Antibiotic substances, activity against fungi

Trichoderma harzianum Rifai (Hypocreaceae) is a widespread soil Ascomycotina known to produce antibiotics active against other microscopic fungi. This species was found in a sponge Mycale cecilid) collected in Japan. The strain, when cultured in seawater, proved capable of producing substances different from those obtained in freshwater medium, including trichoharzin (38) (a colorless glassy solid identified by MS, NMR spectroscopy and chemical conversion extraction yield 0.5 mg/1), which is a new oktaketide with a decalin fi-amework [79]. 

C30H21NO9, Mr 539.50, red powder, mp. >350 °C. A very effective cytotoxic antitumor antibiotic with additional activity against Gram-positive bacteria and fungi. F. A and the minor components F. B and f C are isolated from cultures of Streptomyces griseus. The antitumor activity of F. A is assumed to be due to the formation of free radicals which effect DNA strand cleavage. The water-soluble potassium salt of F. A has been developed for cancer therapy. In contrast to other antineoplastic substances F. A does not show any mutagenicity in the Ames test. 

Meanwhile, with the emphasis on environmental protection, the use of several fungicides was limited or banned and, at the same time, active antibiotics were discovered in increasing numbers, substances with excellent effects against several phytopathogenic fungi but which did not pollute the environment. Thus, the importance of antibiotics in agriculture rapidly increased. 

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