Guava oligosaccharide as well as preparation method and application thereof

The invention discloses guava oligosaccharide as well as a preparation method and application thereof, guava oligosaccharide GPs4 is obtained by combining an ultrafiltration method with DEAE-52 column chromatography purification, and meanwhile, physicochemical properties of the GPs4 are identified by adopting an element analysis method, an ion chromatography and a high performance gel permeation chromatography. Psidium guajave oligosaccharide GPs4 is taken as a raw material, the structure of the GPs4 is determined by combining infrared spectrum, gas phase mass spectrum, nuclear magnetic resonance (NMR) and high-resolution mass spectrum, the guava oligosaccharide GPs4 is a brand new oligosaccharide structure, meanwhile, the immunoregulation activity of the GPs4 on macrophages RAW264.7 is further researched, and experiments show that the GPs4 can exert better immunoregulation activity under extremely low drug concentration. The invention provides a new direction for preparation, structural analysis and applicat