Development of an analytical platform for the affinity screening of natural extracts by SEC-MS towards PPARα and PPARγ receptors.

BACKGROUND: Peroxisome proliferator-activated receptors (PPARs) belong to the superfamily of nuclear receptors and represent the targets for the therapeutical treatment of type 2 diabetes, dyslipidemia and hyperglycemia associated with metabolic syndrome. Some medicinal plants have been traditionally used to treat this kind of metabolic diseases. Today only few drugs targeting PPARs have been approved and for this reason, the rapid identification of novel ligands and/or chemical scaffolds starting from natural extracts would benefit of a selective affinity ligand fishing assay. RESULTS: In this paper we describe the development of a new ligand fishing assay based on size exclusion chromatography (SEC) coupled to LC-MS for the analysis of complex samples such as botanical extracts. The known PPARα and PPARγ ligands, WY-14643 and rosiglitazone respectively, were used for system development and evaluation. The system has found application on an Allium lusitanicum methanolic extract, containing saponins, a class of chemical compounds which have attracted interest as PPARs ligands because of their hypolipidemic and insulin-like properties. SIGNIFICANCE: A new SEC-AS-MS method has been developed for the affinity screening of PPARα and PPARγ ligands. The system proved to be highly specific and will be used to improve the throughput for the identification of new selective metabolites from natural souces targeting PPARα and PPARγ.

Application of a rapid HILIC-UV method for synthesis optimization and stability studies of immunogenic neo-glycoconjugates.

Proteins and glycoproteins with therapeutic activity are susceptible to environmental factors, which can cause their degradation and the loss of their activity. Thus, the maintenance of their stability during the production process is a critical factor. In this work, a simple and rapid hydrophilic interaction liquid chromatography HILIC-UV method was validated in terms of accuracy, precision, linearity, LOD, LOQ and specificity and applied to the investigation of the stability of intact proteins and their neo-glycoconjugates with antigenic activity against tuberculosis. The method proved to be suitable for the estimation of the degradation of the proteins under critical conditions (i.e. freeze-thaw cycles) and for the monitoring of their coupling reaction with saccharidic moieties, without the need of sample preparation. In addition, the chromatographic analysis allowed to calculate the yields of the protein glycosylation reaction.

Red wine polyphenols prevent cyclosporine-induced nephrotoxicity at the level of the intrinsic apoptotic pathway.

Flavonoids, polyphenol derivatives of plant origin, possess a broad range of pharmacological properties. A number of studies have found both pro/anti-apoptotic effects for many of these compounds. For these reasons we investigated whether Provinols flavonoids obtained from red wine, have anti-apoptotic properties. The investigations have been carried out in rats treated with Cyclosporine A (CsA). In particular, four groups of rats have been treated for 21 days with either olive oil (control group), with CsA, with Provinols, or with CsA and Provinols simultaneously. Oxidative stress, systolic blood pressure, body weight, biochemical parameters and different markers of pro/anti-apoptotic pathway were measured. CsA produced an increase of systolic blood pressure, a decrease in body weight, serum creatinine levels, urinary total protein concentration and creatinine clearance. Moreover, CsA induced renal alterations and the translocation of Bax and cytochrome c from cytoplasm to mitochondria and vice versa. These changes activated the caspase cascade pathway, that leads to morphological and biochemical features of apoptosis. Provinols restored morphological and biochemical alterations and prevented nephrotoxicity. In conclusion, this study may augment our current understanding of the controversial pro-/anti-apoptotic properties of flavonoids and their molecular mechanisms.

Atherosclerosis and oxidative stress.

This review focuses on the morphological features of atherosclerosis and the involvement of oxidative stress in the initiation and progression of this disease. There is now consensus that atherosclerosis represents a state of heightened oxidative stress characterized by lipid and protein in the vascular wall. Reactive oxygen species (ROS) are key mediators of signaling pathways that underlie vascular inflammation in atherogenesis, starting from the initiation of fatty streak development, through lesion progression, to ultimate plaque rupture. Plaque rupture and thrombosis result in the acute clinical complications of myocardial infarction and stroke. Many data support the notion that ROS released from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, myeloperoxidase (MPO), xanthine oxidase (XO), lipoxygenase (LO), nitric oxide synthase (NOS) and enhanced ROS production from dysfunctional mitochondrial respiratory chain, indeed, have a causatory role in atherosclerosis and other vascular diseases. Moreover, oxidative modifications in the arterial wall can contribute to the arteriosclerosis when the balance between oxidants and antioxidants shifts in favour of the former. Therefore, it is important to consider sources of oxidants in the context of available antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase and transferases thiol-disulfide oxidoreductases and peroxiredoxins. Here, we review also the mechanisms in which they are involved in order to accelerate the pace of the discovery and facilitate development of novel therapeutic approaches.