RESUMEN
Chemical investigation of the lichen Parmotrema tsavoense led to the isolation of 5 new depsidones, parmosidones Fâ-âJ (1: â-â5: ). These compounds were structurally elucidated using spectroscopic methods including HRESIMS and 2D NMR data. Compounds 1, 3: , and 4: were evaluated for their inhibition of α-glucosidase. All exhibited potent α-glucosidase inhibitory activity with IC50 values ranging from 10.7 to 17.6 µM, which was much lower than that of the positive control acarbose (IC50 449 µM).
Asunto(s)
Líquenes , alfa-Glucosidasas , Depsidos , Inhibidores de Glicósido Hidrolasas , Lactonas , Extractos VegetalesRESUMEN
Three new depsidones, parmosidones Fâ-âG (1â-â2), and 8'-O-methylsalazinic acid (3), and 3 new diphenylethers, parmetherines Aâ-âC (4â-â6), together with 2 known congeners were isolated from the whole thalli of Parmotrema dilatatum, a foliose chlorolichen. Their structures were unambiguously determined by extensive spectroscopic analyses and comparison with literature data. The isolated polyphenolics were assayed for their α-glucosidase inhibitory activities. Newly reported benzylated depsidones 1: and 2: in particular inhibited α-glucosidase with IC50 values of 2.2 and 4.3 µM, respectively, and are thus more potent than the positive control, acarbose.
Asunto(s)
Líquenes , alfa-Glucosidasas , Depsidos , Inhibidores de Glicósido Hidrolasas/farmacología , Lactonas , Extractos Vegetales/farmacología , SalicilatosRESUMEN
Two new cycloartanes, combretic acid C (1) and combretanone I (3), were isolated from the leaves of Combretum quadrangulare Kurz, together with the previously-reported combretic acids A-B (2 and 5) and combretanone A (4). An extensive set of spectroscopic methods were used to elucidate the structures of these compounds. Cytotoxicity against the K562 cancer cell line was evaluated. Compound 1 showed strong activity, with an IC50 value of 9.7 µM. The other compounds showed moderate activity. Alpha-glucosidase inhibition was also evaluated. The isolated compounds showed moderate inhibition, with IC50 values in the range 102.2-194.7 µM.
Asunto(s)
Combretum , Triterpenos , Combretum/química , Vietnam , Triterpenos/química , Hojas de la Planta/químicaRESUMEN
A novel oxime polyketide, maydisone (1), along with two known compounds, 7-hydroxy-2,5-dimethylchromone (2) and 2,5-dimethylbenzoic acid (3) were isolated from the cultures of Bipolaris maydis. Their structures were identified by the application of NMR and MS data analyses and comparison with previous reports. Compound 1 showed the most powerful inhibition of α-glucosidase, with an IC50 value of 68.30 ± 0.83 µM.
Asunto(s)
Policétidos , Bipolaris , Oximas , alfa-GlucosidasasRESUMEN
The aim of this study was to investigate anti-inflammatory activity of 4-hydroxybenzyl-chitooligomers (HB-COS) in Chang liver cells stimulated by a cytokine mixture. It was revealed that HB-COS decreased the level of nitric oxide and prostaglandin E2 (PGE2) production by diminishing the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) without significant cytotoxicity. Moreover, HB-COS exerted inhibitory effects on the production of pro-inflammatory mediator (interleukin-6) in Chang liver cells. Notably, HB-COS exhibited anti-inflammatory activities via blocking degradation of inhibitory kappa B alpha (IκB-α), translocation of nuclear factor kappa B (NF-κB), and phosphorylation of mitogen-activated protein kinases (MAPKs) in a dose-dependent manner. Collectively, these findings indicated that HB-COS possessed potential anti-inflammatory effects in Chang liver cells, and could be a useful therapeutic agent for the treatment of hepatic inflammatory diseases.
Asunto(s)
Antiinflamatorios/farmacología , Inflamación/tratamiento farmacológico , Hígado/efectos de los fármacos , Línea Celular , Ciclooxigenasa 2/metabolismo , Dinoprostona/metabolismo , Humanos , Proteínas I-kappa B/metabolismo , Inflamación/metabolismo , Interleucina-6/metabolismo , Hígado/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Inhibidor NF-kappaB alfa , FN-kappa B/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Fosforilación/efectos de los fármacosRESUMEN
In this study, a bioactive derivative of chitooligomers (1.0-3.0 kDa), 4-hydroxybenzyl-COS (HB-COS), was synthesized to enhance antioxidant activity. Hence, HB-COS was evaluated for its capabilities against H2O2-induced oxidative stress in human Chang liver cells. It was found that HB-COS possessed the free radical scavenging activity via decreasing the intracellular reactive oxygen species production. Furthermore, HB-COS significantly reduced the oxidation of DNA in a dose-dependent manner. Notably, HB-COS treatment upregulated the gene and protein expressions of antioxidative enzymes and thereby enhancing the intracellular antioxidant mechanisms. In addition, HB-COS treatment caused a remarkable blockade on degradation of inhibitory kappa B alpha (IκB-α) protein and translocation of nuclear factor kappa B (NF-κB). The current study demonstrated that HB-COS effectively attenuated hydrogen peroxide-induced oxidative stress in Chang liver cells by increasing levels of antioxidant enzymes and inhibiting reactive oxygen species generation, DNA oxidation and the NF-κB signaling pathway.