Composition and Antioxidant Ability of Extract from Different Flaxseed Cakes and Its Application in Flaxseed Oil.

In this research, extracts from five flaxseed cakes (hot-pressed cake (HPC), cold-pressed cake (CPC), n-hexane extracted cake (HEC), supercritical CO2 extracted cake (SCEC) and subcritical n-butane extracted cake (SBEC)) were analyzed for the contents of total phenolic, total flavonoid and antioxidant ability. At the same time, the antioxidant capacity of HPC extract and synthetic butylated hydroxyanisole (BHA) in the oxidative evolution of flaxseed oil was compared by accelerated storage experiment (8 days at 65°C). The results showed that compared with other flaxseed cake extract, the extract of HPC contained the highest content of total phenolic (78.01 mg GAE/g extract) and total flavonoid (2.73 mg RE/g extract), and showed the strongest antioxidant ability on DPPH, ABTS FRAP and total reducing power assay. We also found that different concentrations (800, 1000, 2000 ppm) of flaxseed cake extract could significantly slow down the oxidation of flaxseed oil during storage at 65°C, and the antioxidant effect strengthened with the increase of extract dosage. The antioxidant effect of the 2000 ppm extract was higher than that of 200 ppm BHA. The results indicated that flaxseed cake extract could effectively inhibit the oxidation of flaxseed oil and was a good substitute for synthetic antioxidants in oil industry.

Changes in Chemical Composition of Flaxseed Oil during Thermal-Induced Oxidation and Resultant Effect on DSC Thermal Properties.

To investigate the changes in chemical composition of flaxseed oil during thermal-induced oxidation and the resultant effect on thermal properties, samples with different oxidation levels were obtained by being heated at 180 °C for two hours and four hours. The oxidation degree was evaluated using peroxide value (PV), extinction coefficient at 232 nm and 268 nm (K232 and K268), and total polar compounds (TPC). Using chromatography, the fatty acid profile and triacylglycerol (TAG) profile were examined. Differential scanning calorimetry (DSC) was used to determine the crystallization and melting profiles. Thermal-induced oxidation of flaxseed oil led to a significant increase (p < 0.05) in PV, K232, K268, and TPC, but the relative content of linolenic acid (Ln) and LnLnLn reduced dramatically (p < 0.05). TPC derived from lipid degradation affected both crystallization and melting profiles. Statistical correlations showed that the onset temperature (Ton) of the crystallization curve was highly correlated with K232, TPC, and the relative content of LnLnLn (p < 0.05), whereas the offset temperature (Toff) of the melting curve was highly correlated with the relative content of most fatty acids (p < 0.05). This finding provides a new way of rapid evaluation of oxidation level and changes of chemical composition for flaxseed oils using DSC.

Sanguinarine, a major alkaloid from Zanthoxylum nitidum (Roxb.) DC., inhibits urease of Helicobacter pylori and jack bean: Susceptibility and mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Zanthoxylum nitidum (Roxb.) DC. (Z. nitidum) is a traditional Chinese medicine and mainly adopted to treat gastric ulcer, gastritis and stomach cancer. Sanguinarine (SNG), a natural alkaloid isolated from Z. nitidum, possesses significant anti-Helicobacter pylori and gastric protection effects. However, the underlying mechanism is sparsely elucidated. AIM OF THIS STUDY: The present study aims to explore the inhibition effect, kinetics and potential mechanism of SNG against H. pylori urease (HPU) and jack bean urease (JBU). MATERIALS AND METHODS: The improved spectrophotometric berthelot method was applied to estimate the inhibitory effect of SNG against HPU and JBU. The Lineweaver-Burk plots were adopted for investigating the inhibitory pattern in enzymatic kinetics. Sulfydryl-containing compounds and competitive active-site Ni2+ binding depressors were used for mechanism research. RESULTS: SNG remarkably suppressed the activities of HPU and JBU in concentration-and time-dependent mode with IC50 of 0.48 ± 0.14 mM and 0.11 ± 0.02 mM, respectively, in comparison with urease retardant acetohydroxamic acid (0.06 ± 0.01 mM for HPU and 0.03 ± 0.00 mM for JBU, respectively). Kinetic analysis demonstrated that the inhibition of SNG against HPU and JBU were separately characterized by slow-binding, mixed-type and slow-binding, non-competitive type. Addition of sulfydryl-containing reagents (dithiothreitol, glutathione and L-cysteine) and competitive Ni2+ binding restrainers (boric acid and sodium fluoride) significantly abrogated the urease inhibitory effect of SNG, suggesting the significant role of the thiols and Ni2+ for the urease inhibition by SNG. By contrast, interaction with thiol groups possibly contributed to the repression of SNG on JBU. Furthermore, the urease suppression was proved to be partially reversible since the SNG-blocked enzyme could be partly reactivated by glutathione. CONCLUSION: SNG could observably inhibit H. pylori urease targeting the thiols and Ni2+, which indicated that SNG was a new urease suppressant with great promise. The present research also provided scientific evidence for the application of SNG and Z. nitidum treating H. pylori-associated gastrointestinal diseases.

Extraction and Characterization of Flaxseed Oil Obtained with Subcritical n-Butane.

In this study, subcritical n-butane was adopted to extract oil from flaxseed. The extraction conditions i.e. extraction temperature, extraction time, and liquid-solid ratio were investigated and optimized by response surface methodology. The flaxseed oil obtained by subcritical n-butane were characterized and compared with those prepared by n-hexane and cold pressing. Results indicated that the optimal combination of parameters was 53.93℃, 56.82 min, and 19.98:1 mL/g. Subcritical n-butane had higher yield (28.75%) than n-hexane and cold pressing. GC analysis indicated that subcritical n-butane extraction had no obvious influence on the fatty acid composition. Nevertheless, the oil obtained by subcritical n-butane with higher contents of phytosterols (2.93 mg/g) and carotenoids (46.56 mg/kg), and presented a higher oxidation stability (9.27 h). Thus, it was suggested that subcritical n-butane extraction is a promising alternative to extract high quality flaxseed oil.

Effect of Accelerated Storage on Fatty Acids, Thermal Properties and Bioactive Compounds of Kenaf Seed Oil.

The effects of thermal oxidation at 65 °C for 24 days on oxidation indices, fatty acid positional distribution, thermal properties, vitamin E composition and sterol composition of kenaf seed oil are investigated. The results showed that total oxidation value (TOTOX) of the oil increased from initial 8.83 to 130.74 at the end of 24 days storage. Linoleic acid at sn-1, 3 positon of kenaf seed oil was less stable than the one at sn-2 positon. Oxidative degradation changed the melting profile of kenaf seed oil, the value of endothermic enthalpy reduced from 58.17 to 20.25 J/g after 24 days of storage. Moreover, the content of vitamin E and total sterol decreased by 84.26% and 38.47%, respectively. Tocotrienols were more stable than tocopherols during the accelerated storage. Correlation analysis indicated vitamin E content was significantly related to p-anisidine value, while sterol content was significantly related to peroxide value. PRACTICAL APPLICATION: Kenaf seed oil is rich in polyunsaturated fatty acids and bioactive compounds. Heating process and long-term storage cause oil oxidation and bioactive compounds degradation. The oxidation process of kenaf seed oil is simulated with accelerated storage. The study evaluates fatty acid composition and distribution, vitamin E and sterol content, melting thermal characteristics of kenaf seed oil at different oxidation levels. The research shows the stability of fatty acid is related with its type and position in backbone of triacylglycerol molecule. There are good correlation among oxidation level, vitamin E and sterol content, and melting enthalpy value of kenaf seed oil.

Effects of gamma irradiation on aflatoxin B1 levels in soybean and on the properties of soybean and soybean oil.

Fungal infection is inevitable in the cultivation and storage process of soybean. Gamma irradiation is an effective method to control fungal growth and inactivate mycotoxins. The effects of gamma irradiation and fungal damage on the number of fungi, aflatoxin B1 content, proximate composition of soybeans, and quality of soybean oil (acid value, peroxide value, iodine value, fatty acid profile, tocopherols content, and oxidation stability) were investigated in this work. Growth of fungi caused some changes in proximate composition of soybean and qualities of soybean oil. However, the changes depended on the damage extent of soybeans. No significant change was found for the soybeans incubated for 30 days (moderately fungi-damaged). Gamma irradiation could completely eliminate the fungi and greatly reduce the content of aflatoxin B1 in soybeans at 10 kGy. For soybeans incubated for 30 days, there were no significant changes in the quality attributes, tocopherols content and oxidation stability of oil when the gamma irradiation dose was less than 20 kGy. Gamma irradiation is a promising method to improve the safety and economy of moderately fungi-damaged soybean used for feedstuff.

Optimization of Supercritical Carbon Dioxide Extraction of Eucommia ulmoides Seed Oil and Quality Evaluation of the Oil.

Supercritical carbon dioxide extraction (SC-CO2) technology was used to extract oil from Eucommia ulmoides seed. The optimum conditions and significant parameters in SC-CO2 were obtained using response surface methodology (RSM). The qualities of the extracted oil were evaluated by physicochemical properties, fatty acid composition, vitamin E composition. It was found that the optimum extraction parameters were at pressure of 37 MPa, temperature of 40°C, extraction time of 125 min and CO2 flow rate of 2.6 SL/min. Pressure, temperature and time were identified as significant parameter effecting on extraction yield. The importance of evaluated parameters decreased in the order of pressure > extraction time > temperature > CO2 flow rate. GC analysis indicated that E. ulmoides seed oil contained about 61% of linolenic acid and its fatty acid composition was similar with that of flaxseed oil and perilla oil. The content and composition of vitamin E was determined using HPLC. The E. ulmoides seed oil was rich in vitamin E (190.72 mg/100 g), the predominant vitamin E isomers were γ- tocopherol and δ- tocopherol, which accounted for 70.87% and 24.81% of the total vitamin E, respectively. The high yield and good physicochemical properties of extracted oil support the notion that SC-CO2 technology is an effective technique for extracting oil from E. ulmoides seed.

Characterization of a New α-Linolenic Acid-Rich Oil: Eucommia ulmoides Seed Oil.

Eucommia ulmoides seed oil is the main byproduct of E. ulmoides cultivation. To better understand its functions, E. ulmoides seed oil is characterized comprehensively in this work. The composition of E. ulmoides seed, physicochemical properties, thermal properties, fatty acid composition, triacylglycerol (TAG) composition and Vitamin E composition of E. ulmoides seed oil were determined. The results show that the E. ulmoides seed contained about 34.63% oil. The excellent physicochemical properties of E. ulmoides seed oil ensured it has a potential to be developed as an edible oil. The main fatty acids in E. ulmoides seed oil were linolenic acid (61.36%), oleic acid (17.02%), and linoleic acid (12.04%). HPLC-ELSD method determined that LnLnLn (37.99%), LnLnO (22.62%), LnLnL (14.5%), and LnLnP (8.78%) were the oil's major TAG components. The oil exhibited a unique thermal curve which contained 2 melting peaks at -38.45 and -22.22 °C, respectively. The total content of vitamin E in E. ulmoides seed oil was 190.96 mg/100g, which exist mainly in γ-tocopherol and δ-tocopherol isomer. Overall, the results indicated that E. ulmoides seed oil is a promising oil in food, pharmaceutics, cosmetics and other nonfood industries.

Enhanced Extraction of Oil from Flaxseed (Linum usitatissimum L.) Using Microwave Pre-treatment.

The effect of microwave (MW) pre-treatment on the extraction of flaxseed oil was investigated by hot extraction (HE). Nine MW pre-treatments were established, combining three MW radiation intensities (12, 18 and 24 W/g) and three MW radiation times of pre-treatment (90, 150 and 210 s). Extraction yield increased significantly with MW pre-treatments of flaxseed, and a max oil extraction yield (78.11%) can be obtained using MW pre-treatment at 18 W/g for 210 s. Scanning electronic microscopy showed that the microstructure of treated samples (18 W/g and 210 s) was modified compared with that of untreated samples. The fatty acid compositions (palmitic acid 5.85±0.01%, stearic acid 3.00±0.01%, oleic acid 17.64±0.07%, linoleic acid 16.16±0.06%, and linolenic acid 57.37±1.32%) of the oils extracted by the MW pre-treatments HE were similar with that of the conventional HE method. Results showed that fatty acid compositions of flaxseed oil were not affected by MW pre-treatments.

[Progress of therapeutic research on cardiovascular and cerebrovascular diseases with chrono-medicine].

Comformed with the natural biological universal view of "harmony of human and nature", the clinical and experimental researches and the achievements on chrono-medicine for cardiovascular and cerebrovascular diseases in recent 10 odd years were analyzed and summarized, and the problems in the current researches and the stressed spots of the future research were put forward in this paper.