Physicochemical and digestive properties of corn starch nanoparticles incorporated different polyphenols.

The corn starch nanoparticles were prepared by incorporating three kinds of polyphenols, including quercetin, proanthocyanidins and tannin acid. The physicochemical and digestive properties of corn starch nanoparticles were researched. The quercetin showed a higher complexation index than proanthocyanidins and tannin acid when they complexed with corn starch. The mean size of corn starch quercetin, proanthocyanidins and tannin acid were 168.5 nm, 179.1 nm and 188.6 nm, respectively. XRD results indicated that all the corn starch-polyphenols complex showed V-type crystalline structure, the crystallinity of corn starch-quercetin complex was 19.31 %, which showed more formation of amylose-quercetin single helical formed than the other two starch-polyphenol complexes. In vitro digestion revealed that polyphenols could resist digestion and quercetin increased the content of resistant starch from 23.32 % to 35.24 % and polyphenols can form complexes with starch through hydrophobic interactions or hydrogen bonding. This study indicated the hydrophobic polyphenols had a more significant effect on the digestibility of corn starch. And the cell toxicity assessments demonstrated that all nanoparticles were nontoxic and biocompatible.

Characterization of resistant starch nanoparticles prepared via debranching and nanoprecipitation.

Cyperus esculentus starch was treated by pullulanase debranching and nanoprecipitation to prepare resistant starch nanoparticles. Amylose contents, rheological properties of debranched starch and the size, crystalline structure, resistant starch contents of the prepared starch nanoparticles were investigated. The results of amylose contents showed that enzymatic hydrolysis 4 h was the most appropriate enzymatic hydrolysis time. Dynamic light scattering analysis and scanning electron microscopy observations showed that when the starch solution was added to the ethanol, the larger the amount of ethanol, the more conducive to the formation of small size starch nanoparticles. When volume ratio of starch solution/ethanol was 1/5, the particle size was 271.1 nm, the content of resistant starch was higher (15.28%). X-ray diffraction results indicated that resistant starch nanoparticles had V-type crystalline structure. Pullulanase debranching and nanoprecipitation can be utilized to prepare smaller size of Cyperus esculentus resistant starch with higher efficiency.

Influence of esterification and ultrasound treatment on formation and properties of starch nanoparticles and their impact as a filler on chitosan based films characteristics.

Starch nanoparticles were prepared by citrate esterification and ultrasound treatment. With the increase of ultrasonic treatment time, the mean size and PDI of the particles decreased gradually, when the ultrasonic treatment time was 5 min, the prepared starch nanoparticles had a mean size and PDI of 352.8 nm and 0.292, respectively. X-ray diffraction (XRD) showed that the starch nanoparticles prepared by ultrasonic treatment for 5 min had an A-type crystalline structure and a crystallinity of 41.42%. The chitosan composite films were reinforced by esterified starch with different ultrasound treatment times, the results indicated that the addition of starch nanoparticles resulted in a significant increase in the mechanical properties of films. This study indicates that esterification and ultrasound treatment can be used to prepare starch nanoparticles with a higher crystallinity and higher efficiency, which will further promote the application of nanocomposite films in packaging applications.

Fat-1 gene inhibits human oral squamous carcinoma cell proliferation through downregulation of ß-catenin signaling pathways.

The ω-3 fatty acid desaturase (fat-1) gene encodes the enzyme that converts ω-6 polyunsaturated fatty acids (PUFAs) to ω-3 PUFAs. Numerous studies have suggested that the ratio of ω-6/ω-3 PUFAs has an impact on tumorigenesis. To investigate the biological function of the fat-1 gene in human oral squamous cell carcinoma (OSCC), the fat-1 gene was introduced into OSCC cells by transfection. The uptake of the gene was confirmed by reverse transcription-polymerase chain reaction and analyzed using gas chromatography. The antitumor effects and mechanisms of the fat-1 gene were evaluated by studying cell survival and tumor growth in vitro and in vivo. Gas chromatography results revealed that the cells transfected with the fat-1 gene had a higher ω-3/ω-6 PUFA ratio than cells transfected with the control vector. An MTT and DNA fragmentation assay indicated that the presence of the fat-1 gene in vitro significantly decreased OSCC cell proliferation and significantly increased the rate of apoptosis. Similar antitumor effects of the fat-1 gene were also observed in vivo. Immunohistochemistry analysis confirmed that Tca8113 cell tumors displayed a significant reduction in cell growth and cell survival following the introduction of the fat-1 gene. The current study suggests that the inhibitory effect of the fat-1 gene on tumor growth may be a result of a reduction in the expression of the tumor survival protein ß-catenin. The results also support the theory that the ratio of ω-3/ω-6 PUFAs has an impact on OSCC tumor growth. The findings of the study provide notable molecular insight into the theory suggesting that ω-3 PUFAs are an intermediate for the chemoprevention and treatment of human OSCC.

A Novel Ribonuclease from Rana Chensinensis and Its Potential for the Treatment of Human Breast Cancer.

Onconase, a member of the pancreatic RNAase A superfamily of ribonucleases, is a chemotherapeutic agent, which has demonstrated selective antitumor activity in a variety of human malignancies. However, little is known about the mechanisms of it's action on human breast cancer cells. To investigate a novel Onconase from the frog of Rana chensinensis changbaishanensis on human breast cancer cells and the underlying mechanisms, a novel Onconase named Rdchonc from Rana chensinensis changbaishanensis was cloned by polymerase chain reaction. SDS-PAGE revealed that the Rdchonc had a high heterologous expression in Escherichia coli BL21(DE3). The MTT assay indicated that purified Rdchonc was cytotoxic to human breast cancer MCF-7 and MD-MB-231 cells. Treatment with 20 µg/mL Rdchonc protein significantly reduced the invasive capacities of MCF-7 and MD-MB-231 cells. Interestingly, the authors found that such inhibitory effort on tumor cell growth induced by Rdchonc treatment may be explained by the regulation of proapoptotic Bcl-2 family proteins and inhibition of MEK/ERK phosphorylation.

Subchronic toxicity study of corn silk with rats.

AIM OF THIS STUDY: Corn silk is a traditional herbal medicine in China, which has been used in many parts of the world for the treatment of edema as well as for cystitis, gout, kidney stones, nephritis, prostatitis and similar ailments. However, there is little scientific evidence about its safety. As a part of its safety assessment, a subchronic toxicity was performed in this paper. METHODS: The subchronic toxicity was investigated in male and female Wistar rats by dietary administration at concentrations of 0.5%, 2.0% and 8.0% (w/w) for 90 days. Overall health, body weight, food consumption, hematology, blood chemistry, organ weights, gross and microscopic appearance of tissues were compared between test and control groups. RESULTS: A number of significant differences were seen between groups, but none of them was considered to be adverse. Based on the present study, the no-observed-adverse-effect level (NOAEL) of corn silk is at least 8.0% which corresponds to a mean daily corn silk intake of approximately 9.354 and 10.308 g/day/kg body weight for males and females, respectively. CONCLUSION: The results obtained in the present study suggest that consumption of corn silk has no adverse effects and support the safety of corn silk for humans.