Growth-inhibiting effect of crude pineal extracts on human melanoma cells in vitro is different from that of known synthetic pineal substances.

The effect was studied of a number of synthetic indoleamines, pteridines, beta-carbolines, of AVT and of crude extracts from rat and ovine pineal glands on human melanoma cells in vitro. The identified pineal substances as well as some of their analogues showed an inhibitory effect only at non-physiologically high concentrations. However, crude pineal extracts were more active than the synthetic pineal substances tested. They contain a compound which may have a tumor-inhibiting potency comparable to that of methotrexate but a different mechanism of action.