TS 155-2, is a macrocyclic lactone related to hygrolidin, is produced by a different Streptomyces species found in oil. It blocks thrombin-evoked calcium (Ca2+) entry into cells. TS155-2 exerts hypotensive, anti-platelet, anti-ischaemic and anti-inflammatory activity showed on the original patent, however, no literature investigation of TS155-2 is available.

A rapid increase in cytosolic Ca2+ is related to the signal transduction events following the induction of thrombin in a wide range of cell types which include fibroblasts, platelets, megakaryocytes, endothelium and smooth muscle. Thrombin-stimulated Ca2+ mobilization has been shown to be involved in both Ca2+ release from internal storage sites and Ca2+influx and has been extensively studied in human platelets. Thrombin triggers phospholipase C resulting in the rapid generation of inositol 1,4,5-trisphosphate (IP3), which elicits the release of Ca2+ from IP3-sensitive stores. However, the thrombin-induced Ca2+ influx is still an area of contention [1].

In vitro: Up to now, in vitro study of TS 155-2 is still in the development stage.

In vivo: Up to now, in vivo study of TS 155-2 is still in the development stage.

Reference:
[1]. Somasundaram, B., Mason, M., & Mahaut-Smith, M. Thrombin-dependent calcium signalling in single human erythroleukaemia cells. The Journal of Physiology.1997;501(3):485-495.