| Summary: | 博士 === 國立臺灣大學 === 食品科技研究所 === 103 === Colorectal cancer (CRC) is one of the top leading causes of death in the world. Recent studies have shown that curcumin, a yellow polyphenol extracted from the rhizome of turmeric (Curcuma longa) has potent anti-colorectal cancer effect. Despite great therapeutic potentials of this phytochemical in CRC, their performance, after oral intake, may be limited by gastrointestinal (GI) motility and pH variations in the digestive system. Hence, there is strong need to develop a controlled release system for protecting curcumin passing through the digestive system and reaching the colon site. Such system takes advantages of the fact that some specific microbial enzymes, which can hydrolyze the biodegradable materials, only exist in the colon. Since, nanoparticles have received a great deal of attention for their usefulness in the controlled release system, the purpose of this research was to fabricate polymeric nanoparticles as drug carriers for encapsulated curcumin with enhanced anti-colorectal cancer activities. Nanoparticles were formed using chitosan and gum arabic, natural polysaccharides, via an emulsification solvent diffusion method. The formation of curcumin nanoparticles was confirmed by fourier transform infrared (FTIR) spectroscopy and differential scanning calorimeter (DSC). The results showed that curcumin was entrapped in carriers with +48 mV, 136 nm size, and high encapsulation efficiency (95%). Based on an in vitro release study, 76% of curcumin was released from nanoparticles after immersing into simulated colonic fluid containing pectinase. We inferred that the curcumin nanoparticles could tolerate hydrolysis due to gastric juice or small intestinal enzymes, and therefore, it should reach the colon largely intact. The cell culture studies with human colorectal cancer cell lines; HCT116, HT29 and LOVO cells revealed that curcumin nanoparticles had higher anti-colorectal cancer properties than the free curcumin due to greater cellular uptake even at low concentration (1 µg/mL). In addition, curcumin nanoparticles could induce cell apoptosis while free curcumin showed cell cycle arrest at S and/or G2/M phase. Therefore, we concluded that curcumin was successful encapsulated in chitosan-gum arabic nanoparticles with superior anti-colorectal cancer properties.
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