DESCRIPTIONS OF ANTIBIOTICS 



395 



Thiomycin 



Produced by: Streptomyces sp. closely related to 

 S. phaeochrotnogenes var. chloromyceticus. 



Method of extraction: Culture adjusted to pH 

 2.0 and filtered to remove the mycelium. Filtrate 

 passed through a column of cation exchange resin, 

 "lonex C" (H+ phase). Column washed with water 

 and eluted with 80 per cent aqueous acetone. 

 Eluate adjusted to pH 2.0 and concentrated in 

 vacuo. The aqueous concentrate thus obtained is 

 saturated with NaCl and extracted with ethyl 

 acetate. Solvent extract concentrated to a syrup 

 in vacuo. Syrup dissolved in chloroform and passed 

 through a column of silica gel, which is then de- 

 veloped with chloroform. The antibiotic is col- 

 lected in a deep yellow fraction. This fraction 

 concentrated in vacuo to a syrup and then dis- 

 solved in ethyl acetate. Upon standing at room 

 temperature, crude crystals are formed. Recrystal- 

 lization from ethyl acetate solution. 



Chemical and physical properties: Golden yellow 

 needle-shaped crystals; m.p. 17(3-178°C (decom- 

 position). Soluble in methanol, ethanol, butanol, 

 acetone, ethyl acetate, chloroform, and benzene. 

 Slightly soluble in water, ether, and petroleum 

 ether. Negative ninhydrin, FeCls , and Fehling 

 reactions. C = 49.6%; H = 5.5%; N = 8.9%; 

 S = 16.3%,. No halogen detected. Light-absorption 

 maximum at 370 mn (£'}c1i, 375) in methanol solu- 

 tion and at 300 mfx (E'lL 555) in 0.5 A^ sodium 

 hydroxide. Stable at pH 2.0 but unstable under 

 alkaline conditions. 



Biological activity: Inhibits the growth of gram- 

 positive and gram-negative bacteria on nutrient 

 agar at concentrations of 3 to 12 ;ug per ml at pH 

 6.0. Less active (25 to 51 ^g per ml) at pH (5.8. 

 Active against M. smegmatis ()07. No activity 

 against Ps. aeruginosa. 



Toxicity: LD50 (mice) 10 mg per kg subcutane- 

 ously. 



Reference: 1. Hinuma, Y. et al. J. Antibiotics 

 (Japan) 8A: 118-119, 1955. 



Tliio-sliepton 



Produced by: Streptomyces sp. This organism 

 also produces two other antibiotics (1, 2). 



Method of extraction: Mycelium extracted with 

 chloroform, dioxane, or dimethylformamide. Ex- 

 tract concentrated in vacuo. Thiostrepton precip- 

 itates out of concentrate on addition of hexane. 

 Purified by: (a) washing with hot benzene and 

 crystallization from chloroform or dioxane on 

 addition of 50 per cent aqueous methanol; (b) 

 chromatography on alumina (chloroform as sol- 

 vent and dioxane as developer); or (c) stirring a 



dioxane solution with carbon and precipitating 

 the antibiotic with water (1, 2). 



Chemical and physical properties: Weak base. 

 White or very yellow crystals. Darkens at 235°C; 

 m.p. 246-256°C (decomposition). Soluble in chlo- 

 roform, dioxane, pyridine, benzyl alcohol, glacial 

 acetic acid, and dimethylformamide. Hardly solu- 

 ble in the lower alcohols. Insoluble in ether, ace- 

 tone, hexane, benzene, ethyl and amyl acetate, 

 dibutyl ether, water, dilute acids and bases. Solu- 

 ble with loss of activity in dilute methanolic acids 

 and bases. [a]f = -98.5° (c = 1 per cent in glacial 

 acetic acid); -61° (c = 1 per cent in dioxane); 

 and —20° (c = 1 per cent in pyridine). Ultraviolet 

 absorption spectrum shoulders at 225, 250, and 

 280 m/x (solvent not given) (1) or shoulders at 240, 

 280, and 305 m^ (methanol) (2). Infrared spectrum 

 given in references 1 and 2. Positive biuret test. 

 Negative ninhydrin and Sakaguchi tests. Forms 

 complexes with alkaline earth metal salts and 

 salts with acids. Both types of compounds are 

 hydrolyzed to the free base when water is added. 

 Most stable at pH 7.0. C = 51.3%; H = 5.4%o; 

 N = 14.6%,; S = 7.4%; (1) or C = 51.75%,; H = 

 5.3%,; N = 15.84%; S = 9.22%; acetyl = 8.7%, (2). 

 No methoxyl groups. Eciuivalent weight, 380. Acid 

 hydrolysis products include leucine (or isoleucine), 

 valine, alanine, threonine, proline, lysine, glycine, 

 aspartic acid, glutamic acid, and possibly cystine 

 and tryptophan (1, 2). 



Biological activity: Bacteriostatic. Active 

 against gram-positive bacteria and mycobacteria 

 (0.01 to 3.1 Mg per ml). Relatively inactive (30 to 

 50 ^^g per ml) on gram-negative bacteria. No cross- 

 resistance, using Staph, aureus, with commonly 

 used antibiotics. Active on micrococcal and strep- 

 tococcal infections in mice. Active against menin- 

 gopneumonitis virus in eggs (1-3). 



Toxicity: LD50 (mice) 41.7 mg per kg intrave- 

 nously (2). Not absorbed from the gastrointestinal 

 tract (1). 



Utilization: Infections caused by gram-positive 

 organisms. Intestinal sterilization (2). 

 References: 



1. Pagano, J. F. et al. Antibiotics Ann. 1955- 



1956, pp. 554-565. 



2. British Patent 795,570, May 28, 1958. 



3. Kellev, J et al. Oral Surg., Oral Med., Oral 



Pathol. 12: 1334-1339, 1959. 



Tolomycin 



Produced by: Streptomyces crystallinus (1). 



Method of extraction: I. Broth-filtrate extracted 

 with n-butanol, amyl acetate, or amyl alcohol at 

 pH 7.5. Adjusted to pH 2.2 to 2.5 with 10 per cent 



