M.Tech. / The plants Salacia leptoclada and Warburgia salutaris possess antioxidant properties and are commonly used in Southern Africa for the treatment of inflammatory and other diseases. In order to determine their therapeutic use in crystalline silica-induced injury, the extracts of S. leptoclada and W. salutaris were investigated on silica-induced increased levels of (i) TNF-a, IL-113, INF-y, (ii) the activation of the transcription factor NE-KB, and (iii) the induction of DNA damage and lipid peroxidation. Through its antioxidant property, W. salutaris exhibited a protective effect against crystalline silica-induced inflammatory cytokine expression, NF-KB activation and DNA strand breakage. The extracts of W. salutaris also inhibited cellular membrane peroxidation induced by crystalline silica. Similarly, the extracts of S. leptoclada showed protection of cells against crystalline silica-induced membrane peroxidation. However, S. leptoclada proved ineffective in protecting against silica-induced DNA damage, proinflammatory cytokine expression and NF-KB activation. Since crystalline silica-induced inflammation, NE-KB activation, DNA damage and lipid peroxidation are involved in the process of crystalline silica-induced fibrogenecity and carcinogenicity, W. salutaris may be a potential therapeutic agent against crystalline silica-induced cellular injury.