Immunostimulatory effects of cycloartane-type triterpene glycosides from astragalus species.

National Center for Natural Products Research, Research Institute of' Pharmaceutical Sciences,The University of Mississippi, 38677, USA.

In the course of our research on the oligoglycosidic constituents of Turkish Astragalus species, we have isolated a number of cycloartane-type triterpene glycosides. The current study examines the immunostimulatory effects of nineteen of these cycloartane-type compounds using a transcription-based bioassay for Nuclear Factor kappa B (NF-kappaB) activation in a human macrophage/monocyte cell line, THP-1. All compounds were inactive at 100 microg/ml except astragaloside I which increased NF-kappaB directed luciferase expression to levels about 65% as compared with maximal stimulation by E. coli lipopolysaccharide (LPS) at 10 microg/ml. None of the compounds were active at low dosage levels (0.1 microg/ml) in combination with 50 ng/ml LPS. Astragaloside I also increased mRNA expression of the inflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) as measured using reverse transcriptase-polymerase chain reaction (RT)-PCR. Based on these results it is clear that certain structural features are required for immunostimulation of cycloartane-type triterpene glycosides.

PMID: 10919362 [PubMed - indexed for MEDLINE]