槲黃素奈米新劑型之物理化學性質探討及其抗氧化、保肝活性之開發研究

Preparation and physicochemical assessment of novel quercetin nanoparticle, and investigation on its antioxidant and hepatoprotective activities

吳姿慧(Tzu-Hui Wu)

指導教授 ： 林俊清

高雄醫學大學/藥學院/藥學研究所/博士(2009年)

摘要

背景及目的：槲黃素是知名可被用來預防急性肝損傷天然化合物之一，但是它難溶於水的特性則限制其臨床上的應用。本研究的目的為發展一個新穎槲黃素奈米製劑，以期改善其溶解度並且增加體外抗氧化及口服體內之保肝活性。
材料及方法：槲黃素奈米製劑物理化學鑑定包含平均粒徑大小、產率、包埋率、穿透式顯微鏡、溶離試驗、示差掃描熱分析、X光繞射及傅立葉轉換紅外光譜儀等分析。在體外試驗比較槲黃素及其奈米製劑的抗氧化藥理活性；在體內試驗則是先利用乙醯氨基酚引發急性肝損傷之動物模式後，再來評估槲黃素及其奈米製劑的抗氧化、抗發炎及保肝等活性。
結果與討論：由體外溶離試驗結果證實槲黃素奈米製劑釋出速率較槲黃素增加74倍，其釋出機轉為降低藥品平均粒徑、非晶形結構及分子間氫鍵產生等特性。另外，有關槲黃素奈米在體外抗氧化活性檢測包含清除DPPH試驗、超氧自由基清除之活性、超氧自由基生成之抑制作用及抗脂質過氧化等試驗都證實比槲黃素更具活性(P < 0.05)。除此之外，槲黃素奈米也進行體內保肝活性並且證實比槲黃素更具療效，歸咎其藥理活性為降低急性肝損傷動物血清中肝功能指數及發炎性細胞激素釋出；增加肝臟抗氧化酵素及降低脂質過氧化等特性 (P < 0.05)。
結論：奈米新劑型在研究中證實能有效改善槲黃素的釋出，在進行急性肝損傷動物試驗中產生較佳的保肝活性，其主要機轉是透過抗氧化及抗發炎作用所致。

關鍵字

槲黃素 ； 奈米 ； 急性肝損傷 ； 抗氧化 ； 抗發炎

並列摘要

Background/Purpose: Quercetin (QU) is known to exert pharmacological effects against acute liver failure (ALF), but its poor aqueous solubility has restricted its clinical applications. Therefore, a novel quercetin-loaded nanoparticles system (QUEN) was developed to resolve the restricted water solubility of QU and to enhance its antioxidant activities in vitro and hepatoprotective effects in vivo on oral administration.
Materials and Methods: Physicochemical characterizations of QUEN included assessment of particle size, morphology, yield, and encapsulation efficiencies, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), and dissolution study. In addition, to evaluate its antioxidant activities in vitro and its oral treatment potential against ALF, the studies compared the antioxidant and hepatoprotective effects of QUEN and QU on acetaminophen (APAP)-induced ALF in rats.
Results and Discussion: The release of the drug from the QUEN was 74-folds higher compared with the pure drug. The release mechanisms of QU from the QUEN were attributed to the reduction of drug particle size, the formation of high-energy amorphous state, and the intermolecular hydrogen bonding. The antioxidant activities in vitro of the QUEN were observed to be more effective than pure QU on DPPH scavenging, anti-superoxide formation, superoxide anion scavenging, and anti-lipid peroxidation. Moreover, QUEN also exhibited more hepatoprotective effects compared to QU with considerable reduction in the serum levels of liver function index and pro-inflammatory cytokines, an increase in the levels of hepatic antioxidant enzymes, and a decrease in lipid peroxidation (P < 0.05).
Conclusion: QUEN effectively improved the release of QU which resulted in more hepatoprotective effects mediated by its antioxidant and anti-inflammatory properties against ALF.

並列關鍵字

Quercetin, nanoparticles ； acute liver failure ； antioxidation ； anti-inflammation

參考文獻

Ader, P., Wessmann, A., Wolffram, S., 2000. Bioavailability and metabolism of the flavonol quercetin in the pig. Free. Radic. Biol. Med. 28, 1056-1067.

Aebi, H., 1984. Catalase in vitro. Methods. Enzymol. 105, 121-126.

Bauer, I., Vollmar, B., Jaeschke, H., Rensing, H., Kraemer, T., Larsen, R., Bauer, M., 2000. Transcriptional activation of heme oxygenase-1 and its functional significance in acetaminophen-induced hepatitis and hepatocellular injury in the rat. J. Hepatol. 33, 395-406.

Bilati, U., Allémann, E., Doelker, E., 2005. Development of a nanoprecipitation method intended for the entrapment of hydrophilic drugs into nanoparticles. Eur. J. Pharm. Sci. 24, 67-75.

Blazka, M.E., Wilmer, J.L., Holladay, S.D., Wilson, R.E., Luster, M.I. 1995. Role of proinflammatory cytokines in acetaminophen hepatotoxicity. Toxicol. Appl. Pharmacol. 133, 43-52.