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

Abstract

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.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.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.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.Significant differences in volatile components across P. cablin parts and its essential oil support QC (not less than 20% leaf) and rational use.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.