A compound having the formula: ** Formula ** wherein - R11, R12, R13, R21, R22, R2, R3 and R4 are each independently selected from the group consisting of -H and C1 to C10 acyloxy group ; - R5 is -H, and where one of the following conditions applies: (i) each of R11, R2 and R4 is -H and each of R12, R13, R21, R22 and R3 is an acetate group; or (ii) each of R11, R13, R2 and R4 is -H and each of R12, R21, R22 and R3 is an acetate group; or (iii) each of R11 and R13 is -H and each of R12, R21, R22, R2, R3 and R4 is an acetate group; or (iv) R11 is -H and each of R12, R13, R21, R22, R2, R3 and R4 is an acetate group; or (v) each of R11, R12, R13, R21 and R22 is an acetate group, R2 is an acetate group and each of R3 and R4 is -H; or (vi) each of R11, R12, R13, R21 and R22 is an acetate group, R3 is an acetate group and R2 and R4 is -H; or (vii) each of R11, R12, R13, R21, R22, R2 and R4 is an acetate group and R3 is -H, for use in proteasome inhibition.Un compuesto que tiene la fórmula:**Fórmula** en donde - R11, R12, R13, R21, R22, R2, R3 y R4 se seleccionan cada uno independientemente a partir del grupo que consiste en -H y grupo aciloxi C1 a C10; - R5 es -H, y en donde se aplica una de las siguientes condiciones: (i) cada uno de R11, R2 y R4 es -H y cada uno de R12, R13, R21, R22 y R3 es un grupo acetato; o (ii) cada uno de R11, R13, R2 y R4 es -H y cada uno de R12, R21, R22 y R3 es un grupo acetato; o (iii) cada uno de R11 y R13 es -H y cada uno de R12, R21, R22, R2, R3 y R4 es un grupo acetato; o (iv) R11 es -H y cada uno de R12, R13, R21, R22, R2, R3 y R4 es un grupo acetato; o (v) cada uno de R11, R12, R13, R21 y R22 es un grupo acetato, R2 es un grupo acetato y cada uno de R3 y R4 es -H; o (vi) cada uno de R11, R12, R13, R21 y R22 es un grupo acetato, R3 es un grupo acetato y R2 y R4 es -H; o (vii) cada uno de R11, R12, R13, R21, R22, R2 y R4 es un grupo acetato y R3 es -H, para uso en la inhibición del proteasoma.