Tracing Different Origins of <i>Astragalus</i> Based on Bulk and α‐Cellulose Stable Isotope Analysis

ABSTRACT The quality of Chinese herbal medicines is heavily influenced by production environments, yet conventional traceability methods remain limited in accurately discerning geographical origins. Stable isotope technology provides a powerful alternative for determining the geographic origin of herbal materials by recording environmental signatures imprinted in biological tissues. In this study, we extracted α‐cellulose from Astragalus membranaceus samples collected from eight different regions and analyzed the δ 2 H, δ 1 8 O, and δ 1 3 C values of both bulk samples and α‐cellulose fractions. The results showed that analysis based solely on bulk samples allowed only preliminary differentiation among origins. In contrast, integrating stable isotope data from both bulk samples and α‐cellulose significantly improved the discrimination accuracy. Principal component analysis (PCA) clearly separated the samples by geographical origin, and the k‐nearest neighbors (KNN) model achieved 100% classification accuracy. In summary, combined stable isotope analysis of bulk samples and α‐cellulose enables precise geographical discrimination of Astragalus membranaceus, establishing it as a reliable and effective technique for origin traceability.