Research On Extraction, Isolation, Purification, Identification And Biological Activities Of Compounds From Young Fruits Of Citrus Subcompressa Tanaka

Citrus subcompressa Tanaka are the plants in the Citrus Linn. family which belong to the RUTACEAE, and widely distributed in southern China. More researches have been studied both at home and abroad for the other citrus plants(such as ponkan, citrus sinensis, huyou and so on.) for a long time, but less researches for Citrus subcompressa Tanaka. Our country is rich in the citrus resources all over the world, and is mainly used to eating the ripe fruits. But in the growth period there will be a large-scale premature-drop stage. And if the environmental conditions are poor, it will also appear fruit-drop. Sometimes fruit growers will do some fruit thinning in order to remove some fruits and ensure the high quality of the other fruits. These young fruits are often put away as rubbish, and not made good use of. This is a waste of resource.Young fruits of Citrus subcompressa Tanaka were studied to investigate the bioactivities compounds. Nine compounds were isolated, and their structures were determined by MS and ID NMR analysis. The results can provide the experimental basis for its future pharmacological and biological activity research. It can provide the guide to make waste profitable.The experiment was to extract the young fruits pretreated with ethanol, and then to extract the concentrated solution respectively by petroleum ether, ethyl acetate and n-butanol. The three extractions were respectively isolated for the compounds.1. The chemical constituent in the petroleum ether extract of Citrus subcompressa Tanaka was separated by chromatography on silica gel to obstain compoundβ-sitosterol(Ⅰ).2. The chemical constituents in the ethyl acetate extract of Citrus subcompressa Tanaka were isolated by repeated chromatography on silica gel, Pre-HPLC and HSCCC. Five compounds were gained:bergapten(Ⅱ), limonexic acid(Ⅲ), nobiletin(Ⅳ),5-o-desmethylnobiletin(Ⅴ),β-daucosterol(Ⅵ). CompoundⅡandⅢwere first separated from this plant.3. The chemical constituents in the n-butanol extract of Citrus subcompressa Tanaka were purified by D101 macroporous adsorption resin eluted with water, 25%,50%,75% and 95% ethanol to obtain the components with different polarity. The fraction of 50% ethanol was isolated by sephadex LH-20 to obtain a compound named neohesperidin (Ⅶ); The fraction of 75% ethanol was isolated by repeated chromatography on silica gel, pre-HPLC to obtain 2 compounds: eriocitrin(Ⅷ) and naringin(Ⅸ). CompoundⅧwas first isolated from this plant.4.The research discovered the three flavonoids of Citrus subcompressa Tanaka had good antioxidant activities. DPPH radical-scavenging appraisal indicated that the order of antioxidant activity of different flavonoids was as follows:Ⅶ<Ⅸ<Ⅷ. In vitro test (MTT method), compound (Ⅳ) and (Ⅴ) showed moderate anti-tumor activities against human Bcap37 cells and SMMC7721 cells.In addition, the advances about components from Citrus Linn. were reviewed. The results of present study will be useful to further phytochemical investigation on Citrus subcompressa Tanaka.