College of Pharmacy and Biological Engineering, Chengdu University, No. 1 Shilling Road, Chenglo Avenue, Longquan District, Chengdu 610106, China.
Institute of Crop Science, Chinese Academy of Agricultural Sciences, No. 80 South Xueyuan Road, Haidian, Beijing 100081, China.
Molecules. 2018 Sep 17;23(9):2373. doi: 10.3390/molecules23092373.
Lunasin, a bioactive peptide initially isolated from soybean, has anticancer, anti-inflammatory, and antioxidant activity. Due its great application value, lunasin seems to be a candidate gene in improving the nutritional value of crops. In this study, lunasin was inserted into the rice genome to evaluate whether it was feasible to express lunasin using the rice expression system and improve the bioactivity of protein in rice for our needs. We generatedlunasin-overexpressing rice lines, and chose three independent transgenic rice lines for further study. The lunasin content in trans-lunasin rice detected by UPLC-MS/MS was 1.01 × 10 g·kg dry rice flour with grease removal in the lunasin extracts. The antioxidant efficacy of LET (lunasin-enriched fraction from trans-lunasin rice) and PEW (peptide-enriched fraction from wild type rice) was compared. Due to the presence of lunasin, LET showed higher ( < 0.05) antioxidant activity than PEW. LET exhibited high DPPH radical scavenging activity (IC value, 8 g·L), strong ABTS⁺ radical scavenging activity (IC value, 1.18 g·L), and great oxygen radical scavenging activity (170 μmol·L Trolox equivalents when the concentration reached 4 g·L). Moreover, LET presented significantly higher ( < 0.05) anti-inflammatory activity on macrophage cells, and the NO production and the release of pro-inflammatory cytokines (IL-6, MCP1, and TNF-α) were significantly inhibited by LET. However, because of the low purity, LET showed weaker antioxidant and anti-inflammatory activity when compared to the Lunasin standard. These results suggested that it is feasible to use the rice expression system to express the exogenous lunasin in rice, and lunasin-overexpressing rice seems to be a candidate resource for application in functional food. Rice rich in lunasin is beneficial for human health, and could be used as a functional food in the diets of cancer and obese patients in the future.
豆蛋白素，一种最初从大豆中分离出来的生物活性肽，具有抗癌、抗炎和抗氧化活性。由于其巨大的应用价值，豆蛋白素似乎是一种候选基因，可以提高作物的营养价值。在这项研究中，我们将豆蛋白素插入水稻基因组中，以评估使用水稻表达系统表达豆蛋白素是否可行，并提高水稻中蛋白质的生物活性以满足我们的需求。我们生成了豆蛋白素过表达的水稻品系，并选择了三个独立的转基因水稻品系进行进一步研究。通过 UPLC-MS/MS 检测，转豆蛋白素水稻中豆蛋白素的含量为 1.01×10 g·kg-1 去脂米粉，提取物中豆蛋白素的含量为 1.01×10 g·kg-1 去脂米粉。比较了 LET（转豆蛋白素水稻富集的豆蛋白素部分）和 PEW（野生型水稻中富含的肽部分）的抗氧化功效。由于豆蛋白素的存在，LET 表现出比 PEW 更高（<0.05）的抗氧化活性。LET 表现出较高的 DPPH 自由基清除活性（IC 值，8 g·L-1）、较强的 ABTS+自由基清除活性（IC 值，1.18 g·L-1）和较强的氧自由基清除活性（浓度达到 4 g·L-1 时，Trolox 当量为 170 μmol·L-1）。此外，LET 对巨噬细胞的抗炎活性显著升高（<0.05），NO 产生和促炎细胞因子（IL-6、MCP1 和 TNF-α）的释放明显受到 LET 的抑制。然而，由于纯度较低，LET 的抗氧化和抗炎活性比豆蛋白素标准弱。这些结果表明，使用水稻表达系统在水稻中表达外源豆蛋白素是可行的，豆蛋白素过表达水稻似乎是应用于功能性食品的候选资源。富含豆蛋白素的水稻有益于人类健康，未来可能成为癌症和肥胖患者饮食中的功能性食品。
