A minor analogue of the cyclosporin complex produced by a number of fungal species, including trichoderma, tolypocladium, fusarium, nectria and acremonium. It has the immunosuppressant activity but has been much less extensively investigated than the major analogue, cyclosporin A. Cyclosporin C is a broad-spectrum antifungal agent against filamentous phytopathogenic fungi but no activity against bacteria or yeasts.