Anti-angiogenic Effects of Betulinic Acid Administered in Nanoemulsion Formulation Using Chorioallantoic Membrane Assay

Betulinic acid (3beta, hydroxy-lup-20(29)-en-28-oic acid, BA), a pentacyclic triterpenoid, is derived from a widely distributed natural anticancer compound betulin. It has selective anticancer activity against several tumor cells, and recently it was shown that it also possess anti-angiogenic effects. The objective of this study was to formulate betulinic acid, a poorly aqueous-soluble compound, in flax-seed oil containing nanoemulsion formulation for enhanced delivery efficiency and to effectively inhibit the tumor angiogenic process. The nanoemulsion was prepared using high pressure homogenization method with a Microfludizer processor. The betulinic acid nanoemulsion was studied for the effect on the angiogenic process by performing the in vivo chick embryo chorioallantoic membrane (CAM) assay. The sample volume of 1 microl and 5 microl of the blank and BA nanoemulsions were applied directly on the CAM. The preliminary results from macroscopic, morphological and immunohistochemical evaluations have shown that morphological change was produced in the CAM mesenchyme with a negative impact on the normal growth of the capillaries. Betulinic acid does possess anti-angiogenic activity in a dose dependent manner, and the nanoemulsion formulation maintained this effect.