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.

Cicadae Periostracum (CP), the cast-off shell of Cryptotympana atrata, is specified in Chinese Pharmacopoeia for relieving fever and eliminating ulcer. N-acetyldopamine oligomers are the major characteristic bioactive components with antioxidant and anti-inflammatory activities that may be responsible for the efficacy of CP. However, the exposed components and metabolites of N-acetyldopamine oligomers of CP (NOCP) in vivo are still unknown. In present study, the metabolic profile of total NOCP and N-acetyldopamine dimer B in rats were systematically investigated by ultra-high liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS/MS). In biosamples of NOCP group, 34 prototypes and 15 metabolites were identified or tentatively characterized, including 5 metabolites in plasma, 3 prototype and 9 metabolites in urine, 2 metabolites in bile, 34 prototypes and 8 metabolites in feces, respectively. In dimer B group, the prototype and 8 metabolites were identified, including 2 metabolites in plasma, 4 metabolites in urine, 1 metabolite in bile and 5 metabolites in feces, respectively. Oxidation, and hydrogenation were supposed to be the major phase I reactions, while methylation, sulfation, and glucuronidation were the main phase II reactions of NOCP and dimer B. M10 and M13 might undergo enterohepatic circulation in rats. It is concluded that NOCP and dimer B were mainly absorbed in the form of metabolites, and metabolites are probably the major bioactive forms of NOCP and dimer B. The outcomes of this study provided helpful information for extensively elucidating biological and pharmacological mechanisms of NOCP.

Quality consistency evaluation on four origins of Cicadae Periostracum by ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry analysis.

Cicadae Periostracum, which is derived from the slough of Cicadidae insects, is a commonly used crude drug in traditional Chinese medicine (TCM). As specified in Chinese Pharmacopoeia, Cryptotympana atrata (CA) is the only official species of this crude drug. However, the slough of other three species, i.e., Auritibicen flammatus (AF), Cryptotympana mandrina (CM) and Platypleura kaempferi (PK), have been also used as the origins of Cicadae Periostracum in Chinese herbal market, although whether the quality of these four origins is consistent or not is still unknown. In present study, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) was employed to qualitatively and quantitatively compare the chemical profiles of the four origins. Totally, 34 N-acetyldopamine polymers were identified from the four origins, including 4 N-acetyldopamine dimers, 11 N-acetyldopamine trimers, 10 N-acetyldopamine tetramers, and 9 N-acetyldopamine pentamers. AF, CM and PK had similar chemical profiles with that of CA. The contents and compositional ratio of the four types of polymers in CA, AF and CM were consistent with each other, but significantly lower or different in PK. All these results suggested that AF and CM might be considered as the potential resources of Cicadae Periostracum concerning their consistent holistic quality, whereas whether PK could be used as potential origin of Cicadae Periostracum or not need further evaluation for their different compositional ratios and contents of the four types of N-acetyldopamine polymers. This is the first study on chemical profiling and comparison of N-acetyldopamine polymers in four origins of Cicadae Periostracum, which is beneficial for potential resources utilization and quality standard improvement of Cicadae Periostracum.