Tyrosine derivatives isolated from Streptomyces sp. IFM 10937 in a screening program for TRAIL-resistance-overcoming activity.

Exploration of actinomycetes for isolation of natural products for abrogating TRAIL resistance led to the isolation of two new tyrosine derivatives (1 and 2) along with novobiocin (3). The structures of 1 and 2 were determined by spectroscopic methods, while the absolute configuration was determined by analyzing CD spectra and by a modified Marfey's method. Compounds 1 (150 μM) and 3 (37.5 and 75 μM) in combination with TRAIL showed synergistic activity in sensitizing TRAIL-resistant human gastric adenocarcinoma cells.