Production and Antifungal Activity of Secondary Metabolites of Trichoderma virens

Toxins namely gliotoxin, dimethyl gliotoxin, viridin and viridiol were isolated from chloroform extract of 15 days old culture filtrate of a strain of Trichoderma virens (ITC-4777) grown in potato dextrose broth. Their structures were confirmed by ¹H-NMR, and mass spectroscopy. Gliotoxin was found to be active against Rhizoctonia bataticola (ED₅₀ 0.03 µg ml-¹), Macrophomina phaseolina (ED₅₀ 1.76 µg ml”¹), Pythium deharyanum (ED₅₀ 29.38 µg ml¹), Pythium aphanidermatum (ED₅₀ 12.02 µg ml-¹), Sclerotium rolfsii (ED₅₀ 2.11 µg ml-¹), Rhizoctonia solani (ED₅₀ 3.18 µg ml⁻¹). Decrease in production of gliotoxin was observed with increase in days of incubation of culture of T. virens. Maximum production of gliotoxin was observed in the 7 day old culture filtrate.