  We consider the parity doublet structure observed in high hadronic
excitations within the instanton model for the QCD vacuum. In the conventional
approach this doubling phenomenon is treated as a manifestation of the partial
restoration of chiral or $U(1)_A$ symmetry. We demonstrate that the suppression
of direct instanton contribution to the masses of excited hadrons leads to the
partial $U(1)_A$ symmetry restoration in hadron spectrum. The origin of X(1835)
resonance observed by BES Collaboration is studied upon the doublet structure.
We argue also how X(1835) be interpreted as the lowest pseudoscalar glueball
state, and derive its coupling constant to proton. It turns out that this
coupling is large and negative. Demonstrated is how this large coupling affects
the gluonic contribution to the proton spin.
