The Study On The Hypoglycemic Components And Its Activity Of Main Propolis Resin Source Plant In China

Diabetes is a metabolic disease caused by insulin secretion or insulin resistance.In recent years,the prevalence of diabetes has continued to rise,and the number of diabetic patients in China is the first in the world.It is urgent for researchers to seek effective methods to treat and intervene in the disease in the fields of medical,food and health care.Propolis is a kind of colloidal substance used by bees to collect plant resins,mixed beeswax,pollen and their own secretions,which are used to fill the inner wall of the honeycomb.The chemical composition of propolis is closely related to the resin source plant.Studies have shown that the resin source plants of several typical propolis in the world are not the same.The source of Chinese propolis is Populus.At present,a lot of studies have shown that propolis has a good effect on regulating blood glucose and lipid metabolism,but the pharmacological activity of its resin source plants in improving the symptoms of diabetes is rarely reported,and it has not been involved in the analysis and identification of the active components.Therefore,this study takes Henan propolis as a reference,focusing on the efficacy of its homologous poplar buds extract in regulating blood glucose,and determining the active component of hypoglycemic effect in the extract of poplar buds by active tracking and liquid chromatography and mass spectrometry.It is expected to provide experimental basis for the development of natural hypoglycemic active substances,and provide theoretical support for the improvement in diabetes of poplar bud extracts from mechanisms such as improving glucose and lipid metabolism,repairing organ damage,and enhancing the antioxidant capacity.The main research contents and results are as follows:?1?To get the extracts of Henan propolis and its homologous poplar buds by ethanol and ethyl acetate respectively.The total flavonoids in the extract of propolis?EP?were301.61±19.02 mg/g,the total phenol content was 181.49±13.77 mg/g;the total flavonoids in the extract of poplar buds?EPB?were 147±5.83 mg/g,and the total phenol content was137.78±9.51 mg/g.HPLC analysis showed that the chromatograms of the two extracts were highly consistent with peaks,and they both contain the typical phenols isoferulic acid,quercetin,apigenin,kaempferol,chrysin and galangin.Which indicating that the two extracts had similarity in the composition.The use of XAD-2 macroporous resin adsorption combined with different concentrations of ethanol solution followed by elution method can be better to separate and enrich the polyphenols in the extracts.The phenolic compounds in the EP were mainly concentrated in the 50%ethanol elution fraction,its total phenol content was 224.04±17.87 mg/g,and the total flavonoid content was446.89±14.22 mg/g;The phenolics of EPB were mainly concentrated in the 50%ethanol elution fraction.The total phenol content of this fraction was 207.00±20.93 mg/g,and the total flavonoid content was 203.86±15.94 mg/g,higher than other fractions.?2?A model of type 2 diabetes was established to determine the effects of EP and EPB on diabetic mice.It was found that EPB can exert the hypoglycemic effect similar to EP.EPB can reduces fasting blood glucose levels,glycated hemoglobin and glycosylated serum proteins,and enhances insulin sensitivity in the body and reduces insulin resistance.It also repairs liver and kidney damage,and strengthens the antioxidant activity of diabetes body?increasing SOD activity,inhibiting MDA accumulation?.Explain that EPB has a good role in regulating blood sugar and improving symptoms of diabetes.?3?The?-glucosidase inhibition assay was used to evaluate the hypoglycemic activity in vitro.The 50%ethanol eluent of poplar buds?50%EEPB?was considered to be the most possible hypoglycemic active ingredient with its lowest IC₅₀ value?28.28±3.79?g/mL?.Oral sucrose tolerance test?OSTT?in vivo showed that 50%EEPB can alleviate the postprandial blood glucose fluctuations in diabetic mice,which is beneficial to the recovery of blood glucose levels,and the effect of inhibiting?-glucosidase activity in vivo is obvious.The composition of 50%EEPB was analyzed by HPLC-ESI-Q-TOF MS and 12 major flavonoids were identified,including 5 flavonoids,4flavonols,2 dihydroflavones,and 1 dihydroflavonol.?4?To observe the effect of 50%EEPB on the condition of diabetic mice.It was found that 50%EEPB was superior to EPB in maintaining body weight gain,reducing fasting blood glucose,reducing impaired glucose tolerance,improving abnormal lipid composition?significantly reducing TC,LDL-C levels,and increasing HDL-C levels?.The effect of repairing oxidative stress in diabetic mice?increasing SOD activity and reducing MDA accumulation?is better than the positive control drug metformin.It is further illustrated that 50%EEPB is most likely to be the main functional component of EP that exerts blood glucose regulation and improves the effects of diabetes-related disorders.