Chemical profile and quantitative comparison of constituents in different medicinal parts of Lactuca indica during varied harvest periods using UPLC-MS/MS method

Lactuca indica L. cv. Mengzao (LIM), acknowledged as a pivotal "One Root of Medicine and Food", boasts dual applications in both culinary and medicinal domains. This research delves into the influence of various harvest periods (vegetative, budding, blossom, and fruiting) on distinct medicinal parts (roots, stems, leaves, flowers, and seeds) of LIM, employing plant metabolomics to assess its chemical constituents. A total of 66 chemical constituents were identified in LIM, with 11 chemical components emerging as potential markers for distinguish medicinal parts. Notably, nutritional organs exhibited elevated levels of cichoric acid, rutin and chlorogenic acid. Specifically, leaves during the budding stage displayed the highest chicoric acid content at 11.70 mg·g−1. Conversely, reproductive organs showed heightened concentrations of cichoric acid, rutin and chlorogenic acid, with seeds exhibiting the peak cichoric acid content at 4.528 mg g−1. This study enriches our understanding of LIM by offering novel insights into quality assessment and the comprehensive utilization of its diverse parts.