Study On Polysaccharides Extraction And Antibacterial Activities From Radix Mirabilis Jalapae

Radix Mirabilis Jalapae is the dry root of Mirabilis jalapa L. (a kind of plants for medicine), which is assigned to Nyctaginaoeae of Mirabilis. As a kind of traditional Chinese medicine, It could clear heat and disinhibit dampness, quicken the blood and resolve toxin. Its efficacy has been well documented in traditional Chinese,Tibetan and Mongolian medicine. Modern pharmacology experimentation indicates: it has much pharmacological effects, such as ant-virus, antibacterial, anticancer hypoglycemic effect and so on.This paper studied the polysaccharides extraction technology and antibacterial activities of the water-soluble polysaccharide from the root of Mirabilis jalapa.Firstly, factors that contribute to the extraction percentage of polysaccharides were studies in the process of water extraction and ultrasonic extraction. On the basis of orthogonal test, the most condition was found, and a new method was adopted for Polysaccharides extraction: ultrasonic-water extraction. The optimal extraction technology conditions are: solid-liquid ratio 1:15, performed ultrasonic extraction(0.5 h, 600 W), then followed water extraction: temperature 100℃, extraction time 2 h, extraction times 3 times. The results showed the yield of the polysaccharides is 16.44%,which is 1.7 and 3.2 times than the yield by water extraction and ultrasonic extraction respectively.Secondly, TLC was used to distinguish the portion,MWD and Mw were also measured by chromatography (Sepharose CL-6B). The results showed the polysaccharide from water extraction was composed of Glc,Man and Gal, their average molecular weight was 50000 to 70000.Lastly, paper disc diffusion was applied in studying antibacterial activities of polysaccharide from the Root of Mirabilis jalapa. The results showed the polysaccharides have good capability to inhibit the growth of Staph. aureus,E. coli,S. paratyphi b and P. aeruginosa. Especially for the first three and the antibacterial activity is obviously related to the concentrations. The broth microdilution method was performed to determine the minimal inhibitory concentration (MIC) of polysaccharide from the Root of Mirabilis jalapa to Staph. aureus,E. coli,S. paratyphi b and P. aeruginosa. The MIC of polysaccharide to them was 52.4 mg/ml, 65.5 mg/ml, 81.9 mg/ml and 102.4 mg/ml respectively.