Patent ID: 8476222

Claim:
An isolated compound of the formula (I): wherein R1 is H, C(O)—(C 1 -C 6 )alkyl or C(O)—O—(C 1 -C 6 )alkyl; R2 is OH, NH 2 , NH—(C 1 -C 6 )alkyl, NH—(C 1 -C 4 )alkylene-phenyl or NH—(C 1 -C 4 )alkylene-pyridyl; R3 and R4 are independently of each other H or OH, or R3 and R4 together are ═O; and m and n are independently of one another 0, 1 or 2; and said compound being in any stereochemical form, or a mixture of any stereochemical forms in any ratio; or a physiologically acceptable salt thereof.