Context : Although there have been numerous studies of chemical abundances in the Galactic bulge , the central two degrees have been relatively unexplored due to the heavy and variable interstellar extinction , extreme stellar crowding , and the presence of complex foreground disk stellar populations .

Aims : In this paper we discuss the metallicity distribution function , vertical and radial gradients and chemical abundances of \alpha -elements in the inner two degrees of the Milky Way , as obtained by recent IR spectroscopic surveys .

Methods : We use a compilation of recent measurements of metallicities and \alpha -element abundances derived from medium-high resolution spectroscopy .
We compare these metallicities with low-resolution studies .

Results : Defining ” metal-rich ” as stars with [ Fe / H ] > 0 , and ” metal-poor ” as stars with [ Fe / H ] < 0 , we find compelling evidence for a higher fraction ( \sim 80 \% ) of metal-rich stars in the Galactic Center ( GC ) compared to the values ( 50-60 % ) measured in the low latitude fields within the innermost 600 pc .
The high fraction of metal-rich stars in the GC region implies a very high mean metallicity of +0.2 dex , while in the inner 600 pc of the bulge the mean metallicity is rather homogenous around the solar value .
A vertical metallicity gradient of -0.27 dex/kpc in the inner 600 pc is only measured if the GC is included , otherwise the distribution is about flat and consistent with no vertical gradient .

Conclusions : In addition to its high stellar density , the Galactic center/nuclear star cluster is also extreme in hosting high stellar abundances , compared to the surrounding inner bulge stellar populations ; this has implications for formation scenarios and strengthens the case for the NSC being a distinct stellar system .