Salvia somalensis essential oil as a potential cosmetic ingredient: solvent-free microwave extraction, hydrodistillation, GC–MS analysis, odour evaluation and in vitro cytotoxicity assays

Salvia somalensis Vatke, a wild sage native of Somalia, has been studied with the aim of assessing the potential cosmetic application of its essential oil, recovered from fresh aerial parts by solvent-free microwave extraction – SFME. To evaluate the efficiency and reliability of this ecofriendly procedure, the recovery of the essential oil was also processed by conventional hydrodistillation (HD) and the results compared. The essential oils obtained by both SFME and HD were analysed by gas chromatography–mass spectrometry using apolar and polar capillary columns. The essential oil recovered by SFME was submitted to an odour evaluation that revealed peculiar olfactive characteristics interesting in alcoholic male perfumery and body detergents. In vitro cytotoxicity assays were carried out using NCTC 2544 human keratinocytes as target cells. The oil displayed slight cytotoxic effects, which were three orders of magnitude lower than those found for sodium dodecyl sulphate positive control. The promising results in terms of chemical composition, scent and safety seem to indicate this essential oil as an interesting potential functional ingredient useful in a cosmetic context.