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KMID : 0386319670040010088
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Korean Leprosy Bulletin
1967 Volume.4 No. 1 p.88 ~ p.90
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The Chomotherapeutic Effects of the Newly Synthesized Thiocarbanilides on the Drug Resis tant Strains of Mycobacterium tuberculosis in vitro
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Oh,Jae Key
Yang, Hyung Ho/Lew,Joon
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Abstract
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Mycobacterium tuberculosis was discovered by R. Kock in 1882, 10 years later, G. H. A. Hansen discovered the Mycobacterium leprae which was the first microorganism known to be pathogenic to the human host.
Brilliant progress has been achieved in the field of tuberculosis, i.e. in it´s artificial culture, animal transmission and chemotherapy, but the progress made in the field of Mycobacterium leprae is far behind though its discovery proceeded the tubercle bacilli by 10 years.
Modern chemotherapy in the treatment of tuberculosis was developed in the late 1930´s. Meanwhile, Domagk recognized the chemotherapeutic effect of 2´,4´-diaminoazobenzene 4-sulfonamide hydrochloride (Prontosil) on mice experimentally infected with streptococci.
Later, Prontosil failed in the chemotherapy of tuberculosis, the introduction of Prontosil, however, encouraged workers to produce many sulfonamides and sulfones in the field of modern chemotherapy.
Thereafter, almost at the same time streptomycin(SM)by Waksman, para aminosalicylic acid (PAS) by Rosdahl et. al. and isonicotinic acid hydrazide (INH) were introduced by the workers at. the laboratories of Farbenfabriken Bayer, Hoffman-Roche and E. R. Squibb and Sons Company.
At the present time SM, PAS and INH used in the treatment of tuberculosis are considered the most effective drugs and they have become the standard chemotherapeutic agents for tuberculosis. However, they are not the final drug in the treatment of tuberculosis and their affectiveness remains for from satisfactory. Because they requires a long period of treatment as in the case of almost all antituberculosis drugs their ultimate value is limited by the development of primary drug-resistant strains in the treated subjects. And also they have strong toxicity with many side reactions. The shortage problems and much disatisfaction of the antituberculosis drugs have led workers to develop new and more effective compounds for the chemotherapeutics of tuberculosis.
Mayer, Eisman and Konopka developed a series of the derivaties of thiocarbanilides (diphenyl thiourea) at the laboratories of Ciba Company (Summit, New Jersey), and among 295 compounds of this derivatives 27 compounds demonstrated significant antituber￢
culosis activities in vitro and in-vivo.
Independently Buu-Hoi and Xuong at the Pasteur Institute reported a series of the symmetric compounds of thiocarbanilides as effective therapeutic agents for leprosy and tuberculosis. Among these compounds 4,4´-diethoxy thiocarbanilides (D.E.T.C.) and 4,4´-diisoamyloxythiocarbanilide (D.A.T.C.) have been widely known as therapeutic drugs for tuberculosis.
Choi et al. reported new compounds of asymmetric thiocarbanilide derivatives in the experimental studies on tuberculosis and leprosy. Among them N-(p-ethoxyphenyl)-N´￢(thiocyanophenyl) thiocarbamide (LK-59) and N-(p-ethoxyphenyl)-N´-(p-aminodiphynyl) thiocarbamide (LK-65) showed remarkable antituberculosis effects in-vitro and in-vivo. Kim et al. also reported antifungal activities of these drugs and Chang et al. reported antimicrobial activities on gram positive and negative microorganisms..
Attention was paid to the thiocarbanilide derivatives and the author has continued to study the chemotherapeutic effects of the newly synthesized LK-59 and LK-65 on Mycobacterium tuberculosis and drug-resistant strains of Mycobacterium tuberculosis.
The results of this study are included in this paper.
MATERIALS and METHODS
A. Newly synthesized and control drugs used in experiments on the antituberculois activities. Newly synthesized compounds of asymmetric thiocarbanilides; LK-59 and LK-65 were used inthe experiments. D.E.T.C., an already known derivative of symmetric thiocarbanilide, SM, PAS, INH and D.D.S. were used as controls.
B. Media and strains used in the experiments.
Mycobacterium tuberculosis (H37Rv, Ravenel and B.C.G.), the strains from the National Institute of Health, Republic of Korea were used. Fresh homogeneously grown organisms which were cultured in Dubos´ tween albumin media at 37°C for 2 weeks, were used for the examination of sensitivity to the newly synthesized compounds.
*Drug-resistant strains of Mycobacterium tuberculosis (six SM-Resistant strains, one PAS-Resistant strain, six INH-Resistant strains, two SM-INH-Resistant strains and one SM-PAS-INH-Resistant strain), which were obtained from the Tuberculosis Diagnostic Center, Korean Tuberculosis Association were used.
C. In-vitro tests for newly synthesized drugs and the method of observation.
1. Experiment on antituberculosis activities.
Okawa egg media containing l7-/ml, 10r/ml, 50r/ml and 100r/ml concentration. of
LK-59, LK-65 and D.E.T.C.; 1r/ml, 10r/ml, 50r/ml and 100r/ml of PAS; 0. 17/ml, IT/ml and 10r/ml of INH; and IT/ml, 5r/ml and 10r/ml of D.D.S. were prepared for the experimentation. Because the LK-59 and LK-65 were insoluble a liquid media they could not be used. Therefore, Okawas´ solid medium was selected and a 380r/ml initial solution in polyethylene glycol was prepared for the further dilution in the subsquent media and varying concentrations of the drugs were used. To each prepared solid medium containing the selected concentrations of the drugs, 0.2ml of mycobacterial strains previously cultured in Dubos´ tween albumin media was added using the
pipette accurately and the inoculated tubes were placed in a horizontal position for 2 hours. After bacterial suspension had evenly spread over the surface of the media, the inoculated tubes were kept in an incubator at 37°G for observation. From the time when colonies were identified macroscopically, observations were made at 2 days intervals and the colonies were counted for comparison and control.
2. Experiments on susceptibility of drug-resistant strains.
Okawa egg media containing 17/ml, 5r/ml, 10;r/ml and 1001-/ml concentration of LK -59 and LK-65 were prepared for the experimentation.
The following procedures were done using the same methods of experimentation on antituberculosis activity. The direct method and the paper disc method were compared.
RESULTS
A series of newly synthesized asymmetric thiocarbanilides, namely LK-59 and LK-65 were studied for their antituberculosis activity and the susceptibility of drug-resistant strains of tuberculosis in-vitro.
1. LK-59 and LK-65 showed remarkable suppressive effects on Mycobacterium tuber￢culosis in-vitro using a solid media loon/ml concentration. This data paralleled that found in the use of IT/ml of I NH and 50T/ml of PAS.
2. LK-59 with 50r/ml and LK-65 with 100 7-/ml concentrations showed remarkable susceptibility against primary drug-resistant strains of Mycobacterium tuberculosis in￢vitro.
3. In-vitro experiments LK-59 showed superior antituberculosis effects and susceptibility against primary drug-resistant strais than was found with LK-65.
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KEYWORD
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