Extraction and isolation of polysaccharide from Portulaca oleracea by traditional process combined with membrane separation technology and evaluation of its anti-oxidant activity Isolation,purification,and structural characterization of polysaccharide POP Ul b from Portulaca oleracea Cyclic dipeptides from Portulaca oleracea Preparation of polysaccharides, alkaloids, and polyphenols from fresh Portulaca oleracea and their anti-diabetic effects Characteristics of Photosynthesis and Chlorophyll Fluorescence in Portulaca oleracea with NaCl Stress Isolation and Assaying of polysaccharides in Portulaca oleracea