Abstract: Betanin is a water-soluble pigment with lots of biological activities.However，its stability is low and it is easily degraded under light，high pH，high temperature，enzyme and oxygen.Meanwhile，it is of low bioavailability and it's hard to be absorbed by the body.This study aimed to prepare the chitosan coated nanoliposome loaded betanin （CH-NLP） to improve the stability and bioavailability of betanin.Firstly，Nanoliposome loaded betanin （NLP） was prepared by reverse evaporation method.Then average size，Zeta potential and PDI were measured to determine the optimum concentration of CH-NLP.Meanwhile，CH-NLP，NLP and betanin were evaluated for cytotoxicity and antiproliferative activity against HepG2 cells.Results show that the optimum preparation conditions of NLP are as blow： the mass concentration of lectin is 60 mg/mL；the ratio of betanin and lectin is 1：18；the ratio of lectin and cholesterol is 6：1；ultrasound time is 8 min.The encapsulation efficiency of NLP is （42.67±1.67）%，and the drug loading is（2.63±0.42）%.The optimum concentration of chitosan binding to liposomes is 0.6%.The average size，PDI and Zeta potential are（194.60±4.43）nm，（0.29±0.05），（5.80±0.79）mV，respectively.CH-NLP shows the most potent antitumor activity against HepG2 cells，followed by NLP with the EC₅₀ of（69.46±1.75）and（108.75±2.31）μg/mL，respectively.Betanin possesses the weakest inhibitory effect against HepG2 cells.Chitosan coated liposome as a novel drug delivery system for betanin can significantly enhance its biological activity.

Key words: liposome, betanin, chitosan, antiproliferative activity