Zhi Zijian, Chen Jianle, Li Shan, Wang Wenjun, Huang Rui, Liu Donghong, Ding Tian, Linhardt Robert John, Chen Shiguo, Ye Xingqian
Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Fuli Institute of Food Science, Zhejiang University, Hangzhou, 310058, China.
Center for Biotechnology & Interdisciplinary Studies, Department of Chemistry & Chemical Biology, Rensselaer Polytechnic Institute, Biotechnology Center 4005, Troy, NY, 12180, USA.
Sci Rep. 2017 Apr 3;7(1):541. doi: 10.1038/s41598-017-00572-3.
Pectin, a natural polysaccharide found in the cell wall of most higher plant such as citrus, has drawn much attention due to its potential beneficial role in facilitating the treatment of many diseases like cancer, hyper cholesterol and diabetes. However, the broad application of pectin faces great limitations as the large molecular size of pectin severely prevents its bioavailability in vivo. In this study, we report an effective and highly convenient approach to degrade natural pectin into lower molecular pectin. By combining ultrasound with Fenton system (US-Fenton), we show that ultrasound synergistically enhances the efficiency of Fenton reaction to degrade pectin into 5.5 kDa within only 35 minutes. Importantly, RG-I domain, the most effective portion of natural pectin, was well preserved and highly enriched. In addition, the antioxidant activities of US-Fenton-treated pectin was significantly elevated. The mechanism of this novel observation was further investigated through the multiple structural analyses including HPLC, IR and NMR. Taken together, we present a novel and convenient approach to generate ultra-low molecular weight pectin with high efficiency and higher bioactivity. We expect our approach will have broader applications in improving the bioavailability and bioactivity of other polysaccharide-based natural compounds.
果胶是一种存在于大多数高等植物（如柑橘）细胞壁中的天然多糖，因其在促进癌症、高胆固醇和糖尿病等多种疾病治疗方面的潜在有益作用而备受关注。然而，由于果胶的大分子尺寸严重阻碍其在体内的生物利用度，果胶的广泛应用面临巨大限制。在本研究中，我们报告了一种有效且极为便捷的方法，可将天然果胶降解为低分子果胶。通过将超声与芬顿体系（US-Fenton）相结合，我们发现超声能协同提高芬顿反应的效率，仅在35分钟内就可将果胶降解为5.5 kDa。重要的是，天然果胶最有效的部分——鼠李糖半乳糖醛酸聚糖-I（RG-I）结构域得到了良好的保留且高度富集。此外，经US-Fenton处理的果胶的抗氧化活性显著提高。通过包括高效液相色谱（HPLC）、红外光谱（IR）和核磁共振（NMR）在内的多种结构分析，进一步探究了这一新颖现象的机制。综上所述，我们提出了一种新颖且便捷的方法，可高效生成具有更高生物活性的超低分子量果胶。我们期望我们的方法在提高其他基于多糖的天然化合物的生物利用度和生物活性方面具有更广泛的应用。
