| Curcumin is a kind of natural phenolic compounds, which is cheap and low toxicity. A large number of studies have reported that curcumin has effects on antioxidant, anticancer,and antibacterial bioactivities. It's also as a kind of food active component applied in food field. However, the low water solubility and low bioavailability has greatly limited its usage in health food and clinic. Porous silicon, due to its unique advantages such as large specific surface area and volume, good chemical stability, controllable size and easy to be modified, is widely used as the carrier material in drug delivery system and the controlled release system. In this paper, we use porous silicon with hydrophobic surface as a carrier to load curcumin and produce a new PSi-Cur microcapsule, and study its release and antioxidant in vitro. We hope that our studies can provide relevant information for the application of curcumin in the field of food and medicine. The main conclusions are as follows:1. The particle size of porous silicon made by electrochemistry anodic oxidation was about 30?m, and its pore size was between 20-50nm. According modifying the surface of porous, we acquired one type hydrophilic porous silicon (TOPSi) and two types hydrophobic porous silicon (PSi-Si(C18),PSi-PFPS),which water contact angle was 140.7°and 131.3° respectively. We used TOPSi,PSi-Si(C18) and PSi-PFPS as carries to load curcumin. The result showed hydrophobic porous silicon had a higher loading efficiency,and PSi-Si(C18) had the highest loading efficiency of 14.84%.2. The factors that may affect the loading efficiency of curcumin were studied. The result showed when 10mg dried porous silicon particles etched by square wave (360mA current) for 30min and modified by octadecyl silane was added with 1mL curcumin liquor and 1mL double distilled water under magnetic stirring with heating(50?,16h),the highest loading efficiency was acquired. The highest loading efficiency of curcumin was 22.3%, the amount of curcumin loaded on the porous silicon was 22.3?g/mg. Recovery ratio and precision met the requirements of sample analysis quality control.3. We studied the release characteristic of PSi-Cur microcapsule in vitro. When in alkaline environment, porous silicon and curcumin were unstable and degradable.At 8 hours, curcumin released from PSi-Cur microcapsule had reached the maximum, which was 94.54%. In neutral and acidic conditions, the release of PSi-Cur microcapsule fit Higuchi equation well, when released 10 h, in pH 7.4 and 5 medium, the release rate of curcumin were 85.29% and 81.61% respectively, and had a tendency of rising.4. We also studied the ability of curcumin and PSi-Cur microcapsule to scavenge free radicals in vitro. The ability of scavenging free radicals of curcumin was remarkable,only microgram level can play a great role. when the concentration of curcumin was 10 ?g/mL,50% of DPPH free radical can be removed after a period of 30 min, and 73.8% of O2-· be removed easily. The release liquid from PSi-Cur microcapsules still had the ability of scavenging free radicals, and the removal efficiency was the same with curcumin standard liquid, showing that the nature of curcumin loaded into the porous silicon was not changed,and still had the physiological activity. It was also showed that curcumin can be released from PSi-Cur microcapsules into the medium.5. We studied the release of PSi-Cur microcapsule in mice and evaluated acute toxicological safety of PSi-Cur microcapsule and PSi. We detected curcumin concentration in experimental mice plasma by HPLC. The results can be seen by the high dose group. 4 h after the treatment, the concentration of curcumin in the blood reached the peak value.When dosing 8 h, the content of curcumin in the bloodstream metabolic almost completely. Compared with single oral curcumin, PSi-Cur microcapsule delayed the release of curcumin in the body metabolism, to a certain extent, improved the bioavailability of curcumin. According mice routine blood count, whatever low dose,medium dose and high dose groups of porous silicon had a little effect on mice. Through the statistical analysis of groups of mice blood biochemical level,We found that no matter low dose, medium dose and high dose groups of porous silicon had no significant influence on mice serum biochemical indexes, liver kidney and biochemical indexes, myocardial biochemical indexes and blood lipids. By observing physiology slices of liver, kidney,spleen, heart, we found that porous silicon can cause liver inflammatory response and had little influence on kidney, spleen and heart. |
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