Analysis And Functional Evaluation Of Phenols And New Compounds In Processed Hawthorn

Hawthorn is a traditional dual-purpose raw material for medicine and food in China.It contains abundant nutrients and bioactive substances,and its phenolic content is 3%-5%.It has the important physiological functions such as antioxidation,lowering blood lipid etc.“Paozhi” is the necessary processing steps for the medicine of hawthorn.Hawthorn experienced different degrees of high temperature treatment during the processing,and how did it affect the phenols? Does it produce new compounds? It is not clear yet.Therefore,according to the Chinese Pharmacopoeia of the 2010 edition,the raw,stir-baked,charred hawthorns were attained by thermal processing.The composition and content changes of the phenolic compounds were compared and analyzed with the fresh hawthorn as control,and the new components of the hawthorn were identified,the way to produce them was explored.In vitro and animal experiments were used to evaluate the antioxidant ability and digestive function of the processed hawthorn and new compounds,respectively.The main results are showed as follows:(1)Identification and analysis of the composition of phenols in processed hawthornFree and bound phenols were extracted from the raw,stir-baked and charred hawthorns,the changes of composition of processed hawthorn were analyzed by UPLC-Q-TOF-MS.The results showed that 26 kinds of phenols,including 9 phenolic acids,9 flavonoids,7 proanthocyanidins and 1 monomer polymer were tentatively indentified from fresh hawthorn.Free phenols mainly include chlorogenic acid,proanthocyanidin B2,epicatechin,rutin,vitex,rhamnosin,hyperoside,isoquercetin.In the combination of phenols,most of them are flavonoid glycosides,such as-3-Ogalactoside and-3-0-glucoside.After the processing,there was no significant change in the composition of bound phenols in the raw,stir-baked and charred hawthorns,butin the composition of free phenols,with the increase of processing temperature,the other proanthocyanidins have been completely degraded except procyanidin dimer hexaglycoside in charred hawthorn.(2)Change of phenolic content in processed hawthornThe content changes of free phenol and bound phenol in hawthorn after processing were determined.The results showed that the content of free phenols decreased significantly during processing(P<0.05),and the higher the processing temperature,the greater the decrease of phenolic content,the raw,stir-baked,charred hawthorns were reduced by 6.09%,10.02% and 27.40% compared with the fresh hawthorn.However,The content of the bound phenols increased first and then decreased with the increase of the processing temperature,and the highest content of phenols in stir-baked hawthorn was 51.35 mg GAE/100 g,The content of charred hawthorn decreased slightly and was 42.95 mg GAE/100 g.The total phenol content of hawthorn decreased.The content changes of 7 main phenolic momomers in processed hawthorn were determined by HPLC.The results showed that there was no obvious change in the content of bound monomer phenols,but the content of free monomer phenol decreased significantly(P<0.05).Among the monomeric phenols,procyanidins B2 and epicatechin were the most unstable,and had been completely degraded in charred hawthorn,chlorogenic acid in charred hawthorn was reduced by 35.23%.From the HPLC diagram,it was found that a new chromatographic peak was produced after processing in hawthorn.(3)Identification and analysis of the new compounds of processed hawthornThe new peak was isolated and enriched with the synthetic HPLC from charred hawthorns.By means of NMR method and standard sample comparison,the compound of the new peak was identified as 5-HMF.The content of 5-HMF in charred hawthorn was the highest with the increase of processing temperature and was 6.11 mg/g.The analysis results of its production routes showed that the contents of protein,reducing sugar and vitamin C in the hawthorn were significantly decreased after processing(P<0.05),and the higher the processing temperature,the greater the decrease of phenolic content,the content of the related products,anthraquinones andblack sperm were significantly increased after the processing(P<0.05).Therefore,it is speculated that 5-HMF is produced by the reaction of Maillard,caramelized and ascorbic acid in the processing of hawthorn.(4)Evaluation of antioxidant function of processed hawthorn phenolsThe antioxidant activity of hawthorn phenol after processing was evaluated by DPPH,ABTS and ORAC.The results showed that the antioxidant activity of hawthorn after processing was significantly decreased(P<0.05),while the antioxidant activity of bound phenol increased significantly(P<0.05),and the total antioxidant capacity decreased with the increase of processing temperature,the total antioxidant activity of hawthorn decreased,and the total ORAC value of raw,stir-baked and charred hawthorn decreased by 3.82%,25.75% and 34.74% respectively.The antioxidant activity of hawthorn showed a significant positive correlation with total polyphenols,flavonoids,chlorogenic acid,proanthocyanidin B2,hyperin and isoquercetin(P<0.05).(5)Evaluation on digestion function of processed hawthorn and its new compoundsThe digestive function of the raw,charred hawthorn(3 g/kg bw),and 5-HMF(18 mg/kg bw)was evaluated by animal experiments.The results showed that 5-HMF,raw and charred hawthorn could improve the gastric acid secretion and pepsin activity in mice,and significantly promote the gastric emptying and small intestinal propulsion in mice(P<0.05),the order of promoting digestion is: charred hawthorn > raw hawthorn > 5-HMF,the small intestine propulsive rate and gastric remnant rate were 91.90% and 33.33%,respectively.It is speculated that charred hawthorn can promote digestion,and 5-HMF may be one of the effective compounds.