Screening and Quantification of Potential Quality Markers in Different Parts of Cyclocodon lancifolius (Roxburgh) Kurz Based on the Spectrum–Effect Relationship

Abstract Cyclocodon lancifolius (Roxburgh) Kurz, a species of the genus Cyclocodon (Campanulaceae), is widely distributed in the subtropical regions of China (Yunnan, Guizhou, and Sichuan), India, and Nepal. Its roots are a traditional ethnic medicinal part, young stems and leaves are used for health teas, and its fruits are a novel food source combining palatability with nutritional value. This study aims to elucidate the pharmacologically active ingredients of C. lancifolius. Ultra-performance liquid chromatography was employed to establish fingerprints for the roots, stems, leaves, and fruits. The antioxidant activities of extracts from these plant parts were evaluated using DPPH and ABTS assays. A spectrum–effect relationship model was constructed through statistical analysis to identify potential active compounds, whose half-maximal inhibitory concentration (IC50) values for antioxidant activity were determined. Based on these findings, a high-performance liquid chromatography method was developed for quantitative analysis of the candidate markers. This study enriches the phytochemical database on the material basis of C. lancifolius and provides a scientific basis for the comprehensive development of this plant resource and the establishment of quality standards.