Abstract
Juzen-taiho-to is an immunostimulatory herbal formulation that is clinically used
in East Asia
for cancer patients undergoing chemotherapy and radiation. The formulation stimulates
various
leukocytes, including T, B, and NK cells and macrophages. Although Juzen-taiho-to
is known to
contain numerous compounds with various pharmacological activities, it is not clear
which
compounds are responsible for the stimulation of individual cell types. Here, we conducted
what
we call “biomarker-guided screening” to purify compounds responsible for the macrophages
stimulatory activity. To this end, gene expression was analyzed by a DNA array for
macrophages
treated with Juzen-taiho-to and DMSO (vehicle control), which identified intercellular
adhesion
molecule 1 as a biomarker of macrophage stimulation by Juzen-taiho-to. A quantitative
reverse
transcription polymerase chain reaction assay of intercellular adhesion molecule 1
was then used
to guide the purification of active compounds. The screening resulted in the purification
of a
glycolipid mixture, containing β-glucosylceramides. The glycolipid mixture potently
stimulated intercellular adhesion molecule 1 expression in primary dendritic cells
as well as in
primary CD14+ (macrophages) cells. The identification of this glycolipid mixture opens
up an
opportunity for further studies to understand how plant-derived glycolipids stimulate
macrophages and dendritic cells in a safe and effective manner as demonstrated by
Juzen-taiho-to.
Key words
biomarker-guided screening - glycolipid - immunostimulation -
β-glucosylceramides