Abstract
The solvent extracts of aromatic plants contain both volatile (e.g. essential oils) and non-volatile compounds. The biological activities (antibacterial, anti-oxidant, antiplasmodial and anticancer) of the solvent extracts of three South African Salvia species (Salvia africana-caerulea, S. africana-lutea and S. lanceolata) were evaluated in the presence and absence of the essential oils. The solvent extract of S. africana-caerulea free of essential oil exhibited the best activity against Gram-positive bacteria (MIC value: 0.4 mg/mL), while the solvent extract containing essential oil of S. lanceolata was the most active against Gram-negative bacteria (MIC value: 2.0 mg/mL). No significant difference was obtained in the antiplasmodial activity of the solvent extract with or without the essential oils of S. africana-caerulea and S. lanceolata, while the activity of the solvent extract without essential oil was significantly higher than that of the solvent extract containing the essential oil in S. africana-lutea (p < 0.05). The toxicity profile of all three species was significantly higher (p < 0.05) with the solvent extracts containing essential oils than when assessed in the absence of the essential oil.