Evaluation of chemical components in Citri Reticulatae Pericarpium of different cultivars collected from different regions by GC-MS and HPLC

Abstract

To discriminate the feasible differences and find potential similarities and relationships of Citri Reticulatae Pericarpium (CRP), this work was accomplished by a comprehensive and reliable method using gas chromatography-mass spectrometer (GC-MS) to analyze the volatile oils and high-performance liquid chromatography (HPLC) simultaneously to determine the contents of five bioactive flavonoids, namely hesperidin, nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone, tangeretin, and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone in 25 batches of CRP samples of 10 cultivars collected from different regions in China. The GC-MS analyses indicated that 98 compounds were successfully identified from the volatile oils obtained and the major constituents of volatile oil are d-limonene, γ-terpinene, α-pinene, linalool, and myrcene. Even 2-(methylamino) benzoate was found in all cultivar samples harvested at maturation stage. Under the optimal condition, the quantitative analyses of five bioactive flavonoids were successfully performed by HPLC and hierarchical cluster analysis (HCA). Results showed significant differences among cultivars in the contents of five bioactive flavonoids mentioned earlier. The HCA and GC-MS results provided a convenient approach which might be applied for rapid similarity evaluation and also holds the potential for analysis of compounds present in other plants. Therefore, this work obtained offers scientific basis to control quality and develop medicinal value of the medicinal materials in CRP.

Keywords: Citri Reticulatae Pericarpium; GC–MS; HPLC; cluster analysis; flavonoids; volatile oil.

Figure 1

Chemical structure of bioactive flavonoids C1–C5

Figure 2

HPLC chromatograms of standard mixture (a) and sample (b). The numbers indicate bioactive flavonoids C1–C5

Figure 3

Dendrogram of hierarchical cluster analysis for 25 Citri Reticulatae Pericarpium samples in HPLC collected from different major citrus‐producing areas in China. Rescaled distance cluster combine was selected as a measurement. Citri Reticulatae Pericarpium samples were divided into two main clusters

Figure 4

Total ion chromatography of volatile oil from CRP. Temperature programmed gas chromatography (TPGC) and electron impact (EI) ion source were used for the analysis of complex samples that we described in the Materials and Methods. Constituents were identified by comparison of authentic compounds with reference spectra in the computer library (NIST 08s.L MS database) and confirmed by comparison of those authentic compounds with data in literature. CRP of (a) Citrus reticulata “Chachi,” (b) C. reticulata “Dahongpao,” (c) C. reticulata “Subcompressa,” (d) C. reticulata “Erythrosa,” (e) C. reticulata “Shiyueju,” (f) C. reticulata “Kinokuni,” (g) C. reticulata “Speciosa,” (h) C. reticulata “Tangerina,” (i) C. reticulata “Unshiu,” and (j) C. reticulata “Ponkan”

Figure 5

Graphic for table of contents