Study On Hydrolysis Of Flavonoid Glycosides In Kuding Tea By β-glucosidase From Rubber Seed

Kudingcha is rich in flavonoids and has important physiological activities.These physiological functions are mainly exerted by aglycon.Therefore,we need to explore a method to convert flavonoid glycosides in kudingcha to flavonoid aglycon.In this study,the optimal extraction technology of flavonoids from Ilex kudingcha,Ilex latifolia Thumb and Ilex cornuta was studied.At the same time,explored The best hydrolysis technology of flavonoid glycosides,and three kinds of kudingcha flavonoid extracts before and after hydrolysis to scavenge free radicals and antibacterial ability.The content of flavonoids in three kinds of Kudingcha is different.The content of Ilex kudingcha is the highest,and the optimal extraction conditions of response surface optimization was as follows: extraction time is 2 h,material-liquid ratio is 52 m L/g,and ethanol concentration is 61%.The extraction rate of flavonoids is 2.18%;The total flavonoid content of Ilex latifolia Thumb is lower than that of Ilex kudingcha,the optimal extraction conditions of response surface optimization was as follows: the extraction time is 2 h,the material-liquid ratio is 54 m L/g,the ethanol concentration is64%,and the extraction rate of flavonoids is 1.86%;The content of flavonoids in Ilex cornuta is the least,and the optimal extraction conditions of response surface optimization was as follows: extraction time is 1 h,the ratio of material to liquid is 60 m L/g,the concentration of ethanol is 60%,and the extraction rate of flavonoids is0.208%.The best conditions to hydrolysis the flavone glycoside of Ilex kudingcha by rubber seed β-glucosidase was as follows: the amount of enzyme added is 4 U/2m L,the time of hydrolysis is 5 h,and the temperature of hydrolysis is 45℃.After enzymolysis,the quercetin content increased from 0.52 μg/m L to 1.39 μg/m L,the kaempferol content increased from 2.01 μg/m L to 5.89 μg/m L,and the isorhamnetin content increased from 2.39 μg/m L to 3.70 μg/m L;The best conditions to hydrolysis the flavone glycoside of Ilex latifolia Thumb by rubber seed β-glucosidase was as follows: the amount of enzyme added is 4 U/2m L,the hydrolysis time is 4 h,and the hydrolysis temperature is 45℃.After enzymolysis,the quercetin content increased from 0.54 μg/m L to 1.47 μg/m L,the kaempferol content increased from 1.79 μg/m L to 2.52 μg/m L,and the isorhamnetin content increased from 1.81 μg/m L to 2.30μg/m L;The best conditions of rubber seed β-glucosidase enzyme hydrolysis the Ilex cornuta flavonoids extract was as follows: the amount of enzyme added is 5 U/2m L,the hydrolysis time is 6h,the hydrolysis temperature is 45℃.After enzymolysis,the content of quercetin increased from 0.35 μg/m L to 0.63 μg/m L,the kaempferol content increased from 0.55 μg/m L to 0.81 μg/m L,and the isorhamnetin content increased from 0.76 μg/m L to 1.16 μg/m L.The enzymatic hydrolysates of the three kudingcha flavonoid extract had stronger scavenging ability to DPPH radical,hydroxyl radicals and ABTS radicals than non-enzymatic hydrolysates.And in the concentration range of 1～15μg/m L,the scavenging ability of flavonoid extracts and its enzymolysis solution of Ilex kudingcha and Ilex latifolia Thumb to three kinds of free radicals gradually increased with the increase of concentration.When the Ilex cornuta flavone extract and its enzymatic hydrolysate were in the concentration range of 1～9 μg/m L,the ability to scavenge free radicals was positively correlated with the concentration.The flavonoid extracts from Ilex kudingcha and Ilex latifolia Thumb and their enzymatic hydrolysates have inhibitory effects on E.coli,Bacillus subtilis,Aspergillus niger,and Staphylococcus aureus,and their enzymatic hydrolysates have stronger inhibitory ability than non-enzymatic hydrolysates.The flavonoid extract from Ilex cornuta flavone extracts and its enzymatic hydrolysis solution had low flavonoid concentration,and had no antibacterial ability to pathogenic bacteria under low concentration conditions.