Ewa Kochan

Yeast Extract Stimulates Ginsenoside Production in Hairy Root Cultures of American Ginseng Cultivated in Shake Flasks and Nutrient Sprinkle Bioreactors

One of the most effective strategies to enhance metabolite biosynthesis and accumulation in biotechnological systems is the use of elicitation processes. This study assesses the influence of different concentrations of yeast extract (YE) on ginsenoside biosynthesis in Panax quinquefolium (American ginseng) hairy roots cultivated in shake flasks and in a nutrient sprinkle bioreactor after 3 and 7 days of elicitation. The saponin content was determined using HPLC. The maximum yield (20 mg g−1 d.w.) of the sum of six examined ginsenosides (Rb1, Rb2, Rc, Rd, Re and Rg1) in hairy roots cultivated in shake flasks was achieved after application of YE at 50 mg L−1 concentration and 3 day exposure time. The ginsenoside level was 1.57 times higher than that attained in control medium. The same conditions of elicitation (3 day time of exposure and 50 mg L−1 of YE) also favourably influenced the biosynthesis of studied saponins in bioreactor cultures. The total ginsenoside content was 32.25 mg g−1 d.w. and was higher than that achieved in control medium and in shake flasks cultures. Obtained results indicated that yeast extract can be used to increase ginsenoside production in hairy root cultures of P. quinquefolium.

The ability of selected plant essential oils to enhance the action of recommended antibiotics against pathogenic wound bacteria

The aim of this work was to characterize the ability of essential oils to support antibiotics against pathogenic bacteria in wounds. Gram-positive and Gram-negative bacteria obtained from wound infections were identified according to standard microbiological methods. Essential oils were analysed by GC-FID-MS. The susceptibility of bacteria to antibiotics, essential oils and their combination was assessed using the disc-diffusion method. The Minimal Inhibitory Concentration and Minimum Bactericidal Concentration of the essential oils were established by the micro-dilution broth method. Although cinnamon, clove, thyme and lavender essential oils were found to have the greatest antibacterial activity when used alone, the greatest additive and synergistic effects against pathogenic wound bacteria in combination with recommended antibiotics were demonstrated by basil, clary sage and rosemary oils.

Field cultivation and in vitro cultures, root-forming callus cultures and adventitious root cultures, of Panax quinquefolium as a source of ginsenosides.

The content of six ginsenosides (Rb1, Rb2, Rc, Rd, Rg1, and Re) was studied in the roots of field-grown plants, as well as in root-forming callus cultures and adventitious root cultures of Panax quinquefolium using high-performance liquid chromatography (HPLC). The highest level of saponins was isolated from root hairs (128 mg/g dry weight). The examined in vitro culture synthesized all identified saponins, although in smaller amounts than those obtained from field cultivation. Metabolites Rb1 and Re dominated in the ginseng biomass from both field crops and in vitro culture.

The Increase of Triterpene Saponin Production Induced by Trans-Anethole in Hairy Root Cultures of Panax quinquefolium

In vitro cultivation is an effective way to increase pharmaceutical production. To increase ginsenoside production in hairy root cultures of American ginseng, the present study uses trans-anethole as an elicitor. The content of nine triterpene saponins was determined: Rb1, Rb2, Rb3, Rc, Rd, Rg1, Rg2, Re and Rf. Trans-anethole was found to stimulate saponin synthesis regardless of exposure time (24 and 72 h). Twenty-four hour exposure to 1 μmol trans-anethole in the culture medium resulted in the highest increase of total saponin content (twice that of untreated roots), and optimum accumulation of Rb-group saponins, with ginsenoside Rc dominating (8.45 mg g−1 d.w.). In contrast, the highest mean content of protopanaxatriol derivatives was obtained for 10 μmol trans-anethole. The Re metabolite predominated, reaching a concentration of 5.72 mg g−1 d.w.: a 3.9-fold increase over untreated roots. Elicitation with use of trans-anethole can therefore be an effective method of increasing ginsenoside production in shake flasks.

Preliminary Study on the Antibacterial Activity of Essential Oils Alone and in Combination with Gentamicin Against Extended-Spectrum β-Lactamase-Producing and New Delhi Metallo-β-Lactamase-1-Producing Klebsiella pneumoniae Isolates

AIM The aim of the study was to investigate possible synergistic effects between several selected, commercially available essential oils and gentamicin against extended-spectrum β-lactamase (ESBL)-producing and New Delhi metallo-β-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae isolates. MATERIALS AND METHODS ESBLs production was confirmed by double-disk synergy test. Isolates positive for blaNDM-1 gene were found among the tested strains. K. pneumoniae ATCC® BAA-1705™ strain was used as a control. The checkerboard method was applied to assess the synergistic and additive action of nine essential oils: caraway, fennel, peppermint, geranium, basil, clove, thyme, clary sage, and lavender, respectively, in combination with gentamicin. RESULTS Our results indicated that peppermint oil combined with gentamicin showed synergistic activity against both control, ESBL-producing and NDM-1-producing isolates. Caraway essential oil demonstrated synergy with gentamicin toward ESBL-producing and additionally gentamicin-resistant strains. The additive effect was observed for gentamicin combined with thyme, fennel, basil, and clary sage. CONCLUSIONS Because of their synergistic activity with gentamicin, peppermint, and caraway oils in particular, can be considered as an alternative or an addition for the control of infections with limited therapeutic options due to multidrug resistance.