A tetracycline antibiotic; has bacteriostatic activity at low concentrations (7.8 μg/ml) and bactericidal activity at high concentrations (15.6 μg/ml) against E. coli; has additive and synergistic effects with penicillin and cephalothin, respectively, in vitro against 34 E. coli and S. aureus strains; active against chloroquine-susceptible and -resistant P. falciparum strains (IC50s = 45-208 μM); reduces Aβ40 fibrilization (IC50 = 59 μM in an immune assay); completely inhibits Aβ40-induced cellular toxicity at a concentration of 20 μM