Exocarpium Citri Grandis Research Articles

Antitussive, expectorant and anti-inflammatory activities of different extracts from Exocarpium Citri grandis

Ethnopharmacological relevanceExocarpium Citri grandis (C. grandis, Huajuhong in Chinese), the epicarp of C. grandis ‘Tomentosa’, is used as an antitussive, expectorant and anti-inflammatory drug for hundreds of years in China. The study was aimed at evaluating the antitussive, expectorant and anti-inflammatory effects of different extracts of C. grandis, providing experimental evidence for its traditional use, and laying a foundation for its further researches. Materials and methodsCrude drugs of C. grandis were extracted with four kinds of solvents (water, 50% ethanol, 70% ethanol and 90% ethanol) in reflux conditions, respectively. Solutions were concentrated in reduced pressure and lyophilized in vacuum to yield the aqueous extract, 50% ethanolic extract, 70% ethanolic extract, and 90% ethanolic extract of C. grandis. Antitussive evaluations were carried out with ammonia liquor induced mice cough; expectorant effects were tested with phenol red secretion experiments in mice; anti-inflammatory effects were assessed by murine model of xylene induced ear edema in mice. ResultsOnly aqueous and 70% ethanolic extracts of C. grandis displayed significant antitussive, expectorant and anti-inflammatory activities. Aqueous extract of C. grandis significantly decreased cough frequency caused by ammonia liquor, increased phenol red secretion and inhibited the development of ear edema in anti-inflammatory assay at the dose of 1005mg/kg (P<0.05). However, aqueous extract of C. grandis did not lengthened the cough period. It was worth noting that, 70% ethanolic extract of C. grandis showed strong effect of decreasing cough frequency, prolonging cough period, increasing phenol red secretion and decreasing the extent of ear edema at the dose of 493mg/kg (P<0.001). The low, middle, and high dose (247, 493, and 986mg/kg) of 70% ethanolic extract of C. grandis showed significant antitussive, expectorant and anti-inflammatory effects in good dose dependant manner. ConclusionThe results supported the folk use of C. grandis (decoction of C. grandis) with scientific evidence, and indicated that the 70% ethanolic extract of C. grandis might have better effects of antitussive, expectorant and anti-inflammatory than those of aqueous extract. Further investigation needs to be conducted to study the bioactive constituents of 70% ethanolic extract of C. grandis and the mechanism of observed antitussive, expectorant and anti-inflammatory activities.

Inhibition Effects of Flavonoids from Exocarpium citri Grandis on Nitrosation

The total flavonoids in Exocarpium citri Grandis were extracted using the optimum ultrasonic extraction conditions and were further separated by ethyl acetate to yield lipid-soluble and water-soluble parts.The inhibitions of these different extracts on nitrosation were studied.The lipid-soluble extract was purified by chromatography on silica gel and the water-soluble extract was purified by macroporous adsorption resin.The structures of the flavonoids were identified and their inhibitions on nitrosation were experimented.The results showed that the extraction yield of the flavonoids was as high as 26.42%.The lipid-soluble and water-soluble extracts had some inhibition effects on nitrosation such as nitrosodimethylamine synthesis and sodium nitrite,in which the inhibition of the water-soluble extract was stronger than the lipid-soluble extract.In the four flavonoids,naringin had stronger inhibition than the others,the maximum blocking rate to nitrosodimethylamine synthesis was as high as 94.7%,while the highest removal rate to sodium nitrite was 92.3%.

UPLC-Q-TOF-MS analysis of naringin and naringenin and its metabolitesin rat plasma after intragastrical administration of alcohol extract of exocarpium Citri grandis

To analyze naringin, naringenin and its metabolites in rat plasma after intragastric administration of exocarpium Citri grandis alcohol extract. Rat blood samples were collected 1.0 hour after oral administration of 50 g x kg(-1) exocarpium Citri grandis alcohol extract and analyzed by UPLC-Q-TOF with MS(E) function. The post-acquisition data were processed using Metabolynx. Naringin (M1), naringenin (M2), naringin-5-O-glucuronide (M3), naringin-4-O-glucuronide (M4), glucuronide conjugate of naringenin (M5), naringin-4-O-sulfate (M6), methylated conjugate of hydroxylated naringenin (M7), glucuronide and sulfate conjugate of naringenin (M8), glucuronide conjugate of hydroxylated naringenin (M9) in rat plasma were detected. M3, M4, M6 were first reported as the metabolites of naringin. M7, M9 were first reported as the metabolites of naringenin. The results indicated that naringin, naringenin can be metabolited as the forms of glucuronidation, sulfation and naringenin can also be metabolited as the forms of methylation with hydroxylation and glucuronidation with hydroxylation in vivo after administration.

Comparative analysis of volatile constituents in Citrus Reticulata Blanco using GC–MS and alternative moving window factor analysis

The similarities and differences of essential oil components in Album Citri reticulatae (ACR), Cylindricae Citri reticulatae (CCR), folium Citri reticulatae (FCR), exocarpium Citri Grandis (ECG), pericarpium Citri reticulatae Viride (PCRV) and pericarpium Citri reticulatae (PCR) were investigated by GC-MS combined with a chemometric method named alternative moving window factor analysis (AMWFA). And temperature-programmed retention indices (PTRIs) were used together with mass spectra for identification of the essential oil components. In essential oils of ACR, CCR, FCR, ECG, PCRV and PCR, 28, 26, 61, 62, 52 and 48 components were determined representing 93.13, 94.44, 93.53, 87.67, 99.03 and 98.03% of the total relative content, respectively. Also, the essential oils significantly differed both qualitatively and quantitatively. There were 14 common components among ACR, CCR, FCR, ECG, PCRV and PCR, their abundance varied in the ranges from 32.39% in FCR to 94.66% in PCRV. The results obtained may be helpful to the further study of pharmacological activity for their potential utilization as therapeutical agents.

Preparative Isolation and Purification of Two Closely Related Glycosidic Flavonoids from Exocarpium Citri Grandis by High-Speed Countercurrent Chromatography

High-speed countercurrent chromatography (HSCCC) was successfully used for the isolation and purification of two closely related glycosidic flavonoids from Exocarpium Citri Grandis. n‐Hexane‐1‐butanol–methanol–0.5% acetic acid (1:3:1:4, v/v) was used as the two‐phase solvent system. From 50 mg of crude extracts of Exocarpium citri Grandis, 28.8 mg of naringin, 1.4 mg of rhoifolin, and 5.7 mg of an unknown compound were obtained with the purity of 97.1%, 95.5%, and 97.5%, respectively, in a single run. Two flavonoids fractions were characterized by ESI‐MS confirming that the data was identical to the literature values.