Oosporein is a mycotoxin that has been found inBeauveriaand has diverse biological activities.^1,2It is cytotoxic to Sf9 and Sf21 insect cells with 50% cytotoxic concentration (CC₅₀) values of 4.23 and 10.43 µM, respectively.³Oosporin induces lethality in day-old cockerels (LD₅₀= 6.12 mg/kg).⁴It inhibits Na⁺/K⁺-, Ca²⁺-, and Mg²⁺-ATPase activities by 27, 52, and 100%, respectively, in equine erythrocyte ghosts when used at a concentration of 200 µg/ml.²Oosporein inhibits herpes simplex 1 (HSV-1), but not HeLa cell orE. coli, DNA polymerase (IC₅₀s = 75, 610, and >700 µM, respectively).⁵It is active against the bacteriumS. pneumoniae(MIC = 32 µg/ml) and the plant pathogenic fungusP. infestans(MIC = 16 µM).^1,6

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