The pluramycin family of antibiotics comprises angucycline compounds derived from actinomycetes that possess anticancer and antibacterial properties. Pluramycins are structurally characterized by two aminoglycosides linked by a carbon-carbon bond next to the γ-pyrone angucycline backbone. Kidamycins (3, 4) and rubiflavins (6-9) were screened through liquid chromatography-mass spectrometry analysis of the crude extracts of Streptomyces sp. W2061, which was cultured in complex media under phosphate-limiting conditions. Newly isolated rubiflavin G (7) and photoactivated compounds (8, 9) were characterized using exhaustive 1D and 2D nuclear magnetic resonance analysis. The cytotoxicity of kidamycin (3), photokidamycin (4), and photorubiflavin G (8) was determined using two human breast cancer cell lines-MCF7 and MDA-MB-231. Compared to MCF7 cells, MDA-MB-231 cells were more sensitive to the active compounds, and photokidamycin (4) considerably inhibited MCF7 and MDA-MB-231 cell growth (IC50 = 3.51 and 0.66 μM, respectively).
© 2023. The Author(s), under exclusive licence to the Japan Antibiotics Research Association.