The composition and antimicrobial activity of the essential oil of the resurrection plant Myrothamnus flabellifolius

An investigation of the antibacterial and antifungal activity of Myrothamnus flabellifolius against eleven different pathogens showed inhibition of all micro-organisms except for Salmonella typhimurium and Alternaria alternata. A preliminary screening was done by the disc diffusion method and three susceptible organisms were selected to demonstrate the rapid onset of antimicrobial activity using time-kill methodology. Essential oil concentrations, ranging from 0.0625% to 2%, exhibited strong fungicidal activity against Candida albicans and were found to be bacteriostatic against Staphylococcus aureus with microbiocidal effects increasing in a concentration-dependant manner. Essential oil rapidly reduced viable counts of Pseudomonas aeruginosa but regrowth was noted after 24 hours. The results have been generated in duplicate in two separate microbiology laboratories using different time-kill methods and the results are in agreement. Eighty-five compounds were identified by GC-MS in the hydro-distilled essential oils which contained pinocarvone and trans-pinocarveol as the major terpenoids. The antimicrobial properties of the essential oil are presented as a possible rationale for the traditional use of the resurrection bush, Myrothamnus flabellifolius in African herbal medicinal preparations.