CAS 64761-66-6) from Streptomyces olivaceus are b-lactamase inhibitors, consisting of seven structurally related members (of which three are sulfated). Certain ampicillin-resistant bacteria are rendered sensitive to ampicillin in the presence of olivanic acid at concentrations that did not inhibit growth when administered separately. Note that these antibiotics are also unstable in the presence of hydroxylamine and cysteine.
