Analysis of blood components of aged tangerine peel based on UHPLC-Q-Orbitrap HRMS
Chenpi is the dried and mature peel of Citrus reticulata Blanco and its cultivated varieties in the Rutaceae family. It has been believed since ancient times that Chenpi produced in Xinhui, Guangdong has better quality. Traditionally, it is believed to have the functions of regulating qi and strengthening the spleen, drying dampness and resolving phlegm, and is used to treat symptoms such as abdominal distension, overeating, vomiting and diarrhea, cough and phlegm. Chenpi mainly contains flavonoids, volatile oils, alkaloids, limonoid and other chemical components. Modern pharmacology has shown that it has lipid-lowering and antioxidant effects, and is widely used in clinical practice.
Traditional Chinese medicine theory suggests that dried tangerine peel should be aged before use. However, regarding the specific aging time of tangerine peel, there have been different opinions in various herbal books throughout history. The “Medicinal Mirror” records that “tangerine peel must be aged every other year”, also known as “tangerine peel must be aged for a long time to be beautiful”; The Compendium of Materia Medica states that ‘tangerine peel can only be used the following year’; The “Daily Materia Medica” records that “aged tangerine peel is even better. Even for the same ancient book, the aging time of tangerine peel is not yet clear. Modern research on the aging period of aged tangerine peel mainly focuses on comparing its chemical composition and pharmacological effects, and often studies the chemical composition of aged tangerine peel with different aging times in vitro. The research team has previously analyzed the flavonoid components in aged tangerine peel at different times using UHPLC-Q-Orbitrap HRMS technology. Most traditional Chinese medicines are still administered orally, and analyzing the chemical composition of serum after oral administration to determine the direct acting substances of traditional Chinese medicine in vivo has become an effective way to quickly and accurately study and determine the pharmacological substance basis of traditional Chinese medicine. At present, there are few reports on the internal components of dried tangerine peel.
This study is the first to use ultra-high performance liquid chromatography quadrupole electrostatic field orbital trap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) technology with high separation, high resolution, and high sensitivity to compare the blood components of different years of dried tangerine peel, providing a reference for the pharmacological substance basis and pharmacological research of dried tangerine peel.

Traditional Chinese medicine has a long history of aging, with tangerine peel being the first of the “Six Chens”. Combining historical works on herbal medicine and modern research, the specific aging time of tangerine peel has not yet been resolved. The research team used UHPLC-Q-Orbitrap HRMS technology to analyze the flavonoid components in aged tangerine peel at different times in the early stage. From an in vitro perspective, it has been proven that “tangerine peel needs to be aged every other year” has certain rationality.

This experiment is based on the fast and accurate characteristics of UHPLC-Q-Orbitrap HRMS, with fixed harvesting time, sampling location, storage environment, and other conditions. For the first time, a comparative analysis of the blood components of aged aged tangerine peel was conducted, and 34, 24, and 15 components were identified for aged tangerine peel at 2, 4, and 8 years, respectively. The experiment found that the types of blood components in aged tangerine peel were roughly the same in three years. Based on the comparison of peak area and relative content, aged tangerine peel was higher in two years than in the other two years, which was consistent with the results of previous in vitro experiments. This proves that the differences in chemical component content in aged tangerine peel can lead to differences in its blood component content, providing further evidence for the explanation that aged tangerine peel should be aged every other year.

The main components of tangerine peel are flavonoids, which have protective effects against liver damage and lower blood lipids. Chuanchenpi extract is a representative component of neuroprotection, which can protect against cerebral ischemia by activating the pAkt, p-CREB, BDNF, and Bcl-2 pathways and improving BBB permeability in rats. Orange peel extract can exert anti apoptotic effects on cardiomyocytes through mitochondrial JNK/Baxpathway. Isoorange flavonoids showed significant anti proliferative effects on four types of cancer cells, HL-60, A549, HO8910, and MCF-7. Emodin has antioxidant, anti-inflammatory, and antiviral effects. Based on the traditional efficacy and modern pharmacological research of dried tangerine peel, it is preliminarily inferred that seven flavonoids, including naringin and tangerine peel extract, may be the potential pharmacological substance basis of dried tangerine peel. However, biological activity testing and pharmacological evaluation are still needed in the later stage, and components that can express activities related to traditional Chinese medicine clinical efficacy need to be screened as pharmacological substance basis. This experiment provides a new and effective method for studying the pharmacological substance basis of dried tangerine peel. In the later stage, comparative studies can be conducted on the blood components of dried tangerine peel from different ages, and the scientific connotation of “aged tangerine peel is good” can be explained together with its pharmacological effects.

For some isomers, Compound Discoverer 3.0 software can only extract specific information about the parent ion from its fragment information for structural inference, and cannot distinguish between isomers. It is necessary to combine nuclear magnetic resonance technology to identify the structure of these isomers.