Study on optimization of extraction process of total flavonoids from Turpiniae folium and in vitro antibacterial activity

XIONG Pingwen; SONG Wenjing; CHEN Jiang; SONG Qiongli; AI Gaoxiang; ZOU Zhiheng; WEI Qipeng; CHEN Xiaolian

doi:10.13557/j.cnki.issn1002-2813.2025.05.019

Abstract：This study aimed to explore the optimal extraction process of total flavonoids from Turpiniae folium,quantitatively analyze the content of flavonoid monomers,and evaluate the in vitro antibacterial activity of the Turpiniae folium extract.Using Turpiniae folium as raw materials,the leaves were pre-treated with a ball mill to obtain activated Turpiniae folium powder.The reflux extraction method with ethanol as the solvent was employed.Based on single-factor experiments,an L16(45)orthogonal experiment was used to study the effects of ethanol concentration,extraction time,extraction temperature,liquid-solid ratio,and extraction frequency on the extraction rate of total flavonoids from Turpiniae folium,and the optimal extraction process was selected.The content of 35 flavonoid monomers in the freeze-dried powder of Turpiniae folium extract was analyzed using liquid chromatography-mass spectrometry.The in vitro antibacterial zone size was determined using the drug sensitivity disc method,and the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of the effective traditional Chinese medicine were measured using the tube dilution method.The results showed that the optimal extraction process for total flavonoids from Turpiniae folium was a liquid-solid ratio of 50 mL/g,extraction time of 1 h,ethanol concentration of 50%,extraction frequency of three times,and extraction temperature of 70℃,with a total flavonoid yield of 20.88 mg/g.A total of 25 flavonoid monomers were detected in the freeze-dried powder of the extract,with rutin having the highest content at 276.450 mg/g.Other monomers with content greater than 0.010 mg/g included quercetin,isoquercitrin,formononetin,kaempferol,astragalin,luteolin,biochanin A,genistein,and isovitexin,with contents of 1.769,1.040,0.085,0.061,0.053,0.016,0.016,0.015,and 0.015 mg/g,respectively.The extract was highly sensitive to Escherichia coli and Salmonella,and moderately sensitive to Staphylococcus aureus.Based on the total flavonoids from Turpiniae folium,the MIC values for Salmonella,Escherichia coli,and Staphylococcus aureus were 1.88,3.75,and 7.50 mg/L,respectively,and the MBC values were 7.50,15.00,and 15.00 mg/L,respectively.The study indicates that the established extraction process for total flavonoids from Turpiniae folium is stable and efficient.Rutin is the main flavonoid monomer in the extract,which has strong antibacterial activity.