  The detailed evolution of exoplanetary atmospheres has been the subject of
decade-long studies. Only recently, investigations began on the possible
atmospheric mass loss caused by the activity of galactic central engines. This
question has so far been explored without using available exoplanet data. The
goal of this paper is to improve our knowledge of the erosion of exoplanetary
atmospheres through radiation from supermassive black holes (SMBHs) undergoing
an active galactic nucleus (AGN) phase. To this end, we extended the well-known
energy-limited mass-loss model to include the case of radiation from AGNs. We
set the fraction of incident power $\epsilon$ available to heat the atmosphere
as either constant ($\epsilon = 0.1$) or flux dependent ($\epsilon =
\epsilon(F_{\textrm{XUV}})$). We calculated the possible atmospheric mass loss
for 54 known exoplanets (of which 16 are hot Jupiters residing in the Galactic
bulge and 38 are Earth-like planets (EPs)) due to radiation from the Milky
Way's (MW) central SMBH, Sagittarius A* (Sgr A*), and from a set of 107,220
AGNs generated using the 33,350 AGNs at $z < 0.5$ of the Sloan Digital Sky
Survey database. We found that planets in the Galactic bulge might have lost up
to several Earth atmospheres in mass during the AGN phase of Sgr A*, while the
EPs are at a safe distance from Sgr A* ($> 7$ kpc) and have not undergone any
atmospheric erosion in their lifetimes. We also found that the MW EPs might
experience a mass loss up to $\sim 15$ times the Mars atmosphere over a period
of $50$ Myr as the result of exposure to the cumulative extreme-UV flux
$F_{\textrm{XUV}}$ from the AGNs up to $z = 0.5$. In both cases we found that
an incorrect choice of $\epsilon$ can lead to significant mass loss
overestimates.
