Isolation and characterization of immunomodulatory compounds from Juzen-Taiho-To: Novel understanding of phytosteryl glucosides nano-aggregates and synergism

This thesis describes the realization of the immunomodulatory properties of four phytosteryl-glucosides (beta-sitosterol-D-Glucoside, campesteryl beta-D-glucoside, 24-epicampestryl beta-D-glucoside, Stigmasteryl beta-D-glucoside) purified from a Japanese Kampo herbal formulation termed Juzen-Taiho-To (JTT). JTT has been used for almost a thousand years and currently is prescribed to people with an impaired immune system. Our screening methodology termed Genomic-Screening allowed us to investigate the immunomodulatory properties of JTT in a new and exciting way. Genomic Screening employs the use of GeneChip RTM oligonucleotide array, and quantitative reverse-transcriptase polymerase chain reaction qRT-PCR. THP-1 human cancerous monocytic cell line was used in our study with JTT due to their accurate representation of healthy monocytes as well as a large variety of receptors. THP-1 treatment with JTT revealed many genes to be differentially regulated most of which were down stream elements of NF-kappaB pathway. We chose (ICAM-1) for our screening since it was the most reproducible assay and it also had a high fold change. By monitoring ICAM-1 response to JTT treatment we were able to uncover known phytosteryl-glucosides that previously were not known for their immunostimulatory properties. In addition our study discovered that a specific ratio of our phytosteryl glucosides that synergistically induced ICAM-1 expression. We have also discovered that the purification approach of the four phytosteryl glucosides greatly affects the immunostimulatory properties. Using Atomic Force Microscopy (AFM) and Dynamic Light Scattering (DLS) we were able to show that nano-aggregated of beta-sitosterol-D-Glucoside formed in a water containing solution diminished ICAM-1 expression in THP-1 cells. These findings underline the importance of natural product chemistry as well as the approach to purifying small organic molecule from natural resources. The underlining mechanism of how our phytosteryl glucosides induce an immune response is still unknown. Nevertheless our finding has opened the door to new research avenues with a family of compound that contain a novel class of pathogen associated molecular patterns.