Chemical composition and antimicrobial activity of Boswellia serrata oleo-gum-resin essential oil extracted by superheated steam

Oleo-gum-resin is a complex mixture of essential oils, polysaccharides, and resin acids. The objectives of the present study were to evaluate the variation in chemical components and antimicrobial activity of essential oils extracted by superheated steam at various temperatures. The optimum essential oil yield was obtained at the highest superheated steam temperature (210 degrees C). In total, twenty-one compounds were quantified by GC-MS with alpha-pinene as the major compound, followed by alpha-thujene, trans-verbenol, beta-thujone, p-cymene, m-cymene, and sabinene. Antimicrobial activity was performed by disc diffusion, resazurin microtitre-plate and micro-dilution broth susceptibility assays in which essential oil extracted at 150 degrees C and 180 degrees C revealed the highest antibacterial and antifungal activity, respectively. It is concluded that superheated steam is an effective method for the isolation of essential oil from oleo-gum-resin that improves the recovery of essential oil as well as antimicrobial activity.