State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China.
Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China.
Molecules. 2023 Jun 12;28(12):4718. doi: 10.3390/molecules28124718.
Mulberry leaves are a well-known traditional Chinese medicine herb, and it has been observed since ancient times that leaves collected after frost have superior medicinal properties. Therefore, understanding the changes in critical metabolic components of mulberry leaves, specifically L., is essential. In this study, we conducted widely targeted metabolic profiling analyses on two types of mulberry leaves, including L. and L., harvested at different times. In total, we detected over 100 compounds. After frost, 51 and 58 significantly different metabolites were identified in the leaves of L. and L., respectively. Further analysis revealed a significant difference in the effect of defrosting on the accumulation of metabolites in the two mulberries. Specifically, in L., the content of 1-deoxynojirimycin (1-DNJ) in leaves decreased after frost, while flavonoids peaked after the second frost. In L., the content of DNJ increased after frost, reaching its peak one day after the second frost, whereas flavonoids primarily peaked one week before frost. In addition, an analysis of the influence of picking time on metabolite accumulation in two types of mulberry leaves demonstrated that leaves collected in the morning contained higher levels of DNJ alkaloids and flavonoids. These findings provide scientific guidance for determining the optimal harvesting time for mulberry leaves.
桑叶是一种著名的中药，自古以来就有观察到霜后采集的叶子具有更好的药用功效。因此，了解桑树，尤其是桑，叶子的关键代谢成分的变化是至关重要的。在这项研究中，我们对两种类型的桑叶，即 L. 和 L. ，在不同时间进行了广泛的靶向代谢组学分析。总共检测到超过 100 种化合物。霜后，L. 和 L. 的叶子中分别鉴定出 51 种和 58 种显著不同的代谢物。进一步的分析显示，解冻对两种桑树上代谢物积累的影响存在显著差异。具体来说，在 L. 中，叶子中 1-脱氧野尻霉素（1-DNJ）的含量在霜后下降，而类黄酮在第二次霜后达到峰值。在 L. 中，DNJ 的含量在霜后增加，在第二次霜后一天达到峰值，而类黄酮主要在霜前一周达到峰值。此外，对两种类型的桑叶中采摘时间对代谢物积累的影响进行分析表明，早上采集的叶子含有更高水平的 DNJ 生物碱和类黄酮。这些发现为确定桑叶的最佳收获时间提供了科学指导。
