Design, Synthesis and Antitumor Activity of Quercetin Derivatives Containing a Quinoline Moiety.

Quercetin is a flavonoid with significant biological and pharmacological activity. In this paper, quercetin was modified at the 3-OH position. Rutin was used as a raw material. We used methyl protection, Williamson etherification reactions, and then substitution reactions to prepare 15 novel quercetin derivatives containing a quinoline moiety. All these complexes were characterized by 1H NMR, 13C NMR, IR and HRMS. Of these, compound 3e (IC50 = 6.722 µmol·L-1) had a better inhibitory effect on human liver cancer (HepG-2) than DDP (Cisplatin) (IC50 = 26.981 µmol·L-1). The mechanism of the action experiment showed that compound 3e could induce cell apoptosis.

Free Radical-Mediated Grafting of Natural Polysaccharides Such as Chitosan, Starch, Inulin, and Pectin with Some Polyphenols: Synthesis, Structural Characterization, Bioactivities, and Applications-A Review.

Polyphenols and polysaccharides are very important natural products with special physicochemical properties and extensive biological activities. Recently, polyphenol-polysaccharide conjugates have been synthesized to overcome the limitations of polysaccharides and broaden their application range. Grafted copolymers are produced through chemical coupling, enzyme-mediated, and free radical-mediated methods, among which the free radical-induced grafting reaction is the most cost-effective, ecofriendly, safe, and plausible approach. Here, we review the grafting reactions of polysaccharides mediated by free radicals with various bioactive polyphenols, such as gallic acid (GA), ferulic acid (FA), and catechins. A detailed introduction of the methods and their mechanisms for free radical-mediated grafting is given. Structural characterization methods of the graft products, including thin-layer chromatography (TLC), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) analysis, and X-ray diffraction (XRD) are introduced. Furthermore, the biological properties of polyphenol-polysaccharide conjugates are also presented, including antioxidant, antibacterial, antidiabetic, and neuroprotection activities, etc. Moreover, the potential applications of polyphenol-polysaccharide conjugates are described. Finally, the challenges and research prospects of graft products are summarized.

Establishment of a quality evaluation system of sweet potato starch using multivariate statistics.

Background: The quality of starch greatly affects the quality of processed products. There are many indexes for quality evaluation of starch. Currently, amylose content is considered the chief index in the quality evaluation of sweet potato starch, which is entirely based on tradition (experience) method. The existing evaluation standards lack quality evaluation standards for sweet potato starch. Purpose: To screen reasonable evaluation indexes of sweet potato starch, and establish a scientific and systematic evaluation system of sweet potato starch. Methods: Twenty-two components and quality indexes of sweet potato starch were measured. The evaluation indexes of sweet potato starch were screened based on a statistical description, correlation analysis, and principal component analysis (PCA), and a quality evaluation model of sweet potato starch for brewing was established based on analytic hierarchy process. The calculated values of the model were verified by linear fitting with standardized sensory evaluation values. Results: The coefficient of variation of total starch content (%), amylose content (%), amylopectin content (%), L* value, ΔE, water absorption capacity (g/g), and pasting temperature was less than 6%, while the coefficient of variation of other indexes was larger. In addition, there were different degrees of correlation among the indexes. PCA was used to identify interrelated variables, and the first six principal components together account for 82.26% of the total variability. Then, seven core indexes - setback (cp), rate of regression (%), ratio of amylose to amylopectin (%), gel strength (kgf/cm2), a* value, ash content (%), and solubility (%) - were selected from the six principal components according to the load value of the rotation matrix. These seven core indexes replaced the original 22 indexes to simplify the evaluation of sweet potato starch. The quality evaluation model of sweet potato starch was Y = 0.034X2 + 0.321X6 + 0.141X8 + 0.08X17 + 0.023X19 + 0.08X21 + 0.321X22. Conclusion: The comprehensive evaluation system of sweet potato starch can accurately predict the quality of sweet potato starch. The development of such a system is of great significance to the post-harvest processing of high-starch sweet potato and the breeding of high-quality and high-starch sweet potato varieties.

Impact of purple sweet potato (Ipomoea batatas L.) polysaccharides on the fecal metabolome in a murine colitis model.

Purple sweet potato polysaccharides (PSPP) play an important role in regulating the gut microbiota, modulating intestinal immunity and ameliorating colonic inflammation. In this study, the impact of two PSPPs (PSWP-I and PSAP-I) on the metabolomic profiling of feces from dextran sulfate sodium (DSS)-induced colitis mice was evaluated by ultra-high performance liquid chromatography coupled with triple time-of-flight tandem mass spectrometry (UPLC-Triple-TOF-MS/MS). Results indicated that there were twenty-five metabolites with significant changes and four remarkable metabolic pathways, i.e., cutin, suberine and wax biosynthesis, biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, and steroid hormone biosynthesis. Two key biomarkers of oleic acid and 17-hydroxyprogesterone were screened that responded to PSPPs in colitis mice. The identified metabolites were correlated with the amelioration of intestinal immune function and the modulation of the gut microbiota. Nine pro-inflammatory and eight anti-inflammatory compounds responded to PSPPs, which were related to Bacteroides, norank_f__Clostridiales_vadinBB60_group, unclassified_o__Bacteroidales, Rikenella and Lachnospiraceae_UCG-001. Moreover, PSWP-I and PSAP-I had different regulating effects on intestinal metabolites. Our results revealed a possible metabolomic mechanism of PSPPs to regulate intestinal inflammation function.

Anti-inflammatory properties and gut microbiota modulation of an alkali-soluble polysaccharide from purple sweet potato in DSS-induced colitis mice.

In this study, the potential effects of a novel alkali-soluble polysaccharide (ASPP) from purple sweet potato on colonic histopathology, inflammation and microbiota composition in dextran sulfate sodium (DSS)-induced colitis mice were evaluated. The results indicated that ASPP restored the immune organ indices, increased colon length, improved colonic histopathology in colitis mice as well as inhibited the levels of pro-inflammatory cytokines (IL-1ß, IL-6 and TNF-α) in colonic tissue and serum. Moreover, 16S rRNA phylogenetic sequencing revealed that ASPP ameliorated the compositions and functions of gut microbiota in DSS-induced colitis mice. It was found that Parasutterella, Desulfovibrio, Lachnospiraceae, Lactobacillus, Erysipelotrichaceae, Bacteroidetes were the key bacteria associated with ulcerative colitis (UC). Taken together, ASPP alleviated colonic inflammation via blocking pro-inflammatory cytokines; meanwhile ASPP could modulate the structure of gut microbiota in DSS-induced colitis mice.

Anti-inflammatory activity of a water-soluble polysaccharide from the roots of purple sweet potato.

In this study, a water-soluble polysaccharide was isolated from purple sweet potato roots. The in vitro and in vivo anti-inflammatory effects of the polysaccharide were evaluated by lipopolysaccharide (LPS)-induced inflammatory RAW264.7 macrophages and mice, respectively. The in vitro anti-inflammatory assay showed that the polysaccharide could effectively inhibit the overproduction of nitric oxide and pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6) while increasing the secretion of anti-inflammatory cytokine (IL-10). The in vivo anti-inflammatory assay revealed that mice administered with the polysaccharide showed higher IL-10, SOD, and T-AOC levels but lower TNF-α, IL-1ß, IL-6 and MDA levels as compared to the LPS-treated model. Meanwhile, mice administered with the polysaccharide showed increased abundance of Lachnospiraceae, Lactobacillales and Parabacteroides but decreased amounts of Psychrobacter and Staphylococcus as compared to the LPS model group. Moreover, mice administered with polysaccharide showed enhanced production of short chain fatty acids by gut microbiota in the lipopolysaccharide-induced inflammatory mice. Our results suggested that the water-soluble polysaccharide from purple sweet potato roots could be utilized as a novel anti-inflammatory agent.

Characterization, antioxidant activity and hepatoprotective effect of purple sweetpotato polysaccharides.

In this study, three kinds of polysaccharides (named PSWP, PSAP-1 and PSAP-2) were successively isolated from purple sweetpotato tubers by hot water, 0.5M and 2M sodium hydroxide solutions. The characterization, in vitro antioxidant activity and in vivo hepatoprotective effect of these polysaccharides were investigated. Results indicated that PSWP, PSAP-1 and PSAP-2 were all ß-type polysaccharides containing different contents of uronic acid, protein and polyphenol. Both PSWP and PSAP-1 were composed by arabinose, glucose and galactose, whereas PSAP-2 was consisted of arabinose, rhamnose and glucose. All the polysaccharides exhibited moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power. As compared with tetrachloromethane (CCl4) treatment group, mice administrated with PSWP, PSAP-1 and PSAP-2 exhibited decreased levels of serum enzymes (alkaline phosphatase, alanine transaminase and aspartate transaminase) and hepatic lipid peroxidation, whereas increased levels of hepatic antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) and non-enzymatic antioxidant (glutathione). Notably, PSWP displayed stronger antioxidant activity and hepatoprotective effect than PSAP-1 and PSAP-2. The hepatoprotective effect of PSWP was comparable to positive standard of silymarin. Our results suggested polysaccharides from purple sweetpotato possessed potential antioxidant activity and protective effect against CCl4-induced acute liver damage.

Identification and Quantitation of Anthocyanins in Purple-Fleshed Sweet Potatoes Cultivated in China by UPLC-PDA and UPLC-QTOF-MS/MS.

The identification and quantitation of the anthocyanins in 12 purple-fleshed sweet potato (PFSP) cultivars ('Jihei 1', 'Xuzi 3', 'Xuzi 6', 'Zhezi 4', 'Ningzi 1', 'Ningzi 2', 'Ningzi 3', 'Ning 2-2', 'Ning 6-8', 'Guangzi 1', 'Ziluolan', and 'Qinzi 1') in China were carried out using a combination of ultraperformance liquid chromatography-photodiode array (UPLC-PDA), quadrupole-time-of-flight mass spectrometry (QTOF-MS), and tandem mass spectrometry (MS/MS) analyses. Thirteen acylated anthocyanins were tentatively characterized, including two new PFSP anthocyanins, cyanidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside and peonidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside. The quantitative analyses of these anthocyanins were conducted using cyanidin 3-O-glucoside as a standard. The total anthocyanin content of the PFSPs depended on the cultivar. The five PFSP cultivars with the highest content of anthocyanins were 'Jihei 1', 'Xuzi 3', 'Zhezi 4', 'Ziluolan', and 'Qinzi 1'. This is the first report of the 'Ningzi 2', 'Ningzi 3', and 'Ning 2-2' PFSP cultivars containing only diacylated anthocyanins and of the 'Xuzi 6' cultivar containing single anthocyanidin-based anthocyanins.