A contribution to the study of hydrophobicity (lipophilicity) of bile acids with an emphasis on oxo derivatives of 5β-cholanoic acid

Novel xanthone derivatives as potent sirtuin 2 inhibitors

Six amino derivatives of xanthone were obtained via chemical synthesis. Biochemical studies revealed their SIRT2 inhibitory activity ranging from 48.5 % (compound 4, 5-chloro-2-((4-(3-methoxyphenyl)piperazin-1-yl)methyl)-9H-xanthen-9-one hydrochloride) to 93.2 % (compound 3, 5-chloro-2-(((2-methoxyphenethyl)amino)methyl)-9H-xanthen-9-one hydrochloride). The structure-activity analysis showed favourable properties of secondary amines relative to tertiary piperazine derivatives. The tested compounds do not possess additional SIRT1 activating activity and no antioxidant activity (DPPH in vitro assay). Comprehensive analysis of the lipophilicity of the obtained compounds was also performed. For compound 3 potential molecular targets and similar active compounds were predicted in order to facilitate further research in this group of compounds.

Highly Hydrophilic and Lipophilic Derivatives of Bile Salts

Lipophilicity of 15 derivatives of sodium cholate, defined by the octan-1-ol/water partition coefficient (log P), has been theoretically determined by the Virtual log P method. These derivatives bear highly hydrophobic or highly hydrophilic substituents at the C3 position of the steroid nucleus, being linked to it through an amide bond. The difference between the maximum value of log P and the minimum one is enlarged to 3.5. The partition coefficient and the critical micelle concentration (cmc) are tightly related by a double-logarithm relationship (VirtuallogP=-(1.00±0.09)log(cmcmM)+(2.79±0.09)), meaning that the Gibbs free energies for the transfer of a bile anion from water to either a micelle or to octan-1-ol differ by a constant. The equation also means that cmc can be used as a measurement of lipophilicity. The demicellization of the aggregates formed by three derivatives of sodium cholate bearing bulky hydrophobic substituents has been studied by surface tension and isothermal titration calorimetry. Aggregation numbers, enthalpies, free energies, entropies, and heat capacities, ΔCP,demic, were obtained. ΔCP,demic, being positive, means that the interior of the aggregates is hydrophobic.

Lactobacillus fermentum FTDC 8312 combats hypercholesterolemia via alteration of gut microbiota

In this study, hypercholesterolemic mice fed with Lactobacillus fermentum FTDC 8312 after a seven-week feeding trial showed a reduction in serum total cholesterol (TC) levels, accompanied by a decrease in serum low-density lipoprotein cholesterol (LDL-C) levels, an increase in serum high-density lipoprotein cholesterol (HDL-C) levels, and a decreased ratio of apoB100:apoA1 when compared to those fed with control or a type strain, L. fermentum JCM 1173. These have contributed to a decrease in atherogenic indices (TC/HDL-C) of mice on the FTDC 8312 diet. Serum triglyceride (TG) levels of mice fed with FTDC 8312 and JCM 1173 were comparable to those of the controls. A decreased ratio of cholesterol and phospholipids (C/P) was also observed for mice fed with FTDC 8312, leading to a decreased number of spur red blood cells (RBC) formation in mice. Additionally, there was an increase in fecal TC, TG, and total bile acid levels in mice on FTDC 8312 diet compared to those with JCM 1173 and controls. The administration of FTDC 8312 also altered the gut microbiota population such as an increase in the members of genera Akkermansia and Oscillospira, affecting lipid metabolism and fecal bile excretion in the mice. Overall, we demonstrated that FTDC 8312 exerted a cholesterol lowering effect that may be attributed to gut microbiota modulation.