Study On Extraction And Biological Activity Of Onion Active Ingredients

Onion is a traditional medicinal and edible plant,nutrients rich,including flavonoids,volatile oils,polysaccharides,phenylpropanoid glycosides,steroidal saponins,prostaglandins,nitrogen compounds and other effective ingredients.The onion has many physiological actions,such as anti-tumor,reducing blood sugar,antibacterial and so on.However,the antioxidative effect of polypeptide and protein in onion has rarely been reported.There are no articles comparing the physiological effects of onion polypeptides,proteins,flavonoids and essential oilsIn this paper,the extraction processes of flavonoids and essential oils from onion were optimized by single factor experiment and orthogonal experiment.And taking vitamin C as positive control,the Prussian blue method,phenanthroline-Fe²⁺oxidation,pyrogallic acid autoxidation method,and DPPH method were used to measure the antioxidative action of flavonoids,essential oils,proteins and polypeptides of onion.Then the MTT colorimetric assay was used to study the anti-tumor effects of flavonoids,essential oils on B16F10,SiHa,A549 and MDA-MB-231cells.On this basis,the onion flavonoids extract was used as raw material,and the prescription of onion tablets was determined by orthogonal test.The onion oral tablets were prepared by the method of wet granulation and tabletting.The results of this work were as followed:?1?The best extraction processes for flavonoids from fresh onion were:70%ethanol of volume fraction,refluxing for 120 min at 60?,the ratio of material to solvent was 1:20,and the average extraction rate was 1.6993%,which of the flavonoids content was 89.3%with rutin as standard.?2?The optimum extraction processes of volatile oil from fresh onion were:the ratio of material to liquid 1:1.5,soaking for 150 min at 35?,extracting for 90 min with volatile oil extractor,and add ether to scale,release mixed liquid,dry ether,then collect the pale yellow pungent onion oil with the extraction rate was 0.389%.?3?The four extracts from onion had certain antioxidant ability in vitro.Among them,the order of the total reducing capacity and scavenging ability of·OH and O₂^-·scavenging capacity were:flavonoids>polypeptide>protein>essential oil,and the order of the DPPH scavenging ability were:polypeptide>flavonoids>protein>essential oil.The results indicated that onion flavonoids could scavenge·OH,O₂^-·and free radicals,with the highest total reducing ability.However,onion polypeptide had the best scavenging effect on DPPH·.In general,the antioxidant capacity of onion flavonoids were stronger,and onion essential oil was weakest.?4?The inhibitory effects of four extracts from onion on B16F10,SiHa,A549 and MDA-MB-231 tumor cells were different.The onion polypeptide and protein hardly inhibited the cells,but the inhibitory effect of onion flavonoids and volatile oil on these cells were observed with dependent on the action time and dosage.The inhibitory effect of onion flavonoids on B16F10 and MDA-MB-231 was stronger than that of volatile oil.?5?The prescription of onion tablet was microcrystalline cellulose 80%,PVPP 3%,PVP K30 5%,magnesium stearate 0.5%,mannitol 2%.The quality evaluation showed that the routine inspection items of onion oral tablets met the requirements of the Chinese Pharmacopoeia?2015 Edition?and the flavonoid content?taking rutin as standard?was13.02 mg per tablet.