Systematic metabolite profiling of N-acetyldopamine oligomers from Cicadae Periostracum in rats by ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry

Enantiomeric N-acetyldopamine trimers from Cicadae Periostracum and their absolute configurations

Six previously undescribed N-acetyldopamine (NADA) trimmer racemates, percicamides A-F (1-6), were isolated from a 70% ethanol extract of Cicadae Periostracum. Subsequent chiral-phase separation afforded six pairs of enantiomers, (+)- and (-)-percicamides A-F (1a/1b-6a/6b). Their structures including absolute configurations were elucidated by combined extensive spectroscopic data and quantum chemical calculations. Compounds 1-6 represent the first examples of NADA trimmers with a cis-relationship of H-7'/H-8' or H-7''/H-8''. Bioassays verified that all isolated compounds showed weak inhibitory effects on nitric oxide production in RAW 264.7 cells.

UPLC-QTOF-MS/MS assisted UPLC-TQ-MS/MS strategy to comparatively investigate the rat pharmacokinetics of N-acetyldopamine oligomers derived from Cicadae Periostracum

Cicadae Periostracum (CP), the slough molted from the nymph of Cryptotympana pustulata, is a widely used medicinal material in traditional Chinese medicine (TCM). N-acetyldopamine oligomers (NAOs), the homologues of acetyldopamine, including N-acetyldopamine dimers/trimers/tetramers/pentamers (NADs/NATrs/NATes/NAPs), side-chain isomer of dimers/trimers (SCIDs/SCITrs), are major bioactive ingredients of CP. However, owing to commercially unavailable reference substances of all NAOs, simultaneous quantification of these NAOs in biological samples is difficult, and thus their pharmacokinetics are still unknown. In this study, a comprehensive strategy for simultaneous quantification/semi-quantification of NAOs in plasma with single N-acetyldopamine dimer A (NAD-A) as reference substance was established and comparatively investigated their pharmacokinetics after oral administration of pure NAD-A and two types of CP extracts, i.e., post-molting-washed slough (CP-WAT) and pre-molting-washed slough (CP-WBT). A UPLC-QTOF-MS/MS assisted UPLC-TQ-MS/MS strategy was developed to quantify NAOs in rat plasma. NAOs in CP extract were qualitatively characterized by UPLC-QTOF-MS/MS, then the quasi-molecular ions and characteristic fragment ions of the identified NAOs by UPLC-QTOF-MS/MS were transferred to UPLC-TQ-MS/MS as parent-daughter ion pairs for MRM mode quantification of the NAOs, and the method was validated with single NAD-A for quantifying NAD-A and semi-quantifying other NAOs in plasma. The established method was applied to compare the pharmacokinetics of NAOs after oral administration of NAD-A and the extracts of CP-WBT/CP-WAT respectively. Six quasi-molecular ions and characteristic fragment ion m/z 192.1 were characterized by UPLC-QTOF-MS/MS and transferred to be the parent-daughter ion pairs for UPLC-TQ-MS/MS analysis of six kinds of NAOs. For the pharmacokinetics, NAD-A showed double peaks absorption character when administered with single compound, but with higher relative bioavailability when administered with CP extracts with the similar dosage. Compared with CP-WAT, NAOs in CP-WBT reached the maximum plasma concentration in much shorter time.

Deciphering chemical and metabolite profiling of Chang-Kang-Fang by UPLC-Q-TOF-MS/MS and its potential active components identification

Chang-Kang-Fang (CKF) formula, a Traditional Chinese Medicine (TCM) prescription, has been widely used for the treatment of irritable bowel syndrome (IBS). However, its potential material basis and underlying mechanism remain elusive. Therefore, this study employed an integrated approach that combined ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) with network pharmacology to systematically characterize the phytochemical components and metabolites of CKF, as well as elucidating its underlying mechanism. Through this comprehensive analysis, a total of 150 components were identified or tentatively characterized within the CKF formula. Notably, six N-acetyldopamine oligomers from CicadaePeriostracum and eight resin glycosides from Cuscutae Semen were characterized in this formula for the first time. Meanwhile, 149 xenobiotics (58 prototypes and 91 metabolites) were detected in plasma, urine, feces, brain, and intestinal contents, and the in vivo metabolic pathways of resin glycosides were elaborated for the first time. Furthermore, network pharmacology and molecular docking analyses revealed that alkaloids, flavonoids, chromones, monoterpenes, N-acetyldopamine dimers, p-hydroxycinnamic acid, and Cus-3/isomer might be responsible for the beneficial effects of CKF in treating IBS, and CASP8, MARK14, PIK3C, PIK3R1, TLR4, and TNF may be its potential targets. These discoveries offer a comprehensive understanding of the potential material basis and clarify the underlying mechanism of the CKF formula in treating IBS, facilitating the broader application of CKF in the field of medicine.

Integrating Multi-Type Component Determination and Anti-Oxidant/-Inflammatory Assay to Evaluate the Impact of Pre-Molting Washing on the Quality and Bioactivity of Cicadae Periostracum

Cicadae Periostracum (CP) is a traditional Chinese medicinal herb derived from the slough that is molted from the nymph of the insect Cryptotympana pustulata Fabricius. Washing with water to remove residual silt is a primary processing method of CP that is recommended by the Chinese Pharmacopoeia, but how washing methods affect the quality and bioactivity of CP is unknown. In this study, the quality and bioactivity of non-washed CP (CP-NW), post-molting-washed CP (CP-WAT), and pre-molting-washed CP (CP-WBT) were comparatively investigated. The quality of these CP samples was evaluated in terms of the UPLC-QTOF-MS/MS-based chemical profiling and semi-quantification of 39 N-acetyldopamine oligomers (belonging to six chemical types), the HPLC-UV-based quantification of 17 amino acids, the ICP-MS-based quantification of four heavy metals, and the contents of ash; the bioactivities of the samples were compared regarding their anti-oxidant and anti-inflammatory activities. It was found that, compared with CP-NW, both CP-WBT and CP-WAT had significantly lower contents of ash and heavy metals. Moreover, compared with CP-WAT, CP-WBT contained lower levels of total ash, acid-insoluble ash, and heavy metals and higher contents of N-acetyldopamine oligomers and amino acids. It also had enhanced anti-oxidant and anti-inflammatory activities. A Spearman's correlation analysis found that the contents of N-acetyldopamine oligomers and free amino acids were positively correlated with the anti-oxidant/-inflammatory activities of CP. All these results suggest that pre-molting washing can not only remove the residual silt but can also avoid the loss of the bioactive components and assure higher bioactivities. It is concluded that pre-molting washing could enhance the quality and bioactivity of CP and should be a superior alternative method for the primary processing of qualified CP.