[Spectral characteristics of sesquiterpene pyridine alkaloids from Tripterygium plants].

Sesquiterpene pyridine alkaloids are important components in Tripterygium plants, possessing a wide range of pharmacological activities, such as anti-inflammation immunosuppression, anti-tumor, anti-virus, and deinsectization, and are of great research value. They are composed of highly oxidized dihydro-ß-furansquiterpene and pyridine dicarboxylic acid through ester bonds. According to the structural characteristics of pyridine dicarboxylic acid fragments, they can be divided into various structural subtypes. Up to now, more than 110 sesquiterpene pyridine alkaloids have been isolated and identified from Tripterygium plants. This study reviewed the structural features and spectral(i.e., UV, IR, MS, and NMR) characteristics of sesquiterpene pyridine alkaloids and summarized the structural elucidation process in detail to provide references for their further research and development.

Structure characteristics and immunomodulatory activities of a polysaccharide RGRP-1b from radix ginseng Rubra.

The present study was undertaken to explore the structure characteristics, immune regulation, and anti-cancer abilities of polysaccharides in radix ginseng Rubra (RGR). For this purpose, RGR polysaccharides (RGRP) were purified through DEAE and S-300 chromatography. Monosaccharide composition, methylation, and GC-MS analyses, as well as field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Fourier-transformed infrared resonance (FT-IR), and nuclear magnetic resonance (NMR) spectra, were used to establish the structure of RGRP-1b. Our results revealed that RGRP-1a and RGRP-1b possess different molecular weights (21.3 kDa and 10.2 kDa, respectively). RGRP-1a was found to be composed of glucose, while RGRP-1b was composed of glucose, galactose, and arabinose. The main chain structure of RGRP-1b was composed of 1,4-α-Glcp, with a 1,4,6-α-Glcp branch unit. Its side chains were branched at the O-4 position of 1,4,6-α-Glcp, namely 1)-ß-Galp-(4 â†’ 1)-α-Araf-(5 â†’ α-Araf and 1)-ß-Galp-(6 â†’ α-Glcp. The changes in the nitric oxide (NO) levels and cytotoxicity revealed that macrophages probably get activated by RGRP-1b. The expressions of IL-6, IL-12, and TNF-α were found to be upregulated after treatment with RGRP-1b. RGRP-1b thus possesses the potential to arrest the growth of Huh7 through immunoregulation. Our cumulative findings indicate that RGRP-1b obtained from radix ginseng Rubra can function as a strong immune modulator.

Recent progress in the research of yam mucilage polysaccharides: Isolation, structure and bioactivities.

Yam (Dioscorea spp.), known as an edible and medicinal tuber crop in China, has been used historically for the treatment of diabetes, diarrhea, asthma, and other ailments in traditional Chinese medicine. Moreover, it has been consumed as starchy food for thousands of years in China. Modern phytochemistry and pharmacological experiments have been proved that non-starch polysaccharide is one of the main bioactive substances of yam. Many studies have been focused on the isolation and identification of polysaccharides and their bioactivities of Chinese yam. However, due to the difference in the variety of raw materials and the method of polysaccharides extracting, the structure and biological activity of the obtained polysaccharides also differ. It has been demonstrated that Chinese yam polysaccharide has various important biological activities, such as hypoglycemia, immunomodulatory, antioxidant, and antitumor activities. This paper is aimed at summarizing previous and current references of the isolation processes, structural features and bioactivities of yam polysaccharides. The review will serve as a useful reference material for further investigation and application of yam polysaccharides in functional foods and medicine fields.

Synthesis and structural features of phosphorylated Artemisia sphaerocephala polysaccharide.

Phosphorylation is a key route to achieve varieties of biological activities for polysaccharides. Currently, conventional phosphorylation reagents are characterized by long processing times and high reaction temperatures. Here, we reported phosphorylation of Artemisia sphaerocephala polysaccharides (PASP) with the degrees of substitution (DS) of 0.34-0.54 in mild reaction conditions (3-4h and 25°C) by employing POCl3/pyridine technique. FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis confirmed the appearance of phosphate ester (P5+) groups in PASP. Size exclusion chromatography combined with multi-angle laser light scattering (SEC-MALLS) result clearly showed temperature-dependent increment of weight average molecular mass (MW). High temperature facilitated the reaction of phosphoryl chloride with primary and secondary hydroxyl groups, favoring the crosslinking of polysaccharide chains by phosphate di-esters as further confirmed in 13C NMR determination. Our results provide insight into the relationship between the structure and reaction conditions of phosphorylated polysaccharide, which is important for understanding and exploiting these derivatives in a wide range of applications.