[Quality evaluation of Asparagi Radix based on saponin fingerprinting and content determination]

This study established a fingerprinting method and a content determination method for Asparagi Radix saponins, providing methodological and data support for the quality control of Asparagi Radix. High-performance liquid chromatography coupled with evaporative light-scattering detection(HPLC-ELSD) was used to construct the fingerprint of Asparagi Radix and to determine the content of protodioscin as a marker compound. A total of 49 batches of samples from different origins were analyzed and 8 common peaks were observed. These peaks were characterized by ultra-performance liquid chromatography coupled with LTQ-Orbitrap mass spectrometry(UPLC-LTQ-Orbitrap-MS) as protoneodioscin(1), protodioscin(2), pseudoprotoneodioscin(3), pseudoprotodioscin(4), asparagoside F(5), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-26-O-β-D-glucopyranosyl-(25S)-5β-furosta-3β,22α,26-triol(6), Asp Ⅳ'(7), and 26-O-β-D-glucopyranosyl-furosta-20(22)-en-3β,26-diol-3-O-[β-D-glucopyranosyl-(1→2)]-[α-L-rhamnopyranosyl-(1→4)]-β-D-glucopyranoside(8). According to the fingerprint characteristics, the samples were clustered into 3 categories. Category A included samples from Yunnan, Chongqing, and Guizhou, with 4 common peaks(peaks 1-4). Category B consisted mostly of samples from Guangxi and a few from Sichuan, showing 4 common peaks(peaks 2, 5, 6, and 7). Category C consisted exclusively of small specifications of samples from Neijiang, Sichuan, with common peaks 3, 5, 6, and 8. The content of protodioscin in Asparagi Radix of different categories varied greatly. The content of protodioscin in samples of category A was significantly higher than that in samples of category B, and this compound was not detected in samples of category C. On the basis of appearance, Asparagi Radix samples were classified into large and small specifications. According to the fingerprint and content determination results, Asparagi Radix samples were classified into three categories above. The medicinal properties of Asparagi Radix are reflected in the bitter saponins, and the edible properties are reflected in the oligosaccharides. Asparagi Radix samples of category C(without bitter saponins) are more suitable to be used as raw materials for edible and medicinal substances, while those of category A are more suitable to be used as medicinal materials.