Tijana Banjanac

Centauries as underestimated food additives: antioxidant and antimicrobial potential.

Methanol extracts of aerial parts and roots of five centaury species (Centaurium erythraea, C. tenuiflorum, C. littorale ssp. uliginosum, C. pulchellum, and Schenkia spicata) were analysed for their main secondary metabolites: secoiridoid glycosides, a group of monoterpenoid compounds, and phenolics (xanthones and flavonoids), and further investigated for antioxidant capacity and antimicrobial activity. The results of ABTS, DPPH, and FRAP assays showed that above ground parts generally displayed up to 13 times higher antioxidant activity compared to roots, which should be related to higher phenolics content, especially flavonoids, in green plant organs. Secoiridoid glycosides showed no antioxidant activity. All the tested extracts demonstrated appreciative antibacterial (0.05-0.5 mg ml(-1)) and strong antifungal activity (0.1-0.6 mg ml(-1)). Our results imply that above ground parts of all centaury species studied, could be recommended for human usage as a rich source of natural antioxidants and also in food industry as strong antimicrobial agents for food preservation.

Antimutagenic effect of sage tea in the wing spot test of Drosophila melanogaster

The present study assayed the antimutagenic potential of Salvia officinalis (sage) in the form of tea infusion, by the somatic mutation and recombination test (SMART) on Drosophila melanogaster. The use of herbal infusions is much common in the human diet, so the aim of the present study was to estimate the antimutagenic effects of the S. officinalis tea rather than essential oils. Methyl methanesulphonate (MMS) was used as the mutagen and positive control. Several types of treatment were performed: short acute treatment with sage infusion or MMS, longer (chronic) treatment with sage solution or MMS, and two combined treatments, i.e. short treatment with sage followed by a longer treatment with MMS and vice versa. Sage infusion used in our experiments showed a clear antimutagenic effect, reducing the frequency of mutations induced by MMS. The inhibition effect of sage tea is obtained and confirmed when pre- or post-treatments with mutagen were used. The results indicate that although sage in this regime decreases the number of mutation events, it is not efficient enough in case of the 2 h sage pre-treatment. Antioxidant activity, suppression of metabolic activation, could be mechanisms through which sage or some of its components act as desmutagen.

Activation of antioxidant response element in mouse primary cortical cultures with sesquiterpene lactones isolated from Tanacetum parthenium

Tanacetum parthenium produces biologically active sesquiterpene lactones (SL). Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to activate a series of genes termed the antioxidant response element (ARE). Activation of Nrf2/ARE may be useful for the treatment of neurodegenerative disease. In this study we isolated 11 SL from T. parthenium with centrifugal partition chromatography and semipreparative HPLC. Compounds were screened in vitro for their ability to activate the ARE on primary mouse cortical cultures as well as for their toxicity towards the cultures. All SL containing the α-methylene-γ-lactone moiety were able to activate the ARE and cause cellular toxicity. The structure-activity relationship among the SL isolated indicates that the guaianolides were more active and when lacking the endoperoxide functionality less toxic then the germacranolides.