Components of 50% ethanolic chamomile (Matricaria recutica L.) flower extract, previously found antibacterial in a TLC-bioautographic study, were separated and isolated by the use of on-line OPLC, which consisted of an OPLC 50 BS system, an on-line coupled flow-through UV detector, and a manual fraction collector. The collected peaks were investigated by GC-MS analysis and by TLC re-chromatography with subsequent visualization, performed after use of the vanillin-sulphuric acid reagent, or under UV illumination, or applying bioautographic detection. The main compounds of the collected 11 fractions were identified by GC-MS. The results showed that the antibacterial effect of 50% ethanolic extract of chamomile is ascribable to cis-, trans-spiroethers, and the coumarins like herniarin and umbelliferone.
Separation and identification of antibacterial chamomile components 3
INTRODUCTIONThere is an increased demand to discover new, effective, easy-to-obtain natural medicinal substances. Chamomile (Matricaria recutica L.) is a very familiar and widely used herb in traditional folk medicine. The flower is a common ingredient of herbal teas because it contains substances which have anti-inflammatory, sedative, analgesic, antispasmodic, antioxidant and antimicrobial properties [1][2][3][4]. The beneficial effects are related to different classes of therapeutically interesting ingredients such as essential oil components, flavonoids, and coumarin derivatives [1, 5, and 6]. The chamomile essential oils, which are of the greatest importance among the bioactive constituents [7], consist of many active compounds such as (-)-alpha-bisabolol, chamazulene (artefact of matricine by steam distillation), (-)-alpha-bisabolol oxide A and B, (-)-alpha-bisabolone oxide A, spiroethers (cis-and trans-en-yn-dicycloether), and sesquiterpenes [8]. The chamomile volatile oils showed antimicrobial activity against certain species of bacteria, fungi and viruses in vitro [9], however, Gram-positive bacteria were found more susceptible than Gram-negative ones [10]. The chamomile oils were effective e.g. [17,18]. Herniarin, the main coumarin component in chamomile, is a more effective antimicrobial agent than umbelliferone, which may be realized by its demethylation [19]. Umbelliferone has been described as a stress metabolite in M. recutita. The amount of umbelliferone characteristically, while that of herniarin mildly rose in the plant after biotic and abiotic stress influences [6,20]. It was also observed that chamomile oil component (Z)-spiroether was lowered after abiotic stress, but increased in the case of biotic stress [6]. Searching for bioactive natural products requires appropriate bioassays, focused on the desired activity (e.g. antifungal, antibacterial). Layer chromatography is an ideal technical solution for the screening of drug ingredients, because of high-throughput, low cost, easy maintenance and selectivity of detection reagents [21]. Direct bioautography [22][23][24][25][26], linking the separation with biological det...