RESUMEN
In an effort to identify novel inhibitors of nuclear factor kappa B (NF-κB), twenty five pyranochalcone derivatives were synthesized and evaluated for their in vitro activities against TNF-α induced NF-κB inhibition in HEK293T cells. Among all of these derivatives, several displaying the same acrylate moiety on the B ring exhibited potent inhibition, with IC50 values ranging from 0.29 to 10.46 µM. A functional study of the most potent of these compounds, designated 6b, revealed that it significantly suppressed the transcriptional expression of inflammatory factor IL-1ß in lipopolysaccharide-induced RAW 264.7 macrophages, and also mildly inhibited CCL2, IL6 and TNF-α. In addition, compound 6b was found to inhibit IL-1ß released in LPS-induced BMDM cells. This study demonstrates that the inhibitory effect of 6b on LPS-stimulated inflammatory mediator production in the mouse macrophage cell line RAW 264.7 correlates with the suppression of the NF-κB and MAPK signaling pathways.
Asunto(s)
Chalconas/farmacología , FN-kappa B/antagonistas & inhibidores , Piranos/farmacología , Chalconas/síntesis química , Chalconas/química , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , FN-kappa B/metabolismo , Piranos/síntesis química , Piranos/química , Relación Estructura-ActividadRESUMEN
Guaipyridine alkaloids (-)-rupestine D, (-)-guaipyridine, (-)-epiguaipyridine, and (-)-cananodine together with two stereoisomers 8-epi-rupestine D and 5-epi-cananodine were synthesized enantioselectively from readily available citronellol. The key steps in this synthesis are (i) intermolecular opening of a trisubstituted epoxide for the formation of a chiral center at C-8; (ii) ring-closing metathesis for the construction of a seven-membered carbocyclic ring; and (iii) biomimetic cyclization of a 1,5-dicarbonyl compound for the construction of a pyridine-fused bicyclic skeleton.
RESUMEN
The first asymmetric total synthesis of (+)-iresin (4), an historically important ent-Drimane sesquiterpene lactone, was realized from aldehyde 3 via cyclic orthoester 6 in 5 steps. Notable transformations in this synthesis include a tandem trifluoroperacetic acid (TFPAA)-mediated Baeyer-Villiger oxidation-olefin epoxidation-epoxy ester cyclization, regioselective Burgess dehydration, and regioselective Fétizon oxidative lactonization.
Asunto(s)
Compuestos Epoxi/química , Lactonas/síntesis química , Sesquiterpenos/síntesis química , Lactonas/química , Estructura Molecular , Oxidación-Reducción , Sesquiterpenos Policíclicos , Sesquiterpenos/química , EstereoisomerismoRESUMEN
Use of novel modulators targeting P-glycoprotein (P-gp, ABCB1 transporter) is among the most accepted strategies for overcoming multidrug resistance in cancer chemotherapy. In the current study, we pursued our structure-activity relationship studies of jatrophane derivatives by structural modification of compound 1, a natural jatrophane isolated from Euphorbia. sororia A. Nine compounds exhibited higher reversal activity in P-gp/ABCB1-mediated MCF-7/ADR cells than verapamil (VRP). The cytotoxicity and doxorubicin (DOX) intracellular accumulation effects of jatrophane derivatives were assessed in normal HEK293T cells and DOX-resistant MCF-7/ADR cells. The most potent compound 17 merits multiple activities, including (1) high efficiency (EC50 = 182.17 ± 32.67 nM) in reversing P-gp-mediated resistance to DOX, low cytotoxicity, and a high therapeutic index; and (2) increasing the accumulation of Rhodamine123 (Rho123) and DOX in a dose-dependent manner compared to verapamil in MCF-7/ADR cells. Our results indicated that the reversal activity of 17 was due to the stimulation of the P-gp ATPase activity instead of the direct inhibition of P-gp protein expression. A docking study demonstrated that 17 has a high binding affinity toward the DOX recognition site of P-gp. This resulted in 17 enhancing the sensitivity of DOX to MCF-7/ADR cells by stimulating P-gp ATPase activity, increasing intracellular DOX and Rho123 concentrations, inhibiting the phosphoinositide 3-kinase/serine-threonine kinase mediated by DOX and further reducing the expression of P-gp. This study provides a promising P-gp inhibitor for reversing multidrug resistance and provides a basis for further research.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP , Euphorbia , Humanos , Células MCF-7 , Células HEK293 , Fosfatidilinositol 3-Quinasas/metabolismo , Resistencia a Antineoplásicos , Doxorrubicina/farmacología , Subfamilia B de Transportador de Casetes de Unión a ATP , Verapamilo/farmacología , Adenosina Trifosfatasas/metabolismoRESUMEN
Seven previously undescribed diterpenoid alkaloids, including five C20-diterpenoid alkaloids, barpuberudine, barpubesines A-D, and two C18-diterpenoid alkaloids, barpubenines A-B, along with 11 known diterpenoid alkaloids were isolated from the whole plant of Aconitum barbatum var. puberulum Ledeb. (Ranunculaceae). Barpuberudine is an unprecedented carbon skeleton of C20-diterpenoid alkaloid, while barpubenines A-B are the first example of rearranged types in C18-diterpenoid alkaloids. Their structures were elucidated based on a comprehensive spectroscopic data analysis. The probable pathway of biogenesis of barpuberudine and barpubenines A-B were discussed. Additionally, the antiarrhythmic, cytotoxic and antimicrobial activities of isolates were also evaluated.
Asunto(s)
Aconitum , Alcaloides , Alcaloides/farmacología , Diterpenos/farmacología , Estructura Molecular , Raíces de PlantasRESUMEN
Rupestine G is a guaipyridine sesquiterpene alkaloid isolated from Artemisia rupestris L. The total synthesis of rupestine G and its epimers was accomplished employing a Suzuki reaction to build a terminal diene moiety. The diene was further elaborated into the desired guaipyridine structure by a ring-closing metathesis reaction. Over all, rupestine G and its three epimers were obtained as a mixture in a sequence of nine linear steps with 18.9% yield. Rupestine G and its optically pure isomers were isolated by chiral preparative HPLC and fully characterized by 1H ,13C NMR, HRMS, optical rotation value, and experimental and calculated electronic circular dichroism spectroscopy.