Comparative Analysis of Volatile Constituents in Different Parts and Essential Oil of Pogostemon cablin Using GC–MS Combined with Chemometrics

BACKGROUND: Pogostemon cablin (P. cablin) is a valuable medicinal plant used in traditional medicine and the fragrance industry, but QC is challenging due to inconsistent stem-to-leaf ratios and frequent essential oil adulteration. OBJECTIVE: This study compares volatile components in different parts (aerial parts, stems, and leaves) and essential oil of P. cablin to support QC (not less than 20% leaf) and its rational use. METHODS: Volatile components in 21 batches of aerial parts, stems, and leaves, and 13 batches of essential oils, were analyzed using GC-MS. Multivariate curve resolution-alternating least-squares (MCR-ALS) was used for resolving co-eluted peaks, and chemical fingerprinting with chemometric techniques including hierarchical cluster analysis (HCA), principal component analysis (PCA), partial least-squares discriminant analysis (PLS-DA), and orthogonal partial least-squares discrimination analysis (OPLS-DA) were applied. RESULTS: Volatile profiling identified 56, 47, 28, and 45 components in the aerial parts, leaves, stems, and essential oil of P. cablin, respectively. MCR-ALS resolved 10 major volatile compounds to create chemical fingerprints for each analytical sample type. Quantitative analysis showed higher patchouli alcohol in leaves (12.47 mg/g) compared to stems (2.05 mg/g), while stems had more pogostone (2.71 mg/g versus 1.40 mg/g in leaves). Aerial parts and essential oil showed significant compositional differences. Based on the results of qualitative and quantitative analysis, chemometric methods, including HCA, PCA, PLS-DA, and OPLS-DA, clearly differentiated the four types of P. cablin analytical samples. CONCLUSION: Significant differences in volatile components across P. cablin parts and its essential oil support QC (not less than 20% leaf) and rational use. HIGHLIGHTS: This study is the first to use MCR-ALS and other chemometrics for qualitative and quantitative analysis of P. cablin parts and essential oils, aiding QC.