TS155-2 is a macrocyclic lactone related to hygrolidin but produced by a different Streptomyces species. TS155-2 is an inhibitor of calcium entry into the cell induced by thrombin stimulation. With the exception of the original patent suggesting hypotensive, anti-platelet, anti-ischaemic and anti-inflammatory activity, no literature investigation of TS155-2 is available.