Constituents of Flavonoids in Different Origins of Fructus Aurantii Immature

Abstract

The major species of Citrus fruits used as Fructus Aurantii Immature (Zhishi) in China include the immature fruits of Citrus aurantium L. (C. aurantium) and its cultivars, Citrus sinensis Osbeck (C. sinensis) and its cultivars, and Citrus junos Sieb. ex Tanaka (C. junos)[1,2]. However, the constituents of flavonoids which are the major components in Zhishi with the different origins are not well identified [3,4]. This study is aimed at exploring the flavonoids in the different origins of Zhishi and setup a chemical approach to identify the origins of Zhishi, since the appearances of commercial Zhishi are too similar to recognize their origins. A total of 77 samples originated from three species and their cultivars were collected from different areas for flavonoids analysis, and another 10 commercial samples were used as origin identification test. The constituents of primary flavonoids were detected with HPLC. The results showed that narirutin (NR), naringin (NG), hesperidin (HE) and neohesperidin (NH) were included in the samples from C. aurantium and its cultivars as well as from C. junos besides from C. sinensis and its cultivars in which neither NG nor NH was detectable. In Zhishi with the same origin, there was no obvious difference of flavonoids collected from different areas. Meanwhile, the content ratios of NG/NR were higher than 10.6 in the samples from C. aurantium and its cultivars, and lower than 0.76 from C. junos. The flavonoids characteristics obtained from the collected samples with confirmed species could classify the 10 commercial Zhishi samples. The differences of constituents and content ratios of NR, NG HE and NH among the three origins of collected Zhishi samples showed that the total contents of the four flavonoids were 18.52%-41.74% in C. aurantium and its cultivars, and 15.90%-32.19% in C. junos, and 9.21%-31.19% in C. sinensis and its cultivars. In conclusion, the primary flavonoids in Zhishi originated from C. aurantium and its cultivars and from C. junos are NR, NG, HE and NH, but the ratios of NG/NR were different in the two species. In Zhishi originated from C. sinensis and its cultivars, only NR and NH were detectable. The results suggest that the flavonoids characteristics could be used to identify the origins of Zhishi.