  Observational data of the Sagittarius A* (Sgr A*) shadow released by the
Event Horizon Telescope (EHT) are used to investigate eventual deviations in
the black hole shadow radius, aiming to seek physics beyond the Standard Model
(SM) coming from extra-dimensional theory. We consider the brane-world scenario
described by the Randall-Sundrum model and determine the black hole shadow
radius correction owing to the higher dimension. From data of the shadow radius
in units of BH mass determined by KECK- and VLTI-based estimates, we imposed
restrictions on the deviation obtained, and one sets an upper limit to the
curvature radius of Anti-de Sitter ($\mathrm{AdS_{5}}$) spacetime
$\ell\lesssim4.3\times10^{-2}\,\mathrm{AU}$ (at $95\%$ confidence level).
