GC-MS fingerprints for discrimination of Ligusticum chuanxiong from Angelica

A GC-MS fingerprinting technique based on the essential oil components has been developed for the discrimination of chuanxiong against Chinese Angelica (Angelica sinensis (Oliv.) Diels) or other herbs with similar compositions. The analytical performance of four different extraction methods for the separation of essential oil components have been compared and these include: ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE), Soxhlet extraction (SHE) and hydro-distillation extraction (HDE). The results showed that UAE was the most effective extraction method, and the operational parameters of UAE were optimized. 3-Butylphthalide, Z-butylidenephthalide, senkyunolide I, senkyunolide H, E-butylidenephthalide, senkyunolide A, neocnidilide, Z-ligustilide and E-ligustilide were tentatively identified in chromatograms of chuanxiong based on their GC-EI-MS data. Similarity coefficient calculations based on correlation methods have been performed on the GC-MS fingerprints. Using an authentic standard Chuanxiong as the reference, the similarity coefficients between the standard and all other chuanxiong samples ranged from 0.90 to 1.0 (with 1.0 being the perfect match), which as a group can be readily separated from the Angelica samples for which the similarity index against the chuanxiong standard ranged from 0.75 to 0.77. Conversely, when an authentic Angelica standard was used as the reference, the respective similarity coefficients fall in the range of 0.70-0.75 and 0.98-1.00 for the chuanxiong and Angelica sample groups. Our results thus demonstrate that the fingerprinting technique developed in the study can indeed discriminate the two herbs with high reliability.