South African Salvia species: A review of biological activities and phytochemistry

The genus Salvia (sage) belongs to the Lamiaceae and encompasses 900 species worldwide of which ca. 26 indigenous species are found in southern Africa. Salvia is the largest genus in this family and constitutes almost one quarter of the Lamiaceae. In South Africa, the majority of Salvia species are distributed predominantly in the Cape region. Salvia species are used in many parts of the world to treat various conditions. Many sages, if not all, form an integral part of traditional healing in South Africa particularly in regions where they occur in abundance. Several species are used to treat microbial infections, cancer, malaria, inflammation, loss of memory and to disinfect homes after sickness. Despite the extensive traditional use and the general interest in phytoconstituents of Salvia it remains ironic that research on the South African counterparts has until recently been neglected. The review aims to collate recent research results on the phytochemistry and pharmacological properties of indigenous species. Bio-active compounds with antiplasmodial and antibacterial activities have been isolated and structurally elucidated from Salvia chamelaegnea, Salvia radula and Salvia verbenaca. The essential oil composition of Salvia showed the dominance of monoterpene hydrocarbons, oxygen-containing monoterpenes and oxygen- containing sesquiterpenes. Salvia runcinata is identified as an alternative source of natural α-bisabolol. Many pharmacological activities are summarised (anti-oxidant, antimicrobial, antiplasmodial, analgesic, antipyretic, anticancer, anti-inflammatory and antinociceptive) as a first attempt to provide scientific support for past and present local traditional uses.