Purification of Kapok Flavonoids by Macroporous Resin and Its Anti-Acne Efficacy

This study use Guangdong Zhaoqing kapok as raw material. After ultrasonic-assisted alcohol extraction, the most suitable macroporous resin type was investigated, and the purification process of the crude kapok flavonoids was determined. The inhibitory effect of purified kapok flavonoids on Staphylococcus and Propionibacterium acnes was measured by tests of antibacterial activity in vitro. The inhibition rate of kapok flavonoids on tyrosinase was determined by in vitro whitening activity method, and the whitening activity of kapok flavonoids was further verified by zebrafish embryo melanin inhibition test method. Finally, the scavenging ability of kapok flavonoids to free radicals such as ABTS•+ and DPPH was investigated by in vitro antioxidant activity assay. By comparing the adsorption and desorption rates of 8 macroporous resins to kapok flavonoids, D101 was screened out as the best resin type and volumetric concentration of ethanol for the best analytical solution is 60%. The optimal adsorption-analytical conditions are: the sample volume is 2BV, and the elution volume of the analytical solution is 0.625BV. After purification, the purity of kapok flavone increased from 32.5% to 98.2%. The IC50 values of the purified kapok flavone for the free radical scavenging rate of ABTS•+ and DPPH are(616.90±11.15)mg/L and (11.80±0.62)mg/L, respectively. The IC50 of kapok flavone on tyrosinase inhibition is (1.69±0.01)g/L. When the concentration of kapok flavone is 1.0g/L, the inhibition rate of zebrafish embryo melanin is 12%, with significant whitening activity.The inhibition zone experiment shows that when the mass concentration of kapok flavonoids is 12.5 g/L, it is moderately sensitive to Propionibacterium acnes and highly sensitive to Staphylococcus epidermidis, and the antibacterial effect shows a dose-dependent effect. The inhibitory effect of kapok flavonoids on the inflammatory factors TNF-α and IL-6 secreted by RAW264.7 cells is detected by ELISA, which shows when the mass concentration of kapok flavonoids is more than 0.5g/L, it can significantly inhibitthe secretion of inflammatory cytokines TNF-α; when the mass concentration of kapok flavonoids is 0.25g/L and above, the secretion of inflammatory factor IL-6 can be significantly inhibited. © 2022, Editorial Department, Journal of South China University of Technology. All right reserved.