The present invention relates to 8-
aryl-substituted and 8-heteroaryl-substituted 9H-pyrido[3,4-b]indoles of the formula (1), in which A, E, G, R1 to R6 and R10 are as defined in the claims, which stimulate
chondrogenesis and
cartilage matrix synthesis and can be used in the treatment of
cartilage disorders and conditions in which a regeneration of damaged
cartilage is desired, for example joint diseases such as
osteoarthritis. The invention furthermore relates to processes for the synthesis of the compounds of the formula (I), their use as pharmaceuticals, and pharmaceutical compositions comprising them.