Pien-Tze-Huang is one of the most famous
traditional Chinese medicine prescriptions and consists of several precious medicinal materials, such as Notoginseng Radix et Rhizoma, Bovis
Calculus, Snake Gall, and Moschus. However, its formula has not been completely revealed. It is mainly applied for the treatment of acute and chronic viral
hepatitis,
carbuncle, and
boils caused by blood stasis, unknown swelling,
bruises, and various
inflammation disorders. The chemical composition of
Pien-Tze-Huang is extremely complicated. Thus far, extensive attention has been paid to the principal chemical families in
Pien-Tze-Huang, such as
ginsenosides,
bile acids, and
muscone derivatives. Comprehensive chemical profiling, although of immense importance for systematic quality control, has not been achieved. Therefore, we configured a platform, namely online pressurized liquid extraction-ultra-high-performance liquid chromatography-ion trap-time-of-flight mass spectrometry (online PLE-UHPLC-IT-TOF-MS), to characterize the chemical profile of
Pien-Tze-Huang in detail as well as to conduct source attribution, aiming to clarify the chemome of
Pien-Tze-Huang and to provide a reliable method for quality assessment. A sub-microgram amount of
Pien-Tze-Huang powder (0.3 mg) was placed in a hollow guard column, which was subsequently filled with clear
silica gel. Filter membranes were used to seal the extraction vessel. The vessel was then placed in an adapted guard column holder and maintained in a thermal column oven (70 ℃).
Metal tubing was used to connect the outlet of the guard column holder to the mass spectrometer. The extraction phase was maintained for 3 min by employing 0.1%(v/v)
formic acid aqueous
solution as the extraction
solvent with a flow rate of 0.2 mL/min. Moreover, a six-port two-position electronic valve was introduced to automatically switch the system from extraction to elution phases. Within the elution phase, 0.1%(v/v)
formic acid aqueous
solution and
acetonitrile composed the mobile phase, and the extracts were eluted with a gradient program. Because of the elevated temperature and pressure, the physical and chemical properties of water, especially polarity and solubility, were modified. Therefore, warm water could be an eligible green
solvent to achieve wide polarity-spanned extraction. In addition, IT-TOF-MS was employed to acquire tandem mass spectrometry information. The mass fragmentation pathways of
saponins and
bile acids were carefully studied. Finally, according to authentic compounds, mass fragmentation pathways, reference information in the literature, and accessible databanks, a total of 73 signals were observed from
Pien-Tze-Huang, of which 71 components were tentatively identified and assigned. Among them, 36 were from Notoginseng Radix et Rhizoma, 15 from Snake Gall, and 9 from Bovis
Calculus, while the occurrences of the other 11 components were synergistically contributed by both Bovis
Calculus and Snake Gall, through retrieving the in-house chemical database that was built by considering all accessible chemical information from Notoginseng Radix et Rhizoma, Bovis
Calculus, Snake Gall, and Moschus. The other two compounds were assigned as unknown compounds. However, none of the components were assigned to Moschus because they mainly contained hydrophobic compounds, such as cycloketones,
cholesterol, and
sterols, among others, and it was difficult to detect them with the current measurement program. The extraction efficiency of online PLE was assessed by comparing it with the efficiency obtained from ultrasonication at the same time. According to base peak ion current chromatograms (BPCs) and mass spectrometry information, the efficiency of online PLE was greater than that of ultrasonic extraction, even through direct analysis. Online PLE-UHPLC-IT-TOF-MS is not only a tool fit for the concept of green analytical chemistry, but also a reliable analytical pipeline for the direct characterisation of other complicated matrixes. Above all, this study clarified the chemome of
Pien-Tze-Huang and provided meaningful information for the quality control of this famous TCM prescription.