Abstract
Continuing our search for biogenic NF-kappa B inhibitors we investigated Solanum diflorum, used by the Istmo Sierra Zapotec Indians of Mexico in the treatment of inflammatory skin conditions. It became obvious very early that the active substance seems to be a degradation product of chlorophyll. Pheophorbide A was identified as one of the key compounds responsible for the NF-kappa B inhibitory activity. The compound interferes with NF-kappa B activation, was cytotoxic if exposed to light, but devoid of any cytotoxic activity in the dark.