Compound of general formula below: in which: - R 1, R 2, R 3, R 4, R 5 and R 6 represent, independently of each other, H, a (C 1 -C 20)alkyl group or a (C 1 -C 20)alkylene-(C 6 -C 10)aryl group; said alkyl, alkylene and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; - X 1, X 2 and X 3 are chosen, independently of each other, from the group constituted by: H,-C N(Re)(Rd), (C 1 -C 20)alkyl, (C 2 -C 20)alkenyl, (C 2 -C 20)alkynyl and (C 6 -C 10)aryl, with Re and Rd being, independently of each other, H or a (C 1 -C 20)alkyl group, said alkyl, alkenyl and alkynyl groups possibly comprising one or more heteroatoms and/or one or more (C 6 -C 10)arylenes in their chain and possibly being substituted with a (C 6 -C 10)aryl; said alkyl, alkenyl, alkynyl and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; - Y 1, Y 2 and Y 3 represent, independently of each other, a C OH group or a group of formula below: in which: - the radicals Ri are chosen, independently of each other, from the group constituted by: H, halogen, N 3, (C 1 -C 20)alkyl, (C 2 -C 20)alkenyl, (C 2 -C 20)alkynyl and (C 6 -C 10)aryl, said alkyl, alkenyl and alkynyl groups possibly comprising one or more heteroatoms and/or one or more (C 6 -C 10)arylenes in their chain and possibly being substituted with a (C 6 -C 10)aryl; said alkyl, alkenyl, alkynyl and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; and at least one of the radicals Y 1, Y 2 and Y 3 being a group of formula; or a pharmaceutically acceptable salt thereof. - R 1, R 2, R 3, R 4, R 5 and R 6 represent, independently of each other, H, a (C 1 -C 20)alkyl group or a (C 1 -C 20)alkylene-(C 6 -C 10)aryl group; said alkyl, alkylene and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; - X 1, X 2 and X 3 are chosen, independently of each other, from the group constituted by: H,-C N(Re)(Rd), (C 1 -C 20)alkyl, (C 2 -C 20)alkenyl, (C 2 -C 20)alkynyl and (C 6 -C 10)aryl, with Re and Rd being, independently of each other, H or a (C 1 -C 20)alkyl group, said alkyl, alkenyl and alkynyl groups possibly comprising one or more heteroatoms and/or one or more (C 6 -C 10)arylenes in their chain and possibly being substituted with a (C 6 -C 10)aryl; said alkyl, alkenyl, alkynyl and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; - Y 1, Y 2 and Y 3 represent, independently of each other, a C OH group or a group of formula below: in which: - the radicals Ri are chosen, independently of each other, from the group constituted by: H, halogen, N 3, (C 1 -C 20)alkyl, (C 2 -C 20)alkenyl, (C 2 -C 20)alkynyl and (C 6 -C 10)aryl, said alkyl, alkenyl and alkynyl groups possibly comprising one or more heteroatoms and/or one or more (C 6 -C 10)arylenes in their chain and possibly being substituted with a (C 6 -C 10)aryl; said alkyl, alkenyl, alkynyl and aryl groups possibly being substituted with one or more substituents chosen from organic acid functions; and at least one of the radicals Y 1, Y 2 and Y 3 being a group of formula; or a pharmaceutically acceptable salt thereof. - the radicals Ri are chosen, independently of each other, from the group constituted by: H, halogen, N 3, (C 1 -C 20)alkyl, (C 2 -C 20)alkenyl, (C 2 -C 20)alkynyl and (C 6 -C 10)aryl,