Optimization of Fabrication Parameters to Prepare Tea Catechin-Loaded Liposomes using Response Surface Methodology

Abstract: The purpose of this study was to optimize the formulation of tea catechin-loaded nano-liposomes using response surface methodology. Response surface methodology based on central composite rotatable design has been successfully used to model and optimize biochemical and biotechnological processes. The mass ratio of phosphatidylcholine and cholesterol (1-3), catechin concentration (3-5 mg/mL), pH values of phosphate buffer solution (6-7) and the volume ratio of organic phase and aqueous phase (2-4) were selected as independent variables with encapsulation efficiency and particle size as dependent variables. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Applying a desirability function method the optimum parameters were: phosphatidylcholine to cholesterol mass ratio of 2.17, catechin concentration of 5 mg/mL, pH values of phosphate buffer solution of 6.62 and organic phase to aqueous phase volume ratio of 3.05. At this optimum point, particle size and encapsulation efficiency were found to be 220 nm and 60.18%, respectively. Furthermore, leakage ratio of nano-liposomes was used to determine the influence of storage period

Optimization of Conditions for Cyanidin-3-OGlucoside (C3G) Nanoliposome Production by Response Surface Methodology and Cellular Uptake Studies in Caco-2 Cells

We aimed to optimize the formulation of C3G nanoliposomes using response surface methodology. Additionally, we evaluated the stability, particle change, and encapsulation efficiency (EE) of C3G nanoliposomes under different temperatures and storage durations, as well as in simulated gastrointestinal juice (SGF) and simulated intestinal fluid. The morphology of C3G nanoliposomes was observed by transmission electron microscope. The ability of C3G nanoliposomes to affect cancer cell morphology and inhibit cancer cell proliferation was studied with Caco-2 cells. Reverse-phase evaporation method is a simple and efficient method for liposome preparation. The optimal preparation conditions for this method were as follows: C3G concentration of 0.17 mg/mL, phosphatidylcholine/cholesterol ratio of 2.87, and rotary evaporation temperature of 41.41 °C. At optimal conditions, the particle size and EE of the C3G nanoliposomes were 165.78 ± 4.3 nm and 70.43% ± 1.95%, respectively. The C3G nanoliposomes showed an acceptable stability in SGF at 37 °C for 4 h, but were unstable under extended storage durations and high temperatures. Moreover, our results showed that different concentrations of C3G nanoliposomes affected the morphology and inhibited the proliferation of Caco-2 cells

Optimization of Preparation Conditions for Lysozyme Nanoliposomes Using Response Surface Methodology and Evaluation of Their Stability

The main purpose of this study was to optimize the preparation of lysozyme nanoliposomes using response surface methodology and measure their stability. The stabilities of lysozyme nanoliposomes in simulated gastrointestinal fluid (SGF), simulated intestinal fluid (SIF), as well as pH, temperature and sonication treatment time were evaluated. Reverse-phase evaporation method is an easy, speedy, and beneficial approach for nanoliposomes’ preparation and optimization. The optimal preparative conditions were as follows: phosphatidylcholine-to-cholesterol ratio of 3.86, lysozyme concentration of 1.96 mg/mL, magnetic stirring time of 40.61 min, and ultrasound time of 14.15 min. At the optimal point, encapsulation efficiency and particle size were found to be 75.36% ± 3.20% and 245.6 nm ± 5.2 nm, respectively. The lysozyme nanoliposomes demonstrated certain stability in SGF and SIF at a temperature of 37 °C for 4 h, and short sonication handling times were required to attain nano-scaled liposomes. Under conditions of high temperature, acidity and alkalinity, lysozyme nanoliposomes are unstable

Optimization on condition of epigallocatechin-3-gallate (EGCG) nanoliposomes by response surface methodology and cellular uptake studies in Caco-2 cells

The major component in green tea polyphenols, epigallocatechin-3-gallate (EGCG), has been demonstrated to prevent carcinogenesis. To improve the effectiveness of EGCG, liposomes were used as a carrier in this study. Reverse-phase evaporation method besides response surface methodology is a simple, rapid, and beneficial approach for liposome preparation and optimization. The optimal preparation conditions were as follows: phosphatidylcholine-to-cholesterol ratio of 4.00, EGCG concentration of 4.88 mg/mL, Tween 80 concentration of 1.08 mg/mL, and rotary evaporation temperature of 34.51°C. Under these conditions, the experimental encapsulation efficiency and size of EGCG nanoliposomes were 85.79% ± 1.65% and 180 nm ± 4 nm, which were close with the predicted value. The malondialdehyde value and the release test in vitro indicated that the prepared EGCG nanoliposomes were stable and suitable for more widespread application. Furthermore, compared with free EGCG, encapsulation of EGCG enhanced its inhibitory effect on tumor cell viability at higher concentrations

Soft-Shelled Turtle Peptide Supplementation Modifies Energy Metabolism and Oxidative Stress, Enhances Exercise Endurance, and Decreases Physical Fatigue in Mice

The potential of soft-shelled turtle peptides (STP) against fatigue was evaluated. Mice orally supplemented with STP significantly increased the swimming time until tiredness by 35.4–57.1%. Although not statistically significant, STP increased muscle and thymus mass. In addition, the serum lactate, ammonia, blood urea nitrogen content and creatine kinase activity in STP-fed mice were dramatically decreased when compared to the control group. Furthermore, STP supplementation increased the reserves of liver glycogen and muscle glycogen, thus improved the energy metabolism system of mice. STP treatment contributed to increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities as well as a decrease in malondialdehyde (MDA), indicating an improvement in oxidative stress protection. The Western blot (WB) results indicated that the STP supplement effectively altered the expression of oxidative stress-related protein by modulating the NRF2/KEAP1 pathway. In summary, STP affected NRF2/KEAP1 levels in skeletal muscle, leading to antioxidant activity and a slower time to exhaustion during exercise

Use of different endpoints to determine the bioavailability of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in Sprague–Dawley rats

Abstract Liver, fat (adipose tissue), blood, and feces are common endpoints used to determine the bioavailability of persistent organic pollutants (POPs). However, it is not known whether the bioavailability of each endpoints is comparable or whether there is a comprehensive endpoint that can be used for all congeners for the measurement of bioavailability. In this study, we observed the accumulation and distribution of 10 polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) in different organs of Sprague–Dawley (SD) rats and calculated the bioavailability based on feces, liver, and fat endpoints. Our results indicated that PCB 126, PCB 169, and 50% of PCDD/F congeners were mainly accumulated in the liver, with a bioavailability ranging from 28.9 to 50.6%. On the other hand, higher chlorinated (> 5 Cl) PCB congeners were mainly accumulated in adipose tissues, with a bioavailability ranging from 20.1 to 82.2%, while lower chlorinated (< 5 Cl) pollutants, such as 2,3,7,8-TeCDF, 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDF, and PCB 28, 52, 77, 81, were likely metabolized over 36% in rats during the 8-week experimental period. If we considered metabolization (degradation) as a type of bioavailable process, then the fecal endpoint was a feasible option. However, if we considered the selective accumulation behavior of some congeners in different organs/tissues, then there was no single comprehensive endpoint suitable for all congeners. Lastly, female rats showed significantly higher PCDD bioavailability than male rats at low dose level (0.2 ng/100 g b.w./d); however, the difference in PCB bioavailability between female and male rats was not significant