Preparation Of EGCG-Nanoparticles And Its Antitumor Activities In Vitro

(-)-Epigallocatechin gallate (EGCG), as the most abundant catechin component in green tea, has shown to possess varieties of health functions such as antioxidant, scavenging free radicals, antitumor, preventing cancer, and etc. The mechanism of antitumor mainly are antioxidation, blocking cancer cell cycle, inducing apoptosis, DNA damage and cell signal transduction, and etc. However, the instability and low bioavailability of EGCG severely limit its application in the fields of food and medicine. The advantages of nanotechnology are improving the solubility, stability and bioavailability of core material, offering major improvements in therapeutics through slow release and site specific. β-Lactoglobulin (β-1g), a water-soluble protein that forms the major component of ruminant milk whey, has been used as a carrier molecule for EGCG to improve its stability and bioavailability. Vitamin C (Vc) is a kind of water-soluble compound with the functions of antioxidant, anticancer, prevention of cancer and so on, which can improve the stability of tea polyphenols.In this paper, EGCG and Vc were contimously loaded in nanoparticles of (3-1g, which are studied for the stability and antitumor activity in vitro.(1) Under the condition of pH 6.5, the heating temperature of β-1g (75℃), the weight ratio of EGCG/Vc/β-1g (1:1:1.2), EGCG-nanoparticles were prepared with size of 30.48 nm, Zeta potential-41.4 mV and PDI 0.134. The EGCG entrapment efficiency of the nanoparticles was 53.2%, and the EGCG loading amount was 928.97 nmol ·mg-1. The nanoparticles were stable in 48 h.(2) Compared with EGCG, the inhibitory effect of EGCG-nanoparticles against A375 and TE-1 cells was significantly better than free EGCG (p<0.05), which indicated that EGCG-nanoparticles improved the availability of inhibiting tumor cells in vitro.(3) The experiments of Annexin V-FITC staining and single cell gel electrophoresis showed that EGCG-nanoparticles had better effects than free EGCG on apoptosis and DNA damage of A375 and TE-1 cells at the concentrations of 40μg/mL and 60μg/mL. The experiment of cell cycle arrest showed that A375 and TE-1 cells were arrested in G2M phase at the concentration of 20μg/mL and 40 μg/mL. At the concentration of 60 μg/mL, A375 cells were arrested in S phase, and TE-1 cells were arrested in G0G1 phase. The result of Western-blot experiment showed that apoptosis of A375 cells induced by EGCG-nanoparticles was relate to the up-regulation of Caspase-3, while TE-1 cells did not show that effect. The up-regulation of p21 Wafl/Cipl was responsible for the cycle arrest and DNA damage of A375 and TE-1 cells.