<unk>  is a bacteriocidal polyether-macrolide antibiotic. It was initially isolated from the Streptomyces antibioticus, and is notable for being the first natural product found to contain the element boron. It is effective against most Gram-positive bacteria, but is ineffective against Gram-negative bacteria.<unk>  kills bacteria by negatively affecting the cytoplasmic membrane, resulting in the loss of potassium ions from the cell.
Boromycin
Valrubicin
Epirubicin
Bleomycin
Doxorubicin
Daunorubicin
Fluorouracil
Vincristine