  It is shown that the gravitational redshift as predicted by Einstein's
theory, is modified in presence of second rank antisymmetric tensor
(Kalb-Ramond) field in a string inspired background spacetime.In presence of
extra dimensions, the Randall-Sundrum brane world scenario is found to play a
crucial role in suppressing this additional shift. The bound on the value of
the warp factor is determined from the redshift data and is found to be in good
agreement with that determined from the requirements of Standard model.
