 and 225) in mixtures with Kocide 3000.
Asunto(s)
Anacardiaceae/química , Antibacterianos/aislamiento & purificación , Flavonoides/aislamiento & purificación , Extractos Vegetales/farmacología , Antibacterianos/farmacología , Argentina , Bacterias/efectos de los fármacos , Flavonoides/química , Flavonoides/farmacología , Pruebas de Sensibilidad Microbiana , Hojas de la Planta/química , Plantas Medicinales/químicaRESUMEN
Pseudomonas aeruginosa is capable to deploy a collection of virulence factors that are not only essential for host infection and persistence, but also to escape from the host immune system and to become more resistant to drug therapies. Thus, developing anti-virulence agents that may directly counteract with specific virulence factors or disturb higher regulatory pathways controlling the production of virulence armories are urgently needed. In this regard, this study reports that Pistacia lentiscus L. fruit cyclohexane extract (PLFE1) thwarts P. aeruginosa virulence by targeting mainly the pyocyanin pigment production by interfering with 4-hydroxy-2-alkylquinolines molecules production. Importantly, the anti-virulence activity of PLFE1 appears to be associated with membrane homeostasis alteration through the modulation of SigX, an extracytoplasmic function sigma factor involved in cell wall stress response. A thorough chemical analysis of PLFE1 allowed us to identify the ginkgolic acid (C17:1) and hydroginkgolic acid (C15:0) as the main bioactive membrane-interactive compounds responsible for the observed increased membrane stiffness and anti-virulence activity against P. aeruginosa. This study delivers a promising perspective for the potential future use of PLFE1 or ginkgolic acid molecules as an adjuvant therapy to fight against P. aeruginosa infections.
RESUMEN
The bis-indole alkaloid indirubin and its analogues bear a very interesting natural pharmacophore. They are recognized mainly as kinase inhibitors, but several other activities make them possible candidates for preclinical studies. Based on the previously reported activity of 7-bromoindirubin-3'-oxime and its derivatives, the synthesis of indirubins bearing a heterocyclic nitrogen atom at position 7 was carried out. Herein, we report the first synthesis of 7-azaindirubin-3'-oxime (12) as well as its antiproliferative activity against 57 cancer cell lines and its inhibitory activity against a series of kinases. 7-Azaindirubin (10) and its 3'-oxime derivative (12) showed reduced activity as kinase inhibitors in comparison with other known indirubin derivatives, but antiproliferative activity with a best GI(50) value of 0.77 microM.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/síntesis química , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/farmacología , Alcaloides Indólicos/síntesis química , Alcaloides Indólicos/farmacología , Secuencia de Aminoácidos , Antineoplásicos/química , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/química , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Humanos , Alcaloides Indólicos/química , Indoles/farmacología , Estructura MolecularRESUMEN
This Data Descriptor announces the submission to public repositories of the monoterpene indole alkaloid database (MIADB), a cumulative collection of 172 tandem mass spectrometry (MS/MS) spectra from multiple research projects conducted in eight natural product chemistry laboratories since the 1960s. All data have been annotated and organized to promote reuse by the community. Being a unique collection of these complex natural products, these data can be used to guide the dereplication and targeting of new related monoterpene indole alkaloids within complex mixtures when applying computer-based approaches, such as molecular networking. Each spectrum has its own accession number from CCMSLIB00004679916 to CCMSLIB00004680087 on the GNPS. The MIADB is available for download from MetaboLights under the identifier: MTBLS142 ( https://www.ebi.ac.uk/metabolights/MTBLS142 ).
RESUMEN
Indirubins are kinase inhibitory bis-indoles that can be generated from various plant, mollusk, mammalian, and bacterial sources or chemically synthesized. We here report on the synthesis and biological evaluation of 3'-substituted 7-halogenoindirubins. Molecular modeling and kinase assays suggest that steric hindrance prevents 3'-substituted 7-halogenoindirubins from interacting with classical kinase targets of other indirubins such as cyclin-dependent kinases and glycogen synthase kinase-3. Surprisingly 3'-substituted 7-halogenoindirubins induce cell death in a diversity of human tumor cell lines. Although some 3'-substituted 7-halogenoindirubins appear to induce effector caspase-independent, nonapoptotic cell death, others trigger the landmarks of classical apoptosis. A structure-activity relationship study was performed to optimize 3'-substituted 7-halogenoindirubins with respect to solubility and cell death induction. Despite their unidentified targets, 3'-substituted 7-halogenoindirubins constitute a new promising family of antitumor agents.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Bromo , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Cloro , Ensayos de Selección de Medicamentos Antitumorales , Flúor , Humanos , Indoles/síntesis química , Indoles/química , Indoles/farmacología , Yodo , Modelos Moleculares , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Traditional aqueous kava extracts were the most probable cause of hepatitis in two patients presenting with markedly elevated transaminases and hyperbilirubinaemia. A consequent survey of 27 heavy kava drinkers in New Caledonia showed elevated gamma glutamyl transferase in 23/27 and minimally elevated transaminases in 8/27. We conclude that not only commercially available, but also traditionally prepared kava extracts may rarely cause liver injury. The increased activity of gamma glutamyl transferase in heavy kava consumers in the presence of normal or minimally elevated transaminases is probably not a sign of liver injury, but rather reflects an induction of CYP450 enzymes.
Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Kava/efectos adversos , Fitoterapia/efectos adversos , Adulto , Enfermedad Hepática Inducida por Sustancias y Drogas/enzimología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Extractos Vegetales/efectos adversos , Transaminasas/sangre , gamma-Glutamiltransferasa/sangreRESUMEN
A number of novel 3,6-disubstituted 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole derivatives, containing the adamantyl moiety, were synthesized and examined in various viral test systems. No antiviral effects were noted with any of the compounds at subtoxic concentrations in cell culture.
Asunto(s)
Adamantano/síntesis química , Adamantano/farmacología , Antivirales/síntesis química , Antivirales/farmacología , Tiadiazoles/síntesis química , Tiadiazoles/farmacología , Triazoles/síntesis química , Triazoles/farmacología , Adamantano/análogos & derivados , Adamantano/toxicidad , Animales , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/toxicidad , Antivirales/toxicidad , Chlorocebus aethiops , VIH-1/efectos de los fármacos , VIH-2/efectos de los fármacos , Células HeLa , Humanos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Linfocitos T/efectos de los fármacos , Linfocitos T/virología , Tiadiazoles/toxicidad , Triazoles/toxicidad , Células Vero , Zidovudina/farmacología , Zidovudina/toxicidadRESUMEN
BACKGROUND: In search of new antiparasitic agents for overcoming the limitations of current leishmaniasis chemotherapy, we have previously shown that 6-bromoindirubin-3'-oxime (6BIO) and several other 6-substituted analogues of indirubin, a naturally occurring bis-indole present in mollusks and plants, displayed reverse selectivity from the respective mammalian kinases, targeting more potently the leishmanial Cyclin-Dependent Kinase-1 (CDK1) homologue [cdc2-related protein kinase 3 (LCRK3)] over leishmanial Glycogen Synthase Kinase-3 (LGSK-3). This reversal of selectivity in Leishmania parasites compared to mammalian cells makes the design of specific indirubin-based LGSK-3 inhibitors difficult. In this context, the identification of compounds bearing specific substitutions that shift indirubin inhibition towards LGSK-3, previously found to be a potential drug target, over LCRK3 is imperative for antileishmanial targeted drug discovery. METHODS: A new in-house indirubin library, composed of 35 compounds, initially designed to target mammalian kinases (CDKs, GSK-3), was tested against Leishmania donovani promastigotes and intracellular amastigotes using the Alamar blue assay. Indirubins with antileishmanial activity were tested against LGSK-3 and LCRK3 kinases, purified from homologous expression systems. Flow cytometry (FACS) was used to measure the DNA content for cell-cycle analysis and the mode of cell death. Comparative structural analysis of the involved kinases was then performed using the Szmap algorithm. RESULTS: We have identified 7 new indirubin analogues that are selective inhibitors of LGSK-3 over LCRK3. These new inhibitors were also found to display potent antileishmanial activity with GI50 values of <1.5 µΜ. Surprisingly, all the compounds that displayed enhanced selectivity towards LGSK-3, were 6BIO analogues bearing an additional 3'-bulky amino substitution, namely a piperazine or pyrrolidine ring. A comparative structural analysis of the two aforementioned leishmanial kinases was subsequently undertaken to explain and rationalize the selectivity trend determined by the in vitro binding assays. Interestingly, the latter analysis showed that selectivity could be correlated with differences in kinase solvation thermo dynamics induced by minor sequence variations of the otherwise highly similar ATP binding pockets. CONCLUSIONS: In conclusion, 3'-bulky amino substituted 6-BIO derivatives, which demonstrate enhanced specificity towards LGSK-3, represent a new scaffold for targeted drug development to treat leishmaniasis.