Analysis Of Microbial Conversion And Antioxidant Activity Of Platycodin D

The Platycodon grandiflorum is a traditional medicine and food homologous raw material in China,and has biological activities such as hypolipidemic,hypoglycemic,anti-obesity,cholesterol,anti-oxidation and other biological activities.Saponins of Platycodon grandiflorum is an important active factor of Platycodon grandiflorum.Among them,Platycodin D is the main component of Platycodin saponin with high activity and good water solubility.However,the content of Platycodin D in Platycodon grandiflorum is low,and it is difficult to separate and purify.Therefore,the transformation of Platycodin D by microorganisms is of great significance for improving the utilization value of Platycodon grandiflorum in food and medicine.This paper first used Platycodon grandiflorum as raw material,using different solvents to extract Platycodin D,and chose the solvent with the highest extraction rate of Platycodin D.The results showed that using distilled water as the extraction solvent had the best effect and the extraction rate was 0.981 mg/g.From traditional fermented foods,selective microorganisms were used to isolate and screen out the microorganisms with high transformation rate of Platycodin D.The results obtained from the nutrient agar medium No.15 strain and YPD-21 strain obtained from the YPD solid medium,the conversion rate of Platycodin D was 48.92%,46.44%.Two strains were identified as Bacillus velezensis and Pichia kudriavzevii,respectively.The transformation of Platycodin D by nutrient No.-15 strain was analyzed.The results showed that the strain-15 transformed the Platycodin D3 to the Platycodin D without degrading the Platycodin D and the Platycodin D2,which may have bond specificity.The use of strain No.15 and strain YPD-21 to ferment Platycodon grandiflorum extract resulted in significant increase in total flavonoids and total phenolic content in the Platycodon grandiflorum extract and higher clearance of DPPH·,hydroxyl radicals and superoxide anions.The ability of the nutrient No.-15 strain to ferment significantly improved the in vitro antioxidant capacity of the Platycodon grandiflorum extract.This experiment provides theoretical support and scientific basis for the further study of the preparation of platycodin D by the microbial fermentation method,which lays the foundation for the future effective resource utilization of Platycodon grandiflorum,and also provides a scientific basis for the research on the in vitro antioxidant capacity of Platycodon grandiflorum.