Studies on the Flavonoid Composition of<i> Pleioblastus amarus </i>Leaves and Shoots Based on Targeted Metabolomics

Pleioblastus amarus (P. amarus) (Keng) Keng f.is widely distributed in the southern region of China and is a medicinal and food resource there. Flavonoids are important bioactive components in P. amarus and play important anti-tumour, anti-inflammatory, and antioxidation roles. In this study, the targeted metabolomics method based on liquid chromatography–mass spectrometry (LC-MS/MS) was used to analyze 35 flavonoids in 6 leaf samples and 6 shoot samples of P. amarus, and the contents of 20 flavonoids were detected. Cynaroside was the most abundant in P. amarus dry leaf samples (13.17 μg/g), while Isovitexin was the most abundant in P. amarus dry shoot samples (1.34 μg/g). The total content and types of flavonoids in P. amarus leaves were higher than those in P. amarus shoots. The cluster diagram results of the similarity heatmap showed that there were significant differences in the structure of flavonoids between leaves and shoots. Fifteen characteristic differential flavonoids were screened by orthogonal partial least squares-discriminant analysis, sorted by importance, including Luteolin, Kaempferide, Naringin, Icariin, Quercetin 3-glucoside, Catechin, Naringenin, Glycitin, Diosmin, Cynaroside, Rutin, Vitexin, Isovitexin, Quercetin, and L-Epicatechin. The correlation cluster diagram analysis showed that the 20 flavo-noids were mainly divided into two groups: Catechin, L-Epicatechin, Formononetin, and Glycitin in one, and Chrysin, Fisetin, Genistin, Kaempferide, Diosmin, Quercitrin 3-glucoside, Quercetin, Naringenin, Apigenin, Rutin, Icariin, Vitexin, Isovitexin, Quercitrin, Cynaroside, and Luteolin in the other. We investigated the metabolic pathways of these two groups of flavonoids, analyzed the reasons for their division into two groups, and provided a foundation for further research on the flavonoid metabolic pathways in P. amarus. In conclusion, this study lays a foundation for the subsequent directional separation and identification of flavonoids in P. amarus.