Separation And Identification Of Flavonoids From Citrus Reticulate CV. Suavissima Fruit And Their Bioactivity Study

Citrus reticulata CV. Suavissima (Ougan) fruit was used as materials to characterize the total phenols, total flavonoids, and antioxidant capacity during fruit development. Extraction and identification of six main citrus flavonoids were optimized and comparison of flavonoids composition were made among different citrus varieties. In addition, separation and purification of poncirin from Ougan fruit was established follwed by the bioactivity assays. The main results were as follows:1. Ougan fruit were extracted twice by sonicationith with80%ethanol for30min at the temperature of50℃. The HPLC system consisted of a C18column and gradient elution by double distilled water (A) and acetonitrile (B) at the concentration of A at78%-78%(0-10min),78%-39%(10-35min),39%-0(35-40min),0-0(40-42min),0-78%(42-45min),78%-78%(45-50min) to finish a cycle; Detection wavelength was280nm; flow rate was1mL/min; injection volume was10μL and the sample was detected at the temperature of25℃. The established method resulted in efficient extraction and detection of flavonoids from citrus fruit.2. Changes in total phenols and total flavonoids showed similar pattern during fruit development. Significant higher levels of total phenols and total flavonoids were found in young fruitlets than the subsequently mature fruits.With the development of fruit, the content of total phenols and total flavonoids declined gradually. The content of the total flavonoids of flavedo and other three parts of fruit showed the lowest level on Oct21th, and content of total phenols and total flavonoids increased slightly later until harvest. The content of different parts of the fruits were varying, and the content total phenols and total flavonoids in flavedo, albedo and SM were higher than that of in JS. In addition, antioxidant capacity and the content of total phenols and total flavonoids are positively related, and the correlation coefficient was more than89.3%. The higher the content of total phenols and total flavonoids were, the stronger the antioxidant capacity was.Main flavonoids in Ougan albedo were characterized during fruit developmental phase w by HPLC. Six flavonoids, i.e. naringin, hesperidin, neohesperidin, poncirin, nobiletin and tangeretin, were detected in Ougan fruit. Naringin, hesperidin, neohesperidin and poncirin are flavonones, while nobiletin and tangeretin are in the polymethoxylated flavanone group. Hesperidin and neohesperidin were found in every part of Citrus tissues, and the content of neohesperidin and hesperidin in albedo of the fruit picked on Oct21were observably higer than those of JS. In albedo and SM, the content of naringin and poncirin were mainly higer than those of in flavedo and JS. Nobiletin and tangeretin were mainly present in flavedo, but they were very poor in albedo, SM and JS.3. Among the nine Citrus varieties, Ougan was unique due to its high content of poncirin. In this paper, efficient seperation and purification of poncirin from Ougan fruit was established using the macroporous resin chromatography and HSCCC. The purified poncirin showed significant inhibitory effect on the growth of gastric cancer SGC cells.The study did esearch on the the total phenols, total flavonoids, and antioxidant capacity during fruit development systematicly and intensively.we obtained the unique component poncirin from Ougan fruit by efficient seperation and purification for the first time.In addition, the biological activities of poncirin were evaluated.