The Occurrence of Antibacterial Substances Active against Mycobacterium Tuberculosis in Seed Plants.

For many centuries green plants have been used for the treatment of various diseases. Tuberculosis is no exception, and numerous plants and plant products have, at one time or another, been reported to be of value in the treatment of this disease. During the past few years a number of investigators have surveyed seed plants for sources of antibacterial activity (1-10). In most of these studies a Gram-positive organism, Staphylococcus aureus or Bacillus subtilis, and a Gram-negative organism, Escherichia coli or Salmonella typhosa, were used for detecting antibacterial properties. In some cases the active materials or purified preparations derived from them were then tested against a variety of microorganisms. In this exploratory survey a strain of Mycobacterium tuberculosis was used for assay because of the assumption that some plants might contain substances specifically antibacterial for the tubercle bacillus. These would be missed in any assay using other test organisms. To obtain more information on the antibacterial properties of the extracts, however, most of them were also tested for their effect on Staph. aureus and E. coli. Early in the study it was found that some plants contained substances active against the tubercle bacillus but that all or much of the activity was lost in the presence of whole blood. In subsequent tests the active plant extracts were also assayed in media to which blood had been added.