Mechercharmycins A and B, Cytotoxic Substances from Marine-derived Thermoactinomyces sp. YM3-251

Abstract

A new cytotoxic substance named mechercharmycin A was isolated from marine-derived Thermoactinomyces sp. YM3-251. The structure of mechercharmycin A was determined by an X-ray crystallographic analysis to be cyclic peptide-like and bearing four oxazoles and a thiazole. Mechercharmycin B, a linear congener of mechercharmycin A, was also isolated from the same bacterium. Mechercharmycin A exhibited relatively strong antitumor activity, whereas mechercharmycin B exhibited almost no such activity.

Predicting the unpredictable: Recent structure–activity studies on peptide-based macrocycles

“…A closely related linear metabolite to M1, Mechercharmycin B (Fig. 5), did not exhibit inhibitory activity to A-549 and Jurkat cells even at 1 lM [55]. Taken together, these data showed that the macrocyclic structure was vital for the cytotoxicity of the molecule.…”

A new 16-membered tetraene macrolide JBIR-100 from a newly identified Streptomyces species

“…Mechercharmycin A (42), a cyclic-peptide, was recently isolated from the bacterium Thermoactinomyces sp. and shows a cytotoxic activity against human lung carcinoma and human leukaemia [70] .…”

“…In vitro, the extract showed antitumor activity against a number of human cancer cells (IC 70 11.565 µg/ml), in addition to 100% cytotoxicity at concentration of 100 µg/ml (Table 45). …”

“…Trioxacarcins exhibited anti-tumor, antibacterial and high antimalaria activity [95,96] , while trioxacarcine D (69d) possesses extremely high antiplasmodial activity. Kettapeptin (70) belongs to the group of cyclic hexadepsipeptides, which was isolated from the terrestrial Streptomyces sp. GW 99/1572 by Maskey [97,98] .…”

Efficient Construction of the Carbon Skeleton of the Novel Polyoxazole-Based Cyclopeptide IB-01211 via a Biomimetic Macrocyclisation

“…1 This, in turn, has generated considerable interest not only in the synthesis of these challenging natural products but also in the design and synthesis of their simpler analogues with a view to obtaining compounds of desired properties. 2 YM-216391 3 (1, Figure 1), IB-01211 4 (2), and telomestatin 5 (4) are good examples in these regards.…”