Lactimidomycin, isolated from Streptomyces, is an inhibitor of eukaryotic translation elongation. It is also a potent and non-toxic inhibitor of dengue virus 2 and other RNA viruses. Lactimidomycin has an antiproliferative effect on tumor cell lines. It inhibits protein synthesis (IC50: 37.82 nM).

Lactimidomycin is an effective inhibitor of DENV2 and Lactimidomycin's inhibition of DENV2 translation causes reduced production of new infectious particles. Lactimidomycin causes a clear dose-responsive inhibition of DENV2 infectious particle production (EC90: 0.4 μM). Lactimidomycin (0.01-100 nM; 24 hours; Hs 579T, HCC 1937, HCC 1395, HCC 2218, BT 474, MCF 7, MDA MB231 cells and MCF 10A) treatment inhibits cell growth with IC50 concentrations in the low nanomolar range, but higher doses are necessary to inhibit the growth of the non-tumorigenic breast cell line MCF10A[1]. No measurable reduction in cell viability was detected at concentrations up to 12.5 μM. Lactimidomycin may protect cells from viral cytopathic effects including apoptosis, likely through inhibition of virus protein production and replication[2].

Lactimidomycin (0.6 mg/kg; intraperitoneal injection; daily; for one month; female nude mice) treatment, shows an appreciable effect on tumor growth in nude mice[1].