The origin of the Galactic center diffuse X-ray emission (GCDX) is still
under intense investigation. We have found a clear excess in a longitudinal
GCDX profile over a stellar number density profile in the nuclear bulge region,
suggesting a significant contribution of diffuse, interstellar hot plasma to
the GCDX. We have estimated that contributions of an old stellar population to
the GCDX are about 50 % and 20 % in the nuclear stellar disk and nuclear star
cluster, respectively. Our near-infrared polarimetric observations show that
the GCDX region is permeated by a large scale, toroidal magnetic field.
Together with observed magnetic field strengths in nearly energy equipartition,
the interstellar hot plasma could be confined by the toroidal magnetic field.