Synergistic effects of essential oils and phenolic extracts on antimicrobial activities using blends of Artemisia campestris, Artemisia herba alba, and Citrus aurantium.

This study explores the synergistic antibacterial effects of essential oils (EOs) and phenolic extracts from three plants against foodborne pathogenic bacteria. The present work aimed to investigate the synergistic effects of the binary and the ternary combinations of extracts using different blend proportions of the following plant extracts: Artemisia campestris (AC), Artemisia herba alba (AHA), and Citrus aurantium (CA). The antimicrobial activities of EOs and phenolic extracts were determined and evaluated against five strains. For the EOs, the results of the DIZ showed the existence of synergism for different combinations of binary blends, such as AC/AHA or AHA/CA against Escherichia coli, and AC/CA against Enterobacter faecalis. In addition, ternary blends of AC:AHA:CA at a ratio of 1/6:2/3:1/6 exhibited a synergy effect, as measured by the CI, against E. coli. On the other hand, for the phenolic extracts, synergistic effects were noticed for binary blends of AC/CA at different ratios against E. coli, E. faecalis, and Pseudomonas aeruginosa strains. Similarly, ternary blends of phenolic extracts presented synergy against E. coli, E. faecalis, P. aeruginosa strains, and even C. albicans. In this case, the blending ratios were crucial determining factors for maximizing the synergy effect. The study established that the proportion of a single drug could play an essential role in determining the bioefficacy of a drug combination treatment. Therefore, the results showed the importance of studying the modulation of antibacterial activities based on the proportions of extracts in the mixture and finding the range of proportions (as determined by SLMD) that have a synergistic/additive/antagonistic effect with no or low side effects, which can be used in a food preservation system.

Synergistic antinociceptive activity of combined aqueous extracts of Artemisia campestris and Artemisia herba-alba in several acute pain models.

In this study, total phenolic and flavonoid contents, acute toxicity and the antinociceptive activity of Artemisia campestris and Artemisia herba-alba, individually and in combination, were investigated using multiple forms of pain in animals. Our results have been shown that plants are relatively safe without clinical signs of toxicity in animals. Thus, extracts were presented high levels in phenolic and flavonoid contents. Artemisia decoctions with 100, 200, 400 mg/kg b-w studied dose, clearly attenuate chemical and thermal noxious stimuli in writhing, formalin and hot-plate tests, and significantly reduced paw oedema in formalin test. Additionally, binary combination forms exhibited a great improvement in intensity and amplitude of antinociceptive activity in comparison with both plants used individually by a relative interference with opioid system. Our findings suggested the central and peripheral analgesic properties and confirmed the folkloric medicinal use of these plants in pain symptom treatment.

Variability of composition and effects of essential oils from Rhanterium adpressum Coss. & Durieu against mycotoxinogenic Fusarium strains.

The antifungal potency of the essential oils of Rhanterium adpressum was evaluated against four mycotoxigenic strains of the genus Fusarium. The essential oils were obtained, separately, by hydro-distillation of the aerial parts of R. adpressum (leaves and flowers). The parts were collected during the period of bloom (3 months) for 3 years. The GC-MS analysis revealed thirty-six compounds for the essential oils, divided into four classes of chemical compounds, with variable percentages according to the month of extraction. The monoterpene hydrocarbons form the main class in these oils. On the other hand, the highest percentages of the oxygenated compounds are observed in the samples collected during the month of May. The direct contact method was used to evaluate the antifungal activity of the essential oils. The activity can be attributed to their relatively high composition of oxygenated monoterpenes. Flowers extract showed strong inhibitory activity, with very interesting concentrations of IC50 and MIC for both tests on solid and liquid medium. The effect of these oils on the production of type B trichothecenes (TCTBs) was evaluated, showing a significant inhibitory effect on TCTBs production, for both extracts (leaves and flowers). The rates of inhibition were 66-97 and 76-100% of FX, 3-ADON and 15-ADON, respectively. The inhibition of fungal biomass and the production of TCTBs depended on the used concentration of the essential oils. These results suggest that the essential oils from R. adpressum are able to control the growth of the tested strains and their subsequent production of TCTB mycotoxins.