Isolation of small chemical compounds from Rubia Cordifolia (Qian Cao, QC) that inhibit Immunoglobulin-E (IgE) production by the human B cells line, U266

It was previously indicated that Rubia Cordifolia (QC) suppressed IgE production in vitro in a non-toxic manner and protected against peanut anaphylaxis in a murine model. Using an isolation method, a previous study was able to isolate three constituents from this herb that were able to significantly reduce IgE production by the human B cell line, U266. This current study was designed to develop a new bioactivity guided isolation method to assess whether the isolated compounds are able to suppress IgE production in vitro as effectively as QC. The two compounds, QCD-X and QCD-7 were able to significantly reduce IgE production by the U266 cells in a non-toxic manner. This study also suggested that the two active compounds show a synergistic effect. However, the individual compound of QCD-7 produced a greater inhibition of IgE production than the combination of QCD-X and QCD-7, QCD-X alone, and QC, thus, suggesting that QCD-7 might serve as a better therapeutic option for treating IgE mediated allergic diseases than QCD-X + QCD-7, QCD-X alone, or QC.