Cui Wen-Si, Zhang Qiang, Zhao Xin-Huai
School of Biology and Food Engineering, Guangdong University of Petrochemical Technology 525000 Maoming PR China
Key Laboratory of Dairy Science, Ministry of Education, Northeast Agricultural University Harbin 150030 PR China.
RSC Adv. 2020 Aug 17;10(51):30415-30427. doi: 10.1039/d0ra05598k.
Black mulberry ( L.) is an edible fruit with various health functions in the body. In this study, the lyophilized black mulberry was extracted using water and 75% (v/v) ethanol-water, respectively; afterwards, the soluble extracts were subjected to these treatments like ethanol removal, heat treatment at 100 °C for various times, or activated carbon-mediated dephenolization. The assaying results indicated that the used heat treatment led to decreased anthocyanin but increased total phenol and flavonoid contents for the water- and ethanol-extracts, while the dephenolized extracts after the heat treatment also had increased total phenol and flavonoid contents. The performed heat treatment decreased anti-oxidative activities of the water- and ethanol-extracts, resulting in reduced scavenging activities to the DPPH and hydroxyl radicals and lower reducing power for Fe(iii) ions. However, the results from cell experiments also demonstrated that the heat treatment at 100 °C for 45 min caused the water- and ethanol-extracts or dephenolized extracts with higher anti-cancer activity against human colon cancer HCT-116 cells. Overall, the heated extracts were more effective than the unheated counterparts to inhibit cell growth, alter cell morphology, generate more intracellular reactive oxygen species, enhance intracellular Ca level, and reduce mitochondrial membrane potential of the cells. It is thereby concluded that the heat treatment of black mulberry might reduce its anti-oxidation but increase its anti-colon cancer effect due to the occurrence of the Maillard reaction and other unidentified reactions, which will deepen our present knowledge and provide a scientific basis to optimize storage or processing conditions of plant-based foods.
黑桑（Morus nigra L.）是一种对人体具有多种健康功能的可食用水果。在本研究中，分别用水和75%（v/v）乙醇 - 水对冻干黑桑进行提取；之后，对可溶性提取物进行诸如去除乙醇、在100℃下进行不同时间的热处理或活性炭介导的脱酚处理。测定结果表明，所用的热处理导致水提取物和乙醇提取物中的花青素含量降低，但总酚和黄酮含量增加，而热处理后的脱酚提取物的总酚和黄酮含量也有所增加。进行的热处理降低了水提取物和乙醇提取物的抗氧化活性，导致对DPPH和羟基自由基的清除活性降低以及对Fe(iii)离子的还原能力降低。然而，细胞实验结果还表明，在100℃下热处理45分钟使水提取物、乙醇提取物或脱酚提取物对人结肠癌HCT - 116细胞具有更高的抗癌活性。总体而言，加热后的提取物在抑制细胞生长、改变细胞形态、产生更多细胞内活性氧、提高细胞内Ca水平以及降低细胞线粒体膜电位方面比未加热的提取物更有效。由此得出结论，黑桑的热处理可能会降低其抗氧化能力，但由于美拉德反应和其他未明确的反应，会增加其抗结肠癌的效果，这将加深我们目前的认识，并为优化植物性食品的储存或加工条件提供科学依据。
