Isolation And Characterization Of Nanoparticles From Radix Isatidis Decoction

Radix isatidis, the dried root of isatis which is a kind of cruciferous plant, is proved to be effective in clearing heat, detoxification, cooling blood and relieving sore throat. Radix isatidis is generally considered to be a common clinical herbal medicine when treating viral infection, however, its antibacterial and antiviral material basis is not clear. In this article we put our concern on the colloidal system of the radix isatidis decoction to investigate the relationship between colloidal particles and antiviral activity by separating and characterizing the colloidal particles from the radix isatidis decoction.In our investigation we found that radix isatidis decoction presents obvious Tyndall phenomenon after centrifugal purification, which shows that colloidal system does exists in radix isatidis decoction. Observed under phase contrast microscope and transmission electron microscopy, the colloidal particles were found to be unequal-sized spherical and ellipsoidal structure, unstable and apt to gather into mound-like or adhesion clusters.In our experiment, the nanoparticles were isolated and purified by gel permeation chromatography Sephacryl TM S-1000 from the Radix decoction to get 7 different Radix nano-particle components, the average grain diameters being respectively 174 nm 99 nm,80 nm,62 nm,42 nm,24 nm and 7 nm, labeling from 1 to 7 successively.The characterizing experiment to the nano-particle components after purification revealed that the Zeta potential was within -9.0±1.0 mV; the nano-particle components were mainly composed of polysaccharide, a small quantity of amino acid, Epigoitrin unable to be detected; the nano-particles were sensitive to pH and temperature in some degree; in MDCK cell model, number 7,8,9 components showed anti-H1N1 virus activity with the repair rates being respectively 29%,37% and 39%, however, the rest components showed insignificant antivirus activities.