Abstract

Information on the specific location of the medicinal substance ginsenoside-Rb1 (G-Rb1) in Ginseng, Panax ginseng, is crucial to obtain the efficient extract of G-Rb1 or to culture G-Rb1 producing cells. In this paper we describe the localization of G-Rb1 in various parts of the plant revealed by immunofluorescence (IF) and immunoelectron microscopy (IEM). IF observations show that G-Rb1 is localized in chloroplasts, peroxisomes and cytoplasm but not mitochondria and vacuoles of leaf parenchymal cells. In the leaf stem, G-Rb1 is localized to vascular bundles as well as vacuoles. In the root, vacuoles of parenchymal cells are stained at various intensities. IEM observations indicate that gold particles showing G-Rb1 antigenic sites are present in the compartments stained by IF technique. In addition, G-Rb1 is localized to the sieve elements of phloem and degrading primary cell wall of xylem and in the root parenchymal cells G-Rb1 is associated with vacuolar protein granules but not in starch granules. The results suggest that G-Rb1 is synthesized in leaf parenchymal cells, transported to the root and stored in vacuoles of these cells.

Key words: Panax ginseng, ginsenosides, immunofluorescence, immunoelectron microscopy, chloroplasts, peroxisomes, vacuoles.

Abbreviation

IF, immunofluorescence; IEM, immunoelectron microscopy; EM, electron microscopy; REM, routine electron microscopy; mAbs, monoclonal antibodies; VG,vacuolar protein granule; TCM, traditional Chinese medicine.