Dynamic variation of the phytochemical and volatile compounds in the pericarp of Citrus reticulata ''Chachi'' (Rutaceae) during 2 years of storage.

The pericarp of Citrus reticulata "Chachi" (CRCP) is used as nutritional food and traditional medicine in China, usually harvested at three periods, namely, immature (CRCP-G1), semi-mature (CRCP-G2), and fully mature (CRCP-G3). Traditionally, if the CRCP is stored for a longer period, then the quality will be better. In this study, the dynamic variation of phytochemical and volatile compounds was profiled in the same batches of CRCP during 2 years of storage. Results illustrated that most of the phytochemical compounds showed a decreasing trend during storage, that is, total flavonoids, total phenolic acids, hesperidin, 3,5,6,7,8,3',4'-heptamethoxyflavone, 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, synephrine, and limonin. The ferulic acid increased significantly, whereas no significant changes were observed in the total polymethoxyflavones, nobiletin, and tangeretin after 2 years of storage. In addition, we found that the extraction yield of volatile oil decreased significantly in CRCP-G1 during storage, and the herb odors were enhanced with the increase of phenols and esters. No significant difference in the extraction yield of volatile oil of CRCP-G2 and CRCP-G3 was found after 2 years of storage, but the citrus-like notes were increased with the promoted generation of alkenes. In particular, the multivariate statistical analysis indicated that 7 volatiles showed a higher level after 1 year of storage, whereas 11 volatiles decreased and 4 volatiles increased after 2 years of storage, respectively. This study could show the early aging mechanism of CRCP harvested at different periods and provide a scientific guidance in the storage of CRCP. PRACTICAL APPLICATION: This study indicated a comprehensive method for rapid analysis of phytochemical and volatile compounds in pericarp of Citrus reticulata ''Chachi'' (Rutaceae) (CRCP) harvested at different periods during 2 years of storage. The results obtained from this study would be valuable for revealing the early aging mechanism and sustainable storage of CRCP.

Identification of Components in Citri Sarcodactylis Fructus from Different Origins via UPLC-Q-Exactive Orbitrap/MS.

To systematically analyze the chemical constituents of Citri Sarcodactylis Fructus (CSF) from different origins, an efficient approach based on ultraperformance liquid chromatography plus Q-Exactive Orbitrap tandem mass spectrometry (UPLC-Q-Exactive Orbitrap/MS) detection for the discrimination of chemical components from of 15 batches of CSF from four main origins was used in this research. Through parent peaks, fragment peaks, fragmentation characteristics, and comparative analysis with the literature and reference standards, a total of 77 components from the methanol extracts including 18 coumarins, 24 flavonoids, seven organic acids, three limonoids, and 25 other compounds were detected and identified. Among them, 15 components have not been reported previously in the CSF. Notably, the stachydrine peak initially showed a higher content in the total ion current chromatogram. Overall, CSF produced in the Zhejiang province contained a richer variety of chemical compositions. These observations provided a theoretical basis for the further quality assessment and application of CSF.

Evaluation of dynamic changes in the bioactive components in Citri Reticulatae Pericarpium (Citrus reticulata 'Chachi') under different harvesting and drying conditions.

BACKGROUND: The Citrus reticulata 'Chachi' pericarp (CRCP) is one cultivar of Citri Reticulatae Pericarpium (Chenpi), which is widely applied in medicine and food. To determine the potential value of CRCP harvested at different stages and subjected to different drying processes, the dynamic changes in the bioactive components were profiled and evaluated in this study. RESULTS: The contents of all non-volatile components, i.e. synephrine, limonin, phenolic acids and flavonoids, decreased with delayed harvest time. The volatiles thujene, α-pinene, ß-pinene, d-citronellol, d-citronellal, decanal, linalool, geraniol, l-cis-carveol, terpinen-4-ol, α-terpineol, carvacrol, perillaldehyde, methyl 2-(methylamino)benzoate and d-limonene were considered the characteristic components for distinguishing CRCP harvested at different stages. Phenolic acids, synephrine and limonin were stable at different drying temperatures; however, high-temperature drying at 60 °C induced a significant transformation in the flavonoids (especially polymethoxyflavones) and volatile substances in CRCP. CONCLUSIONS: The results suggested that most of the bioactive components declined with the growth of Citrus reticulata 'Chachi'. And it is believed that the fresh peel should be naturally sun-dried or dried at low temperature (30 or 45 °C) rather than at high temperature (60 °C) to prevent excessive loss of nutrients. © 2020 Society of Chemical Industry.

Correction to "Supercritical CO2 Fluid Extraction for the Identification of Compounds from Citrus reticulata Semen by Ultra-High-Performance Liquid Chromatography Combined with Q-Exactive Orbitrap Tandem Mass Spectrometry".

[This corrects the article DOI: 10.1021/acsomega.9b03123.].

Identification of lipophilic components in Citri Reticulatae Pericarpium cultivars by supercritical CO2 fluid extraction with ultra-high-performance liquid chromatography-Q Exactive Orbitrap tandem mass spectrometry.

To systematically identify the lipophilic constituents of Citri Reticulatae Pericarpium from different cultivars, supercritical CO2 fluid extraction and ultra-high-performance liquid chromatography-Q Exactive Orbitrap tandem mass spectrometry were integrated for the component analysis of 18 batches of Citri Reticulatae Pericarpium from 12 cultivars for the first time. A total of 57 components from the supercritical CO2 fluid extracts were demonstrably or tentatively identified by the obtained parent peaks, fragment peaks, and retention times. In total, two flavonoids, six organic acids, nine coumarins, three aldehydes, seven esters, three terpenes, one limonoid, and five other compounds were detected for the first time; notably, coumarin components have not yet been reported in Citri Reticulatae Pericarpium. Furthermore, the extract constituents differed between cultivars. In particular, organic acids were more abundant in Citrus reticulata "Chachi" than in other cultivars, and pterostilbene was exclusively found in Citrus reticulata "Yichangju". The results showed that a greater variety of compounds in Citri Reticulatae Pericarpium could be extracted by supercritical CO2 fluid extraction and detected by ultra-high-performance liquid chromatography-Q Exactive Orbitrap tandem mass spectrometry. This study provides a more scientific basis for further analysis of the pharmacological activity and quality of Citri Reticulatae Pericarpium components from different cultivars.

Effects of compound K, a metabolite of ginsenosides, on memory and cognitive dysfunction in db/db mice involve the inhibition of ER stress and the NLRP3 inflammasome pathway.

Accumulating clinical and epidemiological evidence indicates a close relationship between diabetes mellitus and dementia. The ginsenoside compound K (CK) has been reported to ameliorate diabetes mellitus and confer protection to the central nervous system. In this study, we investigated whether CK could improve memory impairment and cognitive dysfunction in diabetic db/db mice. Firstly, we found that CK treatments significantly improved behavioral impairment and cognitive dysfunction based on Morris water maze, Y-maze, and fear conditioning tests. Besides, CK decreased the fasting glucose level, increased lipid metabolism, and ameliorated glucose tolerance, insulin sensitivity, and dyslipidemia in diabetic db/db mice. In addition, CK treatments alleviated oxidative stress and inhibited the inflammatory response in hippocampal tissue. Further investigations showed that CK treatments inhibited the NLRP3 inflammasome pathway, as evidenced by the declined expression of TXNIP, NLRP3 inflammasomes, ASC, cleaved caspase-1, and mature IL-1ß in hippocampal tissues. Moreover, CK treatments alleviated ER stress via down-regulating the level of BiP, CHOP, p-PERK, p-IRE1α and ATF6 in the hippocampus of db/db mice. These results suggest that CK improves memory and cognitive dysfunction, possibly by ameliorating glucose tolerance, insulin sensitivity, and dyslipidemia, suppressing oxidative stress and inflammatory response and modulating the NLRP3 inflammasome pathway and ER stress.

Construction and Chemical Profile on "Activity Fingerprint" of Citri Reticulatae Pericarpium from Different Cultivars Based on HPLC-UV, LC/MS-IT-TOF, and Principal Component Analysis.

Citri Reticulatae Pericarpium (CRP), known as Chenpi (CP) in Chinese, is a medicinal food for health and fitness. In order to find out the characteristic activity chemicals distinguishing various cultivars of CRP and provide a reference for effective development of citrus resources, an "activity fingerprint" of CRP from 21 different cultivars was established based on the evaluation of antitussive and expectorant activities. There were 18 common peaks in the HPLC fingerprint, of which 3 flavonoid glycosides and 14 polymethoxyflavonoids (PMFs) were identified by LC/MS-IT-TOF. Furthermore, five characteristic chemicals were determined and similarity calculation with principal component analysis (PCA) was combined together to compare the similarity and difference among various cultivars. The results showed that some other cultivars were also similar to C. reticulata "Chachi" except for C. reticulata "Tangerina" and C. reticulata "Dahongpao" recorded in Chinese Pharmacopoeia. Most importantly, the peels of C. reticulata "Shiyueju," C. reticulata "Ponkan," C. reticulata "Tribute," and C. reticulata "Bayueju," traditionally rarely used for medicinal food, were highly similar to that of C. reticulata "Chachi" and rich in bioactive flavonoids, which can be considered the effective medicinal resources of CRP.

Supercritical CO2 Fluid Extraction for the Identification of Compounds from Citrus reticulata Semen by Ultra-High-Performance Liquid Chromatography Combined with Q-Exactive Orbitrap Tandem Mass Spectrometry.

A rapid and simple method based on the coupling of supercritical fluid extraction and ultra-high-performance liquid chromatography combined with Q-Exactive Orbitrap tandem mass spectrometry (SFE-UHPLC-Q-Exactive Orbitrap-MS) detection for the identification of compounds from Citrus reticulata semen (CRS) was developed for the first time in this study. Through the optimization of the SFE parameters including extractive pressure, extractive temperature, and time, most of the compounds were successfully extracted at 50 °C, 33 MPa, and 2 h without an entraining agent, among which 32 compounds were successfully identified. Moreover, the operating conditions of UHPLC-Q-Exactive Orbitrap-MS were also optimized for the analysis of the SFE extracts, and the extracts in the CRS showed good separation performance in 20 min. A total of 28 compounds from the SFE extract were identified by comparing the standard sample together with full scan and related literature data, among which esters and flavonoids were the major compounds identified in the CRS extracts. In addition, 2 phenols, 2 aldehydes, 2 triterpenes, and 5 other compounds were identified. The SFE-UHPLC-Q-Exactive Orbitrap-MS method was successfully validated and applied for the identification of compounds from the CRS.

Identification and determination of chemical constituents of Citrus reticulata semen through ultra high performance liquid chromatography combined with Q Exactive Orbitrap tandem mass spectrometry.

Citrus reticulata semen, a traditional Chinese medicinal material, has desirable medicinal and dietary properties. In this study, a method combining ultra high performance liquid chromatography with Q Exactive Orbitrap tandem mass spectrometry was established and validated for the identification and analysis of the chemical components of C. reticulata semen for the first time. The evaluation of different retention times and fragmentation characteristics, as well as comparative analysis with the literature, resulted in the identification of 35 chemical constituents, including 21 flavonoids and 14 other compounds. The 21 flavonoids derived from C. reticulata semen were reported for the first time. Seven of the chemical components of C. reticulata semen were quantitatively analyzed using the developed method under the optimal conditions. The results showed that the content of limonin, hesperidin, nobiletin, synephrine, tangeretin, 3,5,6,7,8,3',4'-heptamethoxyflavone and 5-hydroxide-6,7,8,3',4'-pentamethoxyflavone in C. reticulata semen was 11.1666, 0.0404, 0.0092, 0.0255, 0.0087, 0.0010, and 0.0008 mg/g, respectively. This study demonstrated that the ultra high performance liquid chromatography Q Exactive Orbitrap mass spectrometry based method can be used to rapidly and reliably analyze the chemical constituents of C. reticulata semen. These results provide a scientific basis for further studies of C. reticulata semen.