Antibacterial Substances Separated from Plants.

Interest is arising in the possible use of higher plants as the source of naturally occurring antibiotic substances. The use of higher plants in the treatment of disease is as old as the art of healing itself. Isaiah of Biblical times suggested that a plaster of figs be placed on boils as a treatment of this form of infection. Hyssop and cedarwood were used in the cleansing of lepers. The Orientals (Hume, 1940) have used plants and herbs for centuries in the treatment of many diseases. Preliminary surveys (Osborn, 1943; Lucas and Lewis, 1944; Huddleson et al., 1944) of large numbers of plants suggest that many contain potential antibiotic materials. Further work by several investigators (Irving, Fontaine, and Doolittle, 1946; Cavallito, Bailey, and Kirchner, 1945; Heatley, 1944; Cavallito, Buck, and Suter, 1945; Seegal and Holden, 1945) on individual plants or parts of plants indicated that these substances can be purified and remain active in this form against microorganisms in vitro. Recently (Carlson, Bissell, and Mueller, 1946) it was demonstrated that partially purified extracts of plants are active in vivo against the malaria parasites and against gram-positive bacteria. During the spring and summer of 1946 it was possible to collect 550 plants in regions of Ohio and Oregon. From these plants, 2,115 extracts were prepared and tested. The object of the study here reported was to determine which plants of those collected from these regions contain active substances which would inhibit the growth of microorganisms in vitro.