Chemical Constituents of the Bulbs of Scilla peruviana and Their Pancreatic Lipase Inhibitory Activity.

Scilla species are used as medicinal plants and contain lanosterol-type triterpene glycosides. The phytochemical investigation of the bulbs of Scilla peruviana led to the isolation of 17 compounds, including three new rearranged pentacyclic-lanosterol glycosides (1-3) and two new homoisoflavanone glycosides (12 and 13). The structures of the undescribed compounds were determined by extensive spectroscopic analyses, including two-dimensional (2D) NMR. Among the triterpene glycosides, 2, 3, and 6 showed significant pancreatic lipase inhibitory activity in a concentration-dependent manner in vitro. The oral administration of scillascilloside D-2 (6) reduced serum triglyceride levels in a dose-dependent manner in soybean oil-loaded mice.

Daisaikoto Inhibits Pancreatic Lipase Activity and Decreases Serum Triglyceride Levels in Mice.

Daisaikoto Extract, a Kampo medicine listed in the Japanese pharmacopoeia 17th edition, is clinically used to treat obesity and related symptoms. Lipid metabolism is closely related to obesity, and pancreatic lipase inhibitors are therefore regarded as effective for the treatment of obesity. Although Daisaikoto has shown promise in the treatment of obesity, its mechanism of action has yet to be elucidated. In the present study, we found that Daisaikoto extract inhibits pancreatic lipase activity in a dose-dependent manner and decreases serum triglyceride levels in mice. To determine the crude drugs responsible for lipase inhibition, 8 variants of Daisaikoto extract without one crude drug were prepared and evaluated for lipase inhibitory activity. The lipase inhibitory activity of the Daisaikoto extract was reduced by excluding Scutellariae Radix (SR), which was found to inhibit lipase activity with an IC50 value of 1.70 mg/mL. In conclusion, Daisaikoto represents a natural medicine, in particular SR, capable of inhibiting pancreatic lipase and lipid absorption.

Differential roles of two N-acetylgalactosaminyltransferases, CSGalNAcT-1, and a novel enzyme, CSGalNAcT-2. Initiation and elongation in synthesis of chondroitin sulfate.

By a tblastn search with beta 1,4-galactosyltransferases as query sequences, we found an expressed sequence tag that showed similarity in beta 1,4-glycosyltransferase motifs. The full-length complementary DNA was obtained by a method of 5'-rapid amplification of complementary DNA ends. The predicted open reading frame encodes a typical type II membrane protein comprising 543 amino acids, the sequence of which was highly homologous to chondroitin sulfate N-acetylgalactosaminyltransferase (CSGalNAcT-1), and we designated this novel enzyme CSGalNAcT-2. CSGalNAcT-2 showed much stronger N-acetylgalactosaminyltransferase activity toward glucuronic acid of chondroitin poly- and oligosaccharides, and chondroitin sulfate poly- and oligosaccharides with a beta 1-4 linkage, i.e. elongation activity for chondroitin and chondroitin sulfate, but showed much weaker activity toward a tetrasaccharide of the glycosaminoglycan linkage structure (GlcA-Gal-Gal-Xyl-O-methoxyphenyl), i.e. initiation activity, than CSGalNAcT-1. Transfection of the CSGalNAcT-1 gene into Chinese hamster ovary cells yielded a change of glycosaminoglycan composition, i.e. the replacement of heparan sulfate on a syndecan-4/fibroblast growth factor-1 chimera protein by chondroitin sulfate, however, transfection of the CSGalNAcT-2 gene did not. The above results indicated that CSGalNAcT-1 is involved in the initiation of chondroitin sulfate synthesis, whereas CSGalNAcT-2 participates mainly in the elongation, not initiation. Quantitative real-time PCR analysis revealed that CSGalNAcT-2 transcripts were highly expressed in the small intestine, leukocytes, and spleen, however, both CSGalNAcTs were ubiquitously expressed in various tissues.