Trace of commuting matrices is maximal

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Let $A,B$ be two symmetric positive-definite matrices, and let

$$A=U\Lambda U^T,\qquad B=V\Gamma V^T$$

be their eigenvalue decompositions, where $U,V$ are orthogonal matrices and $\Lambda,\Gamma$ are diagonal, containing the (positive) eigenvalues of $A,B$.

By generating random matrices $A,B$ with these properties, I have numerical evidence that the following inequality seems to hold in general:

$$\mathrm{Tr}(AB) \le \mathrm{Tr}(\Lambda\Gamma)$$

Is it true? If so how can I prove it? (If not, please provide a counter-example).