ABSTRACT
Holarrhena pubescens seeds are used in the treatment of various diseases, especially diabetes and associated complications, in different parts of the world. The present study was undertaken to determine the hypolipidemic and antihyperlipidemic effects of methanolic extract of H. pubescens seeds in rats. The extract was subjected to LC-MS analysis to determine the chemical constituents. The hypolipidemic action was studied by determining the effect of 28-day oral administration of seed extract on serum cholesterol, serum triglycerides, and serum HDL-cholesterol levels. The antihyperlipidemic action was studied in rats fed with a high-fat diet containing cholesterol and saturated fat, and the same lipid parameters were estimated during 28-day treatment. To elucidate its probable mechanism of action, in vitro studies on the inhibition of lipid accumulation in preadipocytes, DPP-IV inhibitory effect, and lipase enzyme inhibition were studied. The seed extract reduced serum levels of cholesterol and triglycerides in both normal rats and animals fed with a high-fat diet without a significant effect on HDL-cholesterol levels. The seed extract was highly effective in inhibiting lipase enzyme activity but showed a modest effect on the inhibition of lipid accumulation and DPP-IV. The results demonstrated that H. pubescens seed extract has hypolipidemic and antihyperlipidemic effects mediated probably through inhibition of lipase enzyme activity.
ABSTRACT
A detailed understanding of the catalytic upgrading of light cycle oil (LCO) is important to achieve effective deep hydrodesulfurization (HDS) when LCO is mixed with straight run gas oil in the diesel pool. Herein, HDS of polyaromatic-rich LCO was studied at the molecular level over three NiMo catalysts on silica-alumina supports, which were synthesized on the pilot scale using different silica/alumina mixing procedures. Gas chromatography with atomic emission detection and two-dimensional gas chromatography with time-of-flight mass spectrometry were used to evaluate the HDS performance through determining the feed and product compositions, respectively, at the molecular level. Furthermore, the textural properties of the catalysts were evaluated using Raman spectroscopy, transmission electron microscopy, and the temperature-programmed desorption of NH3. The performance of the best catalyst was attributed to its higher content of octahedrally coordinated Mo oxide species, a lower number of layered stacks, and the more acidic sites on the surface. In addition, the hydrotreating reactivity of various family groups in LCO over the catalyst was investigated.
