  The isoscaling parameter $\alpha$, from the fragments produced in the
multifragmentation of $^{58}$Ni + $^{58}$Ni, $^{58}$Fe + $^{58}$Ni and
$^{58}$Fe + $^{58}$Fe reactions at 30, 40 and 47 MeV/nucleon, was compared with
that predicted by the antisymmetrized molecular dynamic (AMD) calculation based
on two different nucleon-nucleon effective forces, namely the Gogny and
Gogny-AS interaction. The results show that the data agrees better with the
choice of Gogny-AS effective interaction, resulting in a symmetry energy of
$\sim$ 18-20 MeV. The observed value indicate that the fragments are formed at
a reduced density of $\sim$ 0.08 fm$^{-3}$.
