  Ultralight bosonic dark matter is expected to be able to form a cloud
surrounding the supermassive black hole (SMBH) in the Galactic center. With
increasing precision of the observations of the stellar kinematics around the
SMBH, tiny effects from such a dark matter cloud, including its gravitational
perturbation and the direct coupling with the ordinary matter may be
detectable. In this work, we search for possible evidence of the scalar cloud
using accurate orbital measurements of the S2 star around Sgr~A*. We solve the
first order Post-Newtonian equation, considering simultaneously the extended
mass distribution of the scalar cloud and the frequency shift induced by the
additional coupling via Higgs portal or photon portal interaction. Furthermore,
we also investigate the impact of an astrophysical power-law component from the
gas and stellar remnants. We find that the astrometric and spectroscopic data
of the S2 star are well consistent with the scenario of a point-like mass of
Sgr~A*. We thus derive upper limits of the coupling of the new interaction and
the extended mass, with and without the contribution from the astrophysical
component. The limits of the Higgs/photon coupling and the extended mass of the
scalar cloud are the most stringent ones for the scalar mass window between
$3.2\times 10^{-19}$~eV and $1.6\times 10^{-18}$~eV.
