Let R be an associative ring with center Z(R) and a nonzero ideal I. Let G and F are multiplicative (generalized)derivations of R together with mappings g and f respectively. In this note, we prove that R contains a non-zero central ideal if any one of the following holds for all x, y in I: 1. G(xy) ± F(x)F(y) ± [x,y] ϵ Z(R) 2. G(xy) ± F(x)F(y) ± (xoy) ϵ Z(R) 3. G(xy) ± F(x)F(y) ± yx ϵ Z(R) 4. G(xy) ± F(x)F(y) ± xy ϵ Z(R) Moreover, we investigate the identities F(x)F(y) ± yx ϵ Z(R) and F(xy) ± yx ϵ Z(R) over a non-zero left ideal of R and improve some known results.