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A phytochemical study of n-hexane, CHCl3, and CHCl3-MeOH extracts of Aphanamixis polystachya leaves led to the isolation of 10 compounds. Five of them turned out to be new natural compounds, including two mexicanolide-type (1, 2) and three polyoxyphragmalin-type (3-5) limonoids, together with two known andirobin-type limonoids (6, 7) and three phenolic derivatives. The structures of the new compounds were established on the basis of spectroscopic methods to be 8-hydro-14,15-en-cabralin (1), 3-deacetyl-8-hydro-cabra-lin-14,15-en-3-one (2), 20,22-dihydroxy-21,23-dimethoxy-tetrahydrofuran khayanolide A (3), 1-deacetyl-3-dehydroxy-3-oxokhaysenelide E (4), and meliaphanamixin A (5). All compounds were isolated for the first time from this species. The ability of the isolated limonoids to interact with the molecular chaperone Hsp90 was tested. Compounds 6 and 7 were the most active. [ABSTRACT FROM AUTHOR]

A phytochemical investigation of the inner bark of Tabebuia avellanedae Lorentz ex Griseb was carried out by various chromatographic techniques, resulting in the isolation and characterization of eight new iridoid esters, namely Avelladoids A-H (1-8). Their chemical structures were elucidated on the basis of extensive spectroscopic analyses, especially 2D NMR experiments and HRMS data. The anti-inflammatory effects of 1-8 were determined on an LPS-stimulated RAW 264.7 cell line. Among them, compounds 1, 2, and 3 exhibited anti-inflammatory activities by inhibition of NO and PGE2 production in a dose-dependent manner, without altering cell viability. [ABSTRACT FROM AUTHOR]

Hsp90 is an evolutionarily conserved adenosine triphosphate-dependent molecular chaperone and is one of the most abundant proteins in the cells (1-3%). Hsp90 is induced when a cell undergoes various types of environmental stresses such as heat, cold, or oxygen deprivation. It is involved in the turnover, trafficking, and activity of client proteins, including apoptotic factors, protein kinases, transcription factors, signaling proteins, and a number of oncoproteins. Most of the Hsp90 client proteins are involved in cell growth, differentiation, and survival, and include kinases, nuclear hormone receptors, transcription factors, and other proteins associated with almost all the hallmarks of cancer. Consistent with these diverse activities, genetic and biochemical studies have demonstrated the implication of Hsp90 in a range of diseases, including cancer, making this chaperone an interesting target for drug research. During the last few decades, plant secondary metabolites have been studied as a major source for lead compounds in drug discovery. Recently, several plant-derived small molecules have been discovered exhibiting inhibitory activity towards Hsp90, such as epigallocatechin gallate, gedunin, lentiginosine, celastrol, and deguelin. In this work, an overview of plant secondary metabolites interfering with Hsp90 activities is provided. [ABSTRACT FROM AUTHOR]

The farnesoid X receptor (FXR) and the liver x receptors (LXRs) are bile acid-activated receptors that are highly expressed in the enterohepatic tissues. The mechanisms that support the beneficial effects of bariatric surgery are only partially defined. We have investigated the effects of ileal interposition (IT), a surgical relocation of the distal ileum into the proximal jejunum, on FXR and LXRs in rats. Seven months after surgery, blood concentrations of total bile acids, taurocholic acid, an FXR ligand, and taurohyocholic acid, an LXRα ligand, were significantly increased by IT (P < 0.05). In contrast, liver and intestinal concentrations of conjugated and nonconjugated bile acids were decreased (P < 0.05). These changes were associated with a robust induction of FXR and FXR-regulated genes in the intestine, including Fgf15, a negative regulator of bile acid synthesis. IT repressed the liver expression of glucose-6-phosphatase (G6PC) and phosphoenolpyruvate carboxykinase (Pepck), two gluconeogenetic genes, along with the expression of LXRα and its target genes sterol regulatory element-binding protein (Srebp) 1c and fatty acid synthase (Fas) in the liver. Treating IT rats with chenodeoxycholic acid ameliorated insulin signaling in the liver. Whether confirmed in human settings, these results support the association of pharmacological therapies with bariatric surgeries to exploit the selective activation of intestinal nuclear receptors., The farnesoid receptor (FXR) and liver X receptors (LXRs) are members of the nuclear receptor superfamily of transcription factors activated by bile acids and oxysterols (1,2). FXR, the master regulator [...]