Cyclosporin C is a fungal metabolite that has been found in T. inflatum and has diverse biological activities, including antifungal, antiviral, and immunosuppressant properties. It is active against isolates of B. cinerea, A. niger, and Alternaria, Mucor, and Penicillium species (MICs = 0.1-5 μg/ml). Cyclosporin C (15 μg/ml) inhibits vaccinia virus replication in infected BSC40 cells by 98.82%. It inhibits lymphocyte proliferation induced by the mitogens concanavalin A (ConA; ), phytohemagglutinin L (PHA), and pokeweed mitogen (PWM), as well as proliferation induced by alloantigen in mixed lymphocyte culture when used at a concentration of 100 ng/ml. Cyclosporin C (100 ng/ml) inhibits the local graft versus host (GVH) reaction in mice receiving splenocyte grafts.
Cyclosporin C is a minor analogue of the cyclosporin complex produced by a number of fungal species, including Trichoderma, Tolypocladium, Fusarium, Nectria and Acremonium. Cyclosporin C possesses immunosuppressant activity but has been much less extensively investigated than the major analogue, cyclosporin A.
