The extraction process of alkali-soluble polysaccharide from Premna puberula Pamp leaves(PLAP) was optimized,and the antioxidant and anti-tumor activities activitys of PLAP in vitro was investigated.The residue extracted by acid extraction method was used as raw material.On the basis of single factor,the extraction process of PLAP was optimized by response surface methodology.The in vitro biological activity of PLAP was studied by antioxidant experiments and anti-tumor experiments.The results showed that the optimum extraction process of PLAP was as follows:the ratio of material to liquid was 1∶50 g/mL,the concentration of NaOH was 0.25 mmol/L,and the extraction time was 110 min.Under this condition,the extraction rate of PLAP was (11.80±0.50)%.PLAP had strong antioxidant activity,and the IC₅₀ values of DPPH,hydroxyl and ABTS radicals scavenging rate were 12.38,3.22 and 0.18 mg/mL,respectively.At the same time,cell experiments showed that PLAP could to some range inhibit the proliferation and migration of A549 cells and HepG2 cells,showing a certain dose-effect relationship.This paper provide a theoretical basis for the full development and clinical application of P. puberula resources.

"> Premna puberula Pamp leaves, polysaccharide, extraction process, response surface experiment, antioxidant activity, antineoplastic activity