Studies on the Flavonoid Composition of Pleioblastus amarus Leaves and Shoots Based on Targeted Metabolomics

Background:Pleioblastus amarus (Keng) Keng f. is widely distributed in southern China and serves as both a medicinal and edible resource. Flavonoids represent the main bioactive compounds in this species, contributing to its antioxidant, anti-inflammatory, and anti-tumor activities. Methods: In this study, a targeted metabolomics approach based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to analyze 35 flavonoid compounds in dry leaf and shoot samples of P. amarus. The method demonstrated a detection limit (LOD) of X μg/g and a quantification limit (LOQ) of Y μg/g, with good linearity within the range of A to B μg/g for all compounds. Results: Twenty flavonoids were identified, with cynaroside being the most abundant in leaf samples (0.013 mg/g) and isovitexin being the most abundant in shoot samples (0.001 mg/g). The total flavonoid content in dry leaf (0.19 mg/g) was significantly higher than in dry shoot (0.022 mg/g). Multivariate statistical analyses revealed clear clustering and metabolic differences between the two tissues, and fifteen differential metabolites were identified by orthogonal partial least squares discriminant analysis (OPLS-DA). The correlation and pathway analyses suggested two distinct metabolic groups: one involving catechin, L-epicatechin, formononetin, and glycitin, and another centered on naringenin-derived metabolites. Conclusions: These findings provide new insights into tissue-specific flavonoid metabolism in P. amarus, highlighting distinct patterns in the leaves and shoots. By comparing flavonoid metabolism in other bamboo species, such as Phyllostachys edulis and Indocalamus, this study reveals both differences and similarities across species. It enhances our understanding of flavonoid synthesis and distribution in P. amarus and supports the development of flavonoid-based pharmaceuticals, offering valuable insights for further biochemical and pharmacological research on bamboo species.