The design of propolis flavone microemulsion and its effect on enhancing the immunity and antioxidant activity in mice

The objective of the present study was to formulate a microemulsion system for improving the activity of propolis flavone (PF). Pseudo-ternary phase diagrams were constructed to evaluate the existence area of PF microemulsion (PFM). The formulation was characterized by particle size, zeta potential, morphology and stability. The results showed that the optimal PFM formulation consists of 5.3% ethyl acetate, 14% RH-40, 7% ethanol and 73.7% water (w/w), with a solubility of PF up to 3.0 mg mL−1. The immune-enhancing and antioxidant activity of PFM in vitro and in vivo were performed. The results showed that PFM could significantly promote the splenocyte proliferation and the secretion of IL-2 and IFN-γ in vitro. In vivo, PFM at high and medium doses was able to significantly increase the thymus and spleen indices, enhance splenocyte activity and improve the contents of IgG and IgM in serum, it could also improve the antioxidant activity, significantly increase the levels of superoxidase dismutase and glutathione peroxidase, and decrease the malondialdehyde levels compared with PF. These results indicated that microemulsion could be used as an effective formulation for enhancing the activity of PF. Therefore, microemulsion would be expected to exploit into a new-type preparation of PF.