  We put to the test an effective three-dimensional electrostatic potential,
obtained effectively by considering an electrostatic source inside a
(5+$p$)-dimensional braneworld scenario with $p$ compact and one infinite
spacial extra dimensions in the RS II-$p$ model, for $p=1$ and $p=2$. This
potential is regular at the source and matches the standard Coulomb potential
outside a neighborhood. We use variational and perturbative approximation
methods to calculate corrections to the ground energy of the Helium atom
modified by this potential, by making use of a 6 and 39-parameter trial wave
function of Hylleraas type for the ground state. These corrections to the
ground-state energy are compared with experimental data for Helium atom in
order to set bounds for the extra dimensions length scale. We find that these
bounds are less restrictive than the ones obtained by Morales et. al. through a
calculation using the Lamb shift in Hydrogen.
