Abstract: Objective: To observe the distribution of panax ginseng active glycopeptide (PGG) in the main organ tissues of the mice and its targeting trend by fluorescence labeling. Methods: PGG was labeled with fluorescein isothiocyanate (FITC) as a probe. The structures of PGG fluorescence marker (PGG-FITC) were analyzed by ultraviolet spectrophotometry and infrared spectrophotometry. The fluorescence substitution degree of PGG-FITC was determined by fluorescence spectrophotometry. A total of 78 mice were randomly divided into 13 groups; the mice in 6 groups were injected with PGG-FITC, the mice in another 6 groups were injected with FITC, and the residual group was used as blank control. The heart, liver, spleen, lung, kidney, brain, intestine and stomach tissues of the mice in various groups were collected at 0.5, 1.0, 2.0, 4.0, 8.0 and 24.0 h after administration. The levels of PGG-FITC and FITC in the main organ tissues of the mice were determined by fluorescence spectrophotometry, and the area under concentration time curve (AUC) and targeting efficiency (Te) were calculated. Results: PGG and FITC were linked by covalent bond and the fluorescence substitution degree was 1.435%. Compared with FITC group, the drug levels in main organ tissues of the mice in PGG-FITC group were increased significantly (P<0.01), and the drug levels in brain tissue were increased more significantly. The AUC values in main organ tissues of the mice in FITC group from high to low were liver, brain, stomach, kidney, intestine, heart, spleen and lung tissues;and the AUC values in main organ tissues of the mice in PGG-FITC group from high to low were brain, heart, liver, kidney, spleen, stomach, lung and intestine tissues. Conclusion: PGG labeled by FITC is mainly enrich in the brain tissue of the mice after tail vein injection of PGG, and has a brain targeting trend.

Key words: panax ginseng active glycopeptide, fluorescein isothiocyanate, fluorescence labeling, brain, heart, lung