Influence of molecular distillation on antioxidant and antimicrobial activities of rose essential oils

Chemical compositions, antioxidant and antimicrobial activities of the essential oils (REOs) of roses including Rosa damascene (RD), Rosa centifolia (RC), Rosa pomponia (RP) and Rosa chinensis Jacq “Crimson Glory” H. T. (CG), and their fractions obtained through molecular distillation (MD) were investigated. The major constitutes were: β-citronellol and nonadecane in RDEO, RCEO and RPEO, 1-nonadecene and nonadecane in CGEO. After MD, a larger proportion of more volatile compounds existed in the distillates relative to their original oils and residues. The REOs and fractions exhibited not only moderate antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and reducing power assays, but also obvious broad-spectrum antimicrobial activities towards the seven tested microorganisms. Notably, the higher antioxidant and antimicrobial activities were observed for the distillates of RDEO, RCEO and RPEO. Moreover, the active antioxidant constitutes in the REOs were characterized as eugenol and methyl eugenol, and the potential antimicrobial components were linalool, phenethyl alcohol, β-citronellol, geraniol, eugenol and methyl eugenol. Results demonstrated that MD could be used to obtain fractions from REOs with higher antioxidant and antimicrobial activities, and the distillates of RDEO, RCEO and RPEO have potential to act as novel natural antioxidant and antimicrobial agents.