Secondary metabolites of Santolina africana: chemical profiles and assessment of biological activities

Chemicals and antibiotics are serious problems that cause the resistance of bacteria and the persistence of chemical residues in food. These chemical products affect human health and promote diseases. Therefore, the use of natural resources, especially plants, appears as an alternative to avoid the harmful impacts of such products. Plant active substances such as essential oils, alkaloids and phenols are of great interest to scientists and have been studied for their biological activities. Essential oils (Eos) from the stems of Santolina africana were extracted by hydrodistillation and analyzed by Gaz Chromatography/ Mass Spectrometry (GC-MS). The antioxidant activity of crude extracts and Eos was evaluated by the DPPH assay and the antibacterial activity was evaluated by the disc diffusion method and the broth microdilution method against Gram-positive strains (Bacillus subtilis, Staphylococcus aureus) and Gram-negative strains (Escherichia coli, Salmonella paratyphi, and Pseudomonas aeruginosa). S.africana Eos from Morocco and Tunisia were found to be rich in artemisia ketone (35.4% and 44.3%, respectively), santolina alcohol (16.2%and 3.2%, respectively) and isoborneol (6.1% and 26.6%, respectively). Methanol extracts were rich in phenolic and flavonoids contents and showed the highest DPPH radical scavenging activity. Results exhibited the sensitivity of the strains to essential oils from S. africana especially against Gram-positive bacteria. This current research will provide new information about this plant that can be used as a natural antioxidant and antibacterial for industrial purposes.